Patent Publication Number: US-7586219-B2

Title: Drive guide apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a Divisional of application Ser. No. 10/518,081, filed Dec. 16, 2004, and wherein application Ser. No. 10/518,081 is a national stage application filed under 35 USC §371 of International Application No. PCT/JP03/08172, filed Jun. 27, 2003, the entire disclosures of which are hereby incorporated by reference. 

   TECHNICAL FIELD 
   The present invention relates to a drive guide apparatus that has a guide mechanism including a rail and a moving member provided to be movable relative to the rail and that uses a linear motor as a driving means. 
   BACKGROUND ART 
   Conventional drive guide apparatuses of this type are disclosed in Japanese Patent Post-Exam Publication No. Hei 7-106053 and Japanese Patent Application Unexamined Publication (KOKAI) No. 2001-99151.  FIG. 1  is a diagram showing schematically the arrangement of a conventional drive guide apparatus of the type described above. 
   In the figure, a linear motor  100  comprises a primary side  101  and a secondary side  102 . The primary side  101  is an energized side including armature coils. The secondary side  102  is a non-energized side having magnets, etc. The primary side  101  is connected through a table  103  to moving blocks  105  each serving as a moving member of a guide mechanism  104 . The secondary side  102  of the linear motor  100  is secured to a base  106 . The base  106  is secured to the top of a surface plate  107 . 
   The base  106  is provided thereon with two parallel rails  108  constituting the guide mechanism in combination with the moving blocks  105 . The moving blocks  105  move along the rails  108  in response to driving force obtained from the linear motor  100 . 
   The rails  108  are each formed with a plurality of rolling element rolling surfaces extending longitudinally, as will be detailed later. The moving blocks  105  are each formed with endless recirculation passages including load rolling element rolling passages corresponding to the rolling element rolling surfaces. When the moving blocks  105  move along the rails  108 , a plurality of rolling elements arranged and accommodated in the endless recirculation passages roll and recirculate while receiving a load in the load rolling element rolling passages. 
   In the drive guide apparatus arranged as stated above, the table  103  secured to the moving blocks  105  to extend therebetween is provided with the primary side  101  of the linear motor  100 , which is the energized side including armature coils. Therefore, when a driving electric current is passed through the armature coils (not shown) of the primary side  101 , heat generated from the primary side  101  is transferred to the table  103 , causing the table  103  and the moving blocks  105  to be heated to expand. Consequently, stress due to the thermal expansion of the table  103  and the moving blocks  105  is applied to the moving blocks  105 . 
   The rolling elements arranged and accommodated in the endless recirculation passages of the moving blocks  105  constituting the guide mechanism  104  have been given a predetermined preload. More specifically, rolling elements having a diameter slightly larger than the diameter of the load rolling element rolling passages are inserted into the rolling passages, thereby producing a negative clearance, i.e. causing the rolling elements and the rolling surfaces to be elastically deformed. 
   When stress due to thermal expansion is applied to the moving blocks  105  as stated above, the preload is varied. That is, the preload increases at one side and decreases or becomes zero at the other side. The increase in the preload involves the problem that the rolling resistance to the rolling elements increases, leading to shortening of the lifetime of the drive guide apparatus. 
   Here, let us explain the preload. The preload is applied in order to ensure a predetermined rigidity adequate for each particular purpose. In apparatus that are required to exhibit high accuracy, e.g. precision measuring apparatus, a light preload necessary for removing play is applied because the apparatus cannot perform the desired function if there is play. In machine tools or the like, an intermediate preload is applied in order to ensure the required rigidity because a cutting operation and the like cannot be performed unless the rigidity is sufficiently high. 
   It should be noted that rigidity includes static rigidity and dynamic rigidity. Static rigidity is the ability to resist a static load, i.e. a displacement of the moving block relative to the mounting reference plane. Dynamic rigidity is performance required for machine tools, for example, which is expressed by the reciprocal ratio of the deflection width of a time-varying displacement to the deflection width of a time-varying load. In short, dynamic rigidity is the ability to minimize external vibration transmission. That is, insufficient dynamic rigidity of a machine tool, for example, causes chatter during cutting or other machining process and leads to a problem that the machine tool is readily affected by external vibration. 
   The above-described conventional example has a rolling guide arrangement in which the moving blocks  105  each serving as a moving member are engaged with the rails  108  through rolling elements. It should be noted, however, that the above-described problems also occur in the case of employing a slide guide arrangement in which rolling elements are not interposed between a rail and a moving member. In this case also, the lifetime of the guide apparatus is shortened. 
   In the rolling guide, an increase in rolling resistance gives rise to a problem. In the case of slide guide, an increase in sliding resistance becomes a problem. 
   The present invention was made in view of the above-described circumstances. An object of the present invention is to provide a drive guide apparatus capable of ensuring an increased lifetime by preventing heat generated from a primary side of a linear motor from being transferred to a rail or a moving member of a guide mechanism to which the primary side of the linear motor is connected, thereby preventing variation of rolling resistance of the guide mechanism (when arranged in the form of a rolling guide) or sliding resistance of the guide mechanism (when arranged in the form of a slide guide). 
   DISCLOSURE OF THE INVENTION 
   To attain the above-described object, the present invention provides a drive guide apparatus having a linear motor and a guide mechanism that guides relative movement between a primary side of the linear motor, which is an energized side thereof, and a secondary side of the linear motor, which is a non-energized side thereof, and that carries a load. The guide mechanism has a rail and a moving member provided to be movable relative to the rail. The primary side of the linear motor is connected directly or indirectly to the rail or the moving member of the guide mechanism. Thermal insulating means for blocking heat generated from the primary side of the linear motor is provided between the primary side of the linear motor and the rail or the moving member of the guide mechanism to which the primary side of the linear motor is connected. 
   As stated above, thermal insulating means for blocking heat generated from the primary side of the linear motor is provided between the primary side of the linear motor and the rail or the moving member of the guide mechanism to which the primary side of the linear motor is connected directly or indirectly. Therefore, the heat transfer cutoff action of the thermal insulating means prevents heat generated from the primary side of the linear motor from being transferred to the rail or the moving member of the guide mechanism. Consequently, thermal expansion of the rail or the moving member is prevented, and there is no variation in rolling resistance or sliding resistance of the guide mechanism. Accordingly, it is possible to ensure an increased lifetime for the drive guide apparatus. 
   In the drive guide apparatus, the thermal insulating means may comprise a thermal insulator interposed between the rail or the moving member and the primary side of the linear motor. 
   If the thermal insulating means comprises a thermal insulator interposed between the rail or the moving member and the primary side of the linear motor, as stated above, an increased lifetime can be ensured for the drive guide apparatus with a simple arrangement. 
   In the drive guide apparatus, the thermal insulator may be elongated in the direction of relative movement between the rail and the moving member. 
