JP4011590B2 - Gate cut mechanism and ejector mechanism for injection molding machines - Google Patents

Description

  The present invention relates to a gate cut mechanism and ejector mechanism for an injection molding machine.

  Conventionally, as this type of apparatus, there is one proposed in Patent Document 1. FIG. 5 is a view showing a conventional gate cut mechanism and ejector mechanism for an injection molding machine disclosed in Patent Document 1. As shown in FIG.

  The conventional gate cut mechanism / ejector mechanism for an injection molding machine shown in FIG. 5 is configured such that the gate cut mechanism 110 and the ejector mechanism 130 operate independently of each other. The gate cut mechanism 110 includes a drive side gate cut pin 112 movably disposed on the movable platen 103b, a support member 114 fixed to the movable platen 103b, a gate cut plate 118 fixed to the drive side gate cut pin 112, A nut member 117 fixed to the gate cut plate 118 and a ball screw member 115 with which a threaded portion 115a engages the nut member 117. The ball screw member 115 is rotatable with respect to the support member 114 and cannot move in the central axis direction. The ball screw mechanism supported by the motor, the electric motor 120 fixed to the support member 114, and the motor shaft 120a of the electric motor 120 and the ball screw member 115 are wound around to rotate the ball screw member 115 forward and backward. And a winding transmission device 125 to be driven. The ejector mechanism 130 includes a drive-side ejector pin 132 that is movably disposed in the through hole of the drive-side gate cut pin 112, a pneumatic cylinder device 124 that is fixed to the support member 114 and drives the drive-side ejector pin 132, and It has.

  The gate cut mechanism 110 and the ejector mechanism 130 operate separately and independently as follows.

  When the electric motor 120 fixed to the support member 114 is driven, the gate cut mechanism 110 causes the ball screw member 115 to be wound by a winding transmission device 125 wound between the motor shaft 120a of the electric motor 120 and the ball screw member 115. Are driven to rotate in the forward or reverse direction. Since the ball screw member 115 is supported by the support member 114 so as to be rotatable and immovable in the central axis direction, the nut member 117 with which the threaded portion 115a of the ball screw member 115 is engaged has the gate cut plate 118 and the drive. It moves with the side gate cut pin 112. Since the driving side gate cut pin 112 moves in the movable platen 103b, the gate can be cut by the movement of the driving side gate cut pin 112. When the ball screw member 115 is rotated in the reverse direction by the electric motor 120, the gate is opened.

The drive-side ejector pin 132 of the ejector mechanism 130 is driven in the through hole of the drive-side gate cut pin 112 when the pneumatic cylinder device 124 is operated to protrude. By driving the drive side ejector pin 132, the molded product can be protruded from the cavity. If the pneumatic cylinder device 124 is operated to be immersed, the drive side ejector pin 132 can be returned. Thus, since the gate cut mechanism 110 and the ejector mechanism 130 can be operated by the electric motor 120 and the pneumatic cylinder device 124, unlike the structure of the hydraulic drive system, there is no oil leakage and the oil splashes into the molded product. In addition, it is possible to simplify the structure and reduce the cost by combining these two driving methods.
Japanese Patent No. 3088650

  In the conventional gate cut mechanism and ejector mechanism for an injection molding machine described above, in the gate cut process, the electric motor 120 can precisely control the moving amount, moving speed, and moving torque of the driving side gate cut pin 112. However, in the ejecting process, since the ejector mechanism 130 is driven by the pneumatic cylinder device 124, the same precise control as in the gate cutting process cannot be desired. Since the optimum amount of movement of the drive side ejector pin 132 differs depending on the structure difference or solid difference of each mold, the initial adjustment is troublesome, and a mechanism for adjusting the amount of movement is also necessary. Furthermore, the position accuracy of the drive-side ejector pin 132 during movement is inferior to that of the electric motor 120 that can perform position control using pulse control. Further, due to the compressibility of the air itself, the movement rise response of the drive side ejector pin 132 is generally inferior to the response of the drive side gate cut pin 112 driven by the electric motor 120.

  For the above reasons, in the configuration in which the ejector mechanism 130 is driven by the pneumatic cylinder device 124, it takes time to adjust the optimum movement amount of the drive-side ejector pin 132 at the time of setting the mold, and the molding machine is used during continuous molding. The amount of movement cannot be adjusted without stopping. If the amount of movement of the drive side ejector pin 132 is not properly adjusted, a malfunction may occur in the extraction process after ejecting the molded product during continuous molding (automatic operation stop of the molding machine due to defective extraction). Productivity is significantly reduced.

