JP2020037225A - Two plate-type injection device - Google Patents

Abstract

To provide a two plate type injection device which facilitates attachment/detachment of a ring type load cell that is arranged coaxially with a screw shaft.SOLUTION: A two plate type injection device includes a screw shaft storage part 42 which attachably/detachably stores a rear end of a screw 4, a screw rotation support shaft 44 having a rotation support shaft part 43 continuously configured on the rear part of the screw shaft storage part 42, and a rotation support member 45 which supports the screw rotation support shaft 44 so as to be rotatable with respect to a moving plate 3, in which the screw rotation support shaft 44 and the rotation support member 45 are stored in a rotation support member storage through hole 46 longitudinally passing through the moving plate 3, a retainer which controls movement in an axial direction of the screw 4 of the rotation support member 45 in the rotation support member storage through hole 46 is arranged in an opening of the rotation support member storage through hole 46 on the rear part of the moving plate 3, and the retainer is configured as a ring type load cell 47.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a two-plate injection device used for injection molding.

  The in-line screw type injection device of the injection molding machine includes a fixed plate, a movable plate provided so as to be able to advance and retreat with respect to the fixed plate, a screw supported by the movable plate so as to be rotatable about an axis, and A screw barrel rotatably provided with a cylinder barrel accommodated so as to be able to advance and retreat in the axial direction, and by moving the movable plate forward and backward with respect to the fixed plate, the screw is rotatable within the cylinder barrel and is capable of moving forward and backward. It is an injection device.

  The above-described in-line screw type injection devices are roughly classified into two types according to a configuration in which the movable plate can move forward and backward with respect to the fixed plate. One is a two-plate injection device as disclosed in Patent Document 1. The two-plate injection device includes a driving unit (an electric motor or the like) for moving the moving plate (moving frame) relative to the fixed plate (the fixed frame), a driving unit (an electric motor or the like) for rotating the screw, The mainstream is a configuration in which a moving plate advance / retreat mechanism such as a ball screw mechanism is arranged between the fixed plate and the moving plate.

  The other is a three-plate injection device as disclosed in Patent Document 2. In this three-plate injection device, a fixed plate (front plate) and a rear plate are connected by a plurality of connecting members such as tie bars (tie rods), and a movable plate (pressure plate) arranged between the two plates so as to advance and retreat is provided. The mainstream configuration is to move the moving plate relative to the fixed plate by a moving plate moving mechanism such as a ball screw mechanism arranged between the fixed plate (or moving plate) and the rear plate.

  The former two-plate injection device does not require a rear plate, and the movable plate advance / retreat mechanism is disposed between the fixed plate and the movable plate. Therefore, the overall length of the injection device can be shorter than that of the latter three-plate injection device. . Therefore, it is adopted when there is a restriction on a small injection device or an installation space of an injection molding machine. On the other hand, a three-plate type injection device is often employed especially when there are no restrictions on the size of the injection device or the above-described restrictions on the installation space.

  In addition, in the in-line screw type injection apparatus, the resin material (pellet) supplied from the resin material supply unit such as a hopper at the rear of the injection apparatus is rotated regardless of the two-plate type or the three-plate type by rotating the screw into a cylinder barrel. A measuring step is performed in which the molten resin is melted (plasticized) while flowing into the storage section at the front end (front), and the molten resin necessary for one injection filling step is stored in the storage section. In this measuring step, a predetermined pressure (back pressure) is applied to the molten resin in the storage section.

  After the completion of the measuring step, an injection filling step is performed in which the molten resin stored in the storage section is filled in the mold at a stretch by moving the screw forward. To control the back pressure in these measuring processes and the injection pressure in the injection filling process, the axial force of the screw acting on the rotating shaft of the screw and the components of the moving plate advance / retreat mechanism is used as the molten resin pressure in the storage section. A resin pressure measuring means for measuring is arranged.