   If the thermal insulator is elongated in the direction of relative movement between the rail and the moving member, as stated above, rigidity in this direction increases. Thus, undesired oscillation phenomena can be prevented. 
   In the drive guide apparatus, the thermal insulating means may comprise a thermal insulating space formed between the rail or the moving member and the primary side of the linear motor. 
   If the thermal insulating means comprises a thermal insulating space formed between the rail or the moving member and the primary side of the linear motor, as stated above, it is possible to cut off the transfer of radiation heat from the primary side of the linear motor. Therefore, it is possible to prevent thermal expansion of the rail or the moving member due to radiation heat and hence possible to eliminate variation in rolling resistance or sliding resistance of the guide mechanism. Accordingly, an increased lifetime can be ensured for the drive guide apparatus as in the case of the above. 
   In the drive guide apparatus, the thermal insulating space may have a mirror finished surface at a side thereof closer to the rail or the moving member of the guide mechanism to which the primary side of the linear motor is connected. 
   If the thermal insulating space has a mirror finished surface at a side thereof closer to the rail or the moving member of the guide mechanism to which the primary side of the linear motor is connected, as stated above, the transfer of radiation heat from the primary side of the linear motor can be cut off even more effectively. 
   The drive guide apparatus may also be arranged as follows. The rail is formed with a rolling element rolling surface extending longitudinally of the rail. The moving member has an endless recirculation passage including a load rolling element rolling passage corresponding to the rolling element rolling surface. A multiplicity of rolling elements are arranged and accommodated in the endless recirculation passage. The rolling elements recirculate through the endless recirculation passage while receiving a load in the load rolling element rolling passage. 
   With the above-described arrangement, the preload applied to the rolling elements is not varied by a stress generated by thermal expansion of the rail or the moving member. Accordingly, smooth rolling of the rolling elements is ensured, so that an increased lifetime of the drive guide apparatus is attained. In the rolling guide, if the preload increases, flaking (a phenomenon in which the surface of the raceway surface or the rolling element surface peels off in flakes owing to the rolling fatigue of the material) is likely to occur. If flaking occurs, the lifetime reduces markedly. In the slide guide, such a flaking problem is unlikely to occur. 
   The drive guide apparatus may be provided with a heatsink that dissipates heat generated from the primary side of the linear motor. 
   If a heatsink is provided to dissipate heat generated from the primary side of the linear motor, as stated above, heat generated from the primary side of the linear motor can be dissipated efficiently. Therefore, the transfer of the heat to the rail or the moving member of the guide mechanism is further retarded. As a result, restrictions on the linear motor configuration for heat dissipation are reduced. Accordingly, it is possible to employ a linear motor having an arrangement even more suitable for the drive guide apparatus. 
   In the drive guide apparatus, the heatsink may be a finned heatsink having radiating fins. 
   If a finned heatsink having radiating fins is used, as stated above, the heat dissipation effect is further enhanced. Accordingly, the transfer of heat to the rail or the moving member of the guide mechanism is further retarded. 
   In addition, the present invention provides a drive guide apparatus having a linear motor and a guide mechanism that guides relative movement between a primary side of the linear motor, which is an energized side thereof, and a secondary side of the linear motor, which is a non-energized side thereof, and that carries a load. The guide mechanism has a rail and a moving member provided to be movable relative to the rail. The primary side of the linear motor is connected to the moving member through a heatsink, and an absorbing member is provided at the joint between the primary side of the linear motor and the moving member. The absorbing member absorbs a deformation of the heatsink due to a thermal expansion difference between the moving member and the heatsink by shearing force deformation. 
   In the above-described arrangement, a deformation absorbing member is provided at the joint between the moving member and the heatsink. Thus, when the heatsink is thermally expanded and deformed by heat from the primary side of the linear motor, shearing force acts on the absorbing member. Consequently, the absorbing member is shear-deformed to absorb the deformation of the heatsink. Therefore, no stress is applied to the heatsink, and hence the heatsink is not deformed. There is also no displacement of the primary side of the linear motor that is attached to the heatsink. Accordingly, there is no change in the gap between the primary side and the secondary side of the linear motor. Hence, there is no change in characteristics of the linear motor. 
   In the drive guide apparatus, the absorbing member may have both the function of absorbing a deformation of the heatsink by shear deformation and the thermal insulating function of cutting off the heat transfer from the heatsink to the moving member. 
   With the above-described arrangement, the absorbing member has both the function of absorbing a deformation of the heatsink by shear deformation and the thermal insulating function of cutting off the heat transfer from the heatsink to the moving member. Therefore, no influence is exerted upon the characteristics of the linear motor as stated above. Moreover, there is no variation in rolling resistance or sliding resistance of the guide mechanism. 
   In the drive guide apparatus, the absorbing member may be a laminated glass-epoxy resin material. 
   If a laminated glass-epoxy resin material is used for the absorbing member, as stated above, a deformation of the heatsink is absorbed easily. That is, the laminated glass-epoxy resin material exhibits strong rigidity in the lamination direction (thickness direction) and weak rigidity in a direction (width direction) perpendicular to the lamination direction. Therefore, when the heatsink thermally expands in response to a rise in temperature, shearing force acts on the absorbing member. At this time, the absorbing member is easily deformed to absorb the deformation of the heatsink. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a diagram showing schematically the arrangement of a conventional drive guide apparatus. 
       FIG. 2  is a diagram showing schematically a structural example of the drive guide apparatus according to the present invention. 
       FIG. 3  is a diagram showing schematically a structural example of the drive guide apparatus according to the present invention. 
       FIG. 4  is a plan view showing a structural example of the drive guide apparatus according to the present invention. 
       FIG. 5  is a side view showing a structural example of the drive guide apparatus according to the present invention. 
       FIG. 6  is a view as seen in the direction of the arrow A-A in  FIG. 5 . 
       FIG. 7  is a view as seen in the direction of the arrow B-B in  FIG. 5 . 
       FIG. 8  is a perspective view showing a structural example of a guide mechanism of the drive guide apparatus according to the present invention. 
       FIG. 9  is a sectional view showing a structural example of the guide mechanism of the drive guide apparatus according to the present invention. 
       FIG. 10  is a sectional view showing a structural example of a moving block in the guide mechanism of the drive guide apparatus according to the present invention. 
       FIG. 11  is a diagram showing schematically a structural example of another embodiment of the drive guide apparatus according to the present invention. 
       FIG. 12  is a perspective view showing a structural example of a guide mechanism of the drive guide apparatus according to the present invention. 
       FIG. 13  is a diagram showing schematically a structural example of still another embodiment of the drive guide apparatus according to the present invention. 
       FIG. 14  is a diagram showing schematically a structural example of a drive guide apparatus having a slide guide mechanism according to the present invention. 
       FIG. 15  is a diagram showing schematically a structural example of another drive guide apparatus having a slide guide mechanism according to the present invention. 
