JP2008296504A - Molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten the total length of a machine (molding machine) in the molding machine in which the forward acceleration of a member for injection can be performed promptly. <P>SOLUTION: In the molding machine equipped with the member for injection which can move forward and backward, a first direct drive block holding the base end of the member for injection, a first ball screw mechanism in which a direct drive part is fixed to the first direct drive block, a first servomotor for rotating and driving the rotation part of the first ball screw mechanism, a second direct drive block holding the rotation part of the first ball screw mechanism rotatably, a second ball screw mechanism in which a direct drive part is fixed to the second direct drive block, and a second servomotor for rotating and driving the rotation part of the second ball screw mechanism, a shaft center line of the first ball screw mechanism and a shaft center line of the second ball screw mechanism are arranged in parallel with each other, and part of components of the first ball screw mechanism and part of components of the second ball screw mechanism are arranged to overlap each other when viewed in the length direction of the molding machine. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a molding machine such as an electric drive type injection molding machine or a die casting machine, and in particular, an injection member (a screw in an inline screw type injection molding machine, an injection plunger in a pre-plastic type injection molding machine or a die casting machine). The present invention relates to a technology related to a molding machine that can perform forward acceleration at a very rapid acceleration.

  For example, an electric type inline screw type injection molding machine as a molding machine generally employs a configuration in which only one servo motor (electric servo motor for injection) is used as a drive source for moving the screw back and forth. . By the way, in thin-walled and precision molding, it is essential for good molding to be able to start filling the molten resin quickly in the cavity, but in the configuration using a single injection electric servo motor, injection There is a certain limit to improving acceleration performance and deceleration performance (screw acceleration performance and deceleration performance). Even if a low-inertia and high-response servomotor is used as an injection electric servomotor, acceleration Achieving a raise time of about 30 ms or more is the limit at present.

  Therefore, by using two electric servomotors for injection, the rotation part of one ball screw mechanism is driven to rotate in the same direction by two electric servomotors for injection, improving injection acceleration performance and deceleration performance. Also known are injection molding machines. However, even with such a configuration, the improvement in the acceleration performance and deceleration performance of the injection is limited to about 30% as compared with the configuration using one electric servomotor.

  In addition, in the injection system mechanism, a nut servo motor for rotating the nut body and a screw servo motor for rotating the screw shaft are provided for one ball screw mechanism, and the nut servo motor and the screw servo are provided. A configuration in which the injection operation is controlled in cooperation with a motor is also known from Japanese Patent Publication No. 4-64492 (Patent Document 1) and Japanese Patent Laid-Open No. 9-104028 (Patent Document 2). In Patent Document 1, the rotation of the nut servo motor and the rotation of the screw servo motor cause the motor to rotate, but the screw does not move in the axial direction. From this state, the screw servo motor By making the rotation speed of the screw larger than that of the servo motor for nuts, the screw is advanced, and in particular, the control accuracy in the low speed range is improved. Further, in Patent Document 2, a clutch having a short life is created by creating a state suitable for low-speed injection and a state suitable for high-speed injection in cooperation with the rotation of the nut servo motor and the screw servo motor. It is possible to switch between low speed and high speed without using.

  However, in Patent Document 1, as described above, the rotation of the nut servo motor and the rotation of the screw servo motor cooperate to create a state in which the motor rotates but the screw does not move in the axial direction. However, this state continues until the acceleration of the two motors is completed (until the start-up of the two motors is completed), and the operation behavior of the screw in the acceleration and deceleration regions of the servo motor is taken into consideration. Therefore, the technical idea of improving the acceleration performance of the screw at the initial stage of injection (primary injection) and the deceleration performance at the end of the injection (primary injection) is not found in Patent Document 1.

  Patent Documents 1 and 2 disclose a technique in which high-speed injection is performed by rotationally driving both a nut servo motor and a screw servo motor in a direction in which the screw is advanced. However, even with such a configuration and operation, the acceleration performance of injection is the same as the configuration in which the rotating portion of one ball screw mechanism is rotationally driven in the same direction by the two electric servomotors for injection described above. There is a limit to the improvement of deceleration performance.

  Furthermore, in Patent Document 1 and Patent Document 2, the nut body and the screw shaft of one ball screw mechanism are individually driven to rotate by the nut servo motor and the screw servo motor. It is necessary to hold the nut body and the screw shaft in a rotatable manner, or to attach a rotation driven part to each of the nut body and the screw shaft. Therefore, the specification of the ball screw mechanism becomes special, and a commercially available general-purpose ball screw mechanism It is difficult to use as it is.

