WO2011161747A1

WO2011161747A1 - Injection molding machine

Info

Publication number: WO2011161747A1
Application number: PCT/JP2010/060446
Authority: WO
Inventors: 利彦水谷; 俊二立川; 峰男早川; 宗弘高木
Original assignee: 豊田合成株式会社
Priority date: 2010-06-21
Filing date: 2010-06-21
Publication date: 2011-12-29
Also published as: JP5582191B2; JPWO2011161747A1

Abstract

A vertical injection molding machine is provided with a first mold (16) serving as a stationary mold and also with a second mold (17) serving as a movable mold which ascends and descends beneath the first mold (16). A mold clamp mechanism (30) is provided with a shaft (41) and a female screw section (36). The shaft (41) is supported while being inserted through a through-hole (31) vertically penetrating through the first mold (16). A male screw section (43) is formed at the lower end of the shaft (41). The shaft (41) is rotated by a motor (38). The female screw section (36) is provided in the second mold (17) so as to be coaxial with the through-hole (31). When the shaft (41) is rotated by the motor (38) with both the molds (16, 17) held in contact with each other, the male screw section (43) of the shaft (41) is screwed into the female screw section (36) of the second mold (17). The force generated as the male screw section (43) is screwed into the female screw section (36) and acting in the direction of clamping the molds causes the second mold (17) to be in pressure contact with the first mold (16). The configuration prevents the shaft (41) from tilting due to the weight thereof, and as a result, the male screw section (43) can be easily engaged with the female screw section (36) when the molds are clamped together.

Description

Injection molding machine

The present invention relates to an injection molding machine for forming a molded article by injecting a molten resin into a cavity formed between a stationary mold and a movable mold, with the movable mold approaching and separating the stationary mold.

In the injection molding machine, the movable mold is moved to a position where it contacts the fixed mold, both molds are closed, and the movable mold is pressed against the fixed mold by the mold clamping mechanism. Subsequently, a molten resin is injected into a cavity formed between the fixed mold and the movable mold to form a molded article. The mold clamping mechanism prevents the movable mold from leaving the fixed mold due to the injection pressure of the molten resin during the period from when injection is started to when the molten resin solidifies.

For example, a configuration described in Patent Document 1 is known as a mold clamping mechanism. In the mold clamping mechanism disclosed in this document, ball screw shafts are rotatably supported at four corners of a fixed die plate to which a fixed mold is attached. Ball nuts are fitted at the four corners of the movable die plate to which the movable die is attached. A ball screw shaft is screwed into the ball nut. When the ball screw shaft is rotated by the motor, the movable die plate moves along the ball screw shaft, and the movable die is pressed against the fixed die. In this injection molding machine, components such as a fixed die plate and a movable die plate are used in addition to the fixed die and the movable die that are in pressure contact with each other. These parts are arranged around fixed and movable molds. For this reason, the mold clamping mechanism is enlarged, and the injection molding machine is also enlarged.

For example, Patent Document 2 proposes a technique for solving the increase in size of the mold clamping mechanism. Patent Document 2 describes an injection molding machine of a type called a horizontal type in which the mold is moved in the horizontal direction to open and close the mold.

In the horizontal injection molding machine, the movable mold is formed with a through hole extending in the horizontal direction. The movable through hole is supported in a state where the shaft is inserted. An engagement portion (male screw portion) is provided at the end of the shaft adjacent to the fixed mold. A motor is drivingly connected to an end of the shaft opposite to the fixed type. An engaged portion (female screw portion) is provided coaxially with the through hole at a portion facing the fixed movable type. At the time of mold clamping, the shaft is rotated by the motor with the movable mold in contact with the fixed mold. With the rotation of the shaft, the engaging portion (male screw portion) is engaged (screwed) with the engaged portion (female screw portion), and the movable mold is pressed against the fixed mold. In this injection molding machine, the fixed die plate, movable die plate and the like disclosed in Patent Document 1 become unnecessary. In addition, parts such as the shaft and the engaged portion that constitute the mold clamping mechanism are located in the vicinity of the cavity. Therefore, the mold clamping mechanism can be miniaturized, that is, the injection molding machine can be miniaturized.

Unexamined-Japanese-Patent No. 5-269748 JP 2008-105391 A

The injection molding machine described in Patent Document 2 has a structure for rotatably supporting a shaft inserted into the through hole. However, when the shaft is supported only at the end (proximal end) close to the motor, the shaft is inclined by its own weight, with the end (distal end) close to the fixed mold lower than the proximal end of the shaft. In this case, since the axis of the shaft deviates from the axis of the engaged portion (female screw portion), it becomes difficult to engage (screw in) the engaging portion (male screw portion) with the engaged portion (female screw portion). Therefore, an operation and a mechanism for matching the axis of the shaft with the axis of the engaged portion are additionally required.

An object of the present invention is to provide an injection molding machine capable of easily engaging an engaging portion of a shaft with an engaged portion at the time of mold clamping.

In order to achieve the above object, according to a first aspect of the present invention, a first mold and a second mold are provided, one of which is a fixed mold, the other is a movable mold, and the movable mold is raised and lowered. The movable mold is brought into contact with and separated from the fixed mold, the movable mold is brought into contact with the fixed mold, both molds are closed, and the movable mold is pressed against the fixed mold by the mold clamping mechanism, and formed between the first mold and the second mold. An injection molding machine is provided which injects a molten resin into a cavity to form a molded article. The mold clamping mechanism is a shaft supported in a state inserted through a through hole vertically penetrating the first mold, and has an engaging portion in at least a part in the axial direction of the shaft, and is rotated by an actuator The driven shaft and the engaged portion provided coaxially with the through hole in the second mold, and the first mold and the second mold are in contact with each other, and the shaft is rotated by the actuator. A direction in which the second mold and the first mold are made to approach each other is a mold clamping direction, and an engaging portion is engaged with the engaging portion. The first mold and the second mold are pressed against each other by the generated clamping direction force or the clamping direction force applied to the shaft after the engagement portion and the engaged portion are engaged.

