JP4726013B2 - Lubrication method of mold thickness adjusting nut of mold clamping device - Google Patents

Description

  The present invention relates to a method for lubricating a mold thickness adjusting nut in a mold clamping device.

  A mold clamping device provided in an injection molding machine or the like must cope with molds having various mold thickness dimensions. In particular, in the case of a mold clamping device having a toggle type or crank type mold clamping mechanism, it is necessary to change the effective length of the tie bar by rotating the mold thickness adjusting nut provided on the pressure receiving plate according to the mold thickness dimension. . In such a mold thickness adjusting nut, as shown in Patent Document 1, sufficient lubrication is performed on the pressing surface and the rotational sliding surface with the pressure receiving plate. However, it is difficult to directly apply grease to the portion of the mold thickness adjusting nut that is screwed with the tie bar because the mold thickness adjusting nut is a single rotating body. When the mold thickness is adjusted, the screw thickness of the mold thickness adjustment nut is actually moved on the tie bar by rotating the mold thickness adjustment nut. It is transported through a tieba male screw.

  However, if the mold operation is continued for a long time with the same mold without changing the mold, or with the same mold thickness even if the mold is replaced, the mold thickness adjusting nut does not rotate and receives pressure. Since the plate does not move, the mold thickness adjusting nut and the tie bar screwed at the same position are repeatedly subjected to the mold clamping force, and the oil film of the grease on the screwed surface continues to decrease and falls into a state where it is not lubricated at all. If mold thickness adjustment is performed for mold replacement in such a state, when the mold thickness adjustment nut rotates, the female screw portion of the mold thickness adjustment nut and / or the male screw portion of the tie bar may be damaged.

Japanese Patent No. 3463265

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a method that can satisfactorily lubricate a mold thickness adjusting nut without adjusting the mold thickness.

The present invention is rotatably attached to the back surface of the pressure receiving plate, and performs mold thickness adjustment by changing the effective length of the tie bar by rotating while screwing the tip of the tie bar fixed to the fixed plate, In a method of lubricating a mold thickness adjusting nut that receives a force acting on the pressure receiving plate during mold clamping by a mold clamping device having a toggle type or crank type clamping mechanism and transmits it to the tie bar, the pressure receiving is performed during molding operation. Issued when the time when the panel does not move beyond a predetermined distance or when the pressure receiving panel does not move beyond the predetermined distance is accumulated, and the accumulated amount reaches the first predetermined value. Based on the first signal, the mold thickness adjusting nut is rotated and displaced with respect to the tie bar at a time other than the molding operation, and the pressure receiving plate is moved more than the predetermined distance so that the male screw of the tie bar and the mold clamping are moved. Adjusting nut female thread Part lubrication a lubricating method of mold thickness adjusting nut that performs the.

  According to the method of lubricating the mold thickness adjusting nut in the mold clamping apparatus of the present invention, the mold thickness adjusting nut can be lubricated satisfactorily without adjusting the mold thickness.

  Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view showing a main part of the mold clamping device and a state where the mold thickness adjusting nut is screwed with a tie bar on the back surface of the pressure receiving plate. FIG. 2 is a flowchart showing a method of lubricating the mold thickness adjusting nut of the present invention.

  The mold clamping device 1 is movable by inserting a tie bar 3 between the pressure receiving plate 2, a fixed plate (not shown) that stands up against the pressure receiving plate 2, and a tie bar 3 standing at four corners. A sliding plate 5 is provided on the back surface of the movable platen (not shown), the toggle type or crank type clamping mechanism provided between the pressure receiving plate 2 and the movable platen, and the fixed plate of the pressure receiving plate 2. And a mold thickness adjusting nut 4 having a female screw 15 which is rotatably attached via 8 and is engaged with a male screw 14 which is engraved at the end of the tie bar 3.

  The pressure receiving plate 2 into which the tie bar 3 is loosely inserted has a mold (not shown) sandwiched between the movable platen and the fixed platen, and from the position where the mold clamping mechanism between the pressure receiving plate 2 and the movable plate is extended to the maximum. The die thickness adjusting nut 4 is positioned so that the tie bar 3 is displaced toward the stationary platen by a small distance such that a predetermined mold clamping force is generated by the extension of the tie bar 3. The mold clamping force generated at this time is received from the tie bar 3 via the threaded portion of the male screw 14 and the female screw 15 of the mold thickness adjusting nut 4, the mold thickness adjusting nut 4, and the sliding plate 5. 2 is transmitted.