  Accordingly, the applicant of the present application has disclosed a molding machine capable of performing forward acceleration of an injection member (an injection member such as a screw or an injection plunger) with a very rapid acceleration, as described in Japanese Patent Application No. 2007-76868 (hereinafter referred to as Prior Application 1). It was proposed by FIG. 6 is a diagram showing a main configuration of an injection system mechanism of the injection molding machine according to the prior application 1.

  In FIG. 6, 101 is a head stock, 102 is a support plate that is arranged to face the head stock 101 at a predetermined distance, and 103 is fixed to the head stock 101 and the support plate 102 at both ends. A plurality of connection / guide bars 104, which are connected to the support plate 102, are inserted / guided by the connection / guide bar 103, and can move back and forth between the head stock 101 and the support plate 102. , 105 are also inserted / guided by the connection / guide bar 103 and can move back and forth between the head stock 101 and the support plate 102, and 106 has a base end portion attached to the head stock 101. A fixed heating cylinder, 107 is a nozzle provided at the tip of the heating cylinder 106, and 108 is resin injection at least at the time of injection. , A fixed side mold in which the nozzle 107 is pressed to the periphery, 109 is a movable side mold capable of moving back and forth with respect to the fixed side mold 108, and 110 is formed by both molds 108 and 109 in a clamped state. A cavity (molded product forming space) 111 is disposed in the heating cylinder 106 so as to be able to rotate and move forward and backward, and a screw (having its base end rotatably supported by the first linear motion block 104 ( The screw 111 is rotationally driven by a driving force of a metering electric servo motor (not shown) mounted on the first linear motion block 104 and integrated with the first linear motion block 104. It is designed to move forward and backward.

  112 is a first electric servomotor for screw linear movement mounted on the second linear motion block 105, 113 is a first drive pulley fixed to the output shaft of the first electric servomotor 112, and 114 is a first electric motor. A first ball screw mechanism 15 that converts rotation of the servo motor 112 into linear motion, 15 is a screw shaft of the first ball screw mechanism 114 that is rotatably held by the second linear motion block 105 (rotating portion of the first ball screw mechanism 114). , 116 are screwed into the screw shaft 115 and the end thereof is fixed to the first linear motion block 104, and moves forward and backward integrally with the first linear motion block 104 by the rotation of the screw shaft 115. A nut body of the first ball screw mechanism 114 (a linearly moving portion of the first ball screw mechanism 114) and 117 are fixed to the screw shaft 115 to rotate the first electric servo motor 112 for the first drive. Over Li 113, a first driven pulley which is transmitted via the first timing belt (not shown).

  118 is a second electric servomotor for direct drive of the screw mounted on the support board 102, 119 is a second drive pulley fixed to the output shaft of the second electric servomotor 118, and 120 is a second electric servomotor 118. Is a second ball screw mechanism 121 that converts the rotation of the second ball screw mechanism into a linear motion, 121 is a screw shaft of the second ball screw mechanism 120 that is rotatably held on the support plate 102 (rotating portion of the second ball screw mechanism 120), 122 is a screw shaft A nut of a second ball screw mechanism 120 that is screwed to 121 and that has an end fixed to the second linear motion block 105 and moves forward and backward integrally with the second linear motion block 105 by the rotation of the screw shaft 121. The body (the linear motion portion of the second ball screw mechanism 120) 123 is fixed to the screw shaft 121, and the rotation of the second electric servo motor 118 is illustrated in the second drive pulley 119. A second driven pulley which is transmitted via a second timing belt.

  In the configuration shown in FIG. 6, the rotation of the first electric servo motor 112 is applied to the screw shaft 115 of the first ball screw mechanism 114 via the first driving pulley 113, the first timing belt (not shown), and the first driven pulley 117. When the screw shaft 115 is transmitted, the nut body 116 moves in the axial direction along the screw shaft 115, and the first linear motion block 104 and the screw 111 integrally move forward and backward in the axial direction. Can be advanced. The rotation of the second electric servomotor 118 is transmitted to the screw shaft 121 of the second ball screw mechanism 120 via the second driving pulley 119, the second timing belt (not shown), and the second driven pulley 123, and the screw shaft By rotating 121, the nut body 122 moves in the axial direction along the screw shaft 121, and integrally with the nut body 122, the screw shaft 115 of the second linear motion block 105 and the first ball screw mechanism 114 and the first shaft 115. A member (such as a screw 111) transferred by the linear motion of the ball screw mechanism 114 can be moved back and forth in the axial direction.

