JP4577763B2 - Mold drive device, injection molding machine, drive device - Google Patents

Description

  The present invention relates to a mold driving device and the like suitable for use when opening and closing a mold of an injection molding machine.

In a horizontal injection molding machine in which a fixed mold plate holding a fixed mold and a movable mold plate holding a moving mold are opposed to each other and can be contacted and separated in the horizontal direction, the mold is formed using a pneumatic cylinder or a hydraulic cylinder. Are opened / closed and clamped (see, for example, Patent Document 1).
However, when using the pneumatic cylinder hydraulic cylinder, it is difficult to control the opening and closing of the mold with high precision, for example, the mold has a problem that it is difficult to open and close by a minute dimension.
Further, a pump or the like is required to operate the pneumatic cylinder or the hydraulic cylinder, and it is difficult to reduce the size of the injection molding machine.

Japanese Patent Laying-Open No. 2001-1381 (FIG. 1)

On the other hand, there is an injection molding machine that uses a ball screw to open and close the mold (see, for example, Patent Document 2). By using a ball screw, the opening and closing accuracy of the mold can be improved.
However, when a ball screw is used, since the torque that can be generated to open and close the mold is smaller than that of a hydraulic cylinder or the like, there is a problem that the ball screw cannot be used in a large injection molding machine.

Japanese Patent Laid-Open No. 2000-334796 (FIG. 1)

  The present invention has been made based on such a technical problem, and provides a mold driving device, a driving device, and the like that can drive a mold with high accuracy and can downsize an injection molding machine and the like. With the goal.

For this purpose, the present invention is a mold driving apparatus for holding a fixed mold and a movable mold so as to face each other and moving the movable mold with respect to the fixed mold, and holds the fixed mold. Hold the movable mold so as to face the fixed mold and the fixed mold, move the movable mold relative to the fixed mold, and move the movable mold relative to the fixed mold A drive mechanism. The drive mechanism includes a base member that is rotatably held around an axis parallel to the direction in which the movable platen is moved, a drive source for rotationally driving the base member around the axis, and a surface of the base member above, it is formed continuously in a ring shape in a plane perpendicular to the axis, and a cam crest having a predetermined cam profile, is held in a rotatable state between the mobile platen side and cam nose, A rolling element that is displaced in the axial direction by the cam profile of the cam peak when the base member rotates about the axis, and the cam peak has a plurality of cam peaks having the same cam profile in the circumferential direction. A plurality of rolling elements corresponding to each of the cam peaks, and the shape of the rolling elements is any one of a barrel shape, a truncated cone shape, and a spherical shape. .
According to such a configuration, when the base member is driven to rotate about the axis by the drive source, the cam crest formed on the surface of the base member also rotates in the circumferential direction. As a result, the protruding dimension of the cam crest portion in the axial direction from the surface of the base member changes at a position where it contacts the rolling element held between the cam crest portion and the movable platen side. Then, the rolling element is displaced along the cam profile of the cam crest in the axial direction with respect to the base member while rotating. As a result, the distance between the base member and the movable mold is changed by the rolling elements, and the movable mold is displaced in the axial direction .

This mold drive apparatus can further include a mold platen moving mechanism that moves the movable mold plate with respect to the fixed mold plate with a stroke larger than that of the drive mechanism. As a result, when moving the movable platen with a large displacement, the platen moving mechanism can be used, and when moving the movable platen with a small displacement, the above drive mechanism can be used.
The mold drive device further includes a tie bar that connects the fixed mold plate and the movable mold plate with one end fixed to one of the fixed mold plate and the movable mold plate . The drive mechanism includes the tie bar, the fixed mold plate, and the movable mold plate. It is provided between the other side of the board .

By the way, it is preferable to use an electric drive motor as a drive source of the drive mechanism. Thereby, a clean molding environment can be created.
As described above, according to the configuration in which the rotational motion of the base member is converted into the linear direction by displacing the rolling elements along the cam ridges, the movable platen can be moved with a small torque. Become. At this time, if the gear teeth are formed on the outer periphery of the base member and the drive source drives the drive gear meshing with the gear teeth to drive the base member to rotate, the movable platen moves with a smaller torque. This is preferable.
Such cam crests and rolling elements corresponding to the cam crests can be provided in multiple stages in the axial direction. It is also possible to reciprocate the movable platen in both directions depending on the shape of the cam crest, the rotation direction of the base member, etc. In this case, a plurality of cam crests are provided, and each cam crest is rotated independently. You may make it let it.
Such a mold drive device is suitable for use in an injection molding machine or the like, but even a mold for other purposes can be used to perform a mold opening operation, a mold clamping operation, and the like.