  The sliding plate 5 is fixed to the back surface of the pressure receiving plate 2. The sliding plate 8 is fixed to a mounting plate 11 supported in parallel with the back surface of the pressure receiving plate 2 by a plurality of support rods 12 erected on the back surface of the pressure receiving plate 2. Thus, the mold thickness adjusting nut 4 has a sliding surface that comes into contact with the sliding plate 5 and the sliding plate 8, and is slidably held between the sliding plate 5 and the sliding plate 8. The sliding plates 5 and 8 are perforated with oil supply ports 6 and 9, which communicate with annular grooves 7 and 10 provided on a sliding surface in contact with the sliding plates 5 and 8 of the mold thickness adjusting nut. And grease etc. are inject | poured from the oil supply ports 6 and 9, and is supplied until it reaches the tie bar 3 via the sliding surface from the annular grooves 7 and 10. Since it is configured in this manner, the sliding surface of the mold thickness adjusting nut 4 that is rotated by a drive gear (not shown) that meshes with the outer peripheral surface is lubricated.

  By the way, various molds are mounted on the mold clamping device 1 according to the type of the molded product to be molded. And a metal mold | die changes mold | die thickness according to the kind of molded article. Therefore, the mold clamping apparatus 1 must have a mold thickness adjusting function. The mold thickness adjustment is executed by rotating the mold thickness adjusting nut 4 to change the effective length of the tie bar 3 according to the mold thickness.

  Thus, at the time of mold thickness adjustment, the female screw 15 of the mold thickness adjustment nut 4 rotates while being engaged with the male screw 14 of the tie bar 3 so that the mold thickness adjustment nut 4 is largely displaced on the tie bar 3. Therefore, the grease on the end surface of the mold thickness adjusting nut 4 near the female screw 15 reaches the axial center of the mold thickness adjusting nut 4 so as to be conveyed by the male screw 14, and the male screw 14 and the female screw 15 are screwed together. The part is lubricated.

  However, if the molding operation is performed for a long time with the same mold without replacing the mold, or if the molding operation is performed for a long time with a mold having the same mold thickness even if the mold is replaced, the mold thickness adjustment is not performed. Since the mold thickness adjusting nut hardly rotates and the pressure receiving plate 2 does not move, the male screw 14 and the female screw 15 screwed at the same position are repeatedly subjected to the mold clamping force, and the grease oil film on the screwing surface is It continues to decrease and falls into a state where it is not lubricated at all. If mold thickness adjustment is performed in such a state, when the mold thickness adjustment nut 4 is rotated, the threaded portion of the male screw 14 and the female screw 15 may be damaged.

  In order to avoid such a situation, it is indicated that the pressure receiving plate 2 has not been displaced more than a predetermined distance during a period exceeding the range in which the presence of the oil film at the screwed portion of the male screw 14 and the female screw 15 can be guaranteed. The position is monitored and detected, and the operator is forced to move the pressure receiving panel 2 forcibly. Further, after that, when the pressure platen 2 is not moved, it is detected again by monitoring the position of the pressure platen 2 that the pressure platen 2 has not been displaced more than a predetermined distance again for a short period of time. To stop the molding operation.

  An embodiment of this method will be described in detail based on the flowchart of FIG. A signal from an encoder (not shown) that detects the rotation angle of a position detector 13 provided on the pressure receiving plate 2 or a motor that rotationally drives the mold thickness adjusting nut 4 is input to a control device (not shown). The control device captures and monitors the position signal of the pressure receiving platen 2 every scan time or every predetermined short time (S1). Then, the difference between the acquired position value and the position value acquired and stored last time, that is, the movement amount of the pressure receiving panel 2 is calculated, and whether or not the absolute value of the movement amount is within a predetermined distance is compared (S2). . Here, the value of the predetermined distance is input in advance and stored in the control device, and is preferably a value of half or more of the axial thickness of the mold thickness adjusting nut 4. If the absolute value of the movement amount is not within the predetermined distance, the integrated amount stored in the storage device of the control device is reset and the process returns to step S2 (S3). If the absolute value of the movement amount is within the predetermined distance, the molding operation time or the number of molded products produced while the state continues is integrated as an integrated amount (S4). Then, a comparison operation is performed to determine whether or not the integrated amount has reached the first predetermined value (S5). Here, the first predetermined value is input and stored in the control device in advance, and is within a range in which the presence of the oil film at the threaded portion of the male screw 14 and the female screw 15 can be guaranteed. When the integrated amount has not reached the first predetermined value, the process returns to step S2. When the integrated amount reaches the first predetermined value, the control device issues a first signal (S6). The first signal sends a warning to the display means such as a liquid crystal panel of the control device that the pressure receiving plate 2 needs to be moved by a predetermined distance or more and a warning as necessary. The control device resets the integrated amount, and based on these, the operator moves the pressure receiving platen 2 by a predetermined distance or more when the mold clamping device 1 is not performing the molding operation (S7).

