Abstract:
A base isolation device used for the purpose of absorbing a quake of the ground by, for example, an earthquake to thereby reduce the quake of a building, or used for the purpose of reducing a quake applied to a precision machinery and tool in transportation etc. of the precision machinery and tool. The base isolation device comprises 1st and 2nd track rails disposed orthogonally to each other, a 1st slide member freely linearly movable along the 1st track rail, a 2nd slide member connected to the 1st slide member and freely linearly movable along the 2nd track rail, a ball screw for converting a linear motion of the 2nd slide member into a rotary motion, a rotary sleeve to which a rotation is given by the ball screw, a stationary sleeve forming an action chamber of damping force between it and an outer periphery face of the rotary sleeve, and a viscous fluid sealed in the action chamber.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a base isolation device used for the purpose of absorbing a quake of the ground by, for example, an earthquake to thereby reduce the quake of a building, or used for the purpose of reducing a quake applied to a precision machinery and tool in transportation etc. of the precision machinery and tool. 
     2. Description of the Related Art 
     Hitherto, as an earthquake countermeasure for real estates such as buildings and houses, or as a vibration countermeasure when carrying the precision machine and tool, a case of art work, and the like, there has been used a base isolation device for absorbing the vibration of the ground or a floor to thereby reduce it. As this base isolation device, there have been hitherto known one of a type in which rubber plates are laminated between a basement such as the ground and a structure body such as a construction object, one in which low friction slide faces consisting of fluororesin etc. are formed between the basement and the structure body, and the like. 
     However, in recent years, as a new base isolation device, there is proposed a base isolation device utilizing linear guide units used in a work table etc. of machine tool (Japanese Patent Laid-Open No. 240033/1996 Gazette). As shown in FIG. 14, this base isolation device comprises 1st and 2nd track rails  102 ,  103  in which rolling faces for rolling bodies such as balls are formed along longitudinal directions and which are fixed so as to be mutually orthogonal to a basement  100  and a structure body  101  respectively, a 1st slide member  104  incorporated to the 1st track rail  102  through many rolling bodies and freely linearly movable in reciprocation along the 1st track rail  102 , and a second slide member  105  fixed to the 1st slide member  104 , incorporated to the 2nd track rail  103  through many rolling bodies and freely linearly movable in reciprocation along the 2nd track rail  103 , and it is adapted such that, if the basement  100  quakes by the earthquake and the like, the track rails  102 ,  103  and the slide members  104 ,  105  incorporated to the formers perform relative linear reciprocation motions. 
     FIG. 15 is a schematic view in case where a concrete use method of this base isolation device is seen from above. On the basement  100 , the base isolation devices mentioned above are used in four places, and the 1st track rail  102  of each base isolation device is fixed to the basement  100  along an X-direction. On the other hand, the 2nd track rail  103  is fixed to the structure body (not shown) along a Y-direction orthogonal to the 1st track rail  102 . Since a dynamic frictional coefficient between the track rails  102 ,  103  and the slide members  104 ,  105  is very small, if the basement  100  quakes in a horizontal direction by the earthquake and the like, the slide members  104 ,  105  of each base isolation device move on the track rails  102 ,  103  along the X-direction or the Y-direction to absorb the quake. That is, the structure body provided on the base isolation devices is insulated from the quake of the basement  100  and becomes such a state that as if it floats in the air. It is considered that the structure body violently quakes by the earthquake and the like because a period of the quake of the basement agrees with that of the quake of the structure body, thereby generating a resonance phenomena. However, in case where the structure body is insulated from the basement by the base isolation devices in this manner, since it is possible to avoid a generation of the resonance by setting the period of the quake of the structure body sufficiently large, it becomes possible to reduce the quake of the structure body. 