According to this configuration, when the first mold and the second mold are pressure-welded by the mold clamping mechanism, the shaft is rotated by the actuator. As the shaft rotates, the engaging portion is engaged with the engaged portion, and the shaft is connected to the second mold.

Here, the shaft is supported in a state of being inserted into a vertically extending through hole. For this reason, the direction of gravity acting on the shaft and the axial direction of the shaft are both vertical and coincide with the axial direction of the engaged portion. In this respect, the present invention differs from the horizontal injection molding machine described in Patent Document 2 in which the shaft is inclined by its own weight and the axis of the shaft is easily displaced from the axis of the female screw.

Thus, according to the present invention, since the axis of the engaging portion and the axis of the engaged portion coincide with each other, when the shaft is rotated by the actuator, the engaging portion is easily engaged with the engaged portion. United. The first mold and the second mold are pressed against each other by the force in the mold clamping direction generated with this engagement or the force in the mold clamping direction applied to the shaft after engagement. Then, a molten resin is injected into a cavity formed between the first mold and the second mold to form a molded article.

In the mold clamping mechanism described in Patent Document 1, a fixed die plate, a movable die plate, and the like are arranged around the first mold and the second mold. Then, by moving the movable die plate, the movable die attached to the movable die plate is indirectly moved to press the movable die against the fixed die attached to the fixed die plate. . For this reason, the whole apparatus enlarges. Further, in the vertical injection molding machine, it is necessary to lift the movable mold against gravity. For this reason, more energy is required to move the movable body than the horizontal injection molding machine.

In that respect, in the injection molding machine of the present invention, in a state where the engaging portion is engaged with the engaged portion and the shaft is connected to the second mold, the second mold is pressed by the force in the mold clamping direction. Directly pressed against the mold. From this, in the present invention, unlike the mold clamping mechanism described in Patent Document 1, in order to clamp the first mold and the second mold, the fixed die plate, the movable die plate, etc. become unnecessary. . In addition, parts such as a shaft and an engaged portion that constitute a mold clamping mechanism are located in the vicinity of the cavity. By these, compared with the structure described in patent document 1, size reduction of a clamping mechanism and size reduction of an injection molding machine are attained. In addition, downsizing of the mold clamping mechanism makes it possible to reduce the weight of the movable body, thereby reducing energy for moving the movable body and achieving energy saving.

In the above-mentioned injection molding machine, one of the engaging portion and the engaged portion is constituted by the female screw portion, and the other is constituted by the male screw portion, and the mold clamping mechanism screws the male screw portion into the female screw portion by rotation of the shaft. Thus, it is preferable to generate a force in the mold clamping direction.

In this case, when the engaging portion engages with the engaged portion and the male screw portion is screwed into the female screw portion, the shaft extends in the axial direction. At this time, a tensile force, that is, an axial force is generated on the shaft to return to its original state by repelling it. This axial force is a clamping direction force acting in a direction to make the second mold and the first mold approach each other. The first mold and the second mold are pressed against each other by this axial force, and mold clamping is performed.

In the above-described injection molding machine, the actuator is the first actuator, and the mold clamping mechanism further clamps the shaft with the engaging portion engaged with the engaged portion separately from the first actuator. Preferably, a second actuator is provided for applying a directional force.

The second actuator can apply a force in the mold clamping direction to the shaft in which the engaging portion is engaged with the engaged portion. Therefore, a part of the axial force (required axial force) necessary for bringing the first mold and the second mold into pressure contact with each other is covered by the force generated by the second actuator. Therefore, the axial force to be generated by the extension due to the rotation of the shaft can be reduced. A small actuator with small output torque can be used as a first actuator for generating this axial force on the shaft. That is, the mold clamping mechanism can be miniaturized and the injection molding machine can be miniaturized.

In the above-described injection molding machine, the second actuator includes a cylinder and a piston, the piston is accommodated in the cylinder so as to be vertically movable, and divides the inside of the cylinder into two fluid pressure chambers, and two fluid pressures Preferably, one of the chambers is a clamping fluid pressure chamber, and the clamping fluid pressure chamber is supplied with a working fluid when a force in the clamping direction is applied to the shaft.

After the first actuator is actuated to engage the engaging portion with the engaged portion, the working fluid is supplied to the clamping fluid pressure chamber in the cylinder constituting the second actuator. At this time, the pressure of the working fluid acting in the mold clamping direction is applied to the piston. For this reason, a force acting in the mold clamping direction is applied to the shaft through the piston. The first mold and the second mold are pressed against each other by this force to perform mold clamping. That is, with a simple configuration such as a cylinder and a piston, a force in the mold clamping direction can be applied to the shaft.

In the above-mentioned injection molding machine, the first mold is a fixed mold, the second mold is a movable mold, and the second mold is moved up and down on the lower side of the first mold to form the first mold. The movable body is constituted by the second mold and the member moving along with the elevation of the second mold, and the gravity acting on the movable body is pressed against the first mold by the clamping mechanism. Preferably, it is used as at least a part of a mold release force for releasing the second mold from the first mold.

The second mold functioning as the movable mold moves closer to and away from the first mold by moving up and down on the lower side of the first mold functioning as the fixed mold. In this case, the second mold in which the gravity acting on the movable body consisting of the second mold and the member moving with the second mold is pressed against the first mold by the mold clamping mechanism is the first It is used as part of the mold release force when mold release. Therefore, when the mold release mechanism for separating the second mold from the first mold is provided, mold release with a smaller mold release force becomes possible, so the mold release mechanism can be miniaturized, and the injection molding machine can be miniaturized. Can be In addition, when the gravity acting on the movable body is sufficiently large, it is possible to perform mold release without using a mold release mechanism.