       FIG. 16  is a diagram showing schematically a structural example of still another drive guide apparatus having a slide guide mechanism according to the present invention. 
       FIG. 17  is a graph showing exemplarily the result of a temperature-rise test performed on the drive guide apparatus according to the present invention. 
       FIG. 18  is a graph showing exemplarily the result of a temperature-rise test performed on the drive guide apparatus according to the present invention. 
       FIG. 19  is a graph showing exemplarily the result of a temperature-rise test performed on the drive guide apparatus according to the present invention. 
       FIG. 20  is a graph showing exemplarily the result of a temperature-rise test performed on the drive guide apparatus according to the present invention. 
       FIG. 21  is a diagram showing schematically a structural example of the drive guide apparatus according to the present invention. 
       FIG. 22  is a diagram showing a structural example of the drive guide apparatus according to the present invention. 
       FIG. 23  is a diagram showing the arrangement of a radiating fin plate of a finned heatsink of the drive guide apparatus shown in  FIG. 22 . 
       FIG. 24  is a diagram showing the arrangement of a radiating fin of the radiating fin plate shown in  FIG. 23 . 
       FIG. 25  is a diagram showing a structural example of the drive guide apparatus according to the present invention. 
       FIG. 26  is a diagram showing the relationship between the table and the heatsink that varies in response to a temperature rise in the drive guide apparatus according to the present invention. 
       FIG. 27  is a diagram for explaining the deformation of a thermal insulator. 
       FIG. 28  is a diagram showing the joint structure of the table and the heatsink in the drive guide apparatus according to the present invention. 
       FIG. 29  is a diagram for explaining the deformation of a flanged cylindrical member. 
       FIG. 30  is a diagram showing a structural example of the heatsink. 
   

   BEST MODE FOR CARRYING OUT THE INVENTION 
     FIG. 2  is a diagram showing schematically a structural example of a first embodiment of the drive guide apparatus according to the present invention. In the figure, a linear motor  10  comprises a primary side  11  and a secondary side  12 . The primary side  11  is an energized side including armature coils. The secondary side  12  is a non-energized side having magnets, etc. The primary side  11  is connected through a table  13  to moving blocks  15  each serving as a moving member of a guide mechanism  14 . The secondary side  12  of the linear motor  10  is secured to a base  16 . The base  16  is secured to the top of a surface plate  17 . In this regard, the drive guide apparatus according to the present invention is the same as the conventional example shown in  FIG. 1 . 
   The base  16  is provided thereon with two parallel rails  18  constituting the guide mechanism in combination with the moving blocks  15 . The moving blocks  15  move along the rails  18  in response to driving force obtained from the linear motor  10 . In this regard also, the drive guide apparatus according to the present invention is the same as the conventional example shown in  FIG. 1 . 
   The drive guide apparatus according to the present invention differs from the drive guide apparatus shown in  FIG. 1  in that a thermal insulator  19  is provided between the primary side  11  of the linear motor  10  and the table  13  to prevent heat generated from the primary side  11  from being transferred to the table  13 . As a material for the thermal insulator  19 , a glass-filled epoxy resin material, a ceramic material, etc. are usable. 
   With the above-described arrangement in which the thermal insulator  19  is provided between the primary side  11  of the linear motor  10  and the table  13 , heat generated from the armature coils (not shown) of the primary side  11  when a driving electric current is passed therethrough is prevented from being transferred to the table  13  or the moving blocks  15 . Therefore, thermal expansion of the table  13  or the moving blocks  15  does not occur. 
   Accordingly, there is no variation in preload (contact pressure) applied to a plurality of rolling elements, e.g. balls, arranged and accommodated in the endless recirculation passages of the moving blocks  15  of the guide mechanism  14 , and the rolling resistance can be kept constant. Therefore, an increased lifetime can be ensured for the drive guide apparatus. 
   In the drive guide apparatus arranged as stated above, the thermal insulator  19  is provided over the whole surface of the primary side  11  of the linear motor  10 , by way of example. However, the arrangement may be such that the thermal insulator  19  is not provided over the whole surface of the primary side  11  but positioned at a predetermined region on each side of the primary side  11  in such a manner as to extend longitudinally of the rails  18  as shown, for example, in  FIG. 3 . 
   If a recess  20  acting as a thermal insulating space is provided on the lower side of the table  13  at a position between the thermal insulators  19 , it becomes possible to cut off the transfer of radiation heat from the primary side  11 . 
   In the above-described example, both the thermal insulator  19  and the recess  20  serving as a thermal insulating space are provided. By doing so, the thermal insulating effect is improved more than in the case of employing either of them. However, the required thermal insulating effect can be ensured by using only either of them. 
   If the surface of the table  13  that faces the recess  20  serving as a thermal insulating space (i.e. the inner surface of the recess  20 ) is formed into a mirror finished surface, the transfer of radiation heat can be cut off even more effectively. It should be noted that the mirror finished surface is obtained by electroless nickel plating, polishing, etc. 
   In addition, if the thermal insulator  19  is elongated in the longitudinal direction of the rails  18 , that is, in the direction of movement of the table  13  (moving blocks  15 ), rigidity in this direction increases. Thus, undesired oscillation phenomena can be prevented. 
   Next, a specific structural example of the drive guide apparatus according to the present invention will be described.  FIGS. 4 to 7  show a structural example of the drive guide apparatus according to the present invention.  FIG. 4  is a plan view.  FIG. 5  is a side view.  FIG. 6  is a view as seen in the direction of the arrow A-A in  FIG. 5 .  FIG. 7  is a view as seen in the direction of the arrow B-B in  FIG. 5 . In  FIGS. 4 to 7 , the same reference numerals as those in  FIGS. 2 and 3  denote the same or corresponding portions. 
   The primary side  11  of the linear motor  10  comprises armature coils and armature cores. The secondary side  12  of the linear motor  10  comprises a magnet plate. The secondary side  12  is secured to the base  16 . 
   As shown in  FIG. 7 , thermal insulators  19  made of a glass-epoxy resin are provided between the primary side  11  of the linear motor  10  and the table  13  to prevent heat generated from the primary side  11  from being transferred to the table  13 . 
   The thermal insulators  19  are disposed on both sides of the primary side  11  and elongated in the longitudinal direction of the rails  18 . A recess  20  serving as a thermal insulating space is formed on the lower side of the table  13  at a position between the thermal insulators  19 . The surface of the table  13  that faces the thermal insulating space (i.e. the inner surface of the recess  20 ) is formed into a mirror finished surface. 
   The rails  18  are disposed (secured) on the base  16  in parallel to each other at both sides of the secondary side  12  of the linear motor  10 , which comprises a magnet plate. The rails  18  each have a plurality (two in the illustrated example) of moving blocks  15  provided thereon in such a manner as to be movable along the associated rail  18 . The table  13  is supported by a plurality (four in the illustrated example) of moving blocks  15  movably provided on the rails  18 . 
