JP2014028478A - Toggle type small size mold tightening device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toggle type small size mold tightening device in which elongation allowance of a tie bar can be largely secured, sensibility to disturbance is made dull and a relative position balance of a stationary platen and a movable platen can be easily secured.SOLUTION: A toggle type small size mold tightening device includes: a pressure receiving platen 10 supported to a machine stand 2; a stationary platen 20 fixed to the machine stand 2 and arranged to counter the pressure receiving platen 10; two or more shaft shape tie bars 50 in which one end 51 is supported by the pressure receiving platen 10 and the other end 52 is fixed to the stationary platen 20; a movable platen 60 that is made to be able to approach and retreat to/from the stationary platen 20; and a toggle mechanism 30 that makes the movable platen 60 to be able to approach and retreat to/from the stationary platen 20, wherein a constriction part 53 in which one part of diameters of two or more tie bars 50 are made a smaller diameter than the other part diameters is formed.

Description

  The present invention has a movable platen disposed between a pressure platen and a fixed platen, and uses a toggle mechanism that bends and stretches with the pressure platen side as a fixed side fulcrum. And a toggle type small mold clamping device that guides the displacement of the movable platen by a tie bar straddling the fixed platen.

  Conventionally, a tie bar that supports a movable platen of a toggle-type small mold clamping device has a function of fastening a mold by an elastic force generated by the extension of the tie bar and a function as a guide of the movable platen.

Japanese Patent Publication No. 07-102598

  However, particularly in a toggle type compact mold clamping device that generates a mold clamping force of 20 t or less, a certain amount of tie bar can be used to maintain the rigidity of the pressure receiving plate that supports both ends of the tie bar and the fixed platen. It is required to have Further, the smaller the mold clamping device, the shorter the distance between the pressure receiving plate (or movable platen) and the fixed platen. As a result, the tie bar itself is also shortened, so that the extension allowance of the tie bar when a clamping force is generated is reduced, and the sensitivity to disturbance (temperature) is significantly more sensitive than a larger machine (for example, 30 t). As a result, there is a problem that the mold clamping force is easily changed.

  In addition, if the sensitivity of the tie bar is sensitive, the amount of heat received from the mold placed between the fixed platen and the movable platen varies in the vertical direction, so that the tie bar varies from disturbance due to the difference in the amount of heat. The balance of mold clamping force is easily lost due to

  When the balance of the tie bars is affected by such disturbance, the entire mold clamping mechanism is adversely affected and the service life is shortened.

  Therefore, although it is possible to reduce the diameter of the tie bar if it is a structure that does not guide the movable plate with a tie bar by a linear guide or the like, the linear guide is expensive, and if it does not require accuracy, it will be excessive quality, There was a new problem that it would be less versatile.

  Accordingly, the present invention provides a toggle type small mold clamping device that can secure a large extension allowance of the tie bar and can easily secure a relative position balance between the fixed platen and the movable platen with insensitive sensitivity to disturbance. The purpose is to do.

  In order to solve the above-mentioned problems, a toggle type small mold clamping device of the present invention includes a pressure plate supported by a machine base, a fixed plate fixed to the machine table and arranged to face the pressure plate, A plurality of shaft-shaped tie bars, one end of which is supported by the pressure receiving plate and the other end of which is fixed to the fixed plate, a movable plate that can be moved toward and away from the fixed plate, and the movable plate that is fixed to the fixed plate In a toggle type small mold clamping device provided with a toggle mechanism for approaching and moving away from each other, a constriction portion in which a diameter of a part of the plurality of tie bars is smaller than another diameter is formed. .

  According to such a toggle type small mold clamping device, it is possible to ensure a large extension of the tie bar and to easily ensure a relative position balance between the fixed platen and the movable platen against disturbance.

  Moreover, the toggle type small mold clamping device of the present invention is characterized in that the constricted part is formed between the pressure receiving plate and the movable platen.

  According to such a toggle type small mold clamping device, the tie bar can be extended away from the mold, and the tie bar can be extended in the vicinity of the movable mechanism, and the movable platen is pressed well toward the fixed platen. be able to.

  Furthermore, the toggle type small mold clamping device of the present invention is characterized in that the constricted portion is formed closer to the pressure receiving plate than the movable range of the movable plate.

  According to such a toggle-type small mold clamping device, it is possible to suppress the movement plate from being approached or separated.

