JP2010089295A - Horizontal mold clamping device for injection molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To minimize positional deviation and parallelism deviation of the center of platens due to thermal expansion in a horizontal mold clamping device for an injection molding machine supporting the platens on a machine base by support members. <P>SOLUTION: The mold clamping device for the injection molding machine supports a fixed platen and a movable platen at substantially center height positions in the vertical direction symmetrically from both sides by the support members, then supports a back platen at a substantially center height position in the vertical direction symmetrically from both sides by the support member, and places the lower end faces of the support members slidably on the machine base. All the support members of the platens are formed of material with a low thermal expansion coefficient. The fixed platen, the movable platen and the back platen are fitted, at the bottoms thereof, to a reference member positioned at the center position in a transverse direction orthogonal to a mold opening/closing direction. In addition, it is preferable to attach heat insulating plates to the side faces of the fixed platen and movable platen, and it is also preferable to support a driving device elastically. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a horizontal mold clamping apparatus for an injection molding machine, and more particularly, to an injection molding machine that supports a fixed platen and a movable platen at their vertical center positions to prevent misalignment of the centers and parallelism of the platens. The present invention relates to an improvement of a horizontal mold clamping device.

  A conventional mold clamping device of an injection molding machine includes a fixed platen and a back platen connected by a tie bar, and a movable platen that moves between them on a machine base. The back platen is provided with a drive device for moving the movable platen back and forth. The fixed platen is mounted with the fixed side of the mold, and the movable platen is mounted with the movable side of the mold. The drive device opens and closes the mold by moving the movable mold forward and backward relative to the fixed platen.

  Among such mold clamping devices, particularly in a large mold clamping device having a large mold weight, instead of being guided while the movable platen is suspended from a tie bar, for example, a linear guide device (from a linear motion bearing and a guide rail) is used. Will be guided to the machine base via Therefore, in such a mold clamping device, there has been a problem that the center height position of the platen is distorted due to the thermal expansion of the platen caused by the high heat of the mold. This problem becomes more prominent when the temperature difference between the fixed platen and the movable platen is large. The difference in temperature is, for example, the difference in ambient temperature that the fixed platen is close to the high-temperature injection device while the movable platen is connected to the drive device at room temperature, and the difference in heat capacity due to the volume difference between both platens. Alternatively, the fixed platen is fixed, but the movable platen moves forwards and backwards, resulting in a difference in heat dissipation, which is unavoidable. In a special case, the temperature difference between the fixed platen and the movable platen may become larger as a result of the increased capacity of the hot runner to increase the number of multi-piece forming.

  Therefore, the following mold clamping apparatus is proposed in Japanese Patent Application Laid-Open No. 2006-199004 (Patent Document 1). The mold clamping device includes a fixed platen and a pressure receiving plate that are connected to each other on a machine base with tie bars connected, a movable plate provided so as to be movable back and forth between the plates, mold clamping means for driving the movable plate, and This is a device provided with guide means (same as the linear guide device) for supporting and guiding the movable board, and the guide means are arranged diagonally with a difference in height on both sides of the board body. The movable platen is guided by the guide rail via a linear guide member (hereinafter referred to as a linear motion bearing) fixed to a support portion protruding to the side of the plate body, and in particular, the guide rail. Are arranged on the machine base on the operation side and on the high guide rail laying base on the non-operation side. Further, the fixed platen is supported by support columns disposed symmetrically on both sides at the center height position. Moreover, as an additional embodiment, an embodiment is proposed in which a flow path through which the medium flows is formed in the board, and the thermal expansion of the board body is reduced by the flow of the cooling medium.

  According to the mold clamping device, the movable platen is guided by the guide rail through the linear motion bearing in a state where it is separated from the machine base, and the fixed platen is also separated from the machine base by symmetrical columns on both sides. It is supported. Therefore, even if thermal expansion occurs in the board itself, there is no occurrence of displacement of the mold center height. The thermal expansion of the board itself is also reduced by the additional embodiment. In this apparatus, since the guide rail on the operation side is at a low position, the guide rail does not get in the way when the mold is attached to or detached from the fixed plate or movable plate.