   When a driving electric current is passed through the armature coils (not shown) of the primary side  11  of the linear motor  10 , the primary side  11  moves along the secondary side  12  in response to a magnetic interaction between the primary side  11  and the secondary side  12 . The force of movement of the primary side  11  is transmitted to the moving blocks  15  through the table  13 , causing the moving blocks  15  to move along the rails  18 . 
   End plates  21  are installed on both end portions of the base  16 . Stoppers  22  are mounted on the end plates  21 , respectively. Scrapers  23  are attached to both ends of the table  13 . 
   A linear scale  24  is provided on one side portion of the base  16 . A linear encoder head  25  is attached to one side portion of the table  13  through a bracket  26  to read the linear scale  24  to thereby detect the travel position (travel distance) of the table  13 . 
   A cable bear mount plate  27  is secured to the other side portion of the base  16 . A cable bear socket  28  is secured to the other side portion of the table  13 . 
   On the cable bear mount plate  27  are disposed a power cable  29  for supplying driving electric power to the primary side  11  of the linear motor  10 , a signal cable  30  for transmission and reception of signals, and nylon tubes  31  for supplying water or the like to cool the primary side  11 . The power cable  29 , the signal cable  30  and the nylon tubes  31  are connected to the primary side  11  of the linear motor  10  through the cable bear socket  28 . 
   It should be noted that reference numeral  38  in the figures denotes a center cover, and reference numeral  39  denotes side covers. 
   As has been stated above, the thermal insulators  19  are provided between the primary side  11  of the linear motor  10  and the table  13 , and the recess  20  serving as a thermal insulating space is provided on the lower side of the table  13  at a position between the thermal insulators  19 . Accordingly, heat generated from the primary side  11  of the linear motor  10  is prevented from being transferred to the table  13  by the heat transfer cutoff action of the thermal insulators  19  and the radiation heat blocking action of the recess  20 . Therefore, there is no variation in the preload applied to the rolling elements arranged and accommodated in the endless recirculation passages of the moving blocks  15 . 
   In addition, because the inner surface of the recess  20  formed on the lower side of the table  13  is formed into a mirror finished surface, the radiation heat blocking effect is further improved. 
     FIGS. 8 to 10  are diagrams showing the arrangement of the guide mechanism  14  in detail.  FIG. 8  is a perspective view.  FIG. 9  is a sectional view.  FIG. 10  is a sectional view of a moving block. 
   Each rail  18  with a rectangular sectional configuration has two ball rolling grooves  18 - 1  formed on each of the right and left sides thereof as rolling element rolling surfaces extending along the longitudinal direction of the rail  18 . That is, a total of four ball rolling grooves  18 - 1  are formed on each rail  18 . Each moving block  15  has endless recirculation passages including load rolling grooves  15 - 1  forming load rolling element rolling passages that face opposite the ball rolling grooves  18 - 1 . A plurality of balls  32  as rolling elements are arranged and accommodated in the endless recirculation passages. The balls  32  roll between the ball rolling grooves  18 - 1  and the corresponding load rolling grooves  15 - 1  in response to the relative movement of the rail  18  and the moving block  15 . In this way, the balls  32  recirculate through the endless recirculation passages. 
   The guide mechanism  14  is arranged so as to be able to carry loads applied in all directions, i.e. moments in all directions, not to mention radial loads and horizontal loads. 
   Each moving block  15  comprises a moving block body  15   a  and end caps  15   b . The moving block body  15   a  is formed with the load rolling grooves  15 - 1  and ball return passages parallel to the respective load rolling grooves  15 - 1 . The end caps  15   b  are connected to both ends, respectively, of the moving block body  15   a . Each end cap  15   b  has direction change passages that connect the load rolling grooves  15 - 1  and the ball return passages, respectively. The moving block  15  is mounted in such a manner as to sit astride the rail  18 . The top of the moving block  15  is arranged so that the table  13  is mounted and secured thereto. 
   The load rolling grooves  15 - 1  of the moving block  15  are formed facing opposite the respective ball rolling grooves  18 - 1  on the rail  18 . A plurality of balls  32 , i.e. rolling elements, are put between the load rolling grooves  15 - 1  and the ball rolling grooves  18 - 1 . 
   As the moving block  15  moves, the balls  32  are fed into the ball return passages through the direction change passages formed in the end caps  15   b  and led to the load rolling grooves  15 - 1  again. In this way, the balls  32  recirculate through the endless recirculation passages. 
   As shown in  FIGS. 9 and 10 , the plurality of balls  32  are rotatably and slidably retained in series by a retaining member  33 . The retaining member  33  comprises spacers  34  disposed alternately with the balls  32  and a sheet-shaped flexible belt  35  connecting the spacers  34 . 
   The balls  32  arranged and accommodated in the endless recirculation passages are given a predetermined preload (contact pressure) to ensure smooth rolling of the balls  32 . 
   A seal member  36  is provided between the top of the rail  18  and the moving block  15 . Seal members  37  are provided between the moving block  15  and two sides of the rail  18 . The seal members  36  and  37  prevent leakage to the outside of a lubricant filled between the ball rolling grooves  18 - 1  and the load rolling grooves  15 - 1  and also prevent entry of dust from the outside. 
     FIG. 11  is a diagram showing schematically a structural example of another embodiment of the drive guide apparatus according to the present invention. In the figure, a cylindrical linear motor  50  comprises a cylindrical primary side  51 , which is an energized side including armature coils, and a secondary side  52  formed from a long columnar thrust shaft, which is a non-energized side. 
   A guide mechanism  53  has an outer rail  54  comprising a base portion  54 - 1  and a pair of side walls  54 - 2  standing on both sides of the base portion  54 - 1 . The guide mechanism  53  further has an inner block  55  movable in a groove defined in a recess  58  that is formed between the side walls  54 - 2  of the outer rail  54 . 
   A table  56  is mounted on the inner block  55  of the guide mechanism  53 . The table  56  has a longitudinal recess  58  formed in the center of the top thereof. The linear motor  50  is attached to the table  56  through thermal insulators  57 . 
   In the drive guide apparatus arranged as stated above, if the thermal insulators  57  are not interposed between the table  56  and the linear motor  50 , heat generated from the armature coils (not shown) of the primary side  51  of the linear motor  50  when a driving electric current is passed through the armature coils will be transferred to the inner block  55  through the table  56 , causing the inner block  55  to expand thermally. 
   The outer rail  54  has a plurality of rolling element rolling surfaces extending in the longitudinal direction thereof, as will be detailed later. The inner block  55  is formed with endless recirculation passages including load rolling element rolling passages corresponding to the rolling element rolling surfaces. 
   A plurality of rolling elements (balls) are arranged and accommodated in the endless recirculation passages so as to roll and recirculate therethrough. Because the rolling elements have been given a predetermined preload, if the inner block  55  thermally expands, the preload increases or decreases. 