  In this case, it is preferable that the plurality of tie bars are arranged at positions where the vertical and horizontal separation distances are substantially equal in the vicinity of the four corners of the upper and lower sides and the right and left sides of the pressure receiving plate and the fixed plate, and the same ones are used.

  The toggle type small mold clamping device of the present invention can secure a large tie bar extension, and can easily secure the relative position balance between the fixed platen and the movable platen with insensitive sensitivity to disturbance.

It is a front view of a toggle type small mold clamping device concerning one embodiment of the present invention. It is a rear view of the toggle type small mold clamping device concerning one embodiment of the present invention. It is a perspective view of a toggle type small mold clamping device of one embodiment of the present invention. It is a top view of the toggle type small mold clamping device of one embodiment of the present invention. It is sectional drawing of the principal part of the pressure receiving plate applied to the toggle type small mold clamping apparatus of one Embodiment of this invention. It is a perspective view of the principal part of the toggle pin connection part applied to the toggle type small mold clamping apparatus of one Embodiment of this invention. It is sectional drawing of the principal part of the toggle pin connection part applied to the toggle type small mold clamping apparatus of one Embodiment of this invention. It is a perspective view of the toggle pin applied to the toggle type small mold clamping device of one embodiment of the present invention. It is a perspective view of the movable type applied to the toggle type small mold clamping device of one embodiment of the present invention. It is sectional drawing of the movable type applied to the toggle type small mold clamping apparatus of one Embodiment of this invention.

  Next, a toggle type small mold clamping device according to an embodiment of the present invention will be described with reference to the drawings. The following embodiments are preferred specific examples of the toggle-type small mold clamping device of the present invention, and may have various technically preferred limitations. As long as there is no description which limits this invention, it is not limited to these aspects. In addition, the constituent elements in the embodiments shown below can be appropriately replaced with existing constituent elements and the like, and various variations including combinations with other existing constituent elements are possible. Therefore, the description of the embodiment described below does not limit the contents of the invention described in the claims.

  1 is a front view of a toggle type small mold clamping device according to an embodiment of the present invention, FIG. 2 is a rear view of the toggle type small mold clamp device according to an embodiment of the present invention, and FIG. 3 is an embodiment of the present invention. FIG. 4 is a plan view of the toggle type small mold clamping device of one embodiment of the present invention, and FIG. 5 is applied to the toggle type small mold clamp device of one embodiment of the present invention. FIG. 6 is a perspective view of an essential part of a toggle pin connecting portion applied to a toggle type small mold clamping device according to an embodiment of the present invention, and FIG. 7 is an embodiment of the present invention. FIG. 8 is a perspective view of the toggle pin applied to the toggle type small mold clamping device according to an embodiment of the present invention, and FIG. FIG. 10 is a perspective view of a movable type applied to a toggle type small mold clamping device according to an embodiment of the invention. It is a cross-sectional view of a movable mold that is applied to a toggle type small mold clamping device of facilities forms.

(Overall schematic configuration)
1 to 4, a toggle type small mold clamping device (hereinafter simply referred to as “clamping device”) 1 in an injection molding machine includes a pressure receiving plate 10 positioned and fixed to a machine base 2, and a pressure receiving plate 10. A drive unit 20 disposed; a toggle mechanism 30 disposed on the pressure platen 10 and bent and stretched by the drive of the drive unit 20; and a fixed platen 40 fixed to the machine base 2 so as to face the pressure platen 10 The four tie bars 50 installed between the pressure receiving plate 10 and the fixed platen 40 in the vicinity of the four corners of the fixed platen 40, and the pressure receiving plate 10 and the fixed platen 40 penetrated so as to be guided by the tie bar 50. And a movable platen 60 that is displaced between and an ejecting unit 70 that is provided on the movable platen 60 and for releasing a product after injection molding.

