JP2007210000A - Electric injection device and injection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric injection device and an injection method with a simple constitution where, when a plunger tip inserted into a plunger sleeve is driven by an electric motor, and a fluidized forming material is injected into a die, the progressive driving of the plunger tip can be easily and swiftly shifted from a low speed injection stage to a high speed injection stage at a desired speed with high precision. <P>SOLUTION: This device comprises: a low speed electric mechanism 3 where the rotation of an electric motor 30 is converted into a linear motion, and a plunger tip 2 is progressively driven at a relatively low speed, so as to perform a low speed injection stage; a one way clutch mechanism 4 where the relatively retreat of the plunger tip 2 is prevented, and also, the relative progression is allowed to the low speed electric mechanism 3; and a high speed electric mechanism 5, wherein the rotation of the electric motor 50 is converted into a linear motion, and the plunger tip 2 progressively driven at a low speed by the low speed electric mechanism 3 via the one way clutch mechanism 4 is progressively driven at a speed higher than that in the low speed injection stage, so as to perform a high speed injection stage. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electric injection device and an injection method, and more specifically, a plunger chip fitted in a plunger sleeve is driven by an electric motor to inject a fluidized molding material into a mold at a desired pressure and speed. The present invention relates to an electric injection device and an injection method.

  For example, in a die casting machine, using an injection device in which a plunger tip is slidably fitted in a plunger sleeve, the molten metal (molten metal) is injected and filled into a mold cavity and solidified. Holds up to. As a mechanism for driving at least the plunger tip of the injection device forward, a mechanism using a hydraulic cylinder and an electric injection device using an electric motor are known.

  As shown in FIG. 8, the conventional general electric injection apparatus has a rotation-linear motion conversion mechanism that converts the rotation of the electric motor 60 into linear motion. The rotation-linear motion conversion mechanism is generally composed of a ball screw mechanism 6 that converts the rotation of the electric motor 60 into a linear motion, and includes a reduction means 61 that decelerates the rotation of the electric motor 60 at a predetermined ratio as necessary. I have. The ball screw mechanism 6 includes a ball screw shaft 62 rotated around an axis, a drive member 63 having a ball screw nut screwed to the ball screw shaft 62, and a bearing 64 that supports the ball screw shaft 62 so as to be rotatable around the axis. The drive member 63 is connected to the drive rod 2a ′ of the plunger tip 2 ′.

  By the way, in an injection apparatus, it is generally known that, in one injection process, a low pressure injection process is changed to a high speed injection process, and then a pressurizing process is performed to keep the pressure increased to a predetermined pressure. . Therefore, in the conventional general electric injection device shown in FIG. 8, the rotational speed of the electric motor 60 is controlled to switch from the low-speed injection process to the high-speed injection process.

For example, Patent Document 1 is known as an electric injection device for switching to a low-speed injection process, a high-speed injection process, and a pressure increase / hold pressure process (pressurization process).
Patent Document 1 discloses an electric injection die casting machine that converts rotation of an electric servomotor for injection into linear motion, and fills and pressurizes plastic metal in an injection sleeve into a mold cavity by forward movement of a plunger tip. A flywheel device mounted on the injection electric servomotor via a power supply clutch; and the rotational energy of the injection electric servomotor is stored in the flywheel device, and the high speed injection operation at the time of filling and pressurizing And a control mechanism that performs the power supply timing of the stored rotational energy to the injection electric servomotor in the boosting / holding operation by ON / OFF control of the power supply clutch, etc. A featured electric injection die casting machine is disclosed.

  Patent Document 1 states that “the flywheel device for supplying power to the electric servomotor for injection is provided, so that the necessary output can be obtained by supplying power from the flywheel device. High-speed injection operation and pressurizing / holding operation at the time of filling and pressurizing plastic metal can be performed without increasing the output of the motor. ”(0006)“ And power supply timing at this time is power supply. Since the clutch is controlled by ON / OFF control of the clutch, the inertial force of the flywheel device can be cut off by turning off the power supply clutch, so there is no reduction in responsiveness. "(0007) Injecting with an electric servomotor for a motor makes it easy to change the injection speed in multiple steps, and makes it possible to set the optimum injection speed. "(0008) It has been described.