  As described above, in the configuration shown in FIG. 6, the screw 111 can be transferred in the axial direction by either the rotation of the first electric servo motor 112 or the rotation of the second electric servo motor 118. The motor 112 and the second electric servo motor 118 are rotated synchronously so that the amount of advancement of the screw 111 due to the rotation of the first electric servomotor 112 is equal to the amount of retraction of the screw 111 due to the rotation of the second electric servomotor 118. Thus, it is possible to create a state in which the two servomotors 112 and 118 are rotating but the screw 111 is not moving in the axial direction.

  FIG. 7 is a diagram showing the acceleration principle of the injection member (here, the screw 111) of the prior application 1. In FIG. 7, the horizontal axis represents time, and the vertical axis represents speed (relative speed). As shown in FIG. 7, prior to actual injection (prior to advancement of the screw 111), the first electric servomotor 112 is started to rotate in a first rotational direction Ra1 in which the screw 111 is advanced. The rotation speed of 112 is accelerated, and the second electric servo motor 118 is started to rotate in the second rotation direction Rb2 for moving the screw 111 backward to accelerate the rotation speed of the second electric servo motor 118, and the screw 111 starts injection. When the first electric servo motor 112 and the second electric servo motor 118 are synchronously accelerated and controlled under the control of a controller (not shown) so as to stay in the position, the first electric servo motor 112 The rotational speed and the rotational speed of the second electric servo motor 118 increase, and the rotational inertia force of the rotating system also increases. Here, the timing tm at which the rotational speed of the first electric servomotor 112 is accelerated to the predetermined maximum speed Vm (not necessarily the maximum speed that the motor can output) set in the first rotational direction Ra1, that is, the second The member (here, the second linear motion block 105) linearly driven by the second electric servomotor 118 at the timing tm when the rotation speed of the electric servomotor 118 in the second rotation direction Rb2 is accelerated to the predetermined speed −Vm. When the backward movement is forcibly blocked, the screw 111 is advanced at a stroke and accelerated to the speed Vm with a vertical acceleration characteristic, ignoring the static inertia and the like. Thus, the screw 111 (injection member) of the prior application 1 is controlled so as to release the sufficiently increased acceleration in the first rotation direction Ra1 of the first electric servomotor 112 at a stretch and advance the screw 111 forward. ) Acceleration principle.

  FIG. 8 is a diagram illustrating an example of the forward control (primary injection control) of the screw 111 proposed in the prior application 1. In the example shown in FIG. 8, the first electric servo motor 112 starts to rotate in the first rotation direction Ra1, and the second electric servo motor 118 starts to rotate in the second rotation direction Rb2. The screw 111 holds the injection start position until the timing tn1 when the rotational speeds of 112 and the second electric servomotor 118 reach (accelerate) the predetermined speeds Vn1 and −Vn1, respectively. When the timing tn1 is reached, the rotation speed of the second electric servomotor 118 in the second rotation direction Rb2 is decreased while the rotation acceleration of the first electric servomotor 112 in the first rotation direction Ra1 is continued, and the second electric servomotor. At the timing tn2 when the rotational speed of 118 becomes −Vn2, the backward movement of the second linear motion block 105 is forcibly stopped by bringing the second linear motion block 105 into contact with the support plate 102. And by taking the control method as described above, during the period from the timing tn1 to the timing tn2, the sufficiently increased acceleration of the first electric servo motor 112 in the first rotation direction Ra1 is released at a stretch, and the screw 111 is released. The screw 111 is rapidly accelerated from a speed of 0 (zero) to a predetermined maximum speed Vn3 so that the screw 111 is rapidly advanced.

In the prior application 1, by adopting the configuration and the control method as described above, a molding machine capable of performing forward acceleration of the screw 111 (injection member) with very rapid acceleration is realized. In the prior application 1, two ball screw mechanisms, a first ball screw mechanism 114 and a second ball screw mechanism 120, are provided corresponding to the first electric servo motor 112 and the second electric servo motor 118, respectively. Although the number of ball screw mechanisms increases compared to the configurations of 1 and 2, a general-purpose ball screw mechanism that is not a special specification can be used, making it easy to manufacture a machine (molding machine) and attaching a load cell unit. Can follow the conventional method.
Japanese Examined Patent Publication No. 4-64492 JP-A-9-104028

  By the way, the structure of the injection system mechanism of the molding machine proposed in the prior application 1 is such that the first ball screw mechanism 114 and the second ball screw mechanism 120 are arranged in-line on a straight line as shown in FIG. It was. For this reason, the total length of the machine (molding machine) has become longer, and it has been necessary to increase the installation space accordingly.