  A mold clamping device having a similar basic configuration is also disclosed in Japanese Patent Laid-Open No. 2006-256034 (Patent Document 2). In addition, in another embodiment of the document (FIG. 6), the guide rails on both sides for guiding the linear motion bearing are mounted symmetrically on the guide base, and the heights of these rails are approximately at the height of the tie bar. Such a configuration is also disclosed. Therefore, even in the mold clamping device, the same operation and effect can be achieved by supporting and guiding the disc body in a state of being separated from the machine base as described above. The height of the guide base is limited to the height of the tie bar so that the mold attaching / detaching operation is not restricted.

  A similar configuration is also disclosed in Japanese Patent Publication No. 3476616 (Patent Document 3), which has slightly different operational effects. The structure is a mold clamping device including a fixed die plate, a movable die plate, a cylinder support, and a mold clamping cylinder, and a vertical center position of the fixed die plate and the cylinder support is erected on the molding machine body frame. It is fixed to the leg. In such a mold clamping device, when a pulling force is generated on the tie bar by the mold clamping force, the deformation of the fixed die plate and the cylinder support becomes vertically symmetric with respect to the center position. The problem that the parallelism between the movable molds is lost or the center position is shifted is solved.

  On the other hand, the applicant of this application also proposed a horizontal mold clamping apparatus in Japanese Patent Application No. 2007-272914. The mold clamping device is a device including a fixed support member that supports the fixed platen on the machine base symmetrically with respect to the center at a position of the center height, and a movable support member that similarly supports the movable platen, In particular, the movable platen is an apparatus configured to move on a guide rail laid on the machine base. Both the support members of the fixed platen and the movable platen are configured in substantially the same shape and the lower end of the support member of the movable platen is fixed to the linear motion bearing. The support member for both the fixed and movable platens includes, for example, a heat insulating material, a heat shielding material, a through hole, a fan, or a material having a low coefficient of thermal expansion as a thermal expansion suppressing means for suppressing thermal expansion due to a rise in platen temperature. It is out. With the mold clamping device having such a configuration, the displacement of the center height of the platen and the misalignment of the parallelism caused by thermal expansion between the fixed platen and the movable platen are prevented as much as possible.

JP 2006-199004 A JP 2006-256034 A Japanese Patent No. 3476616

  However, even in the case of the mold clamping device as described above, the accuracy requirements for the positional deviation of the center height and the misalignment of the plate, the plate body, or the platen are becoming stricter. As for the former, the recent shift of the center position of a highly accurate mold causes galling at a highly accurate fitting location and impairs the mold life. This is because, in the latter case, uneven thickness is caused even if the thickness of the precision molded product is small, and burrs are easily generated due to the high pressure of injection accompanying the thinning of the molded product. If the above-mentioned prior application is examined under such circumstances, it must be said that there is room for the following improvements.

  First, Patent Document 1 discloses that the thermal elongation of a high guide rail laying base on the non-operating side is high in the platen center height even though the center height position is offset by moving the movable plate away from the machine base. It does not regard as a problem to cause the positional deviation. As an active measure against thermal elongation, only one embodiment of cooling the disk body with a medium is proposed. Also, since Patent Document 2 basically has the same configuration, it does not take into account the thermal expansion of the guide rail laying base and the support member. Even in the embodiment of FIG. 6 of Patent Document 2, the thermal elongation of the support member is not taken into consideration even though the support member has a certain length. In addition, there is no mention of uniform thermal expansion of the support part of the fixed platen and the support part of the movable platen (referred to as a pedestal or a laying table). Moreover, since the said patent document 3 makes the objective effect different, it does not disclose the heat | fever elongation countermeasure of a support leg naturally.