When the present invention is an injection molding machine that forms a molded product by injecting resin between a fixed mold and a movable mold, the injection molding machine includes a fixed mold plate that holds the fixed mold, and a fixed mold. A movable mold that holds the movable mold so as to face the mold and can be moved back and forth in a direction to move away from the fixed mold, a drive mechanism that moves the movable mold relative to the fixed mold, and a fixed mold And an injection part for injecting resin into a cavity formed between the movable molds. The drive mechanism includes a base member that is rotatably held around an axis parallel to the direction in which the movable platen is moved, a drive source for rotationally driving the base member around the axis, and a surface of the base member On top, a cam crest formed in an annular shape in a plane perpendicular to the axis, having a predetermined cam profile, and held in a rotatable state between the cam crest and the movable platen side, when the base member is rotated about the axis, the cam profile of the cam nose, and the rolling elements that is displaced in the axial direction, the fixed mold platen and a state where one end is fixed to one of the fixed mold platen and movable die plate movement A drive mechanism is provided between the tie bar and the other of the fixed mold plate and the movable mold plate, and the cam crest portion includes a plurality of cam crests having the same cam profile. , Continuous in the circumferential direction Is, rolling elements, a plurality provided corresponding to each of the cam lobes, the shape of the rolling element, a barrel shape, frustoconical, characterized in that it is a one of a spherical shape.

  According to the present invention, the movable platen or the like can be moved in the axial direction by rotating the base member in the axial direction and rolling the rolling element along the cam crest. Since the amount of rotation of the base member can be controlled electrically with high accuracy by using a motor or the like as a drive source, the mold can be operated with high accuracy. In addition, if a motor or the like is used as a drive source, the apparatus can be reduced in size, and the surroundings are not contaminated by hydraulic oil or the like, and injection molding or the like can be performed in a clean environment. Furthermore, since the rotational motion of the cam crest is converted into a linear motion by the rolling elements, there is an advantage that resistance is small and loss is small.

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
FIG. 1 is a diagram for explaining a schematic configuration of a drive device of an injection molding machine 10 according to the present embodiment.
As shown in FIG. 1, for example, a rectangular fixed mold platen 12 is fixed on a base frame 11 of an injection molding machine 10. A fixed mold 13 is attached to one side surface of the fixed mold platen 12.
A guide rail 14 is laid on the base frame 11, and a movable mold plate (driving object) 15 disposed so as to face the fixed mold plate 12 is movably provided along the guide rail 14. Yes. A movable mold 16 is attached to the movable mold plate 15 so as to face the fixed mold 13.

  Through holes 17 are formed in the four corners of the fixed mold platen 12 and the movable mold platen 15. Tie bars 18 are provided through these through holes 17 so as to connect the fixed mold 13 and the movable mold platen 15. On the fixed mold platen 12 side of the tie bar 18, a flange portion 18 a that protrudes to the outer peripheral side and has an outer diameter larger than the through hole 17 is formed. A nut 19 having an outer diameter larger than that of the through hole 17 is screwed to the end of the tie bar 18 on the movable mold board 15 side. As a result, the amount of movement of the movable mold 15 and the movable mold 16 in the direction away from the fixed mold 12 is restricted.

An injection unit (injection unit) 20 for injecting resin for injecting resin into a cavity formed between the fixed mold 13 and the movable mold 16 is provided on the other side surface side of the fixed mold platen 12. .
On the injection unit 20 side, a drive cylinder (template movement mechanism) 21 used for moving the movable mold platen 15 with a large stroke is provided. The distal end portion of the telescopic rod 21 a of the drive cylinder 21 is fixed to the movable mold platen 15. Accordingly, the movable mold platen 15 moves along the guide rail 14 by expanding and contracting the drive cylinder 21, and the fixed mold 13 and the movable mold 16 can be opened and closed.

Further, the injection molding machine 10 is provided with a driving mechanism (driving device) 30 used at the end of each tie bar 18 on the fixed mold platen 12 side to move the movable mold platen 15 with a minute stroke.
FIG. 2 is a diagram for illustrating the operating principle of such a drive mechanism 30.
As shown in FIG. 2, the drive mechanism 30 includes a disk-shaped cam member 31 and a rolling element 32.
The cam member 31 is formed by forming a cam main body (cam peak portion) 34 on a side surface (surface) 33 a of a disk-shaped base member 33. The cam body 34 is formed in an annular shape on the side surface 33 a of the base member 33. The cam body 34 is formed such that a plurality of cam peaks 35 are continuously arranged in the circumferential direction. Each cam crest 35 is formed in each area obtained by equally dividing the annular cam main body 34 into a plurality of parts in the circumferential direction, and has a common (identical) cam profile. Each cam crest 35 is formed so that the protruding dimension (the height of the cam crest 35) in the direction of the central axis L from the side surface 33a of the base member 33 gradually increases from one end side 35a to the other end side 35b. Has been. At this time, the cam crest 35 can be formed with a constant gradient from the one end side 35a to the other end side 35b, or the gradient gradually increases from the one end side 35a to the other end side 35b, or gradually. It can also be formed to be smaller.