     On the other hand, although this base isolation device prevents the resonance between the basement and the structure body, since it is not one capable of completely preventing the quake of the structure body and, moreover, since it is one insulating the quake of the basement from that of the structure body as mentioned above, it follows that the quake remains after the earthquake for instance has quieted down. Therefore, when supporting the structure body by using such base isolation devices, as shown in FIG. 15 it has been necessary to provide damping units  106  between the basement  100  and the structure body separately from the base isolation devices to thereby absorb an energy of the quake of the structure body such that the quake quits down in short time. Hitherto, as such a damping unit, there have been known one adapted such that the basement and the structure body are connected by a rubber cylinder body formed by means of laminating alternately rubber plates and reinforcing plates, and a quake energy of the structure body is converted into a thermal energy accompanying with a shearing deformation of the rubber cylinder body, thereby absorbing the quake energy, and the like. 
     However, with this damping unit, since a shearing deformation amount of the rubber cylinder body connecting the basement and the structure body cannot be set large, it becomes a result that the damping unit limits movements in XY-directions in the base isolation device. Accordingly, in case where the above damping unit is used in combination with the base isolation device utilizing linear guide units, it becomes impossible to completely insulate the structure body from the basement, so that it becomes impossible to sufficiently absorb the quake of the basement by the base isolation device. Further, if the damping unit is provided separately from the base isolation device, there has been such a problem that an excessive labor is required correspondingly, and a work for providing the structure body on the basement in the base isolation device becomes complex. 
     SUMMARY OF THE INVENTION 
     The invention was made in view of such a problem, and its object is to provide a base isolation device with damping mechanism, which can effectively absorb a quake of a basement by insulating a structure body from the basement, and can intend to simplify an attaching work to the basement and the structure body. 
     That is, the invention is a base isolation device with damping mechanism, which is disposed between a basement and a structure body arranged on the basement and suppresses a transmission of a quake from the basement to the structure body, characterized by comprising: 1st and 2nd track rails formed with ball rolling faces along a longitudinal direction and disposed orthogonally to each other; a 1st slide member incorporated to the 1st track rail through many balls and freely linearly movable in reciprocation along the 1st track rail; a 2nd slide member connected to either of the 1st track rail or the 1st slide member, incorporated to the 2nd track rail through many balls and freely linearly movable in reciprocation along the 2nd track rail; motion conversion means which has a rotation transmission body arranged such that its axis agrees with a moving direction of the 1st slide member or the 2nd slide member, and converts a linear reciprocation motion of the slide member into a normal/reverse rotary motion of the rotation transmission body; a rotary sleeve connected to the rotation transmission body; a stationary sleeve accommodating the rotary sleeve and forming an action chamber of damping force between it and the rotary sleeve; and a viscous fluid sealed in the action chamber. 
     The base isolation device of the invention constituted in this manner is used under a state that, for example, the 1st track rail is fixed to the basement, while the structure body is fixed to the 2nd track rail orthogonal to the 1st track rail, and the 1st slide member and the 2nd slide member moving along the 1st and 2nd track rails are mutually fixed. On this occasion, the motion conversion means for converting the linear reciprocation motion of the slide member into the normal/reverse rotary motion, for example a ball screw unit, is connected to the 1st slide member or the 2nd slide member and, if the 1st slide member or the 2nd slide member is moved on the track rail with a quake of the basement, the rotation transmission body provided in the motion conversion means is rotated and, further, the rotary sleeve connected to the rotation transmission body is rotated. The rotary sleeve is accommodated in the stationary sleeve to thereby form the action chamber, and the viscous fluid is sealed in the action chamber. Accordingly if the rotary sleeve is rotated, a shearing frictional force is applied to the viscous fluid in the action chamber, so that a kinetic energy of the rotary sleeve is consumed as a thermal energy of the viscous fluid. In other words, it follows that an energy of the linear reciprocation motion of the slide member is consumed by the viscous fluid as the thermal energy, so that it is possible to reduce the motion of the slide member with respect to the track rail and, in turn, the motion of the structure body with respect to the basement. 