  On the other hand, the Japanese Patent Application No. 2007-272914 has a means for suppressing the temperature rise of the support member and a means for suppressing the thermal elongation itself, and further the thermal elongation of the fixed side support member and the movable side support member. Although a mold clamping device including an adjusting means for adjusting the difference as small as possible has been proposed, further improvement is demanded in recent ultra-precision molding. In particular, there is a demand for a thorough reduction in the center position error and parallelism error between the fixed platen and the movable platen without any center position error and collapse between all the platens including the back platen. It is coming.

  Further, the platen falling due to the weight of the drive device protruding rearward of the back platen has become a problem that cannot be ignored with the recent precise mold clamping device. This problem is caused by the fact that the back platen tipping moment caused by the weight causes the back platen to deform even if it is very small, and the deformation is transmitted to the fixed platen connected via the tie bar, causing the fixed platen to fall. As a result, the parallelism between the fixed platen and the movable platen is distorted. Therefore, conventionally, the drive device has been separately supported on the machine base, but since the support was the fixed support 4, the center position in the vertical direction of the back platen changed due to thermal expansion. In some cases, the parallelism between the platens was adversely affected.

  Therefore, the present invention firstly suppresses the thermal expansion of the support members of each platen as much as possible and makes them as uniform as possible, and secondly prevents the platen from falling down as much as possible and maintains accurate parallelism as much as possible. Propose a fastening device. In addition, the present invention thirdly devise a combination of the platen and the support member so that the cost does not increase more than necessary due to the improvement for that purpose.

  In order to solve the above-described problems, the horizontal mold clamping apparatus of the injection molding machine according to the present invention includes a fixed platen and a back platen connected by a tie bar, and a movable movable between the platens as a first mold clamping apparatus. A platen and a driving device that moves the movable platen back and forth and presses the movable platen toward the fixed platen are provided on the machine base, and the fixed platen and the movable platen are supported at a substantially central height position in the vertical direction of the platens. The movable platen is supported symmetrically from both sides, and with respect to the movable platen, in the horizontal mold clamping device for guiding the movable platen on the guide rail on the machine base by the linear motion bearing on the lower surface of the support member, the back platen It is supported symmetrically by support members from both sides at the height of the approximate center in the vertical direction, and the lower end surface of the support member is A reference member that is movably mounted, and the fixed platen, the movable platen, and the back platen each regulates a position shift thereof in the same direction at a center position in a transverse direction perpendicular to the mold opening / closing direction. And all the support members of the platens are formed of a material having a low coefficient of thermal expansion and configured in the mold clamping device.

  Further, the second mold clamping device of the present invention is configured such that side surfaces of the first mold clamping device facing the support member of the fixed platen and the movable platen are covered with a plate-like heat insulating material.

  Further, the third mold clamping device is a device in which the driving device of the movable platen of the first or second mold clamping device is fixed so as to protrude on the surface of the back platen opposite to the movable platen side. The lower surface of the drive device is configured to be elastically supported by the elastic member on the machine base.

  According to the first mold clamping device of the present invention, each platen is supported on the machine base by the support member at the upper and lower center positions. Then, the fixed platen is fixed to the machine base, the movable platen is guided to be movable to the machine base without being suspended on the tie bar, and the back platen is placed on the machine base so as to be finely movable. In addition, the back platen is connected to the reference fixed platen via a tie bar, and the movable platen and the back platen are connected to each other at the center via the clamping shaft of the driving device. In addition, each platen is fitted with a reference member that regulates displacement in the transverse direction perpendicular to the mold opening / closing direction at the center position of the lower end surface. The three platen support members are all made of a material having a low coefficient of thermal expansion, and are configured symmetrically and substantially in the same shape.

  Therefore, even if the temperature of each platen and its surroundings changes, the thermal elongation generated in each platen itself extends symmetrically vertically and horizontally with respect to the center position, and the thermal elongation of the support members of the platens is uniform. Can be minimized. Therefore, the center position and the parallelism between the fixed platen and the movable platen do not change in the vertical direction or the transverse direction. Of course, non-uniform deformation caused by clamping between the fixed and movable platens is also avoided by supporting the platens at the upper and lower center positions.