JP 2000-33472 A

  However, in the electric injection apparatus configured as shown in FIG. 8 among the above conventional techniques, when switching from the low-speed injection process to the high-speed injection process, the electric motor 60, the speed reducer 61, the ball screw shaft Since the moment of inertia 62 becomes an acceleration resistance and the acceleration of the plunger tip 2 'does not easily increase, it takes time to reach the set speed of the high-speed injection process from the low-speed injection process, and the stroke (ie, the ball screw And the like, it becomes difficult to obtain a set high speed in the high-speed injection process. And if these problems become large, it will become difficult to maintain the temperature of a molten metal, and it will become difficult to maintain the quality of a product by temperature fall.

  Furthermore, in the electric injection device shown in FIG. 8, when it is necessary to set a high pressure in the pressurizing step, it is necessary to increase the reduction ratio of the reduction means 61. However, if the speed reduction ratio of the speed reduction means 61 is increased, the maximum speed in the high-speed injection process is lowered, so that it is impossible to achieve both the speed in the high-speed injection process and the pressure in the pressurization process. In order to achieve this compatibility, it is conceivable to increase the size of the electric motor 60. In this case, however, the required electric power of the electric motor 60 increases and the moment of inertia of the electric motor 60 itself also increases. It becomes difficult to increase the acceleration of the plunger tip 2 '.

  Further, among the above conventional techniques, in Patent Document 1, since the power is supplied from the flywheel device via the power supply clutch in order to obtain a necessary output in the high-speed injection process, the structure and control are performed. There was a problem that became complicated. Further, in Patent Document 1, even if the acceleration of the injection speed when shifting from the low-speed injection process to the high-speed injection process can be set to a variable angle (θVP) (0040), this acceleration angle is limited. Therefore, it is difficult to accelerate rapidly from the low speed injection process to the high speed injection process with high responsiveness.

  The present invention has been made in view of the above-described problems. When a plunger chip fitted in a plunger sleeve is driven by an electric motor with a simple configuration, a fluidized molding material is injected into a mold. Another object of the present invention is to provide an electric injection device and an injection method that can quickly and accurately shift the forward movement of the plunger tip from the low-speed injection process to the high-speed injection process at a desired speed.

In order to achieve the above object, the electric injection device according to the first aspect of the invention injects fluidized molding material from the low-speed injection process to the high-speed injection by driving the plunger tip fitted in the plunger sleeve forward by the electric motor. An electric injection device for shifting to a process and injecting, a low-speed electric mechanism for performing a low-speed injection process by driving a plunger tip forward at a low speed, and a relative retraction of the plunger chip with respect to the low-speed electric mechanism A one-way clutch mechanism that allows relative advancement, and a high-speed electric mechanism that drives a plunger tip that is driven forward at a low speed by a low-speed electric mechanism through the one-way clutch mechanism at a high speed. It is characterized by having.
In order to achieve the above object, the invention according to the second aspect of the invention achieves the above object by moving the plunger tip fitted in the plunger sleeve forward by the electric motor forward and fluidizing the molding material fluidized from the low speed injection process to the high speed injection process. A one-way clutch mechanism that prevents the plunger tip from retreating relative to a low-speed electric mechanism that performs the low-speed injection step and allows relative advancement. Through the low-speed electric mechanism, the plunger tip is driven forward at low speed to perform a low-speed injection process, and the high-speed electric mechanism that performs the high-speed injection process is allowed to run to reach the set speed of the high-speed injection process. The chip is driven forward by the high-speed electric mechanism from a predetermined position to perform a high-speed injection process.