  The number of rolling elements 32 is the same as the number of cam ridges 35 formed in the cam main body 34, or different numbers are provided in the case of double rows. For example, as shown in FIG. 2, the rolling element 32 can have a cylindrical (columnar) shape. Further, as shown in FIG. 3A, the rolling element 32 is formed in a barrel shape in which the outer diameter of the central portion 32a is larger than the outer diameters of both ends 32b, or as shown in FIG. On the other hand, the other end side 32d may have a truncated cone shape with a small outer diameter. In addition to this, the rolling element 32 may be spherical.

  The rolling element 32 is sandwiched and held between the cam main body 34 of the cam member 31 and the driving target (the tie bar 18 in the present embodiment) in the driving mechanism 30. At this time, guide members (not shown) are provided on the inner peripheral side and the outer peripheral side so that the rolling element 32 does not fall off from the cam crest 35 of the cam main body 34, or as shown in FIG. It is preferable that the rolling element 32 is rotatably held.

In such a driving mechanism 30, the cam member 31 is rotated around its central axis L (in the direction of the arrow (A)) by a driving source such as a motor 38, so that the tie bar 18 to be driven is moved to the central axis L Is moved in the direction along the arrow (direction of arrow (B)). That is, when the cam member 31 is rotated by the motor 38 or the like, the cam main body 34 having the plurality of cam peaks 35 rotates integrally. For example, when the rolling element 32 is located on one end side 35 a of the cam crest 35 and is sandwiched between the cam main body 34 and the flange portion 18 a of the tie bar 18, While the rolling element 32 is rotated by the friction with the cam 35, it is relatively displaced along the circumferential direction of the cam body 34 toward the other end side 35 b of the cam crest 35. Thereby, the rolling element 32 climbs the inclined surface 35c of the cam crest 35, and the protrusion dimension from the base member 33 (the side surface 33a) which combined the cam crest 35 and the rolling element 32 increases. As a result, the flange portion 18a of the tie bar 18 in contact with the rolling element 32 is pressed in a direction away from the side surface 33a of the base member 33, and the tie bar 18 is displaced in the axial direction.
Thus, in the drive mechanism 30, the tie bar 18 is displaced in a direction substantially orthogonal to the rotation direction by rotating the base member 33. At this time, the displacement of the tie bar 18 can be controlled by controlling the rotation amount of the base member 33.

FIG. 5 and FIG. 6 are diagrams showing an example of a specific configuration in which the drive mechanism 30 having the operation principle as described above is incorporated in the injection molding machine 10 shown in FIG.
A drive mechanism 30 is provided so as to correspond to the flange portion 18 a of the tie bar 18 protruding from the through hole 17 of the fixed mold platen 12.
The cam member 31 of the drive mechanism 30 is held such that its outer peripheral side is sandwiched between the end surface 12 a of the stationary mold plate 12 and the cover 40. Here, thrust plates 41, 41 are provided between the cam member 31, the end surface 12 a of the fixed mold 12 and the cover 40. These thrust plates 41 are centered while restricting movement in the direction along the central axis L in a state where the cam member 31 is sandwiched between the end surface 12a of the fixed mold plate 12 and the cover 40 by a bearing (not shown), for example. It is held so as to be rotatable around the axis L. The cover 40 is fixed to the end surface 12a of the fixed mold plate 12 with a bolt or the like (not shown) in a state in which a gap for holding the cam member 31 and the thrust plates 41 and 41 is secured by a spacer (not shown). It is fixed to the board 12.

  Gear teeth 33 b are formed on the outer peripheral surface of the base member 33 of the cam member 31. The cam member 31 meshes with a worm gear (drive gear) 42 inserted into a gap between the fixed mold platen 12 and the cover 40. The cam member 31 is rotated by rotating the worm gear 42 by a motor 38.