  When the driving means for moving the moving plate relative to the fixed plate or the driving means for rotating the screw is a servomotor, use the torque measurement / control function of the servomotor to replace the resin pressure measurement means. It is also possible. On the other hand, the resin pressure measuring means for directly measuring the axial force of the screw acting on the screw rotating shaft and the components of the moving plate advance / retreat mechanism can more accurately measure the molten resin pressure in the storage section. It has been.

  For example, both the two-plate injection device of Patent Document 1 and the three-plate injection device of Patent Document 2 employ a ball screw mechanism as a moving plate advance / retreat mechanism. The two-plate injection device disclosed in Patent Document 1 discloses a form in which a ball screw nut of the ball screw mechanism is supported on a moving plate via a load cell serving as a resin pressure measuring means (Patent Document 1). / Figures 3 and 4). In addition, in the three-plate injection device disclosed in Patent Document 2, a strain detector (resin pressure measuring means) is provided on a bearing retainer (reference numeral 19) of a thrust bearing (reference numeral 16) that supports a screw shaft (screw sleeve / reference numeral 11). A form in which (strain gauge / symbol 26) is attached is disclosed (Patent Document 2 / FIG. 1).

JP 2000-108175 A JP-A-62-097818

  The load cell employed as the pressure measuring means generally has a configuration in which the amount of elastic deformation of the load cell itself in the pressure receiving direction is measured by a built-in strain measuring means such as a strain gauge. The pressure receiving direction includes a compression type, a tension type, a dual-purpose type, and the like, and is appropriately selected depending on a pressure measured at a place where the load cell is arranged and an action direction thereof. On the other hand, the load cell employed as the resin pressure measuring means of the injection device has a disk-like shape having an opening penetrating in the thickness direction at the center portion in consideration of the mounting location as in Patent Document 1, and the pressure-receiving direction is the same as that of the disk. In many cases, the shape is in the thickness direction. These shapes are called a ring or a washer, but in the present application, they are called a ring type load cell.

  In the two-plate injection device of Patent Document 1 (Patent Documents 1 / FIGS. 3 and 4), a ball screw nut combined with a ball screw shaft projects rearward via a ring-type load cell fixed behind a moving plate. Supported by the moving plate. For example, when the ball screw shaft is rotated by the injection motor on the fixed plate side and the moving plate (screw) and the ball screw nut are moved forward or backward, the ball screw shaft screwed into the ball screw nut is opened at the opening of the ring type load cell. The rotation of the moving plate does not hinder the forward / backward movement of the moving plate. The molten resin pressure in the storage section in the measuring step or the injection filling step acts on the ring type load cell fixed to the moving plate via the screw, the moving plate, and the ball screw nut, so that the pressure is measured.

  Further, in the three-plate injection device of Patent Document 2 (Patent Document 2 / FIG. 1), an annular intermediate wall of a bearing retainer (reference numeral 19) of a thrust bearing (reference numeral 16) supporting a screw shaft (screw sleeve / reference numeral 11). A strain detector (strain gauge / symbol 26), which is a resin pressure measuring means, is adhered to the outer peripheral surface of. For example, when the ball screw shaft is rotated on the rear plate side by an injection servomotor (injection motor) to move the pressure plate (screw / code 2) forward or backward, the pressure of the molten resin in the storage section is increased by the screw and screw. Since the bearing retainer is distorted by acting on the bearing retainer via the sleeve (reference numeral 11), the distortion is measured by a strain detector (strain gauge) attached to the outer peripheral surface of the annular intermediate wall of the bearing retainer ( (Patent Document 2 / specification, page 3, upper right).