The front view which shows the state which open | released the mold in the vertical injection molding machine which concerns on one Embodiment of this invention. The front view which fractures | ruptures and shows one part of the clamped vertical injection molding machine. (A) is a fragmentary sectional view which expands and shows the A section of FIG. 2, (B) is a fragmentary sectional view which expands and shows the B section of FIG. 3 (A). (A) is a partial sectional view showing a state immediately before the second mold contacts the first mold, or a state immediately after the second mold separates from the first mold, (B) a male screw portion is a female screw FIG. 10 is a partial cross-sectional view showing a state immediately before screwing into a part or a state immediately after a male screw part comes out of a female screw part.

Hereinafter, an embodiment in which the injection molding machine of the present invention is embodied in a vertical injection molding machine will be described with reference to the drawings.
In the vertical injection molding machine, the mold (fixed type and movable type) is moved up and down to open and close. In the present specification, moving the movable mold in a direction to approach the fixed mold is referred to as "mold closing", and pressing the movable mold in contact with the fixed mold against the fixed mold is referred to as "mold clamping". Further, releasing the clamped movable mold from the fixed mold is called "mold release", and moving the mold released movable mold in a direction to separate it from the fixed mold is called "mold opening".

As shown in FIGS. 1 and 2, the vertical injection molding machine 10 includes a base 12 installed on the installation surface 11, a plurality of columns 13 provided on the base 12, and the upper ends of all the columns 13. And a top plate portion 15 fixed to the The top plate portion 15 is supported by the columns 13.

On the lower surface of the top plate 15, a first mold 16 functioning as a fixed mold is fixed. Below the first mold 16, a second mold 17 functioning as a movable mold is disposed. The second mold 17 is raised and lowered between a mold closing position (see FIG. 2) in contact with the first mold 16 and a mold opening position (see FIG. 1) which is largely separated from the first mold 16 downward. The following mechanism is adopted to make it happen.

A pair of ball screw shafts 21 extending in the vertical direction is rotatably supported between the base 12 and the top plate 15 respectively. Each ball screw shaft 21 is drivingly connected to a motor 22 such as a servomotor. A ball nut 23 is screwed into each ball screw shaft 21. A movable stand 24 is bridged between the ball nuts 23. The second mold 17 is fixed on the movable table 24. The second mold 17, both ball nuts 23 and the movable stand 24 constitute a movable body 25. When each ball screw shaft 21 is rotated by each motor 22, the movable body 25 is moved up and down along the ball screw shaft 21.

On the upper part of the second mold 17, a forming protrusion 17A is provided. In the lower part of the first mold 16, a molding recess 16A is provided. With the second mold 17 and the first mold 16 in contact with each other, the forming projection 17A enters the forming recess 16A. Thus, a cavity 18 which is a space for forming a molded product having a desired shape is formed between the molding protrusion 17A and the molding recess 16A (see FIG. 2).

In the second mold 17, a mold in-mold projecting mechanism 28 composed of a projecting plate 26, a plurality of projecting pins 27, and an inclined core (not shown) is provided. The projecting plate 26 is disposed substantially horizontally. Each projecting pin 27 extends upward from the projecting plate 26. The inclined core is provided at the upper end of each projecting pin 27. Each projecting pin 27 is inserted into a guide hole (not shown) or the like which penetrates the second mold 17 up and down. The inclined core constitutes a part of the forming projection 17A.

The base 12 is provided with a forming machine side projecting mechanism 8 consisting of a projecting plate 6, a plurality of projecting pins 7, and a driving device (not shown). The projecting plate 6 is disposed substantially horizontally and is moved up and down by a drive device. Each projecting pin 7 extends upward from the projecting plate 6. Each projecting pin 7 is inserted into a guide hole (not shown) or the like passing through the movable table 24.

When the second mold 17 is lowered to the mold opening position, the forming machine side projecting mechanism 8 moves the projecting plate 26 and the projecting pin 7 upward to move the projecting plate 26 upward. As a result, the projecting pin 27 and the inclined core are protruded upward in order to peel off the molded product in close contact with the second mold 17 (the molding projection 17A).

The top plate portion 15 is provided with a plurality of mold clamping mechanisms 30. The mold clamping mechanism 30 presses the first mold 16 and the second mold 17 substantially uniformly at their contact surfaces. For this reason, the respective mold clamping mechanisms 30 are provided at substantially equal intervals corresponding to the peripheral edge portion of the contact surface.

During molding of the molded product, the mold clamping mechanism 30 prevents the second mold 17 from being separated from the first mold 16 by the injection pressure of the molten resin, from the start of injection to the solidification of the molten resin. The second mold 17 is pressed against the first mold 16.

Next, each clamping mechanism 30 will be described. As shown in FIGS. 3A and 3B, through holes 31 and 32 penetrating in the vertical direction are provided in the first mold 16 and the top plate portion 15, respectively. At an upper portion of the second mold 17, a female screw portion 36 as an engaged portion is disposed and fixed coaxially with the through hole 31. An internal thread 35 is formed on the inner peripheral surface of the internal thread portion 36.

A support member 37 is fixed on the top plate portion 15 via a fluid pressure washer 55 as a second actuator. The support member 37 is elongated and extends in the vertical direction. On the support member 37, a motor 38 such as a servomotor is disposed and fixed coaxially with the through holes 31 and 32. The motor 38 as a first actuator has an output shaft 39 extending downward.