     Here, since the motion conversion means connected to the slide member merely converts the linear reciprocation motion into the rotary motion, it does not limit the motion of the slide member at all, so that the base isolation device of the invention can effectively absorb the quake of the basement. Further, since the rotary sleeve functioning as a damping unit is directly fixed to the slide member through the motion conversion means, when providing the structure body to the basement, it is unnecessary to provide the damping unit separately from the base isolation device, so that a work for arranging the structure body can be simplified correspondingly. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view showing a first embodiment of a base isolation device to which the invention was applied; 
     FIG. 2 is a perspective view showing a support guide section of the base isolation device according to the 1st embodiment; 
     FIG. 3 is a side view showing a damping section of the base isolation device according to the 1st embodiment; 
     FIG. 4 is a sectional view showing a damping rod provided in the damping section according to the 1st embodiment; 
     FIG. 5 is a perspective view showing an example in which a structure body is supported on a basement by using the base isolation devices of the invention; 
     FIG. 6 is a perspective view showing a 2nd embodiment of the base isolation device to which the invention was applied; 
     FIG. 7 is a perspective view showing a 3rd embodiment of the base isolation device to which the invention was applied; 
     FIG. 8 is a perspective view showing a track rail and a slide member of the base isolation device according to the 3rd embodiment; 
     FIG. 9 is a plan view showing the track rail and the slide member of the base isolation device according to the 3rd embodiment; 
     FIG. 10 is a sectional view taken along line X—X in FIG. 9; 
     FIG. 11 is an enlarged view of a main portion of a damping rod according to the 3rd embodiment; 
     FIG. 12 is a sectional view showing fixed states of a 1st slide member and a 2nd track rail according to the 3rd embodiment; 
     FIG. 13 is a sectional view showing an example constituting the base isolation device by fixing the 1st slide member and a 2nd slide member according to the 3rd embodiment; 
     FIG. 14 is a sectional view showing a conventional base isolation device constituted by combining linear guide units; and 
     FIG. 15 is a plan view showing a use example of the conventional base isolation device. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereunder, a base isolation device with damping mechanism of the invention is detailedly explained on the basis of the attached drawings. 
     FIG. 1 shows a 1st embodiment of the base isolation device with damping mechanism to which the invention was applied. This base isolation device  1  comprise a support guide section  1   a  provided between a structure body such as construction object and a basement such as foundation and supporting the structure body while resisting against its load, and a damping section  1   b  for suppressing a quake of the structure body supported by the support guide section  1   a.    
     FIG. 2 is a perspective view showing a constitution of the support guide section. The support guide section  1   a  comprises a 1st track rail  10  fixed to a structure body A, a 1st slide member  11  incorporated to the 1st track rail  10 , a 2nd track rail  12  fixed to a basement B such as foundation so as to be orthogonal to the 1st track rail  10 , and a 2nd slide member  13  incorporated to the 2nd track rail  12  and fixed to the 1st slide member  11 . In each track rail, plural ball rolling grooves are formed in a longitudinal direction, while in each of the slide members  11 ,  13  there are accommodated many balls rolling on the ball rolling grooves, and thus it is adapted such that the slide members  11 ,  13  are freely movable respectively on the track rails  10 ,  12  with a very small dynamic frictional resistance by rolling of the balls. The 1st slide member  11  and the 2nd slide member  13  are completely the same members, and they are fixed back to back through a bracket. And, since the 1st track rail  10  and the 2nd track rail  12  are provided orthogonally to each other, if the 1st slide member  11  is moved along the 1st track rail  10  and the 2nd slide member  13  is moved along the 2nd track rail  12 , it follows that the structure body A is two-dimensionally moved on the basement B. 