A cam body 34 is formed on the side surfaces 33 a and 33 a on both sides of the base member 33, and the rolling elements 32 are provided on both sides of the cam member 31.
On one side of the cam member 31, a rolling element 32 that is rotatably held by a holder 36 includes a flange portion 18 a of the tie bar 18 that protrudes from the through hole 17 of the fixed mold 12, and the cam member 31. It is sandwiched and held between the cam body 34.
A tip end portion 18b of the tie bar 18 projects from the other side of the cam member 31, and a nut 44 is screwed to the tip end portion 18b. On the other side of the cam member 31, a rolling element 32 that is rotatably held by a holder 36 includes a nut 44 and a washer 45, and a cam body 34 on the other side of the cam member 31. It is sandwiched between and held.
Here, the cam main body 34 formed on both surfaces of the cam member 31 includes an inclined surface 35c of the cam crest 35 of the cam main body 34 on one side of the cam member 31, and an inclined surface 35c of the cam crest 35 on the other side. Are provided so as to be parallel to each other.

  Incidentally, as shown in FIG. 6, a cylindrical bush 46 is mounted on the tip 18 b side of the flange portion 18 a of the tie bar 18 in order to prevent interference with the cam member 31 and the holder 36 of the rolling element 32. ing.

  In such a configuration, when the worm gear 42 is rotationally driven by the motor 38, the cam member 31 meshing with the worm gear 42 is sandwiched between the end surface 12 a of the fixed mold platen 12 and the cover 40 and extends along the central axis L. It rotates about the central axis L in a state where movement in the direction is restricted. Then, the rolling member 32 sandwiched between the cam body 34 and the flange portion 18a of the tie bar 18 on one side of the cam member 31, and the cam body 34 and the washer 45 on the other side of the cam member 31. The rolling elements 32 sandwiched between the rollers roll along the slopes of the cam peaks 35 of the cam body 34. As a result, when the rolling element 32 moves relatively from the one end side 35a of the cam crest 35 to the other end side 35b, the interval C1 between the cam member 31 and the flange portion 18a of the tie bar 18 is expanded, and the cam member 31 and the washer The distance C2 from 45 is reduced. As a result, the tie bar 18 extends along the central axis L with respect to the cam member 31 that is sandwiched between the end surface 12a of the fixed mold plate 12 and the cover 40 and is restricted from moving in the direction along the central axis L. The movable mold platen 15 is drawn toward the fixed mold platen 12 side. As a result, the fixed mold 13 and the movable mold 16 can be clamped by minute dimensions (so-called mold clamping). Further, if the cam member 31 is rotated in the reverse direction, the fixed mold 13 and the movable mold 16 can be opened by a minute dimension.

In this manner, according to the drive mechanism 30, the tie bar 18 can be moved in the axial direction (direction along the central axis L) by rotating the disc-shaped cam member 31. Since the rotation amount of the cam member 31 can be controlled with high accuracy by electrically controlling the motor 38, the fixed mold 13 and the movable mold 16 are compared with the case where the tie bar 18 is operated by a pneumatic or hydraulic cylinder. Can be operated with high accuracy. Moreover, in the drive mechanism 30 having such a configuration, the periphery of the drive mechanism 30 is not contaminated by hydraulic oil or the like as in the case of using a hydraulic cylinder, and injection molding can be performed in a clean environment. Can be made small, and space can be saved.
Moreover, since the rotational motion of the cam member 31 is converted into the linear motion of the tie bar 18 by the rolling elements 32, the resistance is small and the loss is small.

In such a configuration, when the rotational movement of the cam member 31 is converted into the linear movement of the tie bar 18, the torque for rotating the cam member 31 and the displacement of the tie bar 18 are adjusted by adjusting the inclination angle of the cam crest 35. You can adjust the relationship of the force to make it. That is, if the inclination angle of the cam crest 35 (the angle of the inclined surface 35c of the cam crest 35 with respect to the side surface 33a of the base member 33) is reduced, the ratio of the displacement of the tie bar 18 to the rotation amount of the cam member 31 is reduced. Is increased, the ratio of the displacement of the tie bar 18 to the amount of rotation of the cam member 31 increases.
When it is desired to rotate the cam member 31 with a small torque, or when it is desired to make the displacement amount of the tie bar 18 more accurate, the inclination angle of the cam crest 35 may be reduced. Conversely, when it is desired to increase the amount of displacement of the tie bar 18, the cam member 31 needs to be rotated with a large torque, but the inclination angle of the cam crest 35 may be increased. As described above, the inclination angle of the cam crest 35 can be set according to the output of the motor 38 to be used or the movement accuracy and the movement amount of the movable mold 16 required for molding.
By the way, in the configuration shown in FIGS. 5 and 6, the motor 38 also has a reduction ratio between the outer diameter of the base member 33 of the cam member 31 and the gear teeth 33 b formed on the outer peripheral surface of the base member 33 and the worm gear 42. The required torque and the amount of displacement of the tie bar 18 can be adjusted. In this case, if the outer diameter of the base member 33 is increased, the reduction ratio of the gear teeth 33b and the worm gear 42 is increased, and the inclination angle of the cam crest 35 is decreased, even the motor 38 having a small output (torque) can move large. The mold 16 can be driven.