  Further, according to the second mold clamping device of the present invention, the side surfaces of the fixed platen and the movable platen on the support member side are thermally insulated to minimize heat radiation to the support members, thereby supporting the platens. By suppressing the thermal elongation of the member as much as possible, the center height position deviation between the platens including the back platen can be reduced more reliably. Therefore, even when the fixed platen and the movable platen are hotter than the back platen during the molding operation, the temperature difference between the support members is reduced, and the thermal expansion of each support member is equalized.

  Further, according to the third mold clamping device of the present invention, the drive device is elastically supported by an elastic member such as a compression coil spring, so that the fall of the back platen is eliminated. In addition, since the spring supports most of the weight on the driving device side, the weight load imposed on the sliding surface at the lower end of the back platen side supporting member is reduced, and as a result, the sliding surface at the lower end of the supporting member and the upper surface of the machine base are reduced. Frictional force and fretting generated between them are reduced. Of course, even if the back platen is slightly moved by the clamping force, the spring absorbs the displacement.

  As shown in FIG. 1, a horizontal mold clamping apparatus 1 of an injection molding machine includes a fixed platen 11 and a back platen 12 connected by a tie bar 10, a movable platen 13 that moves between the platens, and a movable platen 13 that is fixed to the fixed platen. 11 is provided on the machine base 2 with a driving device 14 that moves forward and backward with respect to the mold 11, opens and closes the mold, presses and clamps the mold. The fixed platen 11 is mounted with a fixed side 15a of the mold 15, and the movable platen 13 is mounted with a movable side 15b of the mold. The drive device 14 is, for example, a toggle type, hydraulic type or electric type device provided integrally with the back platen 12. Reference numeral 17 denotes a mold clamping shaft that connects such a driving device and a movable platen at the center. The injection device 3 for plasticizing the molding material is disposed on the fixed platen 11 side, and injects and fills molten resin into the mold 15. The molded product cooled in the mold 15 is solidified and taken out from the mold.

  The present invention is an apparatus including elements around the platens such as a support member that supports the platens 11, 13, and 12 of the mold clamping device 1 and a positioning member that positions the centers of the platens. Among them, the support members are illustrated as 121, 122, and 123, and the peripheral elements including them will be described below.

  First, as shown in FIG. 2, the fixed platen 11 is fixed to a fixed-side support member 121 (hereinafter referred to as a fixed support member 121) at the height position of the center C1 (the center height position in the vertical direction). It is coupled via a key member 131. One fixed support member 121 is prepared on each side of the platen 11, and the lower end thereof is fixed to the machine base 2 as described later. The fixed support member 121 is formed of a material having a low coefficient of thermal expansion such as an invar described later. The fixed platen 11 has a groove 11c parallel to the mold opening / closing direction at a center position in a direction orthogonal to the mold opening / closing direction (hereinafter referred to as a transverse direction) at the bottom thereof, and a reference member implanted in the machine base 2 132 (fixed side reference member) is fitted. Therefore, the reference member 132 positions the fixed platen 11 with reference to the center position in the transverse direction. The tie bars 10 are fixed to the four corners of the fixed platen 11, and the fixed platen 11 and the back platen 12 are connected by the tie bar 10 as in the conventional case.

  More specifically, the fixed support member 121 is formed in a substantially arbitrary shape that is substantially symmetric with respect to the vertical center line of the fixed platen 11. The key member 131 is formed, for example, as a short and small square bar, and closely fits into a groove formed in both the fixed platen 11 and the fixed support member 121. Then, the fixed platen 11 and the fixed support member 121 are fastened together with the bolt 133 or the like as appropriate through the key member 131. In addition, a through-hole 121b penetrating the lower end of the through hole 121a formed below the fixed support member 121 is formed, and the fixed support member is fixed to the machine base 2 by the bolt 134.