     On the other hand, FIG. 3 is a perspective view showing the damping section  1   b . The damping section  1   b  comprises a screw shaft  15  arranged parallel to the 2nd track rail  12  and rotatively supported on the basement B, a nut member  16  meshing with the screw shaft  15  and fixed to the 2nd slide member  13 , and a damping rod  18  connected to one end of the screw shaft  15  through a shaft coupling  17 . In an outer periphery face of the screw shaft  15 , a spiral ball rolling groove is formed with a predetermined lead, and the nut member  16  meshes with the screw shaft  15  through many balls circulating endlessly. Accordingly, the nut member  16  is adapted so as to be spirally movable around the screw shaft  15  with a very small dynamic frictional resistance. Further, one end of the screw shaft  15  is rotatively supported by a bracket  19  uprightly provided on the basement B, the other end of the same is supported by a bracket  20  uprightly provided also on the basement B through the shaft coupling  17  and the damping rod  18 . On the other hand, the nut member  16  is fixed to the 2nd slide member  13  through a connection bracket  21 , and constituted such that, if the 2nd slide member  13  is moved along the 2nd track rail  12 , it is moved accompanying with this in an axis direction of the screw shaft  15 . Since the nut member  16  is held by the connection bracket  21  so as not to be rotatable, if the nut member  16  is moved together with the 2nd slide member  13  in this manner, it becomes a result that a rotary torque is given to the screw shaft  15  by the nut member  16 , so that a rotation amount complying with a movement amount of the 2nd slide member  13  is generated in the screw shaft  15 . That is, in this embodiment  1 , the screw shaft  15  corresponds to a rotation transmission body in the invention. 
     On the other hand, FIG. 4 shows details of the damping rod  18 . The damping rod  18  comprises a rotary sleeve  25  connected to the screw shaft  15  through the shaft coupling  17 , and a stationary sleeve  26  rotatively holding the rotary sleeve  25  and fixed to the bracket  20  uprightly provided on the basement B, and the rotary sleeve  25  is accommodated in a hollow portion of the stationary sleeve  26 . A slight gap is provided between an outer periphery face of the rotary sleeve  25  and an inner periphery face of the stationary sleeve  26 , and a viscous fluid  27  is filled in the gap. Accordingly, it is adapted such that, if the rotary sleeve  25  is rotated with respect to the stationary sleeve  26 , a shearing frictional force is applied to the viscous fluid  27 , so that a kinetic energy of the rotary sleeve  25  is converted into a thermal energy of the viscous fluid  27  and thus consumed, thereby enabling to damp the kinetic energy of the rotary sleeve  25 . In other words, a gap filled with the viscous fluid  27  between the rotary sleeve  25  and the stationary sleeve  26  corresponds to an action chamber of damping force in the invention. 
     Since the rotary sleeve  25  is connected to the screw shaft  15  through the shaft coupling  17 , it follows that the damping rod  18  damps a rotary motion of the screw shaft  15  and, further, since the rotary motion of the screw shaft  15  is one obtained by converting a linear motion of the 2nd slide member  13  on the 2nd track rail  12 , it follows that the damping rod  18  damps the energy of the linear motion of the 2nd slide member  13 . That is, in the base isolation device  1 , if the 2nd slide member  13  performs a linear reciprocation motion on the 2nd track rail  12 , its kinetic energy is converted into an energy of the rotary motion of the screw shaft  15  and, thereafter, damped by the viscous fluid  27  in the damping rod  18 . 
     FIG. 5 shows an example in which the structure body A is supported on the basement B by using the base isolation devices to which the invention was applied. In this example, the base isolation devices  1 - 1 ,  1 - 2 ,  1 - 3 ,  1 - 4  are disposed in four places between the structure body A and the basement B and, for example, in the base isolation devices  1 - 1 ,  1 - 3  a moving direction of the 2nd slide member agrees with the X-direction, and in the base isolation devices  1 - 2 ,  1 - 4  the moving direction of the 2nd slide member agrees with the Y-direction. And, by disposing each base isolation device in this manner and supporting the structure body A on the basement B by the support guide sections  1   a , the structure body A becomes freely movable on the basement B in either of the X-direction and the Y-direction. In other words, the structure body A is under a state of being separated from the basement B and thus, even in case where the basement B is quaked by an earthquake, a quake applied to the structure body A is prevented from resonating with a quake of the basement B, so that it is possible to reduce the quake of the structure body A. Further, since the damping section  1   b  is connected to the 2nd slide member  13  of the support guide section  1   a , if the 2nd slide member  13  is moved on the 2nd track rail  12  in the X-direction or the Y-direction with the quake of the structure body A, its motion is damped by the damping section  1   b , so that the quake of the structure body A can be suppressed in short time. 