  In the two-plate type injection device of Patent Document 1, the ring-type load cell cannot be removed from the rear of the moving plate without removing the ball screw nut from the ball screw shaft due to the arrangement of the ring-type load cell as described above. Generally, if the ball screw nut is removed from the ball screw shaft as it is, the ball in the ball screw nut falls off and becomes unusable. Therefore, when removing the ball screw nut from the ball screw shaft, a special removal jig (temporary shaft, sleeve, etc.) is required. That is, in the two-plate injection device of Patent Document 1, when the ring-type load cell is removed from the rear of the moving plate or newly attached, the ball screw nut is removed from the ball screw shaft using a dedicated removal jig. It is necessary to remove or remove the complete ball screw mechanism including the ball screw shaft and the ball screw nut from the injection device. As a result, there is a problem that it takes time and effort to attach and detach the ring-type load cell to and from the injection device for maintenance or replacement due to failure.

  On the other hand, also in the three-plate injection device of Patent Document 2, the strain detector (strain gauge) cannot be removed without removing the bearing retainer from the pressure plate.

  The present invention has been made in view of the above-described problems, and has as its object to provide a two-plate injection device in which a ring-type load cell coaxially arranged on a screw shaft can be easily attached and detached.

The object of the present invention is to provide a fixed plate, a cylinder barrel disposed in front of the fixed plate, a movable plate provided behind the fixed plate so as to be able to advance and retreat with respect to the fixed plate, A pair of ball screw mechanisms for moving the screw back and forth with respect to the fixed plate, an injection motor for driving the pair of ball screw mechanisms, a screw rotatably supported on the movable plate about an axis, and the screw A two-plate injection device, comprising a weighing motor that rotates the screw, by moving the movable plate forward and backward with respect to the fixed plate, so that the screw can advance and retract within the cylinder barrel.
A screw shaft housing portion for detachably housing the rear end of the screw, and a rotary support shaft portion having a diameter smaller than the outer diameter of the screw shaft housing portion continuously behind the screw shaft housing portion. A screw rotation support shaft having
A rotation support member that rotatably supports the screw rotation support shaft with respect to the moving plate,
The screw rotation support shaft and the rotation support member are housed in a rotation support member housing through hole that penetrates the moving plate back and forth,
A retainer that suppresses axial movement of the screw of the rotation support member in the rotation support member storage through-hole is disposed at an opening of the rotation support member storage through-hole behind the moving plate,
This is achieved by a two-plate injection device, wherein the retainer is configured as a ring-type load cell.

  In such a two-plate injection device, the rotation support member is constituted by a combination of a thrust bearing and a radial bearing, which are arranged continuously in the axial direction of the screw rotation support shaft, and the thrust bearing and the radial bearing Preferably have the same outer diameter.

The two-plate injection device according to the present invention includes a fixed plate, a cylinder barrel disposed in front of the fixed plate, and a movable plate provided behind the fixed plate so as to be able to advance and retreat with respect to the fixed plate. A pair of ball screw mechanisms for moving the movable plate relative to the fixed plate, an injection motor for driving the pair of ball screw mechanisms, and a screw supported by the movable plate so as to be rotatable about an axis. And a metering motor that rotates the screw, a two-plate injection device that allows the screw to move forward and backward in the cylinder barrel by moving the moving plate forward and backward with respect to the fixed plate,
A screw shaft housing portion for detachably housing the rear end of the screw, and a rotary support shaft portion having a diameter smaller than the outer diameter of the screw shaft housing portion continuously behind the screw shaft housing portion. A screw rotation support shaft having
A rotation support member that rotatably supports the screw rotation support shaft with respect to the moving plate,
The screw rotation support shaft and the rotation support member are housed in a rotation support member housing through hole that penetrates the moving plate back and forth,
A retainer that suppresses axial movement of the screw of the rotation support member in the rotation support member storage through-hole is disposed at an opening of the rotation support member storage through-hole behind the moving plate,
Since the retainer is configured as a ring-type load cell, the ring-type load cell coaxially arranged on the screw shaft can be easily attached and detached.

FIG. 2 is a schematic plan view of the two-plate injection device according to the first embodiment. FIG. 2 is a detailed view of a main part A of FIG. 1.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings.

