JP2010173077A - Operation method for toggle type mold clamping device and mold clamping device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an operation method for a toggle type mold clamping device, preventing a movable platen from being fluctuated and inclined. <P>SOLUTION: The first-third seals (38, 39, 40) are provided in a tie bar nut pocket (26), and a sealed space (42) is formed of a tie bar nut (25) and a nut cover (35). Pressure oil is supplied to the sealed space (42), when performing a mold opening process, a mold closing process and mold clamping process, and the tie bar nut (25) is pushed onto a seating face (28) to bring each clearance (S1) into substantially zero. The pressure oil is discharged from the sealed space (42), when regulating mold clamping force, to secure the clearances (S1). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for operating a toggle type mold clamping device and a mold clamping device, and more specifically, a stationary platen to which a fixed side mold is attached, a movable platen to which a movable side die is attached, a mold clamping housing, The tie bar includes a plurality of tie bars penetrating the movable platen and connecting the fixed platen and the mold clamping housing, and a toggle mechanism provided between the movable platen and the mold clamping housing. The tie bar nut is housed in a tie bar nut pocket provided in the mold clamping housing, and the clamping force can be adjusted by rotating the tie bar nut. The present invention also relates to a method for operating a toggle type mold clamping device and a mold clamping device which are adapted to be seated on a tie bar nut seating surface formed in a tie bar nut pocket. It is.

  A toggle type mold clamping device of an injection molding machine includes a fixed platen to which a fixed side mold is attached, a movable platen to which a movable side die is attached, a mold clamping housing, a fixed platen and a mold clamping housing that penetrate the movable platen. Are connected to each other, and a toggle mechanism provided between the movable platen and the mold clamping housing. When the toggle mechanism is driven in the mold clamping direction, the tie bar elastically extends. Then, a predetermined mold clamping force is obtained by the tension of the tie bar. When a molten resin or molten metal is injected into the cavity formed in the mold and the mold is opened after cooling and solidification, a molded product having a desired shape is obtained. An appropriate clamping force can be obtained by driving the cross head constituting the toggle mechanism to a predetermined position. By the way, the thickness of the pair of molds that are closed is different for each mold. Accordingly, the distance between the fixed platen and the movable platen when the mold is closed, that is, the mold thickness, also varies depending on the mold to be attached. Therefore, in order to obtain an appropriate mold clamping force, the distance between the mold clamping housing and the fixed platen in accordance with the thickness of the mold in advance so that the crosshead position becomes a predetermined position when the mold is clamped, that is, It is necessary to adjust the tie bar effective length. This adjustment is called mold clamping force adjustment or mold thickness adjustment.