  Moreover, the invar of the low thermal expansion material employed for the fixed support member 121 is, for example, a nickel iron alloy and is also referred to as amber. Since the thermal expansion coefficient of the invar is about 1/10 of that of a general steel material, the thermal expansion of the support member is about 1/10 of that of steel, and eventually the height of the platen center C1. The displacement due to the thermal elongation of the position is greatly reduced to about 1/10 of that of steel. In addition, since only the support member 121 that is sufficiently smaller than the volume of the platen 11 is formed of an expensive metal material, the material cost is significantly reduced compared to the case where the entire platen 11 is made of invar. That is, by making only the support member 121 have a low coefficient of thermal expansion, both cost and function can be achieved. In addition, a plate-like heat insulating material 135 is attached to the side surface of the fixed platen facing the support member so that heat radiated from the fixed platen 11 is not transmitted to the support member 121. Further, it is preferable that a plate-like heat insulating material 136 is attached to the lower side as much as possible.

  Further, the reference member 132 has a convex portion 132a closely fitted in the groove 11c at its upper end, and is fixed to the machine base 2 at its lower end. And the convex part 132a makes it possible to adjust the fixed platen 11 only in the mold opening / closing direction. In addition, a gap is always secured between the upper surface of the convex portion 132a and the bottom surface of the groove 11c so that the bottom surface of the groove 11c and the upper surface of the reference member convex portion 132a do not come into contact with each other due to the assumed thermal expansion of the platen 11. The position adjustment between the reference member and the platen is useful only for determining the reference position because the fixed platen 11 is fixed to the machine base 2 after assembly.

  Next, as shown in FIG. 3, the movable platen 13 is coupled to the movable side support member 123 (hereinafter referred to as the movable support member 123) via the key member 141 at the height position of the center C <b> 2. One movable support member 123 is prepared on each side of the platen 13, and a lower end thereof is fixed to the base plate 142, and the movable support member 123 is configured to be movable on the machine base 2. Therefore, the linear motion bearing 24 a is attached to the lower surface of the base plate 142, and the linear motion bearing 24 a is configured to guide the guide rail 24 b on the machine base 2. In this case, since the movable platen 13 is supported by the support member 123, it is not necessary to suspend the movable platen 13, and therefore, recesses are provided at the four corners to avoid interference with the tie bar 10. The movable support member 123 is also formed of a material having a low coefficient of thermal expansion, such as invar, like the fixed support member 121. Also, a hole 13c (reference hole 13c) is formed at the center of the bottom of the movable platen 11 in the transverse direction, and a positioning pin 143 (reference pin 143 / movable side reference) is formed at a position of the base plate 142 facing the reference hole 13c. Members) are implanted, and the center position in the transverse direction of the movable platen 11 is positioned with reference to the center position by fitting them.

  More specifically, the movable support member 123 is formed in a shape that is substantially symmetrical with respect to the vertical center line of the movable platen 13 and that is substantially different from each other. The key member 141 is formed as, for example, a short and small square bar, like the fixed platen side 131, and closely fits into a groove formed in both the movable platen 13 and the movable support member 21. The movable platen 13, the movable support member 123, and the key member 141 are fastened together by bolts 143 as appropriate. In addition, a through-hole 123 b that penetrates from a lower hole surface of the support member to a lower end surface of the support member is formed from a punched hole 123 a formed below the movable support member 123, and the movable support member is fixed to the base plate 142 with a bolt 134.

  The reference pin 143 implanted in the base plate 142 is formed as a round bar, for example, and is formed so that a gap always remains between the upper end of the reference pin and the bottom of the reference hole 13c. That is, it is for preventing both from abutting by the temperature rise which can be assumed. The reason why the reference pin 143 is a round bar is to make the processed portion of the base plate 142 small and avoid a reduction in rigidity. The parallelism between the movable platen 13 and the fixed platen 11 is ensured by the fixed positioning accuracy between the support member 123 and the base plate 142 and the fixed accuracy with the end of the mold clamping shaft 17. In addition, a plate-like heat insulating material 145 is attached to the side surface facing the support member of the movable platen. Moreover, the plate-shaped heat insulating material 146 is affixed also to the bottom face, and the thermal expansion of the base plate provided with linear motion bearings on both sides is suppressed. The linear motion bearing 24 a and the guide rail 24 b laid on the upper surface of the machine base 2 constitute a linear guide device 24. The guide rail 24b is attached to the upper surface of the machine base 2 that is as low as possible so that the work of attaching / detaching the mold 15 or taking out the molded product between the platens 11 and 13 is not disturbed. This increases the length of the movable support member 123. However, since invar or the like is adopted as the material, there is no adverse effect on measures against thermal elongation.