In the invention relating to the electric injection device according to the first aspect, the low-speed injection process is performed by driving the plunger tip forward at a low speed by the low-speed electric mechanism. At this time, the plunger tip is connected to the low-speed electric mechanism via the one-way clutch mechanism, and is prevented from moving backward relative to the low-speed electric mechanism and is allowed to move forward. In addition, the high-speed electric mechanism starts running that advances from the rear toward the plunger tip at a predetermined timing. The high-speed electric mechanism performs high-speed injection from the low-speed injection process at a speed that exceeds the speed of the plunger tip that is advanced at low speed relative to the plunger tip that is driven forward at low speed by the low-speed electric mechanism via the one-way clutch mechanism. Continue to move forward by engaging at a predetermined position to be transferred to the process. Therefore, since the plunger tip moves forward relative to the low speed electric mechanism by the one-way clutch, the plunger tip is driven forward at a speed by the high speed electric mechanism, and abruptly shifts from the low speed injection process to the high speed injection process. Note that the low-speed electric mechanism can perform a pressurizing step of increasing the pressure of the molding material to a predetermined pressure and holding it after completion of the high-speed injection step, if necessary.
In the invention according to the second aspect of the invention, the low speed injection process is performed by driving the plunger tip forward at a low speed set by the low speed electric mechanism via the one-way clutch. At this time, the one-way clutch mechanism prevents the plunger tip from retreating relative to the low-speed electric mechanism and allows relative advancement. Further, when performing the low speed injection process, the high speed electric mechanism is moved forward at a predetermined timing from the rear toward the plunger tip so as to reach the set speed of the high speed injection process faster than the low speed electric mechanism. Let it begin. Then, the high-speed electric mechanism performs high-speed injection from the low-speed injection process at a speed exceeding the speed of the plunger tip that is advanced at a low speed with respect to the plunger tip that is driven forward at a low speed by the low-speed electric mechanism via the one-way clutch mechanism As the plunger tip moves forward relative to the low-speed electric mechanism by the one-way clutch when engaged further at a predetermined position to be transferred to the process, it is set in the high-speed injection process by the high-speed electric mechanism. Driven forward at the set speed, abruptly shifts from the low speed injection process to the high speed injection process. When the high-speed injection process is completed, the pressurization process can be performed by increasing the pressure of the molding material to a predetermined pressure by a low-speed electric mechanism as necessary.

According to the first aspect of the present invention, the low-speed electric mechanism that performs the low-speed injection process by driving the plunger tip forward at low speed, the plunger chip is prevented from moving backward relative to the low-speed electric mechanism, and The plunger has a simple structure including a one-way clutch mechanism that allows a simple forward movement, and a high-speed electric mechanism that drives a plunger tip that is driven forward at a low speed by a low-speed electric mechanism through the one-way clutch mechanism at a high speed. Electric injection that allows the forward drive of the chip to be easily and accurately transferred from the low-speed injection process to the high-speed injection process at the desired speed quickly, and thus fluidized molding material can be injected at an appropriate speed An apparatus can be provided.
According to the second aspect of the present invention, the low-speed electric mechanism that performs the low-speed injection process prevents the plunger tip from moving backward relative to the low-speed electric mechanism, and allows the relative advance to move through the low-speed electric mechanism. The plunger tip is driven forward at a low speed by an electric mechanism to perform a low-speed injection process, and a high-speed electric mechanism that performs the high-speed injection process is run to reach a set speed of the high-speed injection process, and the plunger chip is moved from a predetermined position to the predetermined position. With a simple configuration in which a high-speed electric mechanism performs forward drive to perform a high-speed injection process, the forward drive of the plunger tip can be easily and accurately transferred from a low-speed injection process to a desired high-speed injection process quickly. It is possible to provide an injection method capable of injecting the fluidized molding material at an appropriate speed.

First, an embodiment of the electric injection apparatus of the present invention will be described in detail mainly based on FIG. 1 in the case of being applied to a die casting machine. In the drawings, the same reference numerals are given to similar or corresponding parts.
The electric injection apparatus of the present invention is generally driven by a forward drive of a plunger tip 2 fitted in a plunger sleeve 1 by an electric motor, and the fluidized molding material is transferred from a low-speed injection process to a high-speed injection process. A low-speed electric mechanism 3 that converts the rotation of the electric motor 30 into a linear motion to drive the plunger tip 2 forward at a relatively low speed to perform a low-speed injection process, and a plunger for the low-speed electric mechanism 3 The one-way clutch mechanism 4 that prevents the tip 2 from moving backward relative to the tip 2 and allows the relative advancement, and the rotation of the electric motor 50 is converted into a linear motion, and the low-speed electric mechanism 3 through the one-way clutch mechanism 4. A high-speed electric mechanism 5 that performs a high-speed injection process by driving the plunger tip 2 that is driven forward at a low speed by a high-speed drive faster than a low-speed injection process. There.