(Specific configuration of the pressure receiving plate 10)
The pressure receiving board 10 is stopped at a predetermined position of the rail 3 provided on the machine base 2. The predetermined position of the pressure receiving plate 10 is determined according to the size of the mold composed of the movable mold 4 and the fixed mold 5 (illustrated by phantom lines only in FIG. 1), and the mold clamping force is changed or the mold is replaced. The position is adjusted by moving forward and backward along the rail 3 each time. The limit of the forward position or the backward position of the pressure receiving plate 10 at that time is detected via the position switches 6 and 7. The pressure receiving plate 10 supports one end 51 of the tie bar 50 in the vicinity of its four corners. In the present embodiment, as shown in FIG. 5, after one end 51 of the tie bar 50 is passed through the pressure receiving plate 10, a screw groove (not shown) formed in the one end 51 and outside the pressure receiving plate 10. Positioning along the axial direction is performed by the adjusting nut 12 to be screwed. In the adjustment nut 12, an annular contact portion 12 b is integrally formed on an inner end surface 12 a that is in pressure contact with the pressure receiving plate 10 so as to surround the axis of the one end 51. The adjusting nut 12 is provided with a nut holding member 13 that is screwed to the pressure receiving plate 10 on the outer periphery thereof, and a small gear 14 that constitutes a mold thickness adjusting device is screwed to the outer end surface 12c.

(Specific configuration of the drive unit 20)
The drive unit 20 includes a drive source 21 such as an electric motor provided on the back surface of the pressure receiving plate 10, a drive pulley 23 provided on the output shaft 22 of the drive source 21, and an endless belt stretched over the drive pulley 23. And a screw shaft 24 that is rotated by rotation of a driven pulley (both not shown) that is rotated by the pivoting movement. The tip of the screw shaft 24 protrudes toward the movable platen 60. In addition, since this drive part 20 is well-known, the system of the concrete structure etc. is abbreviate | omitted.

(Specific configuration of toggle mechanism 30)
The toggle mechanism 30 is constructed so as to be able to bend and stretch between the pressure receiving plate 10 and the movable platen 60, and bends and stretches as the drive unit 20 is driven to move the movable platen 60 toward and away from the fixed platen 40. Specifically, the toggle mechanism 30 includes a crosshead 31 that is screwed with the screw shaft 24 and moves forward and backward along the axial direction in conjunction with the rotation of the screw shaft 24, and independent from the crosshead 31 in the vertical direction. A pair of upper and lower operation links 32 extending, one pair (left and right) fixed-side link arms 33 supported on one end on the pressure receiving plate 10, and one pair (left and right) on one end supported on the movable plate 60. ) Driven-side link arm 34.

  The base end of the working link 32 is integrally connected to the cross head 31, and the middle portion of the fixed side link arm 33 is pivotally supported at the tip end thereof.

  The fixed side link arm 33 is substantially Y-shaped in plan view, and one end thereof is pivotally supported on the pressure receiving plate 10 via a toggle pin 35 so as to be rotatable. Further, one end of the driven side link arm 34 is pivotally supported on each other end of the fixed side link arm 33. Note that one end of the driven side link arm 34 is positioned between the fixed side link arm 33 branched in a Y-shape.

  The other end of the driven side link arm 34 is pivotally supported by the movable platen 60 via a toggle pin 35 so as to be rotatable. In the present embodiment, the toggle mechanism 30 is configured such that when the fixed side link arm 33 and the driven side link arm 34 change from the bent state to the extended state, the tip of each driven side link arm 34 positioned above and below is The load is inclined so as to be directed toward the center of the movable platen 60 and the load is concentrated.

  The toggle pin 35 employs substantially the same connection structure in the connection between the pressure receiving platen 10 and the fixed side link arm 33 and the connection between the movable platen 60 and the driven side link arm 34. Hereinafter, a connection structure between the pressure receiving plate 10 and the fixed side link arm 33 by the toggle pin 35 will be described.

  As shown in FIGS. 6 and 7, on the inner side of the pressure receiving plate 10, a pair of upper and lower connection base portions 15 projecting toward the movable platen 60 are integrally formed. A through hole 15 a through which the toggle pin 35 penetrates is formed at the protruding end portion of the coupling base portion 15. A pair of recesses 15 b are formed at the projecting end of the coupling base 15 so as to open to the end face and into which one end of the fixed side link arm 33 is inserted. A stepped portion 15 c is formed on the side surface of the protruding end portion of the connecting table 15. A female screw hole 15d is formed on the side surface of the step portion 15c.