  Finally, as shown in FIG. 4, the back platen 12 is placed on the back platen side support member 122 (hereinafter referred to as the back side support member 122) via the key member 151 at the height in the vertical direction of the center C <b> 3. Combined. One back side support member 122 is prepared on each side of the platen 12, and slides on the machine base 2 (strictly, a sliding base) at the lower end surface. This is to allow fine movement of the back platen due to the elongation of the tie bar 10 that occurs during mold clamping. Therefore, the lower end surface of the support member 122 and the upper surface of the machine base 2 slide base are formed smoothly, and the fastening portion of the support member 122 and the machine base 2 can slide relative to each other as will be described later. Configured to allow. The back side support member 122 is also formed of a material having a low coefficient of thermal expansion such as Invar. Further, the tie bars 10 are fixed to the four corners of the back platen, and the back platen 12 is connected to the fixed platen 11. Further, a groove 12c parallel to the mold opening / closing direction is formed at the center position in the transverse direction of the bottom of the back platen 12, and a reference member 152 (back-side reference member) that fits into the groove is fixed to the machine base 2.

  More specifically, the back side support member 122 is formed in a shape that is substantially symmetrical with respect to the vertical center line of the back platen 11 and that is substantially different from each other. The key member 151 is formed as, for example, a short and small square bar, and closely fits into a square groove formed in both the back platen 12 and the back side support member 122. Then, the platen and the support member are fastened together with the bolt 153 or the like as appropriate through the key member 151.

  In particular, the fastening between the back-side support member 122 and the machine base 2 is preferably configured as follows. As shown in FIG. 5, a through hole 122 b that penetrates from the punched hole 122 a formed below the back side support member to the lower end of the support member is formed, and the bolt 154 tightens the spacer 155 inserted into the hole. Configured as follows. That is, a hollow cylindrical spacer 155 having a flange portion at the upper end is interposed between the through hole 122b and the bolt 154 so that the bolt 154 tightens the spacer 155 instead of tightening the back side support member 21. Composed. Then, a gap is secured between the support member through-hole 122b and the outer periphery of the spacer 155 beyond the distance the back platen moves during mold clamping. Further, a small gap, for example, a gap of about 0.02 mm is formed between the lower surface of the flange portion of the spacer 155 and the plane of the hole 122a around the through hole 122b. With such a configuration, the hollow spacer 155 and the back-side support member 21 can be relatively finely moved during mold clamping. In addition, there is no possibility that the back side support member collapses due to the bolt 154 not directly fastening the back side support member 21 due to the support of the elastic member 171 described later.

  The reference member 152 for positioning the center position in the transverse direction of the back platen 12 is configured as follows so that the back platen 12 can be easily positioned when the mold clamping device is assembled.

  Since the straight line is originally defined by two points, the center line (center axis) along the mold opening / closing direction of the mold clamping device is determined by the two reference members 132 and 143 of the fixed platen 11 and the movable platen 13. Therefore, the center of the back platen must also be adjusted to coincide with its centerline. Therefore, blocks 161 to which adjustment bolts 162 (pushing bolts 162) are screwed are arranged on both sides of the reference member 152, and the position of the reference member 152 is changed in the transverse direction by appropriately moving the bolts 162 back and forth. Configure for fine adjustment. With such a configuration, the center position of the back platen 12 can be finely adjusted so as to coincide with the above-described center line during assembly. Such a configuration can adopt various forms as long as only movement in the transverse direction is restricted. For example, an adjustment bolt may be provided only on one side.