  A conventionally known toggle type mold clamping device is provided with a plurality of, for example, four tie bars. The mold clamping force adjusting mechanism is provided in relation to the tie bar, and one tie bar will be described with reference to FIG. 4 as a representative, but the other tie bars are similarly configured. As shown in FIG. 4, the mold clamping device includes a fixed platen 51, a mold clamping housing 52, a tie bar 53, and the like. A through hole 55 is formed in the fixed platen 51, and a tie bar fixing member 56 is fixed to the fixed platen 51 corresponding to the through hole 55. A female screw is provided on the inner peripheral surface of the tie bar fixing member 56. One end portion of the tie bar 53 passes through the through hole 55, and a male screw formed in the penetrating portion is screwed into a female screw of the tie bar fixing member 56. Thereby, one end of the tie bar 53 is fixed to the fixed platen 51. A through hole 58 is also formed in the mold clamping housing 52, but a tie bar nut insertion hole 59 whose diameter is enlarged by a predetermined length is formed in the vicinity of the outlet of the through hole 58, and a bottom portion of the tie bar nut insertion hole 59 is formed. A predetermined step portion on which the tie bar nut 61 is seated, that is, a tie bar nut seating surface 60 is formed. The other end of the tie bar 53 passes through the through hole 58 of the mold clamping housing 52, and a tie bar nut 61 is screwed into a male screw formed near the end. Thus, the other end of the tie bar 53 is attached to the mold clamping housing 52. The tie bar nut 61 is formed with a shoulder portion 64 composed of a small diameter portion 62 and a large diameter portion 63. The tie bar nut 61 has a large diameter portion 63 stored in a tie bar nut insertion hole 59 and a shoulder portion 64 held by a nut cover 66 fixed to the mold clamping housing 52. That is, the large diameter portion 63 of the tie bar nut 61 is stored in a tie bar nut pocket 70 formed by the tie bar nut insertion hole 59 and the nut cover 66, and a part of the small diameter portion 62 protrudes from the nut cover 66 to the outside. Yes. A driven gear 68 is fixed to the side portion of the small-diameter portion 62 that protrudes. Similarly, tie bar nuts 61 are screwed onto the other three tie bars 53, and the driven gears 68 are fixed to the tie bar nuts 61, respectively. Although not shown in FIG. 4, a large-diameter center gear is provided at the center of the mold clamping housing 52, and four driven gears 68 are engaged with the center gear. Therefore, when the center gear is driven, the driven gears 68 are driven, and the tie bar nuts 61 are also rotated. Since the rotation of the tie bar 53 is restricted by the tie bar fixing member 56, when the tie bar nut 61 rotates, the tie bar nut 61 moves in the axial direction. That is, the mold clamping housing 52 moves in the axial direction. Thereby, the tie bar effective length 72 between the tie bar fixing member 56 and the tie bar nut 61 changes. That is, the mold clamping force can be adjusted.

  Such a tie bar nut pocket 70 is formed slightly larger than the large-diameter portion 63 of the tie bar nut 61 so that the tie bar nut 61 can rotate smoothly, and play is provided between the tie bar nut pocket 70 and the tie bar nut 61. A predetermined gap is secured in. Accordingly, a first gap 73 is formed between the tie bar nut 61 and the tie bar nut seating surface 60, and a second gap 74 is formed between the tie bar nut 61 and the nut cover 66. The first and second gaps 73 and 74 change in the mold clamping process and the mold opening process of the mold clamping device. Specifically, in the mold clamping process, a force acts in a direction in which the fixed platen 51 and the mold clamping housing 52 are separated from each other by the reaction of the mold clamping force. Accordingly, the tie bar nut 61 is seated on the tie bar nut seating surface 60, the first gap 73 is substantially zero, and the second gap 74 is widened. In the mold opening process, the separating force is released from the fixed platen 51 and the mold clamping housing 52. Accordingly, the tie bar nut 61 is separated from the tie bar nut seating surface 60 to form the first gap 73. In the plurality of tie bars 53,..., The first and second gaps 73 and 74 as described above do not change uniformly due to the effects of component tolerance and assembly accuracy. If the change is non-uniform for each tie bar 53,..., The mold clamping housing 52 is wobbled or tilted, and the movable platen is also wobbled or tilted via the toggle mechanism. As a result, the following various problems occur. For example, the straightness of the movable plate deteriorates before and after the mold touches, the angle of the movable plate changes, and the parting line shifts. If it does so, a shift | offset | difference will arise also in the shape of the cavity formed with a fixed side metal mold | die and a movable side metal mold | die, and a molding defect will generate | occur | produce. In particular, when a lens that requires high optical characteristics is molded, the optical axis shifts and the aberrations deteriorate. Further, if the straightness of the movable platen is impaired, in the case of a die provided with a guide pin or an inlay type die, the guide pin and the inlay portion are worn. In addition, the so-called injection compression molding method, in which the mold is slightly opened and is then clamped and compressed, is known as an injection molding method with excellent transferability. Variations in product weight and plate thickness will occur. The above-described problems are likely to occur in a molded product that is strongly required to be uniform in weight and thickness, such as an optical disk, and is molded in a high cycle. Problems also arise in the mold opening process. That is, when the mold is opened and the molded product is taken out by a robot arm or the like, the accuracy of the stop position cannot be obtained, so that a takeout failure occurs. Alternatively, when the injection molding machine is operated for a long time, the tie bar nuts 61,... May rotate and loosen, and the mold clamping force may change. Other problems arise in the case of vertical injection molding machines. In the case of a vertical injection molding machine, when the mold is opened, the weight of the movable part acts on the tie bar nuts 61 through the tie bars 53, so that the tie bar nuts 61 are pressed downward. That is, the second gap 74 is substantially zero. At the time of mold clamping, the mold clamping housing 52 is pressed downward by a toggle mechanism, and the first gap 73 becomes substantially zero. Therefore, the tie bar nuts 61,. Will act. Due to such an alternating load, the tie bar nuts 61 and so on alternately collide with the tie bar nut seating surfaces 60 and the nut cover 66 and so on, and the tie bar nuts 61 and so on are damaged early.