   In this example, the thermal insulators  57  are interposed between the table  56  and the linear motor  50 . Therefore, heat generated from the primary side  51  of the linear motor  50  is blocked by the thermal insulators  57  from being transferred to the table  56  or the inner block  55 . Accordingly, the inner block  55  will not thermally expand. Thus, there is no variation in the preload applied to the plurality of rolling elements (balls) arranged and accommodated in the endless recirculation passages as stated above. 
   The recess  58  formed in the center of the top of the table  56  acts as a thermal insulating space that cuts off the transfer of radiation heat from the primary side  51 . If the inner surface of the recess  58  is formed into a mirror finished surface, the effect of cutting off the transfer of radiation heat is further improved. 
   It should be noted that reference numeral  59  denotes a cable socket for connection with a power cable for supplying driving electric power to the primary side  51  of the linear motor  50  and a signal cable for signal transmission and reception. 
     FIG. 12  is a diagram showing a structural example of the guide mechanism  53 . As shown in the figure, the inner block  55  is movable in the groove in the recess  58  formed between the side walls  54 - 2  standing on both sides of the base portion  54 - 1  of the outer rail  54 . 
   The inner side surface of each side wall  54 - 2  has two ball rolling grooves  54 - 3  formed as rolling element rolling surfaces along the longitudinal direction of the outer rail  54 . 
   Each outer side surface of the inner block  55  is formed with load rolling grooves  55 - 1  as load rolling element rolling passages corresponding to the ball rolling grooves  54 - 3  formed on the outer rail  54 . Balls  60  as rolling elements roll between the ball rolling grooves  54 - 3  of the outer rail  54  and the load rolling grooves  55 - 1  of the inner block  55  while carrying a load. 
   The inner block  55  has endless recirculation passages  55 - 2  for the balls  60  in correspondence to the respective load rolling grooves  55 - 1 . By endlessly recirculating the balls  60  rolling along the load rolling grooves  55 - 1 , the inner block  55  moves along the outer rail  54 . 
   A table  56  is secured to the top of the inner block  55 , as stated above. The plurality of balls  60  arranged and accommodated in the endless recirculation passages  55 - 2  of the inner block  55  have been given a predetermined preload to ensure smooth rolling of the balls  60 . 
     FIG. 13  is a diagram showing schematically a structural example of still another embodiment of the drive guide apparatus according to the present invention. In the figure, a cylindrical linear motor  70  comprises a cylindrical primary side  71 , which is an energized side including armature coils, and a secondary side  72  formed from a long columnar thrust shaft, which is a non-energized side. 
   Guide mechanisms  75  respectively comprise rails  77  provided on the respective upper end surfaces of side walls  78 - 2  standing on both sides of a base portion  78 - 1 . Moving blocks  76  are mounted in such a manner as to sit astride the rails  77 , respectively. 
   The primary side  71  of the linear motor  70  is secured to a table  74  through thermal insulators  73 . The table  74  is secured to the moving blocks  76  of the guide mechanisms  75 . A recess  79  acting as a thermal insulating space is formed on the lower side of the table  74  at a position between the thermal insulators  73 . 
   When the armature coils (not shown) of the primary side  71  of the linear motor  70  are supplied with an electric current, the primary side  71  moves in the groove in the recess  79  formed between the side walls  78 - 2  along the rails  77 . Energization of the armature coils causes generation of heat from the primary side  71 . However, the heat is blocked by the thermal insulators  73  from being transferred to the table  74 . The recess  79  formed on the lower side of the table  74  acts as a space for cutting off the transfer of radiation heat from the primary side  71  and thus blocks the radiation heat. 
   It should be noted that if the inner surface of the recess  79  is formed into a mirror finished surface, the effect of cutting off the transfer of radiation heat is further improved. 
   The arrangement of the guide mechanisms  75  is approximately the same as that of the guide mechanism shown in  FIGS. 8 to 10  (however, these guide mechanisms differ from each other in the number of rows of endlessly recirculating ball trains and in the layout thereof). Therefore, a description thereof is omitted. 
   As has been stated above, the thermal insulators  73  are interposed between the primary side  71  of the linear motor  70  and the table  74 , and the recess  79  serving as a radiation heat blocking space is formed on the lower side of the table  74 . With this arrangement, heat generated from the primary side  71  is prevented from being transferred to the table  74 . Consequently, thermal expansion of the table  74  will not occur. Therefore, there is no variation in the preload applied to the rolling elements arranged and accommodated in the endless recirculation passages of the guide mechanisms  75 . 
   In the above-described example, the thermal insulator is provided between the primary side of the linear motor and the moving block, that is, the moving member, indirectly with the table, etc. interposed therebetween. It should be noted, however, that the thermal insulator may be interposed directly between the primary side of the linear motor and the moving block. In addition, although in the above-described example the thermal insulating means is interposed between the primary side of the linear motor and the moving member, the thermal insulating means may be provided between the primary side of the linear motor and the track (rail) to prevent heat generated from the primary side from being transferred to the rail. 
   Incidentally, the guide mechanism for guiding the primary side and the secondary side of the linear motor in the foregoing examples employs a rolling guide arrangement in which the rail (rails  18  and outer rail  54 ) and the moving block (moving blocks  15  and inner block  55 ) are movable relative to each other through the rolling elements (balls or rollers) interposed therebetween. However, the present invention is not limited to the rolling guide arrangement but may employ a slide guide arrangement. 
     FIG. 14  is a diagram showing schematically a structural example of a drive guide apparatus having a slide guide mechanism  84 . This drive guide apparatus is arranged in the same way as the drive guide apparatus according to the first embodiment shown in  FIG. 2  except the following arrangement. 
   As shown in the figure, a pair of guide mechanisms  84  are respectively provided on the right and left sides of the base  16 . Each guide mechanism  84  has a rail  88  with a rectangular sectional configuration and a moving block  85  mounted astride the rail  88  in such a manner as to be movable relative to the rail  88 . The table  13  is fitted to the upper sides of the moving blocks  85 . The rails  88  and the moving blocks  85  are slidably assembled together directly with no rolling elements interposed therebetween to form a slide guide. 
   More specifically, assuming that the mutually opposing surfaces of the rails  88  of the two guide mechanisms  84  are inner surfaces, a gap e is formed between the outer surface of each rail  88  and the outer leg portion  85 - 1  of the associated moving block  85 . That is, the two rails  88  are in sliding contact with the associated moving blocks  85  at their inner and upper surfaces. Further, a predetermined surface pressure is produced between the inner surface of each rail  88  and the inner leg portion  85 - 2  of the associated moving block  85 . 