  As shown in FIG. 8, the toggle pin 35 has a diameter at both ends 35b smaller than that at the center 35a by cutting or the like. Further, the both end portions 35b are formed with notched portions 35c that are notched across the end surface and the peripheral surface. Further, one end of the fixed-side link arm 33 is pivotally supported in the portion exposed to the recess 15b near both ends of the central portion 35a. For example, a carbon bush 36 is interposed between one end of the fixed side link arm 33 and the toggle pin 35. In addition, the toggle pin 35 is fixed to the connection base 15 in a state of retaining and preventing rotation by fixing the fixing plate 37 to the connection base 15 with a bolt 38. In the present embodiment, the toggle pin 35 penetrates the through hole 15a, and as shown in FIG. 6, the notch 35c is made to coincide with the step 15c. In this state, the fixing plate 37 is straddled between the notch portion 35c and the step portion 15c, and the bolt 38 is screwed into the female screw hole 15d. Thereby, the toggle pin 35 can be fixed to the connection base part 15 in the state of retaining and preventing rotation.

  The diameter of the central portion 35a is the same as the inner diameter of the through hole 15a. Accordingly, as shown in FIG. 7, a gap P having a difference in radius is generated between the both end portions 35b and the through hole 15a. Here, the length in the axial direction of the small-diameter portion in both end portions 35b is set to be equal to or longer than the length in the axial direction of the connecting base portion 15 outside the concave portion 15b. As a result, the toggle pin 35 and the pressure receiving plate 10 are sandwiched between the center portion 35a of the toggle pin 35 and a portion closer to the center than the both end portions 35b which are small diameter portions, that is, the pair of left and right fixed side link arms 33. It is in contact only with the connecting base 15 of the part.

(Specific configuration of fixed platen 40)
The stationary platen 40 is fixed to the machine base 2, and the position thereof cannot be adjusted so as to be a reference for the mold clamping device 1. The stationary platen 40 supports the stationary mold 5 on the surface of the mold support part 41. Further, a nozzle insertion hole 42 (see FIG. 3) through which the tip of the injection nozzle 8 faces is penetrated in the center of the fixed platen 40, and the fixed die 5 is inserted by inserting the injection nozzle 8 from the back side of the fixed platen 40. Touch the nozzle.

  The movable mold 4 and the fixed mold 5 described above constitute a mold having a mold cavity. The injection nozzle 8 can be moved back and forth with respect to the fixed platen 40. The injection nozzle 8 moves forward to the fixed platen 40 and touches the fixed die 5 with a nozzle to inject and fill the molten resin into the mold cavity.

(Specific configuration of tie bar 50)
One end 51 of the tie bar 50 is supported by the pressure receiving plate 10 so as to be adjustable as described above, and the other end 52 is fixed to the stationary platen 40 while penetrating the movable platen 60. At this time, the tip of the other end 52 is fixed by the nut 43 while penetrating the fixed platen 40.

  Further, each tie bar 50 is formed with a constricted portion 53 in which a part of the diameter is smaller than the other diameters. The constricted portion 53 is located between the pressure receiving plate 10 and the movable platen 60 and is formed in a range closer to the pressure receiving plate 10 than the movable range of the movable platen 60 in the present embodiment.

  A safety bar 54 is provided between the pressure receiving plate 10 and the movable plate 60 in parallel with the tie bar 50.

  The safety bar 54 prevents the movable platen 60 from closing and closing when the door is opened. The direction of the movable platen 60 approaching the fixed platen 40 (the toggle mechanism 30 extends) is forward, and the movable platen 60 is fixed platen 40. When the direction away from (the toggle mechanism 30 is bent) is the rear, both ends closed recesses 54a having step surfaces perpendicular to the axis and the step inclined so that the front side expands forward A one-side closed recess 54b having a surface and a step surface whose rear side is orthogonal to the axis is formed.

  The tip 54 c of the safety bar 54 has a screw shaft structure and is engaged with the movable platen 60. The rear end 54d of the safety bar 54 is supported by a locking device 55 provided in the pressure receiving plate 10. In addition, since the well-known technique (for example, patent 4315446 etc.) is applied to the specific structure and effect | action of this safety rod 54 and the locking device 55, detailed description is abbreviate | omitted here.