JP 2007-203700 A

  In Patent Document 1, in a vertical injection molding machine, a tie bar nut 61 is fixed in a tie bar nut pocket 70 and the tie bar nut 61 impacts the tie bar nut seating surface 60 and the nut cover 66 even when an alternating load is applied. The mold clamping device 80 is described so as not to collide with the mold. A mold clamping device 80 described in Patent Document 1 is shown in FIG. As is apparent from FIG. 5, a lock nut 81 is added to the conventionally known mold clamping device described with reference to FIG. The lock nut 81 is provided with a female screw that is screwed into the tie bar 53, and cooperates with the tie bar nut 61 to sandwich the mold clamping housing 52. After the tie bar nut 61 is rotated and the tie bar effective length 72 is adjusted as conventionally known, the lock nut 81 is rotated by a predetermined rotation angle. Then, the mold clamping housing 52 is pressed in the arrow Z direction by the lock nut 81, the mold clamping housing 52 is clamped by the tie bar nut 61 and the lock nut 81, and the first gap 73 becomes substantially zero. The tie bar nut 61 is fixed in the tie bar nut pocket 70.

  According to the mold clamping device 80 described in Patent Document 1, since the tie bar nut 61 can be fixed in the tie bar nut pocket 70, an alternating load acts on the tie bar nut 61 when the mold is clamped and when the mold is opened. Do not alternately impact the tie bar nut seating surface 60 and the nut cover 66. That is, early damage to the tie bar nut 61 can be prevented in the vertical injection molding machine. Further, the mold clamping device 80 described in Patent Document 1 can be applied not only to a vertical injection molding machine but also to a general injection molding machine, so that the mold clamping housing and the movable plate can be prevented from wobbling and tilting. Also, it is possible to prevent the parting line from shifting during mold clamping and the cavity shape from shifting. However, there are some problems. For example, in the mold clamping device 80 described in Patent Document 1, a drive mechanism for rotating the lock nut 81 is necessary, and a servo motor, a plurality of pulleys, a belt, and the like need to be provided specially. This complicates the machine structure and increases the machine weight. There is also a problem when adjusting the mold clamping force. That is, the mold clamping force is adjusted by rotating the lock nut 81 by a predetermined rotation angle to secure the first gap 73. However, when the tie bar nut 61 is rotated, the first gap 73 is kept constant. In order to hold, the lock nut 81 must also be driven to rotate at a rotation angle equal to the rotation speed equal to that of the tie bar nut 61. Thus, it is difficult to control the lock nut 81 accurately, and an expensive control device is required. Furthermore, in the case of a vertical injection molding machine, there is a problem that the weight of the movable plate does not act on the tie bar nut 61 but acts on the lock nut 81 when the mold is opened. That is, since the weight of the movable part acts on the mold clamping housing 52 via the lock nut 81, it is necessary to provide a large lock nut 81 so that the lock nut 81 is not damaged, and the machine weight increases.

  An object of the present invention is to provide a method for operating a toggle type mold clamping device and a mold clamping device which have solved the above-described conventional problems or problems. Specifically, it does not require an expensive control device, and the weight of the machine is light and simple, but it can prevent the movable plate from wobbling and tilting. , There is no deviation in the shape of the cavity, and the guide pin and the inlay part die are not worn even in the mold provided with the guide pin or the inlay type mold. Toggle that the movable platen does not fluctuate during injection, can be stopped at the mold opening position with high accuracy even during product removal, and a stable mold clamping force can be obtained without loosening the tie bar nut even after long-term operation. It is an object of the present invention to provide a method for operating a mold clamping apparatus and a mold clamping apparatus.