The shaft 41 is inserted through the through holes 31 and 32 and the fluid pressure washer 55. The shaft 41 is elongated and extends in the vertical direction. The shaft 41 is provided with a general portion 42 which occupies most of the shaft 41 and a large diameter portion 44 provided at the upper end portion of the general portion 42. The diameter of the large diameter portion 44 is larger than that of the general portion 42. The diameter of the general portion 42 is slightly smaller than that of the through holes 31 and 32. The general portion 42 is rotatably and vertically movably supported by a slide bearing (bush) 45 disposed in the through hole 32 of the top plate portion 15. At a lower end portion of the general portion 42, an external thread portion 43 as an engagement portion which can be screwed into the internal thread portion 36 is formed. The large diameter portion 44 is located above the fluid pressure washer 55. The large diameter portion 44 is rotatably and vertically movably supported by a slide bearing (bush) 46 disposed below the support member 37.

A cylindrical body 47 is rotatably supported by a rolling bearing 48 at an upper portion of the support member 37 and between the large diameter portion 44 of the shaft 41 and the motor 38. The cylindrical body 47 is connected to the output shaft 39 of the motor 38 by a coupling 52 or the like. A connecting member 49 is interposed between the cylindrical body 47 and the large diameter portion 44. The connecting member 49 is attached to the cylindrical body 47 so as to be vertically movable and integrally rotatable. The connecting member 49 is attached to the large diameter portion 44 of the shaft 41 so as to be integrally rotatable. Furthermore, the spring 51 is disposed in the cylindrical body 47 in a compressed state. The spring 51 always biases the shaft 41 downward via the connecting member 49.

As shown in FIG. 3B, the fluid pressure washer 55 applies a force in the mold clamping direction to the shaft 41 in a state in which the male screw portion 43 is screwed into the female screw portion 36 separately from the motor 38. The fluid pressure washer 55 includes a cylinder 56 fixed on the top plate portion 15 and a piston 57 into which the general portion 42 of the shaft 41 is inserted. The piston 57 is accommodated in the cylinder 56 so as to be able to move up and down. The inside of the cylinder 56 is divided up and down by a piston 57 to form two

fluid pressure chambers

58 and 59. The lower fluid pressure chamber 59 of the two

fluid pressure chambers

58 and 59 is a clamping fluid pressure chamber 59. A hydraulic fluid such as hydraulic oil is supplied to the clamping fluid pressure chamber 59 when a force in the clamping direction (upward) is applied to the shaft 41.

Here, in the mold clamping mechanism described in Patent Document 1, by moving the movable die plate, the movable die attached to the movable die plate is indirectly moved to move the movable die to the fixed die plate. It is made to press-fit to the fixed mold attached to. On the other hand, in the mold clamping mechanism of the present embodiment, the second mold 17 is directly pressure-welded to the first mold 16 through the shaft 41. From this, in this embodiment, unlike the mold clamping mechanism described in Patent Document 1, in order to clamp the first mold 16 and the second mold 17, a fixed die plate, a movable die plate, and the like are used. Not used. Further, a mold release mechanism for separating the second mold 17 pressed against the first mold 16 by the mold clamping mechanism 30 from the first mold 16 after molding is not provided in the wedge-shaped injection molding machine 10 .

Next, the operation of the vertical injection molding machine 10 will be described.
FIG. 1 shows a vertical injection molding machine 10 in an open mold state. In this state, the second mold 17 is located at the mold opening position largely separated downward from the first mold 16. In the mold clamping mechanism 30, the rotation of the motor 38 is stopped. Further, in the fluid pressure washer 55, the fluid pressure in the

fluid pressure chambers

58 and 59 is both reduced. A downward biasing force by a spring 51 is applied to the piston 57 via the shaft 41 and the like. Therefore, the piston 57 is located at the lowermost position of the cylinder 56. Further, at least a portion of the male screw portion 43 of the shaft 41 protrudes downward from the lower surface of the first mold 16.

In order to close the mold from the above state, the motor 22 rotates the ball screw shaft 21 in a predetermined direction. Then, the movable body 25 screwed to the ball screw shaft 21 by the ball nut 23 starts to ascend. As the movable body 25 rises, the distance between the second mold 17 and the first mold 16 gradually narrows, and the distance between the male screw 43 of the shaft 41 and the female screw 36 of the second mold 17 gradually narrows.

The shaft 41 is inserted into the through holes 31 and 32 and supported by the top plate portion 15 and the support member 37 by the

slide bearings

45 and 46. For this reason, the direction of gravity acting on the shaft 41 and the direction of the axis L1 of the shaft 41 are both vertical, and coincide with the axis L2 of the corresponding female screw portion 36 of the second mold 17. In this respect, the present embodiment is different from the horizontal injection molding machine described in Patent Document 2 in which the shaft is inclined by its own weight and the axis of the shaft is easily deviated from the axis of the female screw.

When the movable body 25 further ascends, as shown in FIG. 4A, the female screw portion 36 contacts the lower end of the shaft 41 with the axis L2 thereof aligned with the axis L1. In this state, the second mold 17 is slightly separated downward from the first mold 16. Further, the shaft 41 biased downward by the spring 51 is pressed by the female screw portion 36 in a state in which the axis L1 thereof coincides with the axis L2 of the female screw portion 36. Therefore, when the second mold 17 further rises, the shaft 41 rises while compressing the spring 51. Due to this rise, the large diameter portion 44 of the shaft 41 is separated upward from the piston 57. Then, as shown in FIG. 4 (B), when the second mold 17 contacts the first mold 16, the operation of the motor 22 is stopped. In this state, a cavity 18 is formed between the molding recess 16A of the first mold 16 and the molding projection 17A of the second mold 17.