[First Embodiment]
A two-plate injection device according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic plan view (including a partial cross section) of a two-plate injection device according to the first embodiment, showing a state in which a screw 4 and a movable plate 3, which will be described later, are at a retreat limit position (a measurement completion position). Show. In FIG. 1, a part of the screw 4 and the movable plate 3 at the forward limit position (injection completion position) are shown by two-dot chain lines. The left side of FIG. 1 is the front, the right side is the rear, and the near side of FIG. 1 is the upper side. Although FIG. 1 is referred to as a plan view, an illustration suitable for describing the configuration of the two-plate injection device according to the first embodiment of the present invention is referred to as a plan view. The two-plate type injection device is not called a plan view based on the mounting posture of the two-plate injection device to the injection molding machine. The two-plate injection device according to the present invention may be attached to the injection molding machine in a vertical, horizontal, or other various mounting posture with respect to the axial direction in which the screw is rotated. FIG. 2 is a detailed view of the main part A of FIG.

  As shown in FIG. 1, a two-plate injection device 10 according to a first embodiment of the present invention includes a fixed plate 2, a cylinder barrel 11 disposed in front of the fixed plate 2, and a rear of the fixed plate 2. The movable plate 3 is provided so as to be capable of moving forward and backward with respect to the fixed plate 2, a pair of ball screw mechanisms 20 and 21 for moving the movable plate 3 toward and away from the fixed plate 2, and a pair of ball screw mechanisms 20 and 21 are driven. The motor includes injection motors 31 and 32, a screw 4 supported on the movable plate 3 so as to be rotatable about an axis, and a metering motor 41 for rotating the screw 4.

  As the guide mechanism for moving the movable plate 3 toward and away from the fixed plate 2, a well-known guide mechanism such as a linear guide disposed on the base member or a guide rod standing upright from the fixed plate is employed. Just do it. In order to simplify the drawing, the illustration of such a base member and a guide mechanism is omitted.

  Then, the ball screw shafts 20a and 21a of the pair of ball screw mechanisms 20 and 21 are rotatably supported on the fixed plate 2 by the ball screw shaft rotation support portions 24, respectively, and are combined with the ball screw shafts 20a and 21a. The nuts 20b and 21b are respectively non-rotatably arranged on the moving plate 3.

  Further, between the end portions of the ball screw shafts 20 a and 21 a penetrating the fixed plate 2 toward the cylinder barrel 11 and the output shafts of the injection motors 31 and 32 disposed on the fixed plate 2, ball screw shaft rotation transmitting means 31 a. 32a are arranged, and the ball screw shafts 20a and 21a are driven to rotate. In the first embodiment, a ball screw shaft rotation transmitting means 31a, 32a is connected to a pulley disposed on an end of the ball screw shafts 20a, 21a, an output shaft of the injection motors 31, 32, and a belt connecting between the pulleys. However, the present invention is not limited to this, and a known rotation transmitting unit may be employed. Further, in FIG. 1, the injection motors 31 and 32 are illustrated as being disposed at both ends above the fixed plate 2 in order to avoid overlapping of the illustrated configuration. May be arranged side by side in the center above, or may be arranged so as to penetrate through the fixed plate 2 instead of above the fixed plate 2.

  The two-plate injection device 10 according to the first embodiment of the present invention has a configuration for supporting the screw 4 on the movable plate 3 so as to be rotatable about an axis. This will be described with reference to FIG.

  First is the screw rotation support shaft 44. The screw rotation support shaft 44 is configured to have a screw shaft storage portion 42 for detachably storing the rear end of the screw 4 and a diameter smaller than the outer diameter of the screw shaft storage portion 41 continuously behind the screw shaft storage portion 41. And a rotation support shaft 43 that is provided. Next, there is a rotation support member 45 that rotatably supports the screw rotation support shaft 44 with respect to the movable plate 3.