(Specific configuration of movable platen 60)
The movable platen 60 is provided on the machine base 2 so as to be slidable. In this embodiment, the movable board 60 is supported by the machine base 2 via a slider 9 that is displaced along the rail 3. The movable platen 60 supports the movable die 4 with a die support portion 61 facing the die support portion 41 of the fixed platen 40. As shown in FIGS. 9 and 10, the movable platen 60 is formed with an eject through hole 62 that opens to the mold support 61. In the movable platen 60, through holes 63 of tie bars 50 are formed at four corners. On the back surface side of the movable platen 60, an insertion hole 64 into which an operation unit 77 of an eject unit 70 described later is inserted, a mounting seat 65 to which the operation unit 77 is fixed at a side of the insertion hole 64, An upper wall portion 67 and a lower wall portion 68 that form a storage space 66 of the operation unit 77 between the eject through hole 62 and the insertion hole 64, and an upper wall portion 67 and a lower wall so as to protrude toward the pressure receiving plate 10. And a connecting stand portion 69 formed integrally with the portion 68. The slider 9 has a known configuration that can adjust the position and height of the movable platen 60 along the direction in which the rail 3 is laid.

  The mounting seat 65 is integrally provided with a base portion 65a that surrounds both sides of the insertion hole 64 and a seat portion 65b that protrudes from above and below the base portion 65a toward the pressure receiving plate 10, and has a substantially U-shape when viewed from the front. Yes. The base portion 65a and the seat portion 65b are integrally formed so as to protrude from the back surface of the movable platen 60 (the same as the opening end surface of the insertion hole 64 on the pressure receiving plate 10 side). At this time, the connecting base portion 69 and the mounting seat portion 65 as the other end support portion of the toggle mechanism 30 are integrally formed as the movable platen 60, but are independent protruding structures so as not to be functionally connected. Are arranged and formed. This also serves as a reinforcing structure that suppresses the opening of the connecting base 69 due to the applied pressure when the toggle mechanism 30 is extended.

  The upper wall portion 67 and the lower wall portion 68 are thick inclined portions 67a and 68a that are inclined so as to increase in thickness toward the outside in a portion continuous from the mold support portion 61 toward the back surface side with the connecting base portion 69. Is formed. The upper surface 67 b and the lower surface 68 b of the upper wall portion 67 and the lower wall portion 68 are the bottom surfaces of the recessed portions 67 c and 68 c located inside the outer periphery of the mold support portion 61. The bottom surfaces (upper surface 67b and lower surface 68b) are located on the same plane (see the two-dot chain line in FIG. 10) including the axis Q of the through hole 69a through which the toggle pin 35 passes. Further, between the inner sides of the upper wall portion 67 and the lower wall portion 68 and the inner surface of the mold support portion 61, thick inclined portions 67d and 68d inclined in the expanding direction from the center side of the mold support portion 61. Is formed.

  A through hole 69 a through which the toggle pin 35 passes is formed at the protruding end portion of the coupling base portion 69. A pair of recesses 69 b are formed at the projecting end of the coupling base 69 and open to the end face thereof and into which one end of the fixed side link arm 33 is inserted. A stepped portion 69 c is formed on the side surface of the protruding end portion of the connecting base portion 69. A female screw hole 69d is formed on the side surface of the stepped portion 69c. Note that the support structure of the toggle pin 35 in the connection base 69 is basically the same as that of the connection base 15.

(Specific configuration of eject unit 70)
The eject unit 70 includes an eject motor 71 provided on the back surface of the movable platen 60, a drive pulley 73 provided on the output shaft 72 of the eject motor 71, and a driven pulley provided in the center of the drive pulley 73 and the movable platen 60. 74, an endless belt 75 stretched around 74, and an operating unit 77 having an eject pin 76 that moves forward and backward by the rotation of the driven pulley 74.

  In the ejecting process, the ejecting unit 70 is driven and controlled, and the ejecting pin 71 is advanced by the operation of the ejecting motor 71, and the molded product in the mold cavity is ejected.

(Specific action)
In the above configuration, when the drive source 21 is driven, the cross head 31 advances while being guided by the screw groove of the screw shaft 24, and at the same time, the operation link 32 advances integrally with the cross head 31. When the operating link 32 advances, the fixed side link arm 33 and the driven side link arm 34 change from the bent state to the extended state.

  When the fixed side link arm 33 and the driven side link arm 34 extend, the movable platen 60 is guided by the tie bar 50 and displaced toward the fixed platen 40, and the movable die 4 and the fixed die 5 are clamped.

  By the way, the mold clamping force when the toggle mechanism 30 is extended is caused by the presence of the gap P in both the end portions 35b of the toggle pin 35 of the pressure receiving plate 10 and the both ends 35b of the toggle pin 35 of the movable platen 60. Load transmission at the portion (both end portions 35b) is not performed, and load transmission can be performed intensively only at the central portion 35a of the toggle pin 35.