Next, the rotation of the output shaft 39 of the motor 38 is started. The direction of rotation is the direction in which the externally threaded portion 43 of the shaft 41 is tightened to the internally threaded portion 36 of the second mold 17. The rotation of the motor 38 is transmitted to the shaft 41 via the coupling 52, the cylindrical body 47 and the connecting member 49. The shaft 41 is biased downward by a spring 51 via a connecting member 49. Further, the axis L1 of the shaft 41 coincides with the axis L2 of the female screw portion 36. For this reason, the end of the male screw portion 43 matches and meshes with the end of the female screw 35, and the male screw portion 43 starts to be screwed (engaged) into the female screw portion 36. With this screwing, the shaft 41 is connected to the second mold 17 through the female screw portion 36 and extends along the axial direction. At this time, a tensile force, that is, an axial force, is generated on the shaft 41 in such a manner as to repel the extension of the shaft 41 and return it to the original state. This axial force is a clamping direction force that matches the direction in which the second mold 17 and the first mold 16 are made to approach each other. The second mold 17 is pressed against the first mold 16 by the force in the mold clamping direction. Further, as the male screw portion 43 is screwed into the female screw portion 36, the large diameter portion 44 approaches the piston 57.

Furthermore, as the output shaft 39 of the motor 38 continues to rotate in the same direction, the shaft 41 also continues to rotate. As shown in FIGS. 2 and 3A and 3B, when the male screw 43 is screwed into the female screw 36 by a predetermined amount, the rotation of the output shaft 39 of the motor 38 is stopped, and the coupling 52 The rotation of the cylindrical body 47, the connecting member 49 and the shaft 41 is also stopped.

Subsequently, the hydraulic fluid is supplied into the clamping fluid pressure chamber 59 of the fluid pressure washer 55. Thereby, the fluid pressure of the clamping fluid pressure chamber 59 is increased, and the fluid pressure is applied to the piston 57. The high fluid pressure is maintained for a period of time from the filling of the molten resin in the cavity 18 to the cooling and solidification. The high fluid pressure pushes the piston 57 upward with a large force. At this time, although the rotation of the shaft 41 is stopped, the pressing by the piston 57 further extends the shaft 41 and generates a large axial force. Here, the axial force necessary to keep the second mold 17 pressed against the first mold 16 is required so that the second mold 17 does not separate from the first mold 16 by the injection pressure of the molten resin. I assume. In the present embodiment, a part of the required axial force is covered by the axial force generated by the fluid pressure washer 55. In other words, the difference between the axial force generated as the shaft 41 rotates and the required axial force is compensated by the axial force generated by the fluid pressure washer 55. As a result, even if the axial force generated with the rotation of the shaft 41 is not large enough, the required axial force is generated at the shaft 41, so the second mold 17 is pressed against the first mold 16 and clamping is performed. To be done. Thereafter, molten resin is supplied from the injection device (not shown) into the cavity 18 and filled. The molten resin is cooled and solidified to be shaped into the desired molded article in the cavity 18.

After molding of the molded article, the reverse operation is performed. First, the above-described mold clamping state is released. That is, in the mold clamping mechanism 30, the hydraulic fluid is discharged from the lower mold clamping fluid pressure chamber 59, and the working fluid is supplied into the upper hydraulic pressure chamber 58. As a result, while the fluid pressure of the clamping fluid pressure chamber 59 is reduced, the hydraulic pressure of the other fluid pressure chamber 58 is increased. The piston 57 in the cylinder 56 is lowered. Therefore, the axial force by the fluid pressure washer 55 is reduced.

Subsequently, the rotation of the output shaft 39 of the motor 38 is started. The direction of rotation is such that the externally threaded portion 43 of the shaft 41 is loosened relative to the internally threaded portion 36 of the second mold 17. The rotation of the motor 38 is transmitted to the shaft 41 via the coupling 52, the cylindrical body 47 and the connecting member 49. The shaft 41 retracts against the biasing force of the spring 51 and rises toward the motor 38. As a result, the axial force generated on the shaft 41 by screwing the male screw portion 43 into the female screw portion 36 is reduced, and the mold clamping state is released. As shown in FIG. 4B, the large diameter portion 44 of the shaft 41 is separated upward from the piston 57 and the male screw portion 43 is disengaged from the female screw portion 36 of the second mold 17 as the shaft 41 is retracted. Then, since the connection between the shaft 41 and the second mold 17 is released, the second mold 17 can be lowered.

In this state, the second mold 17 is in close contact with the first mold 16. Further, a molded product obtained by cooling and solidifying the molten resin in the cavity 18 is in close contact with the molding recess 16 A of the first mold 16 and the molding projection 17 A of the second mold 17. However, in the vertical injection molding machine 10, the direction of gravity acting on the movable body 25 including the second mold 17 is the same as the direction in which the second mold 17 is released from the first mold 16. Therefore, the gravity acting on the movable body 25 can be used as at least a part of the mold release force. For this reason, the second mold 17 is released from the first mold 16 even if the mold release force is not separately applied between the first mold 16 and the second mold 17 (even by the release mechanism). can do.

Thereafter, each ball screw shaft 21 is rotated by the motor 22 in the opposite direction to the time when the movable body 25 is lifted. Thereby, the movable body 25 starts to descend. As the movable body 25 descends, the second mold 17 separates from the first mold 16. On the other hand, as shown in FIG. 4A, since the shaft 41 is biased downward by the spring 51, the shaft 41 is lowered so as to follow the movable body 25 while keeping the male screw 43 in contact with the female screw 36. Do. When the large diameter portion 44 of the shaft 41 is lowered to a position where it contacts the piston 57, the lowering of the shaft 41 stops. On the other hand, the movable body 25 continues to descend. Therefore, as shown in FIG. 1, the female screw portion 36 descends and separates from the shaft 41. When the second mold 17 separates from the first mold 16, the molded product is separated from the molding recess 16A but keeps in close contact with the molding projection 17A of the second mold 17.

When the second mold 17 is lowered to the mold opening position, the drive device of the forming machine side projecting mechanism 8 raises the projecting plate 6 and the projecting pin 7. In the in-mold extrusion mechanism 28, the ejection plate 26 pushed by the ejection pin 7 ascends with the ejection pin 27 and the inclined core. The molded article is peeled off from the forming projection 17A by the inclined core projecting from the forming projection 17A and taken out from between the first mold 16 and the second mold 17.