  A plunger tip 2 is slidably fitted into the plunger sleeve 1. A drive rod 2a is provided on the rear (right side in FIG. 1) end surface of the plunger tip 2, and a head 2b is provided on the rear end of the drive rod 2a. A metal material (molten metal) heated and melted as a fluidized molding material is supplied into the plunger sleeve 1 from its hot water supply port, and the plunger tip 2 is moved to the left in FIG. 1 at a predetermined speed and force. As a result of the advance, the molten metal is injected into the mold at a predetermined speed and pressure.

  The low-speed electric mechanism 3 includes a servo motor 30 that can be controlled to rotate as an electric motor, a speed reduction means 31 that reduces the rotation of the electric motor 30 at a predetermined ratio, a ball screw shaft 32 connected to the speed reduction means 31, and a ball screw shaft. And a bearing 35 that supports the ball screw shaft 32 so as to be rotatable around the shaft. The speed reduction ratio by the speed reduction means 31 is sufficiently increased to a predetermined pressure by the driving force of the servo motor 30 to a predetermined pressure through the ball screw shaft 32 and the ball screw nut of the low speed driving member 33 in the pressurizing step described later. It is set so that it can be held.

  The one-way clutch mechanism 4 in the figure is conceptually shown and prevents the plunger tip 2 from retreating relative to the low-speed electric mechanism 3 and allows relative advancement, that is, in a low-speed injection process. Any combination of the head 2b and the low-speed drive member 33 and the head 2b can move forward free from the low-speed drive member 33 in the high-speed injection process, such as a ratchet mechanism, a dog clutch, or the head 2b. A known mechanism such as a hook for engaging with the low speed driving member 33 can be provided so as to correspond to the head 2 b at the rear end of the plunger chip 2 and the low speed driving member 33 of the low speed electric mechanism 3.

  The high-speed electric mechanism 5 includes a servo motor 50 that can be controlled for rotation as an electric motor, a ball screw shaft 52 that is directly connected to a rotation drive shaft of the servo motor 50, and a ball screw nut that is screwed to the ball screw shaft 52. A high-speed drive member 53 and a bearing 55 that supports the ball screw shaft 52 so as to be rotatable around the shaft are provided. The high-speed electric mechanism 5 can also be provided with a predetermined ratio of speed reduction or speed increasing means between the servo motor 50 and the ball screw shaft 52 as required. On the front surface of the high-speed drive member 53, a pressing member 53a that is pressed against the head 2b is provided. It should be noted that at least one of the pressing member 53a and the head 2b of the plunger chip 2 may be provided with a buffer mechanism for reducing the impact at the time of collision, which will be described later, as necessary. Further, at least one of the low-speed drive member 33 of the low-speed electric mechanism 3 and the high-speed drive member 53 of the high-speed electric mechanism 5 is connected to the head 2b in order to pull back and retract the plunger chip 2 after one injection process is completed. A mechanism may be provided. Further, in order to drive the head 2b forward at high speed by the high speed driving member 53, instead of the pressing member 53a, as shown conceptually in FIG. 5, the upper surface of the support member of the high speed driving member 53 provided with a ball screw nut, Clutch members 53b and 23b for coupling the corresponding side surfaces of the head 2b may be provided. Further, as conceptually shown in FIG. 6, the high-speed drive member 53 having a ball screw nut and the head 2b of the plunger chip 2 Link mechanisms 53c and 23c for coupling the wires, or a wire such as a flexible wire may be provided. The link mechanisms 53c and 23c transmit the forward drive force of the high-speed drive member 53 to the plunger tip 2 when extending linearly from the bent state (the state shown in FIG. 6).

  Comparing the low-speed electric mechanism 3 and the high-speed electric mechanism 5 configured as described above, the high-speed electric mechanism 5 has a ball screw more than the ball screw shaft 32 by the amount that does not include the speed reducing means 31 unlike the low-speed electric mechanism 3. The shaft 52 rotates at a high speed. Therefore, even when the servomotors 30 and 50 are driven and controlled at the same rotational speed, the high speed drive member 53 can move forward at a higher speed than the low speed drive member 33.