  The screw rotation support shaft 44 and the rotation support member 45 are housed in a rotation support member storage through-hole 46 penetrating the moving plate 3 back and forth, and the opening of the rotation support member storage through-hole 46 behind the movement plate 3. A retainer 47 for suppressing the axial movement of the screw 4 of the rotation support member 45 in the rotation support member storage through-hole 46 is coaxially disposed in the portion. The two-plate injection device of the present invention is characterized in that the retainer 47 is configured as a ring type load cell.

  The above structure will be described in more detail. The screw shaft storage portion 42 in front of the screw rotation support shaft 44 allows the rear end of the screw 4 to be inserted and withdrawn in the axial direction, and stores the screw 4 so that it cannot rotate with respect to the screw rotation support shaft 44. Is done. With such a configuration, the screw 4 and the screw rotation support shaft 44 can be arbitrarily attached and detached, and can be integrated coaxially. In the first embodiment, the outer peripheral surface of the rear end portion of the screw 4 and the inner peripheral surface of the screw shaft storage section 42 form a spline structure for preventing relative rotation. However, the present invention is not limited to this. A known configuration such as a relative rotation prevention configuration may be adopted. In the first embodiment, the rear end of the screw 4 inserted in the screw shaft housing 42 in the axial direction is connected to the screw rotation support shaft 44 by a split collar 42a that can be fixed to the front end surface of the screw shaft housing 42. The screw 4 and the screw rotation support shaft 44 are fixed, and the relative movement in the axial direction is restricted. For this, a well-known configuration capable of restraining the relative movement of the screw 4 and the screw rotation support shaft 44 in the axial direction may be adopted.

  In addition, the rotary support shaft portion 43 that is formed continuously behind the screw shaft housing portion 42 of the screw rotation support shaft 44 and has a smaller diameter than the outer diameter of the screw shaft housing portion 42 has a larger outer diameter. A rotation support member 45 composed of a combination of a thrust bearing and a radial bearing is inserted with a stepped portion with the screw shaft storage portion 42 as a front end. In the first embodiment, the rotation support member 45 is composed of two bearings having the same outer diameter, a thrust bearing 45a and a radial bearing 45b, from the front. However, the present invention is not limited to this, and the number of bearings inserted into the rotation support shaft 43 and the order in which the bearings are inserted may be appropriately selected according to the specifications of the injection device. The rotation support member 45 is fastened and fixed to the screw rotation support shaft 44 by a bearing nut 43a. For this reason, the rear outer peripheral surface of the rotation support shaft portion 43 is formed with a male screw according to the bearing nut 43a to the extent that the rotation support member 45 can be tightened and fixed to the screw rotation support shaft 44.

  Then, the screw rotation support shaft 44 and the rotation support member 45 are stored in the rotation support member storage through-hole 46 penetrating the moving plate 3 back and forth. By making the outer diameters of the two bearings constituting the rotation support member 45 the same, the rotation support member storage through-hole 46 may be formed by processing a through-hole having the same diameter. That is, through-hole processing in the movable plate 3 for rotatably supporting the screw 4 is performed by machining the stepped tubular bearing retainer and storing the bearing retainer in the three-plate injection device of Patent Document 2. It is very easy to process through holes in the pressure plate.

  On the front side of the rotary support member 45 in the rotary support member storage through-hole 46, a ring-shaped bearing pressing plate 46 a and a bearing press for fixing the bearing press plate 46 a from the front of the rotary support member storage through-hole 46 of the moving plate 3. It is positioned with the ring 46b. The inner peripheral side of the rear surface of the bearing holding plate 46a makes surface contact with the outer ring of the thrust bearing 45a constituting the rotation support member 45.