Here, each projecting pin 27 in the mold inward projecting mechanism 28 extends in the vertical direction, and is supported by the projecting plate 26 at its lower end. For this reason, the direction of gravity acting on the ejector pin 27 and the direction in which the axis L3 of the ejector pin 27 extends are both vertical and coincide with each other. Further, each projecting pin 7 in the forming machine side projecting mechanism 8 extends in the vertical direction, and is supported by the projecting plate 6 at its lower end. For this reason, the direction of gravity acting on the ejector pin 7 and the extending direction of the axis L4 of the ejector pin 7 are both vertical, and coincide with each other.

In this respect, the present embodiment is different from the horizontal injection molding machine described in Patent Document 2. In a lateral injection molding machine, the ejector pin extends horizontally and is supported at one end by a ejector plate. The axis of the ejector pin and the direction of gravity acting on the ejector pin are significantly different. For this reason, when the projecting pins move horizontally in a state of being inclined so as to become lower toward the tip, the projecting cores of the tips of the projecting pins and the projecting pins rub against the second mold, generating metal powder. There is a risk of In addition, when the molded product is also protruded in an inclined state due to the inclination of the protruding pin and the inclined core, the molded product and the second mold are rubbed, which may generate resin waste.

In that respect, in the present embodiment, each protrusion pin 27 extends vertically and ascends in that state, so that each protrusion pin 27 and the inclined core do not easily rub against the second mold 17 and generation of metal powder is suppressed. Ru. Further, since the molded product is not protruded in the inclined state due to the inclination of the protruding pin 27, the molded product and the second mold 17 are not easily rubbed, and the generation of resin debris is also suppressed. Furthermore, in the present embodiment, each protrusion pin 7 extends in the vertical direction and rises in that state, so that each protrusion pin 7 does not easily rub against the movable table 24 and generation of metal powder is suppressed. In this way, through the series of operations of the vertical injection molding machine 10, a molded article is molded.

According to the embodiment described above, the following effects can be obtained.
(1) The first mold 16 is a fixed mold, and the second mold 17 is a movable mold. The second mold 17 approaches and separates from the first mold 16 by moving up and down. Through holes 31 and 32 extending in the vertical direction are provided in the first mold 16 and the top plate portion 15, respectively. The shaft 41 is supported by the through holes 31 and 32 in the inserted state. The shaft 41 is rotated by the motor 38. At the lower end portion of the shaft 41, a male screw portion 43 as an engaging portion is provided. In the upper part of the second mold 17, a female screw portion 36 is provided coaxially with the through holes 31 and 32. The male screw portion 43 of the shaft 41 is engaged (screwed) in the female screw portion 36 as the engaged portion by rotating the shaft 41 in a state where the two

molds

16 and 17 are in contact with each other. Then, in a state in which the second mold 17 is in contact with the first mold 16, the second mold 17 is generated by a force (axial force) in a mold clamping direction generated by screwing the male screw portion 43 into the female screw portion 36. Is pressed into contact with the first mold 16 (FIGS. 3A and 3B).

Therefore, unlike the horizontal injection molding machine described in Patent Document 2, it is possible to suppress the shaft 41 from being inclined by its own weight. Also, the axis L1 of the shaft 41 and the axis L2 of the female screw 36 can be aligned, and the male screw 43 of the shaft 41 can be easily screwed into the female screw 36, and the second mold 17 can be used as the first mold. It can be pressed to 16.

(2) The in-mold protrusion mechanism 28 and the forming-machine-side protrusion mechanism 8 are used for protruding and removing the molded product from the second mold 17 opened. The in-mold extension mechanism 28 comprises a protrusion plate 26, a plurality of protrusion pins 27, and a tilted core. Each projecting pin 27 extends vertically and is fixed to the projecting plate 26 at its lower end. The inclined core is provided on the upper end of each projecting pin 27 (FIGS. 1 and 2). For this reason, since each protrusion pin 27 does not incline easily by dead weight at the time of protrusion of a molded article, and it becomes difficult to rub with the 2nd metal mold 17, generation | occurrence | production of metal powder can be suppressed. Moreover, since it becomes difficult to rub a molded article with the 2nd metal mold 17 (forming protrusion 17A), generation | occurrence | production of resin debris can also be suppressed.

Further, the forming machine side projecting mechanism 8 is provided with a projecting plate 6, a plurality of projecting pins 7, and a driving device. Each projecting pin 7 extends in the vertical direction, and is fixed to the projecting plate 6 at its lower end. The ejector plate 6 is moved up and down by a drive (FIGS. 1 and 2). For this reason, since each protrusion pin 7 does not incline easily by dead weight at the time of protrusion of a molded article, and it becomes difficult to rub with the movable stand 24, generation | occurrence | production of metal powder can be suppressed.

(3) In the mold clamping mechanism described in Patent Document 1, a fixed die plate, a movable die plate, a ball screw shaft, a ball nut and the like are arranged around the first mold and the second mold. Then, by moving the movable die plate, the movable die attached to the movable die plate is indirectly moved to press the movable die against the fixed die attached to the fixed die plate. . For this reason, the enlargement of the whole apparatus has become a problem. In addition, in a typical vertical injection molding machine that raises and lowers a movable body including a movable type, when raising the movable body against gravity, more energy is required than a horizontal injection molding machine.

In this respect, in the mold clamping mechanism 30 of the present embodiment, the second mold 17 is directly pressure-welded to the first mold 16 through the shaft 41 (FIGS. 1 and 2). From this, in this embodiment, unlike the mold clamping mechanism described in Patent Document 1, in order to clamp the first mold 16 and the second mold 17, a fixed die plate, a movable die plate, and the like are used. It becomes unnecessary. In addition, a shaft 41, an internal thread portion 36, and the like that constitute the mold clamping mechanism 30 are disposed in the vicinity of the cavity 18. Therefore, the miniaturization of the mold clamping mechanism 30 and the miniaturization of the vertical injection molding machine 10 become possible. Moreover, thereby, weight reduction of the movable body 25 is attained, energy saving for moving the movable body 25 can be reduced, and energy saving can also be achieved.