     Next, FIG. 6 shows a 2nd embodiment of the base isolation device to which the invention was applied. 
     Also in this 2nd embodiment, a constitution of the support guide section for supporting the structure body A on the basement B is completely the same as the embodiment  1 . However, a constitution of the damping section is somewhat different. Accordingly, as to the support guide section, the same reference numerals as the embodiment  1  are affixed in FIG. 6 to thereby omit their detailed explanations, and only the damping section is explained. 
     In the dam ping section  1   b  of the 1st embodiment if the nut member  16  is moved together with the 2nd slide member  13 , a rotation is given to the screw shaft  15  with such a movement, but in a damping section  1   c  of the 2nd embodiment it is constituted such that a nut member  30  itself is rotated with a movement of the 2nd slide member  13 . That is, the nut member  30  is rotatively accommodated through a rotary bearing inside a cylindrical casing  31  fixed to the 2nd slide member  13 , and the nut member  30  and a rotary sleeve  33  of a damping rod  32  are connected by a coupling  34 . A screw shaft  35  meshing with the nut member  30  is fitted in its both ends into one pair of fixing brackets  36  uprightly provided on the basement B, and arrange parallel to the 2nd track rail  12  and so as not to be rotatable. A constitution of the damping rod  32  is approximately the same as the 1st embodiment, but differs only in points that the screw shaft  35  penetrates through the rotary sleeve  33 , and that it is fixed to the 2nd slide member  13  by a connection bracket  37 . 
     And, in the damping section  1   c  of the 2nd embodiment constituted in this manner, if the 2nd slide member  13  is moved on the 2nd track rail  12 , the nut member  30  is moved in the same direction together with the damping rod  32  and the 2nd slide member  13 . On this occasion, since the screw shaft  35  meshing with the nut member  30  is provided fixedly to the basement B, it follows that the nut member  30  moving on the screw shaft  35  rotates by itself, so that a rotation amount complying with a movement amount of the 2nd slide member  13  is given to the nut member  30 . And, since the rotary sleeve  33  of the damping rod  32  is connected to the nut member  30 , it follows that the rotary sleeve  33  is rotated with a movement of the 2nd slide member  13 , so that it follows that an energy of a linear motion of the 2nd slide member  13  is damped by the damping rod  32 . In other words, also in the 2nd embodiment, if the 2nd slide member  13  performs a linear reciprocation motion on the 2nd track rail  12 , its kinetic energy is converted into an energy of rotary motion and, thereafter, damped by the viscous fluid in the damping rod  32 . 
     Since an outer diameter of the nut member is naturally lager than that of the screw shaft, a torque for rotating the nut member may be less than that for rotating the screw shaft and thus, in case where the 1st embodiment is compared with the 2nd embodiment, rather the 2nd embodiment becomes possible to efficiently convert the energy of linear motion of the 2nd slide member  13  into the energy of rotary motion. Accordingly, rather the base isolation device of the 2nd embodiment shown in FIG. 6 can more efficiently damp the energy of quake applied to the structure body A than the base isolation device of the 1st embodiment. 
     Next, FIG. 7 shows a 3rd embodiment of the base isolation device to which the invention was applied. 