  Thereafter, returning to the molding operation again, the difference between the acquired position value and the position value acquired and stored last time, that is, the movement amount of the pressure receiving panel 2 is calculated, and whether or not the absolute value of the movement amount is within a predetermined distance. A comparison operation is performed (S8). If the absolute value of the movement amount is not within the predetermined distance and it is confirmed that the pressure receiving plate 2 has been moved, the process returns to step S1. If the absolute value of the moving amount is within the predetermined distance, it is determined that the pressure receiving plate 2 has not been moved, and the moving amount of the pressure receiving plate 2 is calculated in the same manner as in step S8, and the absolute value of the moving amount is calculated. Is compared or not (S9). If the absolute value of the moving amount is not within the predetermined distance, the integrated amount stored in the storage device of the control device is reset and the process returns to step S9 (S10). If the absolute value of the movement amount is within the predetermined distance, the molding operation time or the number of molded products produced while the state continues is integrated as an integrated amount (S11). Then, a comparison operation is performed to determine whether or not the integrated amount has reached the second predetermined value (S12). Here, the second predetermined value is input and stored in the control device in advance, and is in a range where the oil film in the threaded portion of the male screw 14 and the female screw 15 is insufficient, Usually, it is set to a value smaller than the first predetermined value. When the integrated amount has not reached the second predetermined value, the process returns to step S9. When the integrated amount reaches the second predetermined value, the control device issues a second signal (S13). At this time, the control device stops the molding operation of the mold clamping device 1 and automatically moves the pressure receiving plate 2 by a predetermined distance or more (S14, S15). The control device does not stop the molding operation immediately when the second signal is transmitted, but performs the control mode of the mold clamping device 1 in steps from automatic to semi-automatic, and further from semi-automatic to manual, or Alternatively, the operation may be stopped after a predetermined time or a predetermined number of shots, or after a continuous operation until a predetermined process such as completion of mold opening. It is also effective to automatically adjust the mold thickness in preparation for resuming the molding operation after the pressure receiving plate 2 is automatically moved over a predetermined distance.

  The present invention is not limited to the embodiments described above, and various modifications can be added and implemented without departing from the spirit of the invention.

It is a principal part of a mold clamping device, and is a longitudinal sectional view showing a screwed state with a tie bar of a mold thickness adjusting nut on a back surface of a pressure receiving plate. It is a flowchart which shows the lubrication method of the mold thickness adjustment nut of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Clamping device 2 Pressure receiving board 3 Tie bar 4 Mold thickness adjustment nut 5,8 Sliding plate 6,9 Oil supply port 7,10 Annular groove 11 Mounting plate 12 Support rod 13 Position detector 14 Male screw 15 Female screw

Claims (2)

It is pivotally attached to the back of the pressure plate and adjusts the mold thickness by changing the effective length of the tie bar by rotating while screwing the tip of the tie bar fixed to the fixed plate. In a method of lubricating a mold thickness adjusting nut that receives a force acting on the pressure receiving plate during mold clamping by a mold clamping device having a type mold clamping mechanism and transmits it to the tie bar,
During the molding operation, the time when the pressure receiving plate does not move beyond the predetermined distance or the number of productions when the pressure receiving plate does not move beyond the predetermined distance is integrated, and the integrated amount is a first predetermined value. On the basis of the first signal generated when the pressure reaches, the mold thickness adjusting nut is rotated and displaced with respect to the tie bar at a time other than the molding operation, and the pressure receiving plate is moved beyond the predetermined distance. A lubrication method for a mold thickness adjusting nut, characterized by lubricating a threaded portion of a male thread of a tie bar and a female thread of a mold clamping adjustment nut . The lubrication of the mold thickness adjusting nut according to claim 1, wherein the greasing to the threaded portion of the mold thickness adjusting nut is performed by transferring grease on both end faces of the mold thickness adjusting nut through male screws of a tie bar. Method.

Images