  The present invention has been made in view of the above points, and its object is to perform forward acceleration of the injection member at a very rapid acceleration as proposed in the prior application 1 (Japanese Patent Application No. 2007-76868). In a molding machine capable of reducing the total length of a machine (molding machine).

  In order to achieve the above-described object, the present invention provides an injection member that can move forward and backward, a first linear motion block that holds a base end portion of the injection member, and the linear motion portion of the first linear motion block. A first ball screw mechanism to which the rotating portion of the first ball screw mechanism is rotated, a second linear motion block rotatably holding the rotating portion of the first ball screw mechanism, In the molding machine, comprising: a second ball screw mechanism whose linear motion portion is fixed to the second linear motion block; and a second servo motor that rotationally drives the rotating portion of the second ball screw mechanism. And a part of the components of the first ball screw mechanism and a part of the components of the second ball screw mechanism are arranged in a molding machine. Over looking in the length direction Tsu is up to arrange.

  The present invention includes a first ball screw mechanism and a first servo motor capable of moving the injection member forward and backward, and a second ball screw mechanism and a second servo motor capable of moving the injection member forward and backward, and forward acceleration of the injection member. In a molding machine capable of performing rapid acceleration at a very rapid acceleration, a part of the components of the first ball screw mechanism and a part of the components of the second ball screw mechanism are overlapped when viewed in the length direction of the molding machine. Therefore, the total length of the machine (molding machine) can be made shorter than the configuration of the prior application 1 by the overlapping amount.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 5 relate to an inline screw type injection molding machine according to an embodiment of the present invention (hereinafter referred to as the present embodiment), and FIG. 1 illustrates the configuration of an injection system mechanism of the injection molding machine of the present embodiment. 2 is a simplified front view of the injection system mechanism of the injection molding machine of the present embodiment, and FIG. 3 is a diagram of three electric servo motors in the injection system mechanism of the injection molding machine of the present embodiment. It is explanatory drawing which shows arrangement | positioning relationship.

  1 to 3, 1 is an injection system base board, 2 is a rail member laid on the injection system base board 1, and 3 is a linear guide 4 that can run on the rail member 2 at a lower portion thereof. The head stock 5 is disposed opposite to the head stock 3 at a predetermined distance, and a support plate having a linear motion guide 6 that can run on the rail member 2 fixed to the lower portion of the head stock 5. The four connection / guide bars 8 fixed to the support plate 5 and connecting the head stock 3 and the support plate 5 have a linear guide 9 capable of traveling on the rail member 2 fixed to the lower part thereof. The first linear motion block 10 that can move back and forth between the head stock 3 and the support plate 5 is fixed to the lower portion thereof with a linear motion guide 11 that can run on the rail member 2 to support the head stock 3. The second linear motion block that can move forward and backward with the board 5 , 12 is a heating cylinder whose base end is fixed to the headstock 3, 13 is a nozzle provided at the tip of the heating cylinder 12, and 14 is capable of rotating and moving back and forth in the heating cylinder 12. A screw (injecting member) 16, which is disposed and fixed to a rotating body 15 whose base end portion is rotatably held by the first linear motion block 8, 16 is a measurement mounted on the first linear motion block 8. The electric servomotor 17 is a driving pulley fixed to the output shaft of the metering electric servomotor 16 for screw rotation, 18 is a driven pulley fixed to the rotating body 15, and 19 is a rotation of the driving pulley 17. It is a timing belt that is transmitted to the driven pulley 18. The rotation of the metering electric servomotor 16 is transmitted to the screw 14 via the driving pulley 17, the timing belt 19, the driven pulley 18, and the rotating body 15.

  Further, 20 is a first linear motion electric servomotor for screw linear motion mounted on the second linear motion block 10, 21 is a drive pulley fixed to the output shaft of the first linear motion electric servomotor 20, 22 is , A driven pulley that transmits the rotation of the drive pulley 21 via the timing belt 23, a first ball screw mechanism 24 that converts the rotation of the first linear motion electric servomotor 20 into a linear motion, and 25 a second linear motion A screw shaft (rotating portion of the first ball screw mechanism 24) 26 of the first ball screw mechanism 24, which is rotatably held by the block 10 and has a driven pulley 22 fixed to the end thereof, is screwed to the screw shaft 25. The first ball screw is fixed to the first linear motion block 8 through the load cell block 27 and is moved forward and backward integrally with the first linear motion block 8 by the rotation of the screw shaft 25. A nut mechanism 24 (linear motion portion of the first ball screw mechanism 24).