     Also this 3rd embodiment comprises a support guide section  40   a  for supporting the structure body A in the X- and Y-directions with respect to the basement B, and a damping section  40   b  for suppressing the quake of the structure body. The support guide section  40   a  comprises a 1st track rail  41  fixed to the basement B, a 1st slide member  42  moving along the 1st track rail  41 , a 2nd track rail  43  fixed to the 1st slide member  42  so as to be orthogonal to the 1st track rail  41 , and a 2nd slide member  44  moving along the 2nd track rail  43 . As shown in FIG. 8 to FIG. 10, each of the track rails  41 ,  43  is formed in a channel form with a concave groove  46  being provided, and four ball rolling grooves  47  in total are formed in an inside face of the concave groove  46  with the two being formed per one side. On the other hand, each of the slide members  42 ,  44  is formed approximately in a rectangular shape, and loosely fitted in the concave groove  46  of each of the track rails  41 ,  43  through a slight gap. Load rolling grooves  48  facing the ball rolling grooves  47  of the track rail  41 ( 43 ) are formed in both side faces of the slide member  42 ( 44 ), and it is constituted such that many balls  49  roll between the load rolling grooves  48  and the ball rolling faces  47  of the track rail  41 ( 43 ) while bearing a load. Further, no-load ball passages  50  for circulating the balls  49  having finished to roll in the load rolling grooves  48  are formed in the slide member  42 ( 44 ). That is, the slide member  42 ( 44 ) is incorporated to the track rail  41 ( 43 ) through many balls  49 , and it is constituted such that the slide member  42 ( 44 ) is freely movable in reciprocation inside the concave groove  46  of the track rail  41 ( 43 ) with a circulation of the balls  49 . 
     Further, the damping section  40 b comprises a screw shaft  51  arranged inside the concave groove  46  of the track rail  41 ( 43 ), and a damping rod  52  connected to the screw shaft  51  at one end of the track rail  41 ( 43 ). A support plate  53  is fixed to one end in a longitudinal direction of the track rail  41 ( 43 ), while a support block  54  is fixed to the other end, and the screw shaft  51  is supported by the support plate  53  and the support block  54  so as to be rotatable and such that its axis agrees with a longitudinal direction of the track rail  41 ( 43 ). Further, the support block  54  functions as a bracket for fixing the damping rod  52  to the track rail  41 ( 43 ). The screw shaft  51  meshes with the slide member  42 ( 44 ) through many balls, and it is adapted such that, if the slide member  42 ( 44 ) is moved along the track rail  41 ( 43 ) inside the concave groove  46 , the screw shaft  51  is rotated in compliance with its movement amount. That is, the slide member  42 ( 44 ) and the screw shaft  51  constitute a ball screw. 
     On the other hand, the damping rod  52  comprises, similarly to that of the 1st embodiment, a rotary sleeve  57  connected to the screw shaft  51  through a shaft coupling  56 , and a stationary sleeve  58  rotatively holding the rotary sleeve  57  and fixed to the support block  54 , and the rotary sleeve  57  is accommodated in a hollow portion of the stationary sleeve  58 . As shown in FIG. 11, a slight gap is provided between an outer periphery face of the rotary sleeve  57  and an inner periphery face of the stationary sleeve  58 , and a viscous fluid  59  is filled in the gap. Incidentally, as the shaft coupling  56 , it is preferable to use an Oldham coupling in order that a rotation of the screw shaft  51  can be surely transmitted to the rotary sleeve  57  even in case where an axis of the rotary sleeve  57  is somewhat eccentric with respect to that of the screw shaft  51 . 
     And, in the damping section  40   b  of the 3rd embodiment constituted in this manner, if the slide member  42 ( 44 ) is moves inside the concave groove  46  of the track rail  41 ( 43 ), it follow that the screw shaft  51  meshing with the slide member  42 ( 44 ) is rotated, so that a rotation amount complying with a movement amount of the slide member  42 ( 44 ) is given to the screw shaft  51 . And, since the rotary sleeve  57  of the damping rod  52  is connected to the screw shaft  51 , it follows that the rotary sleeve  57  is rotated with a movement of the slide member  42 ( 44 ), so that it follows that an energy of linear motion of the slide member  42 ( 44 ) is damped by the damping rod  52 . In other words, also in this 3rd embodiment, if the slide member  42 ( 44 ) performs a linear reciprocation motion on the track rail  41 ( 43 ), its kinetic energy is converted into an energy of rotary motion And, thereafter, damped by the viscous fluid in the damping rod  52 . 