  Thus, the present invention provides a gate cut mechanism and ejector mechanism for an injection molding machine capable of precisely controlling not only the drive side gate cut pin but also the movement amount, speed and torque of the drive side ejector pin even during continuous molding. The purpose is to do.

  In order to achieve the above object, the gate cut mechanism and ejector mechanism for an injection molding machine according to the present invention includes a support member fixed to the movable plate and a drive side provided movably with respect to the movable plate. It consists of a gate cut plate fixed to the gate cut pin, a nut member fixed to the gate cut plate, and a ball screw member whose screw part engages with the nut member, and the ejector mechanism is fixed to the support member and inside A ball screw member engaged with a rotation mechanism having a nut member, and a drive side ejector pin fixed to the ball screw member. The gate cut mechanism and the ejector mechanism include an electric motor fixed to the support member, A belt wound between the motor shaft of the electric motor and each ball screw member, and the ball screw members are opposite to each other. Characterized in that it is driven by a belt-driven for rotating the.

  According to the gate cut mechanism and ejector mechanism for an injection molding machine of the present invention, since all of them can be driven by an electric motor, the movement amount, the movement speed of the drive side gate cut pin and the drive side ejector pin, The moving torque can be precisely controlled even during continuous molding. Further, unlike the configuration of the hydraulic drive system, there is no occurrence of oil leakage, and it is possible to prevent oil scattering to the molded product.

  As described above, according to the present invention, not only the driving side gate cut pin but also the moving amount, moving speed, and moving torque of the driving side ejector pin can be precisely controlled even during continuous molding.

  Next, embodiments of the present invention will be described with reference to the drawings.

  1 and 2 are views showing a gate cut mechanism / ejector mechanism for an injection molding machine according to an embodiment of the present invention. Referring to FIG. 2, reference numeral 1 in FIG. 2 denotes a mold for an injection molding machine, and the mold 1 includes a fixed mold 2a and a movable mold 3a facing the fixed mold 2a. . The fixed mold 2a forms a sprue 9 extending on the central axis of the fixed mold 2a, and includes a sprue bush 2c that fits into the fixed mold 2a, and is fixed to the fixed platen 2b. On the other hand, the movable mold 3a is clamped with the fixed mold 2a to form a plurality of cavities 7. The movable mold 3a is fixed to the movable plate 3b, and the movable plate 3b is toggle type or direct pressure type. It is driven back and forth by a mold clamping device (not shown). The sprue 9 and each cavity 7 can be connected via a runner 5 and a gate 6 formed between a driven gate cut pin 13 and a sprue bushing 2c, which will be described later.

  The movable platen 3b is equipped with a gate cut mechanism 10 and an ejector mechanism 30. The gate cut mechanism 10 includes a gate cut pin 11 as shown in FIG. The gate cut pin 11 includes a drive side gate cut pin 12 and a driven side gate cut pin 13 arranged coaxially. The driven-side gate cut pin 13 has a cylindrical shape, is accommodated in the movable die 3a so as to be movable in the central axis direction, and is compressed by a first return spring 40 disposed between the movable die 3a and being compressed. , Always energized in the return direction. The driven-side gate cut pin 13 is in a non-operating state returned by the first return spring 40, the projection 13a abuts against the stepped surface 3c of the movable mold 3a, and the runner between the runner-side gate cut pin 13 and the front end surface of the sprue bush 2c. 5 and the gate 6 connected to the inner end of each cavity 7 can be formed in an open state. The driving side gate cut pin 12 has a cylindrical shape, the rear end portion is screwed to the gate cut plate 18, and the front end surface faces the rear end surface of the driven side gate cut pin 13.