(4) In the vertical injection molding machine 10 of the present embodiment, the second mold 17 is positioned below the first mold 16 and moved up and down to perform mold closing and mold opening (FIG. 1, FIG. 1). 2). Such mold closing and mold opening directions do not affect the footprint of the vertical injection molding machine 10. In this respect, the vertical injection molding machine 10 can make the installation space smaller than a horizontal injection molding machine in which the second mold is moved in the horizontal direction at the time of mold closing and mold opening.

(5) When the second mold 17 pressed against the first mold 16 by the mold clamping mechanism 30 is released from the first mold 16, the gravity acting on the movable body 25 including the second mold 17 is It is used as at least a part of mold release force (Fig. 1, Fig. 2). Therefore, mold release can be performed without using a mold release mechanism. Therefore, compared with the case where a release mechanism is separately provided, further miniaturization of the vertical injection molding machine 10 is possible.

(6) A fluid pressure washer 55 for applying a force in the mold clamping direction is provided to the shaft 41 in a state in which the male screw portion 43 is screwed into the female screw portion 36 (FIGS. 3A and 3B) . Therefore, a part of the required axial force, which is an axial force necessary to press the first die 16 and the second die 17, can be covered by the force generated by the fluid pressure washer 55. Therefore, the axial force to be generated with the rotation of the shaft 41 can be reduced. That is, as the motor 38 which generates an axial force on the shaft 41, a small motor with small output torque can be used. Therefore, the miniaturization of the clamping mechanism 30 and the further miniaturization of the vertical injection molding machine 10 become possible.

(7) The fluid pressure washer 55 is used as the second actuator. The fluid pressure washer 55 comprises a cylinder 56 and a piston 57. The piston 57 is vertically movably accommodated in the cylinder 56 in a state where the general portion 42 of the shaft 41 is inserted. Also, the piston 57 divides the inside of the cylinder 56 up and down to form two

fluid pressure chambers

58 and 59. The lower fluid pressure chamber in the cylinder 56 is a clamping fluid pressure chamber 59. A working fluid is supplied to the clamping fluid pressure chamber 59 when a force in the clamping direction is applied to the shaft 41 (FIG. 3 (B)). Thus, with a simple configuration such as the cylinder 56 and the piston 57, a force in the mold clamping direction can be applied to the shaft 41.

The present invention can be embodied in the following another embodiment.
In addition to supporting the shaft 41 by the

slide bearings

45 and 46 at the end (upper end) close to the motor 22, the end (lower end) away from the motor 22 is also supported by the slide bearing or the like It is also good. In this case, as compared to the horizontal injection molding machine described in Patent Document 2, it is advantageous in the following point.

Even in a horizontal injection molding machine, the inclination of the shaft due to gravity can be suppressed by supporting the shaft of the mold clamping mechanism at the end close to the motor and the end remote from the motor by a slide bearing or the like. . However, when mounting the mold clamping mechanism in the first mold, it is not easy to insert the shaft inclined by its own weight into all the slide bearings.

In this respect, in the mold clamping mechanism 30 of the present embodiment, the shaft 41 extending in the vertical direction is used. Therefore, even when the shaft 41 is supported by the slide bearing or the like at the end close to the motor and the end away from the motor, the direction of gravity acting on the shaft 41 and the axis of the slide bearing are aligned. Therefore, the shaft 41 can be easily inserted into all the slide bearings.

This effect is particularly effective when one mold clamping mechanism 30 is commonly used for a plurality of types of first molds 16. In this case, every time the first mold 16 is replaced, it is necessary to remove, attach, or adjust the mold clamping mechanism 30, and the frequency of inserting the shaft 41 into the slide bearing is increased.

The male screw portion 43 may be provided not only at the lower end but also in a wide area including the lower end in the direction of the axis L1 of the shaft 41. When the long shaft 41 is used, the male screw portion 43 may be provided at an intermediate portion in the direction of the axis L1 of the shaft 41.

The female screw portion (engaged portion) 36 is provided not only at the upper end but also in a wide area including the upper end in the direction of the axis L2 of the second mold 17, on the condition that it is coaxial with the through hole 31. May be That is, the female screw portion 36 may be longer downward than the present embodiment. Alternatively, a hole or a hole coaxial with the through hole 31 may be provided in the second mold 17, and an internally threaded portion 36 may be provided at an axial intermediate portion of the hole or the hole.

In the shaft 41 and the second mold 17, the target provided with the male screw portion 43 and the female screw portion 36 may be the reverse of the present embodiment.
That is, when the shaft 41 having a large diameter is used, a female screw is provided at the end (for example, the lower end) of the shaft 41 close to the second mold 17 and the end close to the first mold 16 of the second mold 17 A male screw may be provided on the part (for example, the upper end). Also in this case, when the motor 41 rotates the shaft 41 to screw the male screw portion into the female screw portion, a force in the mold clamping direction can be generated.

The fluid pressure washer 55 may be omitted. In this case, it is necessary to generate an axial force only by the extension due to the rotation of the shaft 41, and it is necessary to use a larger motor 38 than the case of using the fluid pressure washer 55. However, compared with the case of using a fixed die plate, a movable die plate, etc., the mold clamping mechanism 30 and the vertical injection molding machine 10 can be made smaller and lighter.

-When the second mold 17 can not be released from the first mold 16 only by the gravity acting on the movable body 25 including the second mold 17, a mold release mechanism is provided separately from the mold clamping mechanism 30. May be In this case, if the gravity acting on the movable body 25 is used as at least a part of the mold release force, mold release can be performed with a smaller force. Therefore, the mold release mechanism can be miniaturized, and the vertical injection molding machine 10 Miniaturization is possible.