     FIG. 12 shows a fixed state between the 1st slide member  42  and the 2nd track rail  43 . Tap holes  62  meshing with fixing bolts  61  are formed in an upper face of the 1st slide member  42 , while through-holes  63  for inserting the fixing bolts  61  are formed in a bottom face of the 2nd track rail  43 , and the 2nd track rail  43  is fixed to the 1st slide member  42  by means of screwing the fixing bolts  61  by utilizing the tap holes  62  and the through-holes  63 . On this occasion, the 2nd track rail  43  is fixed such that its longitudinal direction is made orthogonal to a moving direction of the 1st slide member  42 , i.e., a longitudinal direction of the 1st track rail  41 . By this, when the 1st track rail  41  is fixed to the basement B and the 2nd slide member  44  is fixed to the structure body A, it become possible to freely guide the structure body A on the basement B in the X-direction and the Y-direction. 
     Incidentally, in the base isolation device of the 3rd embodiment, it is not necessarily required to fix the 2nd track rail  43  to the 1st slide member  42  and, as shown in FIG. 13, it may be constituted such that the 2nd slide member  44  is fixed back to back to the 1st slide member  42 , and the 2nd track rail  43  is fixed to the structure body A. Further, if the 1st slide member  42  and the 2nd slide member  44  are mutually connected in this manner, it may be constituted such that both the slide members  42 ,  44  are integrally formed from the beginning, and this is incorporated to the 1st track rail  41  and the 2nd track rail  43 . Additionally, also as to the 1st track rail  41 , it is not necessarily to fix this to the basement B, so that it may be constituted such that the 1st track rail  41  and the 2nd track rail  43  are mutually connected orthogonally and back to back and the 1st slide member  42  moving along the 1st track rail  41  is fixed to the basement B, while the 2nd slide member  44  moving along the 2nd track rail  43  is fixed to the structure body A. 
     And, also with respect to the base isolation device of the 3rd embodiment, by disposing the base isolation devices between the structure body A and the basement B, the structure body A becomes possible to be freely movable on the basement B in either of the X-direction and the Y-direction, so that the structure body A becomes a state of being insulated from the basement B. By this, even in case where the basement B is quaked by the earthquake, the quake applied to the structure body A is prevented from resonating with that of the basement B, so that it is possible to reduce the quake of the structure body A. Further, since the damping rod  52  is connected to the screw shaft  51  meshing with the slide member  42 ( 44 ), if the slide member  42 ( 44 ) is moved on the track rail  41 ( 43 ) in the X-direction or the Y-direction with the quake of the structure body A, its motion is damped by the damping rod  52 , so that the quake of the structure body A can be suppressed in short time. 
     As mentioned above, in each of the base isolation devices of the invention shown in the 1st to 3rd embodiments, since the damping section for damping the linear motion of the slide member is provided integrally with the support guide section, in case where this base isolation device is used, it is unnecessary to separately provide a damping unit, so that a labor required for arranging the device can be reduced correspondingly. 
     Additionally, in the base isolation device of the invention, since the linear motion between the track rail and the slide member with the earth quake is converted into a rotary motion by the screw shaft and the rotary motion is damped by being converted into a thermal energy of the viscous fluid filled between the rotary sleeve and the stationary sleeve, it is possible to deal with a great earth quake by increasing a length of the screw shaft. Moreover, since the damping section does not restrict the movement of the slide member in the support guide section at all, it becomes possible to avoid such abuses that a base isolation effect is limited by the damping section. 
     As explained above, according to the base isolation device with damping mechanism of the invention, since the motion conversion means connected to the slide member merely converts the linear reciprocation motion into the rotary motion, the motion of the slide member is not limited at all, so that it become possible to effectively absorb the quake of the basement by insulating the structure body from the basement. Further, since the rotary sleeve functioning as a damping unit is directly fixed to the slide member through the motion conversion means, when providing the structure body to the basement, it is unnecessary to provide the damping unit separately from the base isolation device, so that it becomes possible to intend to simplify an attaching work to the basement and the structure body correspondingly and, in turn, reduce a labor for arranging the structure body.