   In this drive guide apparatus also, the thermal insulator  19  is provided between the primary side  11  of the linear motor  10  and the table  13 . Thus, heat generated from the armature coils (not shown) of the primary side  11  when a driving electric current is passed through the armature coils is prevented from being transferred to the table  13  or the moving blocks  85 . Accordingly, neither the table  13  nor the moving blocks  85  will thermally expand. Therefore, sliding resistance between the rails  88  and the moving blocks  85  is prevented from varying and kept constant. Thus, it is possible to ensure an increased lifetime for the drive guide apparatus. 
     FIG. 15  is a diagram showing schematically the arrangement of another drive guide apparatus having a slide guide mechanism. This drive guide apparatus is arranged in the same way as the drive guide apparatus shown in  FIG. 14  except the following arrangement. 
   As illustrated in the figure, assuming that the mutually opposing surfaces of the rails  88  of two guide mechanisms  84  provided on the right and left sides are inner surfaces, a gap e is formed between the inner surface of each rail  88  and the inner leg portion  85 - 2  of the associated moving block  85 . That is, the two rails  88  are in sliding contact with the associated moving blocks  85  at their outer and upper surfaces. Further, a predetermined surface pressure is applied between the outer surface of each rail  88  and the outer leg portion  85 - 1  of the associated moving block  85 . 
   In this drive guide apparatus also, the transfer of heat generated from the armature coils of the primary side  11  of the linear motor  10  is cut off by the thermal insulator  19  in the same way as in the drive guide apparatus shown in  FIG. 14 . Accordingly, neither the table  13  nor the moving blocks  85  will thermally expand. Therefore, sliding resistance between the rails  88  and the moving blocks  85  is prevented from varying. Thus, it is possible to ensure an increased lifetime for the drive guide apparatus. 
     FIG. 16  shows schematically the arrangement of still another drive guide apparatus having a slide guide mechanism. This drive guide apparatus is arranged in the same way as the drive guide apparatus shown in  FIGS. 14 and 15  except the following arrangement. 
   In this drive guide apparatus, as shown in the figure, the rail  88  of one of the two guide mechanisms  84  provided on the right and left sides, i.e. the right guide mechanism  84  in the illustrated example, has gaps e formed respectively between the inner and outer surfaces thereof and the inner and outer leg portions  85 - 1  and  85 - 2  of the associated moving block  85 . In other words, the rail  88  is in sliding contact with the moving block  85  only at the upper surface thereof. 
   The rail  88  of the other, or left guide mechanism  84  is in sliding contact with the associated moving block  85  at the inner and upper surface thereof. The outer surface of the rail  88  is in engagement with the inner leg portion  85 - 2  of the moving block  85  through a gib  89 . In other words, a predetermined surface pressure is applied between the outer surface of the rail  88  and the outer leg portion  85 - 1  of the associated moving block  85 . In addition, a predetermined surface pressure is applied between the inner surface of the rail  88  and the inner leg portion  85 - 2  of the moving block  85 . 
   In this drive guide apparatus also, the transfer of heat generated from the armature coils of the primary side  11  of the linear motor  10  is cut off by the thermal insulator  19  in the same way as in the drive guide apparatus shown in  FIGS. 14 and 15 . Accordingly, neither the table  13  nor the moving blocks  85  will thermally expand. Therefore, sliding resistance between the rails  88  and the moving blocks  85  is prevented from varying. Thus, it is possible to ensure an increased lifetime for the drive guide apparatus. 
     FIGS. 17 and 18  are graphs showing the results of temperature-rise tests performed on the drive guide apparatus arranged as shown in  FIG. 11 . In the graphs, the abscissa axis represents the elapsed time (h (hour)), and the ordinate axis represents the rise in temperature (°C.). Temperature measurement points are a point P 1  on the linear motor  50  and a point P 2  on the inner block  55 . In a state where the travel of the primary side  51  as the energized side of the linear motor  50  was suspended (retrained), the primary side  51  was supplied with an electric current to measure a rise in temperature thereof. 
     FIGS. 17 and 18  show examples of temperature-rise tests performed on linear motors  50  different in ratings from each other.  FIGS. 17 and 18  show the results of temperature-rise tests in which a rated peak current of 2.86 A and a rated peak current of 2.96 A were supplied to the primary sides  51  of the linear motors  50 , respectively. 
   In the example of  FIG. 17 , the temperature at the point P 1  on the linear motor  50  rises to 63.0° C., whereas the temperature at the point P 2  on the inner block  55  rises only to 10.2° C. Thus, the graph shows a remarkable thermal insulating effect produced by providing the thermal insulators  57  between the table  56  and the linear motor  50  and further forming a space defined by the recess  58  in the center of the top of the table  56 . 
   In the example of  FIG. 18 , the temperature at the point P 1  on the linear motor  50  rises to 57.2° C., whereas the temperature at the point P 2  on the inner block  55  rises only to 8.9° C. Thus, the graph shows a remarkable thermal insulating effect produced by providing the thermal insulators  57  between the table  56  and the linear motor  50  and further forming a space defined by the recess  58  in the center of the top of the table  56 . 
     FIGS. 19 and 20  are graphs showing the results of temperature-rise tests performed on the drive guide apparatus arranged as shown in  FIG. 13 . In the graphs, the abscissa axis represents the elapsed time (h), and the ordinate axis represents the rise in temperature (° C.). Temperature measurement points are a point P 3  on the linear motor  70  and a point P 4  on the top of the table  74 . In a state where the travel of the primary side  71  as the energized side of the linear motor  70  was suspended (retrained), the primary side (armature coils)  51  was supplied with an electric current to measure a rise in temperature thereof. 
     FIGS. 19 and 20  show examples of temperature-rise tests performed on linear motors  70  different in ratings from each other.  FIGS. 19 and 20  show the results of temperature-rise tests in which a rated peak current of 2.34 A and a rated peak current of 2.23 A were supplied to the primary sides  71  of the linear motors  70 , respectively. 
   In the example of  FIG. 19 , the temperature at the point P 3  on the linear motor  70  rises to 58.7° C., whereas the temperature at the point P 4  on the table  74  rises only to 8.2° C. Thus, the graph shows a remarkable thermal insulating effect produced by providing the thermal insulators  73  between the table  74  and the linear motor  70  and further forming a space defined by the recess  79  in the center of the lower side of the table  74 . 
   In the example of  FIG. 20 , the temperature at the point P 3  on the linear motor  70  rises to 65.1° C., whereas the temperature at the point P 4  on the table  74  rises only to 13.0° C. Thus, the graph shows a remarkable thermal insulating effect produced by providing the thermal insulators  73  between the table  74  and the linear motor  70  and further forming a space defined by the recess  79  in the center of the lower side of the table  74 . 