The gravity acting on the movable body 25 may not necessarily be used as a release force. In this case, for example, a plurality of weights and a plurality of pulleys are used. Each pulley is rotatably mounted on the top of the vertical injection molding machine 10. Then, a wire may be hung from the upper side on each pulley, one end of the wire may be fixed to the movable body 25, and the other end of the wire may be fixed to the weight.

In a typical vertical injection molding machine, the influence of gravity is large during movement of the movable mold, and the load on the motor is large in order to maintain the movement and stop of the movable mold. However, according to this configuration, the load applied to the motor can be reduced by maintaining the balance between the weight and the movable body through the wire hung on the pulley.

For example, the second mold 17 may be raised and lowered by a hydraulic cylinder, or the chain belt may be driven by a motor to raise and lower the second mold 17.
The second mold 17 may be a fixed mold and the first mold 16 may be a movable mold. In this case, the first mold 16 approaches and separates from the second mold 17 by moving up and down on the upper side of the second mold 17.

The positional relationship between the first mold 16 and the second mold 17 may be opposite to that of the present embodiment. That is, the first mold 16 may be disposed below the second mold 17. In this case, in each mold clamping mechanism 30, the motor 38 is disposed below the shaft 41. Further, in this case, the second mold 17 may be a fixed mold, and the first mold 16 may be a movable mold which is moved up and down below the second mold 17. Alternatively, the first mold 16 may be fixed, and the second mold 17 may be movable above the first mold 16.

In the present embodiment, the second mold 17 is pressed against the first mold 16 by the force in the mold clamping direction generated by screwing the male screw 43 into the female screw 36, but instead of this, After the engaging portion is engaged with the engaged portion, a force in the mold clamping direction may be applied to the shaft 41.

For example, on the outer peripheral surface of the end of the shaft 41 close to the second mold 17, a plurality of engagement peaks are formed as the engagement portion. In addition, an engaged portion in which the engaging portion is engaged is provided at an end of the second mold 17 close to the first mold 16. The engaged portion comprises an insertion hole that matches the outer shape of the end of the shaft 41. A plurality of engagement grooves are formed in the inner wall surface of the insertion hole. Then, the tip end of the shaft 41 is inserted into the insertion hole of the second mold 17 so that the engagement peak of the shaft 41 and the engagement groove of the second mold 17 are alternated. Then, in this state, by slightly rotating the shaft 41 by the motor 38, the engagement peak is engaged with the engagement groove. In this case, for example, a force generated by the fluid pressure washer 55 is applied to the shaft 41 as a force in the mold clamping direction.

DESCRIPTION OF SYMBOLS 10 ... Vertical mold injection molding machine (injection molding machine), 16 ... 1st mold, 17 ... 2nd mold, 18 ... Cavity, 25 ... Movable body, 30 ... Clamping mechanism, 31, 32 ... Through hole, 36 ... Female screw part (engaged part), 38 ... motor (first actuator), 41 ... shaft, 43 ... male screw part (engagement part), 55 ... fluid pressure washer (second actuator), 56 ... cylinder, 57 ... Piston, 58: fluid pressure chamber, 59: clamping fluid pressure chamber, L1 to L4: axial line.

Claims

The first mold and the second mold are provided, one of which is a fixed mold and the other is a movable mold, and the movable mold is moved up and down toward and away from the fixed mold to move the movable mold to the fixed mold. Close both molds, press the movable mold against the fixed mold by the mold clamping mechanism, and inject molten resin into the cavity formed between the first mold and the second mold. An injection molding machine for forming a molded article, wherein
The mold clamping mechanism
A shaft supported in a state inserted through a through hole vertically penetrating the first mold, wherein at least a part of the shaft in the axial direction has an engaging portion and is rotationally driven by an actuator When,
An engaged portion provided coaxially with the through hole in the second mold, and in a state where the first mold and the second mold are in contact with each other, by rotation of the shaft by the actuator And an engaged portion engaged with the engaging portion;
The direction in which the second mold and the first mold approach each other is a mold clamping direction, and a force in the mold clamping direction generated with the engagement of the engaging portion and the engaged portion, or the engagement Injection molding characterized in that the first mold and the second mold are pressed against each other by the force in the mold clamping direction applied to the shaft after engagement of the joint portion and the engaged portion. Machine.
One of the engaging portion and the engaged portion is constituted by a female screw portion, and the other is constituted by a male screw portion,
The injection molding machine according to claim 1, wherein the mold clamping mechanism generates a force in the mold clamping direction by screwing the male screw part into the female screw part by rotation of the shaft.
The actuator is a first actuator, and the mold clamping mechanism further clamps the mold against the shaft in a state in which the engaging portion is engaged with the engaged portion separately from the first actuator. The injection molding machine according to claim 1 or 2, further comprising a second actuator for applying a directional force.
The second actuator comprises a cylinder and a piston, and the piston is accommodated in the cylinder so as to be vertically movable, and divides the inside of the cylinder into two fluid pressure chambers,
One of the two fluid pressure chambers is a clamping fluid pressure chamber, and a working fluid is supplied to the clamping fluid pressure chamber when a force in the clamping direction is applied to the shaft. The injection molding machine according to claim 3, characterized in that:
The first mold is the fixed mold, the second mold is the movable mold, and the second mold approaches the first mold by moving up and down on the lower side of the first mold. And spaced apart,
A movable body is composed of the second mold and a member that moves along with the elevation of the second mold, and gravity acting on the movable body is pressed against the first mold by the clamping mechanism. The injection molding machine according to any one of claims 1 to 4, wherein the injection molding machine is used as at least a part of a mold release force for releasing the second mold from the first mold.