Next, the injection method of the present invention will be described in detail based on FIGS. 1 to 4 and FIG. 7 by using the electric injection device applied to the die casting machine configured as described above.
In the injection method of the present invention, generally, the plunger tip 2 fitted in the plunger sleeve 1 is driven forward by an electric motor to cause the fluidized molding material to be transferred from the low-speed injection process to the high-speed injection process for injection. The one-way clutch mechanism 4 that prevents the head 2b of the plunger tip 2 from retreating relative to the low-speed drive member 33 of the low-speed electric mechanism 3 that performs the low-speed injection process and that allows relative advancement. Accordingly, the low-speed electric mechanism 3 drives the plunger tip 2 at low speed to perform the low-speed injection process, and the high-speed driving member 53 of the high-speed electric mechanism 5 that performs the high-speed injection process reaches the set speed of the high-speed injection process. The high-speed electric mechanism 5 is driven at a predetermined position with respect to the head 2b of the plunger chip 2 that is driven forward and driven forward at a low speed by the low-speed electric mechanism 3. Speed and performs high-speed injection step by a driving member 53 to collide further to maintain its forward drive.

  When the molten metal is injected into the mold, first, as shown in FIG. 1, the plunger tip 2, the low-speed drive member 33 of the low-speed electric mechanism 3, and the high-speed drive member 53 of the high-speed electric mechanism 5 are positioned at the retreat limit. Therefore, in the one-way clutch mechanism 4, the head 2 b of the plunger tip 2 is located at the backward limit with respect to the low-speed drive member 33. When a predetermined amount of molten metal is supplied into the plunger sleeve 1 in this state, the servo motor 30 is driven to rotate as shown in FIG. 2, and the ball screw shaft 32 is rotated around the axis at a predetermined reduction ratio via the speed reduction means 31. The low-speed drive member 33, which is rotationally driven at the same time and screwed with the ball screw nut, is driven forward to the left in the figure at a predetermined speed, and the head 2b is relatively moved by the one-way clutch mechanism 4 with respect to the low-speed drive member 33. Since the backward movement is prevented, the plunger tip 2 moves forward following the forward movement of the low speed driving member 33, and the low speed injection process is performed. At this time, the rotational speed of the servo motor 30 of the low-speed electric mechanism 3 is constant, and therefore the forward speed of the low-speed drive member 33 is constant as shown in FIG.

  In the initial stage of the low-speed injection process, the servo motor 50 of the high-speed electric mechanism 5 is not yet driven, so that the head 2b of the plunger tip 2 is separated from the pressing member 53a of the high-speed drive member 53. Then, as shown in FIG. 7B, a change in the forward speed by the high-speed electric mechanism 5, the drive of the servo motor 50 of the high-speed electric mechanism 5 is started after a predetermined time has elapsed from the start of driving the servo motor 30 of the low-speed electric mechanism 3. Is started, the high-speed drive member 53 accelerates its forward speed to a set speed (that is, to run up), and thereafter, a point in time when the plunger tip 2 should move from the low-speed injection process to the high-speed injection process. Thus, the pressing member 53a of the high-speed driving member 53 collides with the head 2b of the plunger chip 2. At this time, since the high-speed driving member 53 has a speed set in the run-up, the momentum due to the moment of inertia is given to the plunger tip 2, and the change in the forward speed of the plunger tip 2 is shown in FIG. As shown, the plunger tip 2 that has been performing the low-speed injection process is immediately and quickly shifted to the high-speed forward drive. As shown in FIG. 3, the head 2b of the plunger tip 2 is allowed to move forward relative to the low speed drive member 33 by the one-way clutch 4, so that the high speed drive member 53 further moves forward. As a result, the high-speed injection process is stably performed. Note that the drive start timing of the servo motor 50 of the high speed electric mechanism 5 is the position and timing at which the low speed injection process is shifted to the high speed injection process, the forward speed of the low speed drive member 33 of the low speed electric mechanism 3, and the high speed electric mechanism 5. This can be determined by calculating backward from the time and stroke required for the high speed drive member 53 to accelerate to the set speed. Further, the speed at which the high-speed drive member 53 is accelerated (the maximum speed in FIG. 7B) is calculated in reverse so that it becomes a desired speed when the high-speed drive member 53 is engaged with the head 2b and continues to drive forward. Is set by