   As has been stated above, a thermal insulating effect is produced by providing a thermal insulator and a space for blocking heat generated from the primary side of the linear motor between the primary side and the rail or the moving member of the guide mechanism to which the primary side of the linear motor is connected. However, to further improve the thermal insulating effect (heat dissipation effect), a multiplicity of fins  70   a  may be provided on the outer surfaces of the linear motor  70 , as shown in  FIG. 21 . It should be noted that the drive guide apparatus shown in  FIG. 21  is the same as the drive guide apparatus shown in  FIG. 13  except that a multiplicity of fins  70   a  are provided on the outer surfaces of the linear motor  70 . The operation of the drive guide apparatus shown in  FIG. 21  is the same as that of the drive guide apparatus shown in  FIG. 13 . 
     FIG. 22  is a diagram showing a specific structural example of the drive guide apparatus according to the present invention. The drive guide apparatus is approximately the same as the drive guide apparatus shown in  FIGS. 4 to 7  in terms of the arrangement of the main body part thereof but differs from the latter in the structure of the linear motor and in the arrangement for dissipating heat from the heat generating part of the linear motor. That is, a linear motor  10 ′ of the drive guide apparatus has a secondary side (stationary side)  12 ′ formed with a U-shaped sectional configuration. The primary side (moving side)  11 ′ of the linear motor  10 ′ has a plate-shaped configuration. The primary side  11 ′ is movable through a groove with a U-shaped sectional configuration defined in the secondary side  12 ′. 
   The primary side  11 ′ has a finned heatsink  40  secured thereto integrally. The heatsink  40  has a multiplicity of radiating fins  41 . A table  13  is provided over the finned heatsink  40  with thermal insulators  19  interposed therebetween. 
   In the drive guide apparatus arranged as stated above, when a driving electric current is passed through the armature coils (not shown) of the primary side  11 ′, the table  13 , which is secured to the primary side  11 ′ with the finned heatsink  40  and the thermal insulators  19  interposed therebetween, moves in response to driving force from the primary side  11 ′ while being guided by the guide mechanisms  14 . That is, the table  13  secured to the moving blocks  15  moves along the rails  18 . 
   Thus, the linear motor  10 ′ is arranged such that the plate-shaped primary side  11 ′ moves through the groove in the secondary side  12 ′ formed with a U-shaped sectional configuration. With this arrangement, the primary side (armature coils)  11 ′ is surrounded by the secondary side (consisting essentially of magnets)  12 ′. Therefore, dissipation of heat generated from the primary side  11 ′ is prevented. 
   In this example, the finned heatsink  40  is integrally secured to the primary side  11 ′, as stated above. Therefore, heat generated from the primary side  11 ′ is transferred to the finned heatsink  40  and efficiently dissipated from the radiating fins  41 . 
   The finned heatsink  40  employs an already-known arrangement in which a heat pipe is provided in the heatsink  40 , for example. By attaching the finned heatsink  40  to the primary side  11 ′ of the linear motor  10 ′ as stated above, heat generated from the primary side  11 ′ is dissipated efficiently even in the case of the linear motor  10 ′ having an arrangement in which the primary side  11 ′ is surrounded by the secondary side (magnets)  12 ′ and hence the heat dissipation effect is not good. Thus, it becomes possible to minimize the rise in temperature of the linear motor  10 ′. 
   Further, because the thermal insulators  19  are interposed between the finned heatsink  40  and the table  13 , the transfer of heat to the table  13  or the moving blocks  15  is further retarded. 
     FIG. 23  is a diagram showing a structural example of a radiating fin plate of the above-described finned heatsink.  FIG. 24  is an enlarged view of a radiating fin. 
   The radiating fin plate has a structure in which a multiplicity of long plate-shaped radiating fins  41  are stood at predetermined intervals on the top of a base plate  42 . As shown in  FIG. 24 , each individual radiating fin  41  has corrugations  41   a  provided on both sides thereof. With this arrangement, the heat radiation area of each individual radiating fin  41  is increased. 
     FIG. 25  is a diagram showing a specific structural example of the drive guide apparatus according to the present invention. The illustrated drive guide apparatus is approximately the same as the drive guide apparatus shown in  FIG. 22  in terms of the arrangement. The drive guide apparatus differs from the latter in the material constituting the thermal insulators  19  interposed between the table  13  and the finned heatsink  40  and in the structure for connecting together the table  13  and the finned heatsink  40 . 
   The thermal insulators  19  in this example absorb a deformation of the finned heatsink  40  due to thermal expansion to prevent deformation of the primary side (moving element)  11 ′ of the linear motor  10 ′ that is connected to the finned heatsink  40 . 
   Because the finned heatsink  40  is secured to the table  13 , when it thermally expands, the finned heatsink  40  is curvedly deformed owing to a thermal expansion difference therebetween. 
   The deformation of the finned heatsink  40  causes the primary side (moving element)  11 ′ of the linear motor  10 ′ to be displaced. Consequently, the gap between the primary side  11 ′ and the secondary side (stator)  12 ′ changes. This exerts an influence upon the characteristics of the linear motor  10 ′. 
   In this example, when the finned heatsink  40  thermally expands in the directions shown by the double-headed arrow B in  FIG. 26A , shearing force acts on the thermal insulators  19  at both sides of the finned heatsink  40 . In such a case, the thermal insulators  19  are deformed as shown in  FIG. 26B , thereby absorbing the deformation of the finned heatsink  40  due to the thermal expansion. That is, the thermal insulators  19  are deformed from the shape shown in (a) of  FIG. 27  to the respective shapes as shown in (b) and (c) of  FIG. 27 , thereby absorbing the deformation of the finned heatsink  40 . 
   Thus, the deformation of the finned heatsink  40  disappears. Therefore, there is no change in the gap dimension between the primary side  11 ′ and the secondary side (stator)  12 ′ of the linear motor  10 ′. Accordingly, no influence is exerted upon the characteristics of the linear motor  10 ′. For the thermal insulators  19 , a material that has excellent thermal insulating properties and that is easily deformable by shearing force (i.e. a material easy to deform in the width direction and rigid in the thickness direction) is used. For example, a laminated glass-epoxy resin material is suitably used for the thermal insulators  19  because it is excellent in thermal insulating performance and easily deformable by shearing force. 
   The finned heatsink  40  is fastened to the table  13  with the thermal insulators  19  interposed therebetween by using bolts  43 .  FIG. 28  is a diagram showing a fastening structure using bolts  43 . 
   As shown in the figure, a spot-faced hole  13   a  is provided in a portion of the top of the table  13  at which a bolt  43  extends through the table  13 . The spot-faced hole  13   a  has a flanged cylindrical member  44  and a washer  45  inserted therein. The bolt  43  extends through the flanged cylindrical member  44  and the washer  45  and engages a threaded hole  46  provided in the finned heatsink  40 . That is, the finned heatsink  40  is fastened to the table  13  with the bolts  43  in a state where the thermal insulators  19  are interposed between the finned heatsink  40  and the table  13  and the flange of the cylindrical member  44  and the washer  45  are interposed between the head  43   a  of the bolt  43  and the table  13 . 