  In order to achieve the above object, the present invention provides a tie bar comprising a tie bar nut insertion hole provided in a mold clamping housing and a nut cover for pressing a predetermined portion of the tie bar nut inserted into the tie bar nut insertion hole. A predetermined seal is provided in the nut pocket to form a liquid-tight sealed space from the side surface of the tie bar nut on the nut cover side and the side surface of the nut cover on the tie bar nut side. The tie bar nut pocket is provided with a pipe line that opens into a sealed space and supplies and discharges pressure oil from the outside. At least during the mold opening process, mold closing process, and mold clamping process, pressure oil is supplied to such a sealed space and the tie bar nut is seated on the tie bar nut seating surface. The pressure oil is drained from the sealed space, and a predetermined gap is secured between the tie bar nut and the tie bar nut seating surface.

Specifically, in order to achieve the above object, the invention according to claim 1 includes a stationary platen to which a stationary mold is attached, a movable plate to which a movable mold is attached, a mold clamping housing, and the movable plate. A plurality of tie bars penetrating through and connecting the fixed plate and the mold clamping housing; and a toggle mechanism provided between the movable plate and the mold clamping housing. A nut is provided, and a predetermined portion of the tie bar nut is stored in a tie bar nut pocket provided in the mold clamping housing, and the mold clamping force can be adjusted by rotating the tie bar nut. In a toggle type mold clamping device in which the tie bar nut is seated on a tie bar nut seating surface formed in the tie bar nut pocket when tightening. The tie bar nut pocket is composed of a tie bar nut insertion hole of a predetermined depth provided in the mold clamping housing, and a nut cover for pressing a predetermined part of the tie bar nut inserted into the tie bar nut insertion hole, and at least During the mold opening process, mold closing process, and mold clamping process, a liquid-tight sealed space composed of the side surface of the tie bar nut on the nut cover side and the side surface of the nut cover on the tie bar nut side is formed. Adjusting the mold clamping force is performed by draining the pressure oil from the sealed space and securing a predetermined gap between the tie bar nut and the tie bar nut seating surface. Configured to do. According to a second aspect of the present invention, there is provided a fixed platen to which the fixed side mold is attached, a movable platen to which the movable side die is attached, a mold clamping housing, the fixed platen and the mold clamping through the movable platen. A plurality of tie bars connecting the housing, and a toggle mechanism provided between the movable platen and the mold clamping housing, the tie bar is provided with a tie bar nut, and the tie bar A predetermined portion of the nut is housed in a tie bar nut pocket provided in the mold clamping housing, and the mold clamping force can be adjusted by rotationally driving the tie bar nut. In a toggle type mold clamping device adapted to be seated on a tie bar nut seating surface formed in the tie bar nut pocket, A tie bar nut insertion hole having a predetermined depth provided in the tightening housing and a nut cover for pressing a predetermined portion of the tie bar nut inserted into the tie bar nut insertion hole, the nut cover side of the tie bar nut The hydraulic oil is supplied to and discharged from a liquid-tight sealed space formed by sealing means from the side face of the nut cover and the side face of the nut cover on the tie bar nut side.
According to a third aspect of the present invention, in the apparatus according to the second aspect, pressure oil is supplied and discharged from the nut cover into the liquid-tight sealed space.