  The gate cut plate 18 is driven by a plurality of ball screw mechanisms arranged at an equal distance from the drive side gate cut pin 12. That is, a pair of nut members 17 are fixed to the gate cut plate 18, and the threaded portions 15 a at the tips of the ball screw members 15 are engaged with the nut members 17 via balls (not shown). Each ball screw member 15 has an intermediate portion of the shaft portion supported by the support member 14 via a bearing 44 so as to be rotatable and immovable in the central axis direction, and a pulley 16 is fixed to the shaft portion at the rear end. ing. An electric motor 20 as a servo motor is fixed to the bracket portion 14a of the support member 14, and a drive pulley 21 is fixed to the motor shaft 20a. A belt 53 is wound around the drive pulley 21, the gate cut pulley 16, and the ejector pulley 52 to constitute a winding transmission device 25 (see FIG. 3). In the winding transmission device 25, the belt 53 is preferably formed of a toothed belt because the ball screw members 15 and 50 need to be driven synchronously.

  On the other hand, the support member 14 is disposed behind the gate cut plate 18 and fixed to the movable platen 3b via a plurality of guide pins 43 screwed to the movable platen 3b. Thereby, each ball screw member 15 supported by the bearing 44 is rotated by rotating the drive pulley 21, the gate cut pulley 16 and the ejector pulley 52 forward and backward by the electric motor 20. 17 and the gate cut plate 18 and thus the drive side gate cut pin 12 can be driven back and forth in the direction of the central axis. The gate plate 18 is slidably fitted to the intermediate portion of the guide pin 43 with the bush 45 interposed therebetween, and moves forward and backward stably while being guided by the guide pin 43.

  The ejector mechanism 30 includes an ejector pin 31 as shown in FIG. The ejector pin 31 includes a drive side ejector pin 32 and a driven side ejector pin 33 arranged coaxially. The drive-side ejector pin 32 has a rod shape and is freely and concentrically inserted into the through-hole of the drive-side gate cut pin 12 having a cylindrical shape, and its rear end is fixed to the ball screw member 50 for the ejector mechanism 30. Has been. The driven-side ejector pin 33 has a rod shape, and has a pin main body 33a whose rear end face faces the front end face of the drive-side ejector pin 32, and two branch pins 33b branched from an intermediate portion of the pin main body 33a. . The pin body 33a is slidably and concentrically supported in the driven side gate cut pin 13, and is always urged in the return direction by a second return spring 41 that is compressed between the driven side gate cut pin 13 and disposed. ing. Each branch pin 33b is L-shaped, and the rear end portion is received in the radial cut groove 13b of the rear end portion of the driven side gate cut pin 13 so that relative movement in the central axis direction is possible. The front end surfaces form cavities 7 in a state where the front end side is supported in the movable mold 3a so as to be freely movable in the direction of the central axis, and returned to the rear by the second return spring 41.

  The rotation mechanism 51 having a nut member therein is fixed to the support member 14 and is engaged with the screw portion 50 a of the ball screw member 50. As described above, since the belt 53 is wound around the drive pulley 21, the gate cut pulley 16, and the ejector pulley 52, the electric motor 20 is driven to rotate in the forward and reverse directions to be fixed to the support member 14. When the rotation mechanism 51 having the nut member is rotated, the drive-side ejector pin 32 fixed to the ball screw member 50 for the ejector mechanism 30 can be driven back and forth in the central axis direction. In the present embodiment, as shown in FIG. 3, the belt 53 is in contact with the drive pulley 21 and the gate cut pulley 16 on the inner peripheral surface of the belt 53, and the ejector pulley 52 is in contact with the outer peripheral surface of the belt 53. It is wrapped like so. Therefore, the wrapping transmission 25 rotates the ball screw members 15 and 50 in opposite directions, and when the electric motor 20 is rotated forward, the drive side gate cut pin 12 advances from the control origin position, At the same time, the drive-side ejector pin 32 retracts from the control origin position (see FIG. 4B). On the other hand, when the electric motor 20 is rotated in the reverse direction, the drive side gate cut pin 12 moves backward from the control origin position, and at the same time, the drive side ejector pin 32 moves forward from the control origin position (see FIG. 4C). . When the electric motor 20 is rotated forward from the state shown in FIG. 4C, both the drive side gate cut pin 12 and the drive side ejector pin 32 return to the control origin position (see FIG. 4A).

  Next, the operation of the gate cut mechanism and ejector mechanism for an injection molding machine of this embodiment will be described. In the injection molding, a well-known mold closing process, mold clamping process, injection unit advance process, injection process, metering process, injection unit retraction process, mold opening process, eject process and intermediate process are sequentially performed. First, a mold closing process and a mold clamping process are performed, and as shown in FIG. 2, an injection unit advancing process is performed in a state where the movable mold 3a is in close contact with the fixed mold 2a, and a nozzle of an unillustrated injection molding machine is in close contact. After closely contacting the part 2d, the process proceeds to the injection process.