  Also, 28 is a second linear motion electric servomotor for screw linear motion mounted on the support board 5, 29 is a drive pulley fixed to the output shaft of the second linear motion electric servomotor 28, and 30 is a drive pulley. 29 is a pair of driven pulleys that transmit the rotation of 29 via the timing belt 31, 32 is a pair of second ball screw mechanisms that convert the rotation of the second linear motion electric servomotor 28 into a linear motion, and 33 is a support The screw shaft (rotating portion of the second ball screw mechanism 32) 34 of the second ball screw mechanism 32, which is rotatably held by the panel 5 and has the driven pulley 30 fixed to the end thereof, is screwed to the screw shaft 33. In addition, the nut body (second ball screw mechanism 32) is fixed and held by the second linear motion block 10 and moves forward and backward integrally with the second linear motion block 10 by the rotation of the screw shaft 33. It is a linear movement portion). In the present embodiment, the acceleration / deceleration performance of the second linear motion electric servomotor 28 is superior to that of the first linear motion electric servomotor 20.

  The entire injection system mechanism shown in FIGS. 1 and 2 can be moved back and forth on the rail member 2 by a known nozzle touch / nozzle back mechanism and a nozzle touch / nozzle back motor, at least before the injection process. The injection system mechanism is held in the forward position, and takes a state (nozzle touch state) in which the tip of the nozzle 13 is pressed around the resin injection port of a fixed mold (not shown). In the nozzle touch state, the head stock 3, the support plate 5, and the heating cylinder 12 are maintained at fixed positions. Thus, the first linear motion block 8 and the second linear motion block 10 can move forward and backward on the rail member 2, respectively. The second linear motion block 10 is loosely inserted into the connection / guide bar 7 and corresponds to the four connection / guide bars 7 between the second linear motion block 10 and the support board 5. Four impact mitigating mechanisms 35 are provided. The impact relaxation mechanism 35 will be described later with reference to FIG.

  As shown in FIGS. 1 and 2, in this embodiment, the axial center line of the first ball screw mechanism 24 that converts the rotation of the first linear motion electric servo motor 20 into linear motion is an extension of the axial center line of the screw 14. The axial center line of the pair of second ball screw mechanisms 32 that are arranged on a line and convert the rotation of the second linear motion electric servomotor 28 into linear motion is parallel to the axial center line of the first ball screw mechanism 24. Is arranged. The pair of second ball screw mechanisms 32 are arranged in line symmetry with respect to the axial center line of the first ball screw mechanism 24, and a part of the components of the pair of second ball screw mechanisms 32 and the first A part of the components of the ball screw mechanism 24 is disposed so as to overlap when viewed in the length direction of the injection molding machine. Therefore, the total length of the machine (injection molding machine) is shorter than that of the configuration of the prior application 1 due to the overlap.

  As shown in FIGS. 1 and 3, in this embodiment, the electric servo for weighing is viewed from the right side or the left side of the machine (injection molding machine) (FIG. 3 is a view from the right side). The motor 16, the first linear motion electric servo motor 20 and the second linear motion electric servo motor 28 are arranged on the top, left and right. Thus, the three electric servo motors used in the injection system mechanism are arranged from the side of the machine. By arranging them on the top, left and right, the space factor of the motor arrangement can be made suitable, and three electric servo motors can be easily arranged between the headstock 3 and the support board 5. This also makes it possible to contribute to shortening the overall length of the machine (injection molding machine).