  When the high-speed drive member 53 reaches the forward limit or advances to a predetermined position and the drive of the servo motor 50 is stopped, the plunger tip 2 is moved with respect to the low-speed drive member 33 by the one-way clutch 4 as shown in FIG. The relative retraction of the head 2b is restricted, and the servo motor 30 of the low speed electric mechanism 3 is driven via the speed reducing means 31, so that the plunger tip 2 is melted in the plunger sleeve 1 with a predetermined pressure. The pressure is increased and held to perform the pressurizing step.

  As described above, in the present invention, the low-speed electric mechanism 3 is not simply divided into the low-speed injection process by the low-speed electric mechanism 3 and the high-speed injection process by the high-speed electric mechanism 5 but via the one-way clutch mechanism 4. The high-speed drive member 53 of the high-speed electric mechanism 5 that is accelerated to the set speed by the running is collided, collided, or coupled to the plunger chip 2 that is driven forward at a low speed by a predetermined time. Since it is configured to be driven forward at a high speed, it is possible to shift from the low speed injection process to the high speed injection process easily and accurately, and the forward drive speed of the plunger tip 2 is low speed injection. It can be realized with high accuracy as set in the process and the high-speed injection process.

It is explanatory drawing which showed notionally one Embodiment of the electric injection apparatus of this invention in the state before the injection start. It is explanatory drawing which showed notionally the state which performs a low-speed injection process from the state of FIG. It is explanatory drawing which showed notionally the state which performs a high-speed injection process from the state of FIG. It is explanatory drawing which showed notionally the state which performs a pressurization process from the state of FIG. It is explanatory drawing which partially showed another embodiment which provided the clutch member in order to couple | bond a high-speed drive member with respect to the head of a plunger chip | tip. It is explanatory drawing which showed partially another embodiment which provided the link mechanism in order to couple | bond a high-speed drive member with respect to the head of a plunger chip | tip. It is a graph which shows the change of the advance speed with respect to time passage of (a) low-speed electric mechanism, (b) high-speed electric mechanism, and (c) plunger tip by this invention, respectively. It is explanatory drawing which showed the conventional electric injection apparatus notionally.

Explanation of symbols

1: Plunger sleeve, 2: Plunger tip, 3: Low speed electric mechanism, 4: One-way clutch, 5: High speed electric injection device, 30: Servo motor (electric motor): 31: Deceleration means, 32: Ball screw shaft, 33: Ball A low-speed drive member having a screw nut,
50: Servo motor (electric motor), 52: Ball screw shaft, 55: High speed drive member having ball screw nut

Claims (2)

An electric injection device for causing a plunger chip fitted in a plunger sleeve to be driven forward by an electric motor to inject the fluidized molding material from a low-speed injection process to a high-speed injection process,
A low-speed electric mechanism that performs a low-speed injection process by driving the plunger tip forward at low speed;
A one-way clutch mechanism that prevents the plunger tip from retreating relative to the low-speed electric mechanism and that allows relative advancement;
A high-speed electric mechanism for driving a plunger tip that is driven forward at a low speed by a low-speed electric mechanism through the one-way clutch mechanism at a high speed;
An electric injection device comprising: An injection method for causing a plunger tip fitted in a plunger sleeve by an electric motor to move forward to cause a fluidized molding material to be transferred from a low-speed injection step to a high-speed injection step, and to be injected,
The plunger tip is moved at a low speed by the low-speed electric mechanism through a one-way clutch mechanism that prevents the plunger tip from retreating relative to the low-speed electric mechanism that performs the low-speed injection process and allows relative advancement. Is driven forward to perform the low-speed injection process, and the high-speed electric mechanism that performs the high-speed injection process is allowed to run to reach the set speed of the high-speed injection process,
An injection method characterized in that a high-speed injection process is performed by driving a plunger tip forward from a predetermined position by the high-speed electric mechanism.

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