  Next, when the molten molding material is injected from the nozzle of the injection molding machine, the molten molding material flows into the cavity 7 through the sprue 9, the runner 5 and the gate 6. When the cavity 7 is filled with the melt molding material, the gate cut mechanism 10 is operated. That is, when the drive pulley 21 is driven by rotating the electric motor 20 forward, the pulley 16 is rotationally driven in one direction via the belt 53. When the pulleys 16 are rotated in one direction, the ball screw members 15 are rotated, and the nut members 17 and the gate cut plates 18 and the drive side gate cut pins 12 are advanced in the direction of the central axis. At this time, the drive side ejector pin 32 moves backward. As a result, the driven side gate cut pin 13 is pushed out against the repulsive force of the first return spring 40, and the gate 6 is cut by the distal end portion of the driven side gate cut pin 13.

  If the gate 6 is cut | disconnected, it will transfer to a mold opening process, will move back the movable metal mold | die 3a, will also transfer to an ejection process, and operate the ejector mechanism 30. That is, when the drive pulley 21 is driven by rotating the electric motor 20 in the reverse direction, the ejector pulley 52 is rotationally driven via the belt 53, and the drive-side ejector pin 32 fixed to the ball screw member 50 for the ejector mechanism 30 is moved. The driven-side ejector pin 33 is pushed out while moving in the direction of the central axis and moving in the driving-side gate cut pin 12. The driven-side ejector pin 33 projects a molded product (not shown) in which each branch pin 33b is solidified in each cavity 7, and at the same time, the pin body 33a projects a solidified product (not shown) in the sprue 9. In this way, the gate cut mechanism 10 and the ejector mechanism 30 operate independently, and the gate 6 is cut and the molded product is ejected individually. In addition, while the drive side ejector pin 32 moves forward in the central axis direction, the drive side gate cut pin 12 moves backward in the central axis direction.

It is a figure which shows the gate cut mechanism and ejector mechanism for injection molding machines concerning one Embodiment of this invention. It is another figure which shows the gate cut mechanism and ejector mechanism for injection molding machines concerning one Embodiment of this invention. It is a figure which shows the belt wound around the drive pulley, the pulley for gate cuts, and the pulley for ejectors. It is a figure which shows operation | movement of a drive side gate cut pin and a drive side ejector pin. It is a figure which shows the conventional gate cut mechanism and ejector mechanism for injection molding machines.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mold 2a Fixed mold 2b Fixed board 3a Movable mold 3b Movable board 5 Runner 6 Gate 7 Cavity 9 Sprue 10 Gate cut mechanism 12 Drive side gate cut pin 13 Drive side gate cut pin 14 Support member 15, 50 Ball screw member 15a, 50a Screw part 16 Gate cut pulley 17 Nut part 18 Gate cut plate 20 Electric motor 20a Motor shaft 21 Drive pulley 25 Winding transmission device 30 Ejector mechanism 32 Drive side ejector pin 33 Drive side ejector pin 33a Pin body 33b Branch pin 40 First return spring 41 Second return spring 43 Guide pin 44 Bearing 45 Bush 51 Rotating mechanism 52 Ejector pulley 53 Belt

Claims (1)

A gate cut mechanism and ejector mechanism for an injection molding machine,
A gate fixed by a gate cut mechanism (10) to a support member (14) fixed to the movable platen (3b) and a drive side gate cut pin (12) provided to be movable with respect to the movable platen (3b). A cut plate (18), a nut member (17) fixed to the gate cut plate (18), and a ball screw member (15) in which the screw portion (15a) engages with the nut member (17),
An ejector mechanism (30) is fixed to the ball screw member (50) and a ball screw member (50) which is fixed to the support member (14) and engages with a rotation mechanism (51) having a nut member therein. Drive side ejector pin (32),
The gate cut mechanism (10) and the ejector mechanism (30) include an electric motor (20) fixed to the support member (14), a motor shaft (20a) of the electric motor (20), and each ball screw member (15, 50). ), And is driven by a winding transmission device (25) that rotationally drives the ball screw members (15, 50) in opposite directions to each other. , Gate cut mechanism and ejector mechanism for injection molding machines.

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