  On the other hand, on the rear side of the rotation support member 45 in the rotation support member storage through hole 46, at the opening of the rotation support member storage through hole 46 behind the moving plate 3, A retainer 47 for suppressing the axial movement of the screw 4 of the rotation support member 45 is coaxially arranged. The two-plate injection device of the present invention is characterized in that the retainer 47 is configured as a ring-type load cell, and hence the retainer 47 is hereinafter referred to as a ring-type load cell 47. On the inner peripheral side of the front surface of the ring type load cell 47, a pressure-receiving annular projection 47a that is in surface contact with the outer ring of the radial bearing 45b constituting the rotation support member 45 is formed. The axial movement of the screw 4 of the rotation support member 45 in the through hole 46 is suppressed.

  Note that, in order to protect the rotation support member 45, a dust seal or the like that prevents foreign substances from entering inside is preferably disposed in front of or behind the rotation support member storage through hole 46. For example, a dust seal or the like may be provided on the bearing holding ring 46b in front of the rotation supporting member storage through hole 46, and on the ring type load cell 47 in the rear. The illustration of the dust seal in FIGS. 1 and 2 is omitted for easy understanding of the drawings.

  Further, a screw shaft rotation transmitting means 48 for transmitting a rotational motion to the shaft of the screw 4 is arranged on the screw rotation support shaft 44 in front of the moving plate 3. In the first embodiment, the screw shaft rotation transmitting means 48 is connected to a pulley disposed on the screw shaft storage section 42 side of the screw rotation support shaft 44 and an output shaft of a weighing motor 41 (not shown) and a belt for connecting the two pulleys. Although the combination is used, the invention is not limited to this, and a known rotation transmitting unit may be employed. The metering motor 41 may be disposed at any position on the moving plate 3 as long as the screw 4 can be driven to rotate via the screw shaft rotation transmitting means 48. Directly above the axis is preferred. In FIG. 1, in order to avoid duplication of the illustrated configuration, the illustration of the metering motor 41 and the pulley of the output shaft of the motor is omitted, and the pulley arranged on the screw shaft storage section 42 side of the screw rotation support shaft 44. And only a part of the belt is shown.

  Next, in the two-plate injection device 10 according to the first embodiment of the present invention, the ring-type load cell 47 controls the back pressure in the measuring step and the injection pressure in the injection filling step. The measurement of the molten resin pressure will be described.

  First, in the measuring step, with the increase in the volume of the molten resin in the storage section, the screw on which the molten resin pressure acts rearward was retracted to apply a predetermined pressure (back pressure) to the molten resin in the storage section. In this state, the molten resin required for one injection filling step is stored in the storage section.

  In the injection filling step, the ball screw shafts 20a, 21a are rotationally driven by the injection motors 31, 32, and the movable plate 3 is advanced in the direction approaching the fixed plate 2 via the ball screw nuts 20b, 21b. At this time, the advancing screw 4 pushes out (injects) the molten resin in the storage section from the nozzle side in front of the cylinder barrel 11 to the front (die) and receives the reaction force (injection pressure). This reaction force applies a thrust to the ring type load cell 47 rearward via a screw rotation support shaft 44 coaxially integrated with the screw 4 and a thrust bearing 45 a and a radial bearing 45 b constituting a rotation support member 45. Let it work. This pressing force is measured as the pressure of the molten resin stored in the storage section at the tip of the cylinder barrel 11. Note that, also in the measuring step, a pressing force acts on the ring type load cell 47 due to the pressure of the molten resin stored in the storage unit.

  As described above, in the two-plate injection device 10 according to the first embodiment of the present invention, the screw rotation support shaft 44 and the rotation support member 45 are inserted into the rotation support member storage through-hole 46 penetrating the moving plate 3 back and forth. The screw 4 is stored in the opening of the rotation support member storage through-hole 46 at the rear of the moving plate 3 to prevent the rotation support member 45 from moving in the axial direction of the screw 4 in the rotation support member storage through-hole 46. The retainer 47 is configured as a ring type load cell 47. Therefore, since the ring-type load cell 47 is disposed at the rearmost position of the two-plate injection device 10, the ring-type load cell 47 coaxially disposed on the screw shaft (the screw rotation support shaft 44) can be easily attached and detached.