  As described above, according to the present invention, the mold clamping force is adjusted with a predetermined gap between the tie bar nut pocket and the tie bar nut, so that the tie bar nut can be smoothly smoothed as in the conventional injection molding machine. The mold clamping force can be easily adjusted. According to the present invention, the mold opening process, the mold closing process, and the mold clamping process are performed by a predetermined sealing means in a tie bar nut pocket constituted by a tie bar nut insertion hole and a nut cover. It is carried out by supplying pressure oil to a liquid-tight sealed space consisting of a side surface on the nut cover side and a side surface on the tie bar nut side of the nut cover. That is, the pressure oil acts on the side surface of the nut cover on the tie bar nut side, the mold clamping housing moves slightly, the mold clamping housing is pressed against the tie bar nut, and the tie bar nut is seated on the tie bar nut seating surface. Therefore, the mold clamping housing does not fluctuate in the mold opening process, the mold closing process, and the mold clamping process. Therefore, the movable plate does not fluctuate, and the movable plate is driven with high accuracy while maintaining straightness. The angle of the movable side mold does not change immediately before and after the touch with the fixed side mold, and the parting line does not shift, so the shape of the cavity formed in the mold does not distort. Accordingly, molding defects do not occur. Even in the case of a lens for which high accuracy is required, there is no variation in optical axis deviation or aberration. Further, even if the mold is provided with a guide pin or an inlay portion, the movable plate keeps straight running, so that the guide pin and the inlay portion are not easily worn. Furthermore, even when the injection compression molding method is performed, the movable platen does not fluctuate at the time of injection, so there is no variation in the weight or thickness of the molded product. Accordingly, uniformity in weight and plate thickness is strongly required, and even when an optical disc is molded at a high cycle, molding defects are unlikely to occur. In addition, since the movable plate can be stopped with high accuracy even when the mold is opened, defective take-out of the molded product is reduced. Furthermore, since the tie bar nut is substantially fixed in the tie bar nut pocket and cannot be rotated, the tie bar nut does not loosen even when operated for a long period of time, and the clamping force is stabilized. The mold clamping force is adjusted by draining the pressure oil from the sealed space and securing a predetermined gap between the tie bar nut and the tie bar nut seating surface, that is, only draining the pressure oil. Since the mold clamping force can be easily adjusted, an expensive control device is not particularly required. Further, according to the present invention, the toggle type mold clamping device only needs to have a predetermined seal provided in the tie bar nut pocket and a pressure oil supply / discharge pipe provided in the tie bar nut pocket. The apparatus is simple and lightweight, and the mold clamping apparatus can be provided at low cost.

  Embodiments of the present invention will be described below. The toggle type mold clamping apparatus according to the embodiment of the present invention is also generally configured in the same manner as a conventionally known toggle type mold clamping apparatus. That is, in the toggle type mold clamping apparatus 1 according to the present embodiment, as shown in the front view of FIG. 1, the fixed platen 3 to which the fixed side mold 2 is attached and the movable side mold 5 are attached. The movable plate 6, the mold clamping housing 8, four tie bars 10, 10... That pass through the movable plate 6 and connect the fixed plate 3 and the mold clamping housing 8, and the movable plate 6 and the mold clamping housing. 8 and a toggle mechanism 11 provided between the two. Through holes are made in the fixed platen 3, and tie bar fixing members 13, 13,... Made of female screws are fixed at positions corresponding to these through holes. One end of each of the tie bars 10, 10,... Penetrates through the through hole of the fixed platen 3, and the male screw formed in the penetrating portion is screwed into the female screw of the tie bar fixing members 13, 13,. Yes. Thereby, one end of the tie bars 10, 10,... Is fixed to the stationary platen 3. The other end of each of the tie bars 10, 10,... Penetrates a through hole opened in the mold clamping housing 8, as will be described in detail later. .. Although not shown in FIG. 1, a tie bar nut is screwed into a male screw provided at the other end of the tie bars 10, 10,.

  According to the present embodiment, the movable plate wobbling prevention mechanisms 21, 21,... For pressing the tie bar nut to prevent the wobbling of the movable platen are toggle mechanisms 11 indicated by the arrow Y1 of the mold clamping housing 8 as described above. It is provided on the opposite side. As shown in FIG. 2, the movable plate wobbling prevention mechanisms 21, 21,... Are provided corresponding to the four tie bars 10, 10,. FIG. 3A also shows such a movable plate wobbling prevention mechanism 21, the mold clamping housing 8, the tie bar 10, and the like.