  1 to 3, the rotation of the first linear motion electric servomotor 20 is transmitted to the screw shaft 25 of the first ball screw mechanism 24 via the drive pulley 21, the timing belt 23, and the driven pulley 22. By rotating the screw shaft 25, the nut body 26 moves in the axial direction along the screw shaft 25, and the first linear motion block 8 and the screw 14 can move forward and backward in the axial direction integrally with the nut body 26. It is like that. The rotation of the second linear motion electric servomotor 28 is transmitted to each screw shaft 33 of the paired second ball screw mechanism 32 through the driving pulley 29, the timing belt 31, and the paired driven pulley 30. As each screw shaft 33 rotates, each nut body 34 moves in the axial direction along each screw shaft 33 and is integrated with each nut body 34 so as to be integrated with the second linear motion block 10 and the first ball screw mechanism 24. A member (screw 14 or the like) transferred by the direct movement of the screw shaft 25 or the first ball screw mechanism 24 can be moved back and forth in the axial direction. Thus, in this embodiment, the screw 14 can be transferred in the axial direction by either the rotation of the first linear motion electric servomotor 20 or the rotation of the second linear motion electric servomotor 28. The electric servomotor 20 for movement and the electric servomotor 28 for second linear motion are rotated synchronously, and the advance amount of the screw 14 by the rotation of the electric servomotor 20 for first linear motion and the rotation of the electric servomotor 28 for second linear motion By making the amount of retraction of the screw 14 equal, it is possible to create a state in which the two linear motion electric servomotors 20 and 28 are rotating but the screw 14 is not moving in the axial direction.

  One example of forward control (control of primary injection) of the screw 14 of this embodiment will be described with reference to FIGS. FIG. 4 is an explanatory diagram showing an example of the screw forward control of the present embodiment, in which the horizontal axis represents time, the vertical axis represents speed (relative speed), and the time axis The changes in the rotational speed of the first linear electric servomotor 20, the rotational speed of the second linear electric servomotor 28, and the forward speed of the screw 14 are shown.

  In the injection standby state in which the weighing and the suckback performed as necessary are completed, the screw 14 is at the injection start position (predetermined reverse position). In the injection standby state, when the timing t1 immediately before the primary injection start timing shown in FIG. 4 is reached, the first linear motion electric servo is controlled under the control of a controller (not shown) that controls the entire machine (injection molding machine). The motor 20 is started to rotate in the first rotation direction Ra1 in which the screw 14 is moved forward, the rotational speed of the first linear motion electric servomotor 20 is accelerated, and the second linear motion electric servomotor 28 is moved backward in the screw 14. The rotation is started in the two rotation directions Rb2, the rotation speed of the second linear motion electric servomotor 28 is accelerated, and the rotation speeds of the first linear motion electric servomotor 20 and the second linear motion electric servomotor 28 are respectively set to a predetermined speed V1, The screw 14 is held at the injection start position until the timing t2 at which -V1 is reached (accelerated). At this time, although the screw 14 is held at the injection start position, the nut body 26 of the first ball screw mechanism 24 moves forward with respect to the screw shaft 25, and the nut body 34 of the second ball screw mechanism 32 is screwed. Accordingly, the second linear motion block 10 is retracted.

  Timing at which the rotational speed of the first linear motion electric servomotor 20 in the first rotational direction Ra1 is accelerated to V1 and the rotational speed of the second linear motion electric servomotor 28 in the second rotational direction Rb2 is accelerated to -V1. At t2, the controller (not shown) continues the rotational acceleration of the first linear motion electric servomotor 20 in the first rotational direction Ra1, and the rotational speed of the second linear motion electric servomotor 28 in the second rotational direction Rb2. Is rapidly decelerated, thereby releasing the sufficiently increased acceleration in the first rotation direction Ra1 of the first linear electric servomotor 20 at a stretch, whereby the screw 14 is started to be driven forward with rapid acceleration. Since the rotation in the second rotation direction Rb2 of the second linear motion electric servomotor 28 is a rotation direction in which the second linear motion block 10 is moved backward, after the timing t2, the second rotation of the second linear motion electric servomotor 28 is performed. At the timing t3 when the rotational speed in the direction Rb2 is decelerated to −V2, in the screw forward control of this example, the second linear motion block 10 is received by the support board 2 via the impact relaxation mechanism 35, so that the second The linear motion block 10 is forcibly prevented from moving backward. Further, at the timing t3, the controller (not shown) ends the rotation acceleration of the first linear motion electric servomotor 20, thereby rotating the first linear motion electric servomotor 20 in the first rotational direction Ra1. The speed is set to a predetermined maximum speed V3 (not necessarily the maximum speed that the motor can output), and after timing t3, the first linear motion electric servomotor 20 is controlled at a constant speed in the first rotational direction Ra1. Switch to. Accordingly, the screw 14 that has started forward acceleration at the timing t2 is rapidly accelerated from the speed 0 (zero) to the speed V3 between the timing t2 and the timing t3. For example, the screw 14 is accelerated with a G-digit acceleration of a two-digit order, and the forward acceleration time of the screw 14 from timing t2 to timing t3 is about several ms (several milliseconds).