  The cross-sectional shape of each of the support members 121, 122, 123 described above is preferably formed to be wide in the mold opening / closing direction and thin in the transverse direction, and to be formed into a simple plate shape of a rectangular thick plate as a whole. . By doing so, the usage amount of invar or the like, which is an expensive material, can be minimized. In this case, the transverse rigidity is reduced, but this does not cause a practical problem. This is because the reference members 132, 143, and 152 for positioning the position of each platen in the transverse direction prevent displacement of each platen in the same direction.

  Of course, by aligning the reference members 132, 143, and 152 at the center position of each platen, the following effects can be obtained. That is, since the thermal elongation in the transverse direction of each platen extends equally on both sides with respect to their centers, there is no deviation in the center position. This is similar to the fact that the thermal expansion in the vertical direction that occurs in each platen extends equally up and down with respect to the platen center position supported by the support member.

  On the other hand, the fall of the back platen 12 occurs because the drive device 14 protrudes to the rear of the back platen 12 as shown in FIG. 5, and therefore the drive device 14 is separately provided with an elastic member 171 as follows. The moment can be offset by elastically supporting by. More specifically, the contact seating surface 14a of the compression coil spring 171 is provided on the lower surface of the drive device 14, and a pocket hole for accommodating the lower portion of the compression coil spring is formed on the machine base 2 side facing the seating surface. The holder 172 is provided, and the preload adjusting tool including the compression coil spring 171 and the washer 173 is set in the pocket hole to constitute the elastic support device. The preload adjuster includes a washer 173 formed as a disk member substantially equal to the outer diameter of the compression coil spring 171, a push bolt 174 that pushes up and adjusts the position of the washer, and a lock nut 175 that locks the bolt. Is done. The elastic member is not limited to the compression coil spring as long as it is elastically supported.

  With such a configuration, the preload for pushing up the driving device 14 of the compression coil spring 171 is adjusted by adjusting the amount of pushing of the push bolt 174 during assembly and moving the washer 173 up and down. Then, after the adjustment, the lock nut 175 is tightened to set the preload. The pre-pressure is adjusted to a repulsive force that cancels the back platen overturning moment that occurs when the total weight of the drive device 14 and the back platen 12 is biased backward. That is, the pre-pressure on the compression coil spring 171 side is a force that cancels the overturning moment due to the compression coil spring side component force when the total weight is represented by the support member side component force and the compression coil spring side component force. is there. The support member side component force and the compression coil spring side component force divided the total gravity in inverse proportion to the distance between the gravity center position of the total gravity and the coil spring support position and the distance between the gravity center position and the support member center position. The sum of both component forces is the total weight.

  With such a configuration, the problem of the fall of the back platen 12 is avoided. In addition, the pressing force of the support member 122 against the machine base 2 is greatly reduced, and the friction resistance and fretting (fine movement wear) between the support member 122 and the machine base 2 caused when the back platen 12 slightly moves every time the mold is clamped. ) Is also solved. Strictly speaking, as the mold is opened and closed, a part of the mold clamping shaft 17 in the driving device 14 moves in the driving device and its weight changes, but its weight is smaller than the whole, so that Fluctuation is not a problem. Further, even if the center of the back platen 12 rises due to the thermal expansion of the support member 122, the elastic member 171 elastically allows the rise. However, since the support member is Invar, such thermal expansion does not actually occur. Further, even if the back platen moves slightly with mold clamping, the spring absorbs the displacement.