   The finned heatsink  40  is fastened at both sides thereof with the same fastening structure using the bolts  43 . It should be noted that a gap  49  is provided between the outer peripheral portion of the bolt  43  and the inner wall surface of a bolt receiving hole  13   b  to prevent heat from the finned heatsink  40  from being transferred to the table  13  from the outer peripheral portion of the bolt  43 . 
   The flanged cylindrical member  44  uses a material excellent in thermal insulating performance and easily deformable by shearing force (e.g. laminated glass-epoxy resin material) as in the case of the thermal insulators  19 . Thus, when the finned heatsink  40  thermally expands owing to a rise in temperature, the thermal expansion of the finned heatsink  40  is absorbed by deformation of the thermal insulators  19  as stated above and further by deformation of the flanged cylindrical members  44  from the shape shown in (a) of  FIG. 29  to the respective shapes as shown in (b) and (c) of  FIG. 29 . Accordingly, the finned heatsink  40  will not be curvedly deformed even if it thermally expands owing to a rise in temperature. 
   Although heat from the finned heatsink  40  is transferred to the bolts  43 , there is no possibility of the heat being transferred to the table  13  because the flanged cylindrical members  44 , which are excellent in thermal insulating performance, are interposed between the bolts  43  and the table  13 . 
   In this drive guide apparatus, as shown in  FIG. 25 , a heatsink  47  is attached to an end portion of the primary side of the linear motor  10 ′. As shown in  FIG. 30 , the heatsink  47  has a U-shaped sectional configuration. One wall of the U-shaped structure of the heatsink  47  is provided with a multiplicity of slits  47   a  at predetermined intervals, thereby providing radiating fins  48 . The effect of dissipating heat from the primary side of the linear motor  10 ′ is further improved by providing the heatsink  47  arranged as stated above on the end portion of the primary side of the linear motor  10 ′. 
   INDUSTRIAL APPLICABILITY 
   As has been stated above, according to the invention recited in claim  1 , thermal insulating means for blocking heat generated from the primary side of the linear motor is provided between the primary side of the linear motor and the rail or the moving member of the guide mechanism to which the primary side of the linear motor is connected. Therefore, heat generated from the primary side of the linear motor is prevented from being transferred to the rail or the moving member of the guide mechanism. Consequently, thermal expansion of the rail or the moving member is prevented, and there is no variation in rolling resistance or sliding resistance of the guide mechanism. Accordingly, it is possible to ensure an increased lifetime for the drive guide apparatus. 
   According to the invention recited in claim  2 , the thermal insulating means comprises a thermal insulator interposed between the rail or the moving member and the primary side of the linear motor. Thus, an increased lifetime can be ensured for the drive guide apparatus with a simple arrangement. 
   According to the invention recited in claim  3 , the thermal insulator is elongated in the direction of relative movement between the rail and the moving member. By doing so, rigidity in this direction increases. Thus, undesired oscillation phenomena can be prevented. 
   According to the invention recited in claim  4 , the thermal insulating means comprises a thermal insulating space formed between the rail or the moving member and the primary side of the linear motor. With this arrangement, it is possible to cut off the transfer of radiation heat from the primary side of the linear motor. Therefore, it is possible to prevent thermal expansion of the rail or the moving member due to radiation heat and hence possible to eliminate variation in rolling resistance or sliding resistance of the guide mechanism. Accordingly, an increased lifetime can be ensured for the drive guide apparatus as in the case of the above. 
   According to the invention recited in claim  5 , the thermal insulating space has a mirror finished surface at a side thereof closer to the rail or the moving member of the guide mechanism to which the primary side of the linear motor is connected. With this arrangement, the transfer of radiation heat from the primary side of the linear motor can be cut off even more effectively. 
   According to the invention recited in claim  6 , the guide mechanism is arranged in the form of a rolling guide. That is, the rail is formed with a rolling element rolling surface extending longitudinally of the rail. The moving member has an endless recirculation passage including a load rolling element rolling passage corresponding to the rolling element rolling surface. A multiplicity of rolling elements are arranged and accommodated in the endless recirculation passage. The rolling elements recirculate through the endless recirculation passage while receiving a load in the load rolling element rolling passage. In the rolling guide according to this invention, the preload applied to the rolling elements is not varied by a stress generated by thermal expansion of the rail or the moving member. Accordingly, smooth rolling of the rolling elements is ensured, so that an increased lifetime of the drive guide apparatus is attained. In the rolling guide, if the preload increases, flaking (a phenomenon in which the surface of the raceway surface or the rolling element surface peels off in flakes owing to the rolling fatigue of the material) is likely to occur. If flaking occurs, the lifetime reduces markedly. 
   According to the invention recited in claim  7 , a heatsink is provided to dissipate heat generated from the primary side of the linear motor. With this arrangement, heat generated from the primary side of the linear motor can be dissipated efficiently. Therefore, the transfer of the heat to the rail or the moving member of the guide mechanism is further retarded. As a result, restrictions on the linear motor configuration for heat dissipation are reduced. Accordingly, it is possible to employ a linear motor having an arrangement even more suitable for the drive guide apparatus. 
   According to the invention recited in claim  8 , the heatsink is a finned heatsink having radiating fins. By using the finned heatsink, the heat dissipation effect is further enhanced. Accordingly, the transfer of heat to the rail or the moving member of the guide mechanism is further retarded. 
   According to the invention recited in claim  9 , when the heatsink is thermally expanded and deformed by heat from the primary side of the linear motor, shearing force acts on the absorbing member. Consequently, the absorbing member is shear-deformed to absorb the deformation of the heatsink. Therefore, the heatsink is not deformed, and the primary side of the linear motor is not displaced. Accordingly, there is no change in the gap between the primary side and the secondary side of the linear motor. Hence, there is no change in characteristics of the linear motor. 
   According to the invention recited in claim  10 , the absorbing member has both the function of absorbing a deformation of the heatsink by shear deformation and the thermal insulating function of cutting off the heat transfer from the heatsink to the moving member. Therefore, no influence is exerted upon the characteristics of the linear motor as stated above. Moreover, there is no variation in rolling resistance or sliding resistance of the guide mechanism. Accordingly, it is possible to ensure an increased lifetime for the drive guide apparatus. 
   According to the invention recited in claim  11 , a laminated glass-epoxy resin material is used for the absorbing member. By doing so, a deformation of the heatsink is absorbed easily. That is, the laminated glass-epoxy resin material exhibits strong rigidity in the lamination direction (thickness direction) and weak rigidity in a direction (width direction) perpendicular to the lamination direction. Therefore, when the heatsink thermally expands in response to a rise in temperature, shearing force acts on the absorbing member. At this time, the absorbing member is easily deformed to absorb the deformation of the heatsink. Accordingly, it is possible to ensure an increased lifetime for the drive guide apparatus.