  Therefore, the mold clamping force when the toggle mechanism 30 is extended is, for example, from the both end portions 35b of the toggle pin 35 of the movable plate 60 to the central portion 35a in the state where the load from the driven side link arm 34 is concentrated to the movable plate 60. In addition to being connected (transmitted), even if the both ends 35b of the toggle pin 35 are out of balance, the presence of the gap P can make it difficult for the both ends 35b of the toggle pin 35 to deteriorate over time. Can also be improved.

  At this time, the toggle mechanism 30 is configured such that when the fixed side link arm 33 and the driven side link arm 34 change from the bent state to the extended state, the tip of each driven side link arm 34 positioned above and below the movable platen 60. Since it inclines so that it may face a center direction, a load is added to the front end side of the connection stand part 69 in the direction which pushes and spreads mutually.

  Here, on the back side of the connecting base part 69, a thick inclined part 67a that inclines so as to increase in thickness toward the outside in a portion continuous with the connecting base part 69 from the mold support part 61 toward the back side. , 68a are formed. As a result, the concave portions 67c and 68c are formed, thereby contributing to the weight reduction of the movable platen 60, and the load against the reaction force described above can be received by the thick inclined portions 67a and 68a, thereby ensuring the load resistance. be able to.

  Further, since both end portions 35b of the toggle pin 35 are supported by the pressure receiving plate 10 and the movable plate 60 in a state of being prevented from being rotated and prevented from being detached by the fixed plate 37, a clearance P that allows the bending (curvature) of the toggle pin 35 to be allowed. Can be secured.

  Further, the mold clamping force when the toggle mechanism 30 is extended is fixed by fixing the one end 51 of the tie bar 50 with the adjusting nut 12 and the other end 52 of the tie bar 50 with the nut 43, respectively. Can be easily secured.

  At this time, one end 51 of the tie bar 50 is fixed with the adjusting nut 12 and an annular contact portion 12b provided on the inner end surface 12a of the tie bar 50 so as to surround the axis of the tie bar 50 is brought into pressure contact with the pressure receiving plate 10 to thereby fix the tie bar 50. The surface pressure on one end 51 side of the tie bar 50 can be secured to improve the loosening prevention effect, and the tension on the other end 52 side of the tie bar 50 can be made uniform over the four corners of the fixed platen 40.

  Furthermore, the tie bar 50 is formed with a constricted portion 53 in a range closer to the pressure receiving plate 10 than the movable range of the movable platen 60. The tie bar 50 has one end 51 supported by the pressure receiving platen 10 and the other end 52 fixed to the fixed platen 40. For this reason, in the mold clamping state where the toggle mechanism 30 is extended and the movable platen 60 is pressurized toward the fixed platen 40, a reaction force from the fixed platen 40 is generated in the tie bar 50.

  Here, the extension of the tie bar 50 against a disturbance (for example, the temperature rises by 1 ° C.) is set to 0.01 mm, the tie bar 50 (shaft diameter 40Φ) having the same diameter without the constricted portion 53 is used, and a small 15t mold clamping is performed. The elongation of the tie bar 50 when using the mold clamping device 1 that generates force was 0.146 mm.

Therefore, the sensitivity of the disturbance that the clamping force receives is
(0.01 / 0.146) * 100 ≒ 7%
It becomes.

  On the other hand, when a tie bar 50 having a constricted portion 53 with a shaft diameter of 30Φ is formed on a part of the same shaft diameter of 40Φ and the mold clamping device 1 that generates a small mold clamping force of 15t is used, It was 0.183 mm.

Therefore, the sensitivity of the disturbance that the clamping force receives is
(0.01 / 0.183) * 100 ≒ 5%
Thus, the sensitivity can be made insensitive to the tie bar 50 having the same diameter. This is because the relatively small toggle type mold clamping device 1 of the 15t class (20t or less) is likely to be affected (large) by the disturbance, but by forming the constricted portion 53, the sensitivity to the disturbance is increased. By making it insensitive, I was able to make it hard to be affected.

  On the other hand, the extension of the tie bar against disturbance (temperature change 1 ° C) is 0.02 mm, and the tie bar 50 (shaft diameter 40Φ) having the same diameter without the constricted part 53 is used to generate a large mold clamping force of 30 t. The elongation of the tie bar 50 when the mold clamping device 1 to be used was 0.381 mm.