  As shown in FIGS. 2 and 3, through-holes 23 through which the tie bars 10 penetrate are opened at the four corners of the mold-clamping housing 8, and the diameter is increased by a predetermined length near the outlet of the through-holes 23. A tie bar nut insertion hole 26 is formed. The tie bar nut 25 is stored or stored in the tie bar nut insertion hole 26. The bottom surface of the tie bar nut insertion hole 26 is a tie bar nut seating surface 28 on which the tie bar nut 25 is seated during mold clamping. The tie bar 10 passes through the through hole 23, and a male screw is formed in the vicinity of the end, and a tie bar nut 25 is screwed into the male screw. Thus, the other end of the tie bars 10, 10,... Is attached to the mold clamping housing 8. The tie bar nut 25 is provided with a small diameter portion 30 and a large diameter portion 31, and a shoulder portion 32 is formed. The large diameter portion 31 of the tie bar nut 25 is inserted into the tie bar nut insertion hole 26, and the shoulder portion 32 is pressed by the nut cover 35. The nut cover 35 is provided with an opening through which the small diameter portion 30 is inserted, and is fixed to the mold clamping housing 8 with a bolt or the like. Accordingly, the tie bar nut 25 has its large-diameter portion 31 stored in the tie bar nut pocket 36 constituted by the tie bar nut insertion hole 26 and the nut cover 35, and is restricted from moving in the axial direction. A part of the small diameter portion 30 of the tie bar nut 25 protrudes from the nut cover 35 to the outside. The depth of the tie bar nut insertion hole 26, that is, the axial length of the tie bar nut pocket 36 is slightly longer than the length of the large diameter portion 31 of the tie bar nut 25. Accordingly, a first gap S1 is provided between the tie bar nut 25 and the tie bar nut seating surface 28, and a second gap S2 is provided between the tie bar nut 25 and the nut cover 35, so-called play is provided. Yes. Accordingly, the tie bar nut 25 can rotate in the tie bar nut pocket 36.

  The driven gear 45 is fixed to the portion of the tie bar nut 25 that protrudes outside the small diameter portion 30. As shown in FIG. 2, the mold clamping housing 8 is provided with a center gear 46 having a relatively large diameter at the center, and driven gears 45, 45,. Therefore, although not shown in FIG. 2, when a predetermined drive gear is driven, the center gear 46 meshed with the drive gear is driven, and as a result, the driven gears 45, 45,. 25, 25, ... also rotate. Then, the tie bar effective length L changes and the mold clamping force can be adjusted.

  The movable plate wobbling prevention mechanisms 21, 21,... Will be described. The movable plate wobbling prevention mechanisms 21, 21,... Are composed of first to third seals 38, 39, 40 made of a rubber material having a ring shape. The first to third seals 38 to 40 are provided in association with the tie bar nut pockets 36, 36,... The first seal 38 seals between the outer peripheral portion of the tie bar nut 25 and the inner peripheral surface of the tie bar nut insertion hole 26, and the inner diameter thereof is substantially the same as the outer diameter of the large diameter portion 31 of the tie bar nut 25. Equally, the inner peripheral surface is slidably in close contact with the outer peripheral surface of the large-diameter portion 31 of the tie bar nut 25. On the other hand, the outer peripheral portion is fitted into a circumferential groove 41 formed on the inner peripheral surface of the tie bar nut insertion hole 26. The inner diameter of the second seal 39 is substantially equal to the outer diameter of the small diameter portion 30 of the tie bar nut 25, and is in close contact with the outer peripheral surface of the small diameter portion 30 of the tie bar nut 25. The outer peripheral portion is positioned by being fitted into a circumferential groove provided in the opening of the nut cover 35. The third seal 40 seals between the mold clamping housing 8 and the side surface of the nut cover 35, and the mold clamping housing 8, the nut cover 35, and the outer side in the radial direction from the inner diameter of the tie bar nut insertion hole 26. Is sandwiched liquid-tightly. Accordingly, a sealed space 42 that is liquid-tightly sealed is formed between the side surface of the shoulder portion 32 of the large-diameter portion of the tie bar nut 25 and the side surface of the nut cover 35. The wall surface forming the sealed space 42 does not include the tie bar nut seating surface 28 and the bottom surface of the large-diameter portion 31 of the tie bar nut 25. A supply / discharge pipe 43 for supplying and discharging pressure oil to / from such a sealed space 42 is provided toward the nut cover 35, and an end portion 44 of the supply / discharge pipe 43 is open to the sealed space 42. Therefore, pressurized oil can be supplied to the sealed space 42 from the outside, or the pressurized oil can be discharged to the outside.