  As described above, the mold clamping apparatus 1 is configured such that the fixed platen 11, the movable platen 13, and the back platen 12 are symmetrically mounted on the machine base 2 from both sides by the support members 121, 122, 123 at the upper and lower center positions. To support. And the bottom part of each platen is positioned by the reference members 132, 143, and 152 at the center position in the transverse direction, and the center position of each platen in that direction is aligned on one center line. In addition, the platen support members are all made of a material having a low coefficient of thermal expansion, and are symmetrically configured in the same shape. Of course, the mold clamping device moves and guides the movable platen 13 on the machine base in the mold opening / closing direction with the tie bar 10 being unconstrained, and the back platen 12 is placed on the machine base so as to be finely movable in the same direction. Thus, the back platen 12 is connected to the reference fixed platen 11 via the tie bar 10, and the movable platen 13 and the back platen 12 are connected via the mold clamping shaft 17 at the respective center positions.

  Therefore, even if the temperature of each platen and its surroundings rises, the mold clamping device 1 of the present invention has the thermal elongation generated in each platen itself extending symmetrically up and down and left and right with respect to the center position. The thermal elongation of the platen support member is uniformly minimized. Therefore, the center position and the parallelism between the fixed platen and the movable platen do not change in the vertical direction or the transverse direction. In addition, non-uniform deformation due to clamping between the fixed and movable platens is also avoided by supporting the platens at the upper and lower center positions.

  Further, since the plate-like heat insulating plates are attached to the fixed platen and the movable platen, the temperature rise of these supporting members can be minimized. This is because radiant heat from a fixed and movable platen on which a mold that is particularly hot is mounted can be minimized. Therefore, even if the fixed platen and the movable platen become higher than the back platen during the molding operation, the temperature difference between the support members is reduced, and the thermal expansion of each support member is equalized.

1 is an elevation view schematically showing the entire horizontal mold clamping apparatus of the present invention. It is the figure which looked at the fixed platen of FIG. 1 from the mold opening / closing direction, and is the figure partially shown by the cross section. It is the figure which looked at the movable platen of FIG. 1 from the mold opening / closing direction, and is the figure partially shown by the cross section. It is the figure which looked at the back platen of FIG. 1 from the type | mold opening / closing direction, and is the figure partly shown by the cross section. It is a figure of the back platen which has the drive device supported by the elastic member based on the 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Horizontal mold clamping apparatus of injection molding machine 2 Machine stand 10 Tie bar 11 Fixed platen 12 Back platen 13 Movable platen 14 Drive apparatus 24a Linear motion bearing 24b Guide rail 121 Fixed side support member 122 Back platen side support member 123 Movable side support member 135 Plate-shaped heat insulating material 136 Plate-shaped heat insulating material 145 Plate-shaped heat insulating material 146 Plate-shaped heat insulating material 132 Fixed side reference member 143 Movable side reference member 152 Back side reference member 171 Elastic member

Claims (3)

  A fixed platen and a back platen connected by a tie bar, a movable platen that moves between the platens, and a drive device that moves the movable platen forward and backward and presses the movable platen toward the fixed platen are provided on the machine base. The platen and the movable platen are supported symmetrically from both sides by a support member at a substantially central height position in the vertical direction of the platens, and the movable platen is supported by the linear motion bearing on the lower surface of the support member. In the horizontal mold clamping apparatus that guides on a guide rail on a table, the back platen is supported symmetrically by support members from both sides at a height position of a substantially center in the vertical direction, and the lower end surface of the support member is The fixed platen, the movable platen, and the back platen are slidably mounted on the machine base. The bottom part is fitted with a reference member that regulates the displacement in the same direction at the center position in the transverse direction perpendicular to the mold opening and closing direction, and all the support members of the platens are made of a material having a low coefficient of thermal expansion. A horizontal mold clamping apparatus for an injection molding machine, characterized by being formed.   The lateral mold clamping apparatus for an injection molding machine according to claim 1, wherein side surfaces of the fixed platen and the movable platen facing the support member are covered with a plate-shaped heat insulating material.   The drive device for the movable platen is a device fixed so as to protrude from the surface of the back platen opposite to the movable platen side, and the lower surface of the drive device is elastically formed on the machine base by an elastic member. 3. The horizontal mold clamping apparatus for an injection molding machine according to claim 1, wherein the horizontal mold clamping apparatus is supported.

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