  As described above, after the timing t3, the controller (not shown) switches the control of the first linear motion electric servo motor 20 to the constant speed rotation control in the first rotation direction Ra1, and also after the timing t3, The controller (not shown) continues the deceleration control of the rotational speed of the second linear motion electric servomotor 28 in the second rotational direction Rb2, and sets the rotational speed of the second linear motion electric servomotor 28 to 0 (zero) at timing t4. And Thus, the screw 14 is driven forward at a constant speed by the constant rotational speed V3 in the first rotational direction Ra1 of the first linear motion electric servomotor 20 after the timing t3.

  Next, the controller (not shown) switches the rotation control of the first linear motion electric servomotor 20 from the constant speed rotation control at the rotation speed V3 to the deceleration control when the predetermined time elapses from the timing t4 to the timing t5. The first linear motion electric servomotor 20 decelerates the rotational speed in the first rotational direction Ra1, and the second linear motion electric servomotor 28 advances the screw 14 (advances the second linear motion block 10). By starting the rotation in one rotation direction Rb1, and accelerating the rotation speed of the second linear motion electric servomotor 28, the rotation speed in the first rotation direction Rb1 of the second linear motion electric servomotor 28 reaches a predetermined speed V4. Until the timing t6, the screw 14 is kept at constant speed advance corresponding to the motor rotation speed V3.

  Next, when the controller (not shown) reaches the above-described timing t6, the first linear motion electric servomotor 28 continues to decelerate in the first rotational direction Ra1 of the first linear motion electric servomotor 20 and continues to the first linear motion electric servomotor 28. The screw 14 is controlled to be rapidly stopped by rapidly decelerating the rotation speed in the rotation direction Rb1. As a result, the primary injection completion timing t7 when the screw 14 stops moving forward is reached. As described above, the rotation speed in the first rotation direction Rb1 of the second linear motion electric servomotor 28 is rapidly decelerated from the acceleration while the rotation deceleration in the first rotation direction Ra1 of the first linear motion electric servomotor 20 is continued. Since the screw 14 is rapidly stopped, the sufficiently reduced deceleration in the first rotational direction Ra1 of the first linear motion electric servomotor 20 is released at a time, and at the same time, the second linear motion electric servomotor 28 By adding the rapid deceleration in the first rotation direction Rb1 to this, the screw 14 can be controlled to stop, whereby the forward deceleration of the screw 14 can be performed with extremely rapid deceleration. It is possible to obtain a deceleration performance equivalent to or better than

  Next, the impact mitigating mechanism 35 disposed between the support board 5 and the second linear motion block 10 will be described. As described above, four impact relaxation mechanisms 35 are provided corresponding to the four connection / guide bars 7, respectively. FIG. 5 is a cross-sectional view of the main part showing one shock relaxation mechanism 35 and its periphery. FIG. 5A shows a state where no load is applied to the shock relaxation mechanism 35, and FIG. The state where the maximum load is applied to the impact relaxation mechanism 35 is shown.

  As shown in FIG. 5, the impact mitigating mechanism 35 is loosely inserted into the connection / guide bar 7, and the first spring holding body 41 fitted and fixed to the second linear motion block 10, and the connection / guide bar 7. A plurality of second spring holders 42 slidably inserted in the first and second spring holders 41 and 42 and loosely inserted into the connection / guide bar 7. A flat spring 43 and a coil spring 44 disposed between the support plate 5 and the second spring holder 42 and inserted through the connection / guide bar 7 are configured. Compared to the spring constant of the coil spring 44, the spring constant of one flat spring 43 is set to be significantly larger. Therefore, the force to bend the four flat springs 43 is equal to one coil spring 44. It is much larger than the force required to compress. In this embodiment, the impact is mitigated by the cooperation of the four sets of impact mitigating mechanisms 35. When a load is applied to each of the impact mitigating mechanisms 35, first, the coil spring 44 is compressed to hold the second spring. The body 42 comes into contact with the support board 5, and then the flat spring 43 is bent to absorb a large load. For example, when the impact relaxation mechanism 35 transitions from the state shown in FIG. 5A to the state shown in FIG. 5B, the amount of bending of the four flat springs 43 is 2.5 mm, and this amount of bending is 2.5 mm. The amount can receive a load of 2500 kgf (24768 N) when the four sets of impact relaxation mechanisms 35 are combined. The spring specification can be arbitrarily selected according to the set load, and it is needless to say that the spring specification can accept a load greatly exceeding 2500 kgf.