Therefore, the sensitivity of the disturbance that the clamping force receives is
(0.02 / 0.381) ≒ 5%
It becomes.

  On the other hand, when the tie bar 50 in which the constricted portion 53 of 30Φ is formed on a part of the same shaft diameter 40Φ is used and the mold clamping device 1 that generates a large mold clamping force of 30 t is used, the elongation of the tie bar 50 is 0. It was 444 mm.

Therefore, the sensitivity of the disturbance that the clamping force receives is
(0.02 / 0.444) * 100 ≒ 5%
Therefore, in the large mold clamping device 1 having a mold clamping force larger than 20 t, since the mold clamping force is large, the length of the tie bar 50 is also increased, so that the elongation amount is increased. For this reason, even when the constricted portion 53 is formed, the sensitivity to disturbance is hardly changed, and it has been found that the smaller the mold clamping device 1, the higher the effect of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Toggle type small mold clamping apparatus 2 ... Machine stand 3 ... Rail 4 ... Movable type 5 ... Fixed type 6 ... Position switch 7 ... Position switch 8 ... Injection nozzle 9 ... Slider 10 ... Pressure receiving plate 12 ... Adjustment nut 12a ... Inner end surface 12b ... annular contact part 12c ... outer end face 13 ... nut holding member 14 ... small gear 15 ... coupling base part 15a ... through hole 15b ... concave part 15c ... step part 15d ... female screw hole 20 ... drive part 21 ... drive source 22 ... output Shaft 23 ... Drive pulley 24 ... Screw shaft 30 ... Toggle mechanism 31 ... Cross head 32 ... Actuation link 33 ... Fixed side link arm 34 ... Driven side link arm 35 ... Toggle pin 35a ... Center part 35b ... Both ends 35c ... Notch part 36 ... Carbon bush 37 ... Fixing plate 38 ... Bolt 40 ... Fixing plate 41 ... Mold support part 42 ... Nozzle insertion hole 43 ... Nut 50 ... Tie bar 51 ... one end 52 ... the other end 53 ... part 54 ... safety rod 54a ... both ends closed recess 54b ... one side closed recess 54c ... front end 54d ... rear end 55 ... locking device 60 ... movable plate 61 ... mold support 62 ... eject through Hole 63 ... Through hole 64 ... Insertion hole 65 ... Mounting seat 65a ... Base 65b ... Seat 66 ... Storage space 67 ... Upper wall 67a ... Thick inclined portion 67b ... Upper surface 67c ... Recessed portion 67d ... Thick inclined portion 68 ... Lower wall part 68a ... Thick wall inclined part 68b ... Lower surface 68c ... Recessed part 68d ... Thick wall inclined part 69 ... Connecting base part 69a ... Through hole 69b ... Recessed part 69c ... Stepped part 69d ... Female screw hole 70 ... Eject part 71 ... Ejector motor 72 ... Output shaft 73 ... Driving pulley 74 ... Driving pulley 75 ... Endless belt 76 ... Eject pin 77 ... Operating unit P ... Gap Q ... Shaft center Y ... Omitted in plan view

Claims (4)

A pressure plate supported by the machine base;
A stationary platen fixed to the machine base and disposed opposite the pressure platen;
A plurality of shaft-shaped tie bars, one end of which is supported by the pressure plate and the other end of which is fixed to the fixed plate;
A movable plate capable of approaching and moving away from the fixed plate;
A toggle mechanism for moving the movable plate toward and away from the fixed plate;
Toggle type compact mold clamping device with
A toggle type compact mold clamping device, wherein a constricted portion in which a diameter of a part of the plurality of tie bars is smaller than another diameter is formed. The toggle type small mold clamping device according to claim 1, wherein the constricted portion is formed between the pressure receiving plate and the movable platen. The toggle type small mold clamping device according to claim 2, wherein the constricted portion is formed on the pressure receiving plate side with respect to a movable range of the movable platen. The plurality of tie bars are arranged at positions where the vertical and horizontal separation distances are substantially equal in the vicinity of four corners of the upper and lower sides and the right and left sides of the pressure receiving plate and the fixed plate, and the same tie bars are used. Item 4. The toggle type compact mold clamping device according to Item 3.

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