  The operation of the toggle type mold clamping apparatus according to this embodiment will be described. A fixed-side mold 2 and a movable-side mold 5 having a predetermined thickness are attached to the fixed platen 3 and the movable platen 6, respectively. The mold clamping force adjustment is automatically performed when a predetermined operation button provided in the injection molding machine is pressed. However, in order to simplify the description, the following description will be made manually. The toggle mechanism 11 is driven to close the mold until the fixed mold 2 and the movable mold 5 are touched, and the crosshead position of the toggle mechanism 11 at that time is stored. The touch of the mold is confirmed by a torque limiter of a servo motor for opening and closing the mold. The toggle mechanism 11 is driven to open the mold. The length of the effective tie bar length L to be adjusted is calculated from the difference between the stored crosshead position and the crosshead position that generates the desired clamping force. The movable plate wobbling prevention mechanisms 21, 21, ... are driven. That is, the pressure oil injected into the sealed space 42 is discharged to the outside through the supply / discharge pipe 43. Then, pressure oil does not act on the tie bar nut 25, so that the first and second gaps S 1 and S 2 are secured and the tie bar nut 25 can be freely rotated in the tie bar nut pocket 36. The mold clamping force adjustment motor is driven to drive the drive gear. Then, the driven gears 45, 45,... Are rotated through the center gear 46, and the tie bar nuts 25, 25,. When the tie bar effective length L reaches a predetermined length, the mold clamping force adjustment motor is stopped to complete the mold clamping force adjustment.

  When the adjustment of the mold clamping force is completed, the movable plate wobbling prevention mechanisms 21, 21, ... are driven. That is, pressurized oil is supplied to the sealed space 42 from the outside via the supply / discharge pipe 43. Then, as shown in FIG. 3A, pressure oil acts on the shoulder portion 32 of the tie bar nut 25 and the mold clamping housing 8 is pressed in the direction of the arrow Y2. That is, the tie bar nut 25 is seated on the tie bar nut seating surface 28, and the first gap S1 becomes substantially zero. The tie bar nut 25 is substantially secured within the tie bar nut pocket 36. In this state, the following molding cycle is performed. The toggle mechanism 11 is driven to clamp the mold. Since the tie bar nut 25 is fixed to the tie bar nut pocket 36, the mold clamping housing 8 does not fluctuate and the movable plate 6 does not fluctuate. As is conventionally known, molten resin or molten metal material is injected into a cavity formed between the fixed mold 2 and the movable mold 5. After cooling and solidification, the toggle mechanism 11 is driven to open the mold. Take out the molded product. Even when the mold is opened, the mold clamping housing 8 and the movable platen 6 do not wobble.

  The toggle type mold clamping device provided with the movable plate wobbling prevention mechanism according to the present embodiment can be implemented in various forms without being limited to the above embodiment. For example, although the first and second seals 38 and 39 are described as being provided on the tie bar nut insertion hole 26 and the nut cover 35 side, they may be provided on the tie bar nut 25 side. In this manner, in the mold clamping device of the existing injection molding machine, the tie bar nut 25 provided with the first and second seals 38 and 39 is attached instead of the existing tie bar nut, and the nut cover is pressurized with oil. The movable plate wobbling prevention mechanism according to the present embodiment can be configured only by providing the supply / discharge pipe, and the mold clamping device can be provided at a low cost. Furthermore, although the first to third seals 38, 39, and 40 are described as being made of rubber material, they may be formed of other materials as long as they have a sealing action, for example, formed of synthetic resin material. It is also possible to do. Further, although the pressure oil supply / discharge pipe 43 is described as being provided on the nut cover 35, it may be provided on the mold clamping housing, and the number of the supply / discharge pipes 43 may be one. However, even if two oil supply and oil discharge are provided, it can be similarly implemented.