  By providing the impact mitigating mechanism 35 as described above, as described above, the second linear motion electric servomotor 28 is rotating in the rotational direction in which the second linear motion block 10 is moved backward. Even if the control is performed so as to forcibly prevent the backward movement of the second linear motion block 10, when the backward movement is forcibly blocked, the coil spring 44 of the impact relaxation mechanism 35 is first compressed, After the second spring holder 42 abuts the support board 5 relatively softly and the second spring holder 42 abuts the support board 5, a large load applied to the impact relaxation mechanism 35 is a robust flat spring 43. Since it absorbs by bending, there is almost no impact which a mechanical contact part receives, and generation | occurrence | production of an impact sound is also suppressed as much as possible.

It is a perspective view which shows the structure of the injection system mechanism of the injection molding machine which concerns on one Embodiment of this invention. 1 is a simplified cutaway front view of an injection system mechanism of an injection molding machine according to an embodiment of the present invention. It is explanatory drawing which shows the arrangement | positioning relationship etc. of three electric servomotors in the injection system mechanism of the injection molding machine which concerns on one Embodiment of this invention. It is explanatory drawing which shows the mode of one example of screw advance control in the injection molding machine which concerns on one Embodiment of this invention. It is a principal part cross section which shows the impact mitigation mechanism and its periphery in the injection type | system | group mechanism of the injection molding machine which concerns on one Embodiment of this invention. It is explanatory drawing which shows the structure of the injection system mechanism of the injection molding machine by a prior application. It is explanatory drawing which shows the acceleration principle of the screw by a prior application. It is explanatory drawing which shows the mode of one example of screw advance control in the injection molding machine by a prior application.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Injection system base board 2 Rail member 3 Headstock 4 Linear motion guide 5 Support panel 6 Linear motion guide 7 Connection / guide bar 8 First linear motion block 9 Linear motion guide 10 Second linear motion block 11 Linear motion guide 12 Heating cylinder DESCRIPTION OF SYMBOLS 13 Nozzle 14 Screw 15 Rotating body 16 Electric servomotor for measurement 17 Drive pulley 18 Driven pulley 19 Timing belt 20 First linear motion electric servomotor 21 Drive pulley 22 Driven pulley 23 Timing belt 24 First ball screw mechanism 25 Screw shaft (first shaft Ball screw mechanism rotating part)
26 Nut body (linear motion part of the 1st ball screw mechanism)
27 Load cell block 28 Electric servo motor for second linear motion 29 Drive pulley 30 Driven pulley 31 Timing belt 32 Second ball screw mechanism 33 Screw shaft (rotating part of second ball screw mechanism)
34 Nut body (linear motion part of the second ball screw mechanism)
35 Shock Mitigation Mechanism 41 First Spring Holder 42 Second Spring Holder 43 Sarah Spring 44 Coil Spring

Claims (3)

An injection member capable of moving back and forth, a first linear motion block holding a base end portion of the injection member, a first ball screw mechanism having the linear motion portion fixed to the first linear motion block, A first servo motor that rotationally drives the rotating part of the one ball screw mechanism, a second linear motion block that rotatably holds the rotating part of the first ball screw mechanism, and the linear motion part fixed to the second linear motion block A molding machine comprising: the second ball screw mechanism, and a second servo motor that rotationally drives the rotating portion of the second ball screw mechanism;
The axial center line of the first ball screw mechanism and the axial center line of the second ball screw mechanism are arranged in parallel, and a part of the components of the first ball screw mechanism and a part of the components of the second ball screw mechanism Are arranged so as to overlap each other when viewed in the length direction of the molding machine. The molding machine according to claim 1,
Either the axial center line of the first ball screw mechanism or the axial center line of the second ball screw mechanism is disposed on an extension line of the axial center line of the injection member, and the axial center line of the first ball screw mechanism or Either one of the axial center lines of the second ball screw mechanism is arranged in parallel with an extension line of the axial center line of the injection member, and the axial center line is parallel to an extension line of the axial center line of the injection member. There is a plurality of ball screw mechanisms arranged in the molding machine. The molding machine according to claim 1 or 2,
The injection member is a screw capable of rotating and moving back and forth, and a third servo motor for rotating the screw, the first servo motor, and the second servo motor are arranged on the right side surface of the molding machine or A molding machine characterized by being arranged on the top, left and right as viewed from the left side.

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