  Further, by making the outer diameters of the two bearings constituting the rotation supporting member 45 the same, the rotation supporting member storage through-hole 46 can be formed with the same diameter as the through-hole, and the through-hole processing is very easy. However, the molten resin pressure in the storage portion acting on the screw 4 is the same as that of the screw 4. The screw rotation support shaft 44 is coaxially integrated with the screw 4, and the same diameter thrust bearing 45 a and radial bearing 45 b that constitute the rotation support member 45. , The pressing force is applied to the ring-type load cell 47, so that the pressure of the molten resin acting on the screw 4 in the storage portion can be accurately measured by the ring-type load cell 47 without being dispersed.

  On the other hand, in the three-plate injection device of Patent Document 2, as described above, the strain detector (strain gauge) cannot be removed without removing the bearing retainer from the pressure plate.

  In addition, the bearing retainer for accommodating thrust bearings and radial bearings with different outer diameters must be stepped tubular, and multiple surface contact portions with the pressure plate (moving plate) perpendicular to the screw axis direction are formed. Therefore, the molten resin pressure acting on the bearing retainer and distorting the bearing retainer is dispersed, and the measurement accuracy of the molten resin pressure is reduced.

  Further, in the two-plate injection device of Patent Document 1, as described above, the ring-type load cell is disposed between the moving plate and the ball screw nut erected so as to protrude rearward of the moving plate. Therefore, it is not possible to remove the ring type load cell from the back of the moving plate without removing the ball screw nut from the ball screw shaft. It is necessary to remove the ball screw nut from the ball screw shaft by using the removal jig, or to remove the complete ball screw mechanism including the ball screw shaft and the ball screw nut from the injection device.

  Here, in the two-plate injection device 10 according to the first embodiment of the present invention, as described in the first embodiment, the screw shaft that transmits the rotational motion to the shaft of the screw 4 (the screw rotation support shaft 44). By disposing the rotation transmitting means 48 in front of the movable plate 3, the ring-type load cell 47 is arranged at the rearmost position of the two-plate injection device 10, and the ring-type load cell 47 is easily attached and detached. . On the other hand, although not shown, the shaft of the screw 4 (the screw rotation support shaft 44) is penetrated to the rear of the moving plate 3, and the screw shaft rotation transmitting means 48 is disposed in the penetrated portion, ie, the screw shaft. Even if the rotation transmitting means 48 is arranged behind the moving plate 3, the ring type load cell 47 can be attached and detached by removing the pulleys and belts of the screw shaft rotation transmitting means 48. In the case of this embodiment, the ease with which the ring-type load cell 47 can be detached from the first embodiment in which the screw shaft rotation transmitting means 48 is disposed in front of the moving plate 3 is reduced. The ring-type load cell 47 is used for a configuration in which the strain detector (strain gauge) cannot be removed without disassembling the entire screw rotation support portion of the pressure plate (moving plate), such as a three-plate injection device. The easiness of desorption is ensured.

  As described above, the first embodiment and another related embodiment have been described as to the embodiments for carrying out the invention. However, the invention is not limited to the above-described embodiments, and is described in the claims. It goes without saying that the present invention can be implemented in various forms without departing from the scope of the present invention.

  For example, in the two-plate injection device 10 according to the first embodiment of the present invention, the end portions of the ball screw shafts 20a and 21a penetrating the fixed plate 2 toward the cylinder barrel 11 and the fixed plate 2 are arranged. The embodiment in which the ball screw shaft rotation transmitting means 31a and 32a are arranged between the output shafts of the injection motors 31 and 32 and the ball screw shafts 20a and 21a are driven to rotate has been described. However, as described above, it is not always necessary that each of the two ball screw shafts is rotationally driven by a different injection motor. Although not shown, an injection motor and a ball screw shaft rotation transmitting means may be arranged so that two ball screw shafts are rotationally driven by one injection motor, or two ball screw shafts are provided. An injection motor and a ball screw shaft rotation transmitting means may be arranged so that the above injection motors are rotated and driven in cooperation. As described above, the rotational driving form of the ball screw shaft in the fixed plate may be appropriately adjusted according to the injection capacity required of the two-plate injection device and the size of the two-plate injection device. good.