It is a front view which shows the outline of the toggle type injection molding machine which concerns on this Embodiment. It is a perspective view which shows typically a part of toggle type mold clamping apparatus which concerns on this Embodiment. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows a part of toggle type mold clamping apparatus which concerns on this Embodiment, (a) is the mold clamping apparatus at the time of adjustment of mold clamping force, (a) is the mold clamping of other states It is front sectional drawing which shows an apparatus, respectively. It is sectional drawing which shows a part of conventional toggle mold clamping apparatus. It is sectional drawing which shows the toggle type | mold clamping apparatus of the vertical type injection molding machine described in patent document.

DESCRIPTION OF SYMBOLS 1 Clamping apparatus 2 Fixed side metal mold 3 Fixed board 5 Movable side metal mold 6 Movable board 8 Mold clamping housing 10 Tie bar 11 Toggle mechanism 21 Movable board wobbling prevention mechanism 25 Tie bar nut 26 Tie bar nut insertion hole 28 Tie bar nut seating surface 35 Nut Cover 36 Tie bar nut pockets 38, 39, 40 First, second and third seals 42 Sealed space 43 Supply / exhaust pipe 45 Driven gear
S1 First gap S2 Second gap

Claims (3)

A fixed plate to which the fixed mold is attached, a movable plate to which the movable mold is attached, a mold clamping housing, and a plurality of plates that pass through the movable plate and connect the fixed plate and the mold clamping housing. A tie bar nut, and a toggle mechanism provided between the movable platen and the mold clamping housing. The tie bar is provided with a tie bar nut, and the tie bar nut includes a predetermined portion of the mold. A tie bar nut seat that is housed in a tie bar nut pocket provided in a clamping housing, and that the mold clamping force can be adjusted by rotationally driving the tie bar nut. The tie bar nut is formed in the tie bar nut pocket during mold clamping. In a toggle type clamping device designed to be seated on a surface,
The tie bar nut pocket is composed of a tie bar nut insertion hole of a predetermined depth provided in the mold clamping housing, and a nut cover for pressing a predetermined part of the tie bar nut inserted into the tie bar nut insertion hole,
At least during the mold opening process, the mold closing process, and the mold clamping process, a liquid-tight sealed space composed of a side surface of the tie bar nut on the nut cover side and a side surface of the nut cover on the tie bar nut side. To supply pressure oil to
The method for operating the toggle type mold clamping device is performed by adjusting the mold clamping force by draining pressure oil from the sealed space and securing a predetermined gap between the tie bar nut and the tie bar nut seating surface. . A fixed plate to which the fixed mold is attached, a movable plate to which the movable mold is attached, a mold clamping housing, and a plurality of plates that pass through the movable plate and connect the fixed plate and the mold clamping housing. A tie bar nut, and a toggle mechanism provided between the movable platen and the mold clamping housing. The tie bar is provided with a tie bar nut, and the tie bar nut includes a predetermined portion of the mold. A tie bar nut seat that is housed in a tie bar nut pocket provided in a clamping housing, and that the mold clamping force can be adjusted by rotationally driving the tie bar nut. The tie bar nut is formed in the tie bar nut pocket during mold clamping. In a toggle type clamping device designed to be seated on a surface,
The tie bar nut pocket is composed of a tie bar nut insertion hole of a predetermined depth provided in the mold clamping housing, and a nut cover for pressing a predetermined part of the tie bar nut inserted into the tie bar nut insertion hole, Pressure oil is supplied and discharged to a liquid-tight sealed space formed by a sealing means from a side surface of the tie bar nut on the nut cover side and a side surface of the nut cover on the tie bar nut side. A toggle type mold clamping device, characterized in that 3. The apparatus according to claim 2, wherein pressure oil is supplied and discharged from the nut cover to the liquid-tight sealed space. apparatus.

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