  The arrangement of the ring-type load cell of the two-plate injection device according to the present invention, that is, a retainer for suppressing the axial movement of the screw of the rotation support member in the rotation support member storage through hole is a ring-type load cell. Particularly, in the two-plate type injection device in which the rear plate is not disposed behind the moving plate, the configuration in which the ring-type load cell coaxially arranged on the screw shaft is easily attached and detached is provided. However, the arrangement of the ring-type load cell of the two-plate injection device according to the present invention may be adopted in a three-plate injection device. For example, although not shown, in the case of a three-plate injection device in which a weighing motor is arranged on the moving plate side and a moving plate advance / retreat mechanism is arranged between the fixed plate and the rear plate, the moving plate is moved to the fixed plate side. By moving the moving plate forward, a space is secured between the moving plate and the rear plate, and the ring type load cell disposed behind the moving plate can be easily attached and detached. Further, even in a three-plate injection device in which a moving plate moving mechanism is disposed between the moving plate and the rear plate, the moving plate moving mechanism (a pulley, a belt, or the like) may prevent the ring type load cell from being detached from the rear. By arranging the ring-type load cell disposed behind the moving plate, ease of attachment and detachment of the ring-type load cell is ensured.

    2 fixed plate, 3 moving plate, 4 screw, 10 two-plate injection device, 11 cylinder barrel, 20 ball screw mechanism, 20a ball screw shaft, 20b ball screw nut, 21 ball screw mechanism, 21a ball screw shaft, 21b ball screw Nut, 24 Ball screw shaft rotation support part, 31 Injection motor, 31a Ball screw shaft rotation transmission means, 32 Injection motor, 32a Ball screw shaft rotation transmission means, 41 Metering motor, 42 Screw shaft storage part, 42a split collar, 43 rotation Support shaft part, 43a bearing nut, 44 screw rotation support shaft, 45 rotation support member, 45a thrust bearing, 45b radial bearing, 46 rotation support member storage through hole, 46a bearing holding plate, 46b bearing holding ring, 47 retainer Na (ring type load cell), 47a pressure receiving annular projection, 48 screw shaft rotation transmitting means,

Claims (2)

A fixed plate, a cylinder barrel disposed in front of the fixed plate, a moving plate provided at the rear of the fixed plate so as to be able to advance and retreat with respect to the fixed plate, and the moving plate with respect to the fixed plate. A pair of ball screw mechanisms for advancing and retreating, an injection motor for driving the pair of ball screw mechanisms, a screw supported on the moving plate so as to be rotatable around an axis, and a metering motor for rotating the screw. A two-plate injection device, wherein the screw is capable of moving back and forth in the cylinder barrel by moving the moving plate forward and backward with respect to the fixed plate,
A screw shaft housing portion for detachably housing the rear end of the screw, and a rotary support shaft portion having a diameter smaller than the outer diameter of the screw shaft housing portion continuously behind the screw shaft housing portion. A screw rotation support shaft having
A rotation support member that rotatably supports the screw rotation support shaft with respect to the moving plate,
The screw rotation support shaft and the rotation support member are housed in a rotation support member housing through hole that penetrates the moving plate back and forth,
A retainer that suppresses axial movement of the screw of the rotation support member in the rotation support member storage through-hole is disposed at an opening of the rotation support member storage through-hole behind the moving plate,
The two-plate injection device, wherein the retainer is configured as a ring-type load cell. The rotation support member is configured by a combination of a thrust bearing and a radial bearing, which are arranged continuously in the axial direction of the screw rotation support shaft, and the outer diameters of the thrust bearing and the radial bearing are the same. The two-plate injection device according to claim 1, wherein:

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