The drive mechanism 30 as described above can be various other modified examples and application examples.
5 and 6, the cam member 31 is rotationally driven by the worm gear 42. Instead of this, the cam member 31 is coaxially driven by the motor 38 as shown in FIG. You can also.
Here, in the configuration shown in FIG. 7, the cam member 31 is placed on the central axis L while being sandwiched between the fixed mold platen 12 and the cover 40 by the thrust plates 41, 41 as in the configuration of FIG. 5. While being restricted from moving in the direction along, it is held so as to be rotatable about the central axis L. On the other side of the cam member 31, a holder 36 (not shown in FIG. 7) that holds the rolling elements 32, a washer 45, and a hollow case member 50 that covers the nut 44 are provided on the side surface of the base member 33. 33a is attached. A hole 50a is formed in the central portion of the case member 50, and a shaft 51 having a spline 51a formed on the outer peripheral surface is engaged with the hole 50a. The shaft 51 passes through the through hole 40 a of the cover 40 and is connected to a motor 38 provided outside the cover 40.
In such a configuration, when the shaft 51 is rotationally driven by the motor 38, the rotation is transmitted to the cam member 31 via the case member 50, and via the rolling elements 32, as in the configurations shown in FIGS. 5 and 6. Thus, the tie bar 18 can be displaced.

The configuration shown in FIG. 8 is an example when the drive mechanism 30 has a multi-stage configuration.
In the configuration shown in FIG. 8, the cam member 31 is sandwiched between the fixed mold platen 12 and the cover 40 by the thrust plates 41 and 41 as in the configuration of FIGS. In this state, the movement in the direction along the central axis L is restricted, and is held so as to be rotatable around the central axis L. Cam bodies 34 are formed on both surfaces of the base member 33 of the cam member 31. A rolling element 32 is sandwiched between the cam member 31 and the nut 44 screwed to the tip end portion 18 b of the tie bar 18 via a washer 45. On the other hand, a disc-shaped transmission plate 60 is newly disposed between the cam member 31 and the flange portion 18 a of the tie bar 18, and the rolling elements 32 constituting the first-stage drive mechanism 30 are cam members 31. Between the cam body 34 and the transmission plate 60.

  As the second stage drive mechanism 30, a cam main body 34 similar to the cam member 31 is formed on one surface side of the transmission plate 60 (side facing the flange portion 18 a of the tie bar 18), and the flange portion of the tie bar 18 is formed. A rolling element 32 held by a holder 36 (not shown in FIG. 8) is sandwiched between 18a and the transmission plate 60 (cam body 34 provided on the transmission plate 60).

  Further, like the cam member 31, the transmission plate 60 needs to be held so as to be rotatable around the central axis L. The transmission plate 60 operates the first stage drive mechanism 30 as described later. As a result, it is displaced along the central axis L. For this reason, a pressing member 61 such as a coil spring is interposed between the transmission plate 60 and the fixed mold platen 12, and the transmission plate 60 is rotatably held by the thrust plate 62 in a state of pressing the transmission plate 60 toward the cam member 31.

  As shown in FIG. 9, the transmission plate 60 is formed with a substantially fan-shaped groove 63 on the surface facing the cam member 31. On the other hand, the cam member 31 is provided with a claw 64 or a protrusion inserted into the groove 63 on the surface facing the transmission plate 60. Accordingly, as shown in FIGS. 10A to 10C, the movement range of the claw 64 is restricted by the groove 63. That is, the relative rotation range of the cam member 31 and the transmission plate 60 is restricted by the claw 64 and the groove 63.

In such a configuration, when the cam member 31 is rotated by the motor 38, as shown in FIGS. 10A and 10B, when the claw 64 is in a range where it does not reach the end 63b from the start end 63a side of the groove 63. Only the cam member 31 rotates. As a result, the rolling elements 32 provided on both sides of the cam member 31 constituting the first stage drive mechanism 30 move along the cam bodies 34 on both sides of the cam member 31, and the cam member 31, washer 45, And the distance C3 between the cam member 31 and the transmission plate 60 is reduced (at this time, the distance C4 between the transmission plate 60 and the flange portion 18a of the tie bar 18 is not changed because the transmission plate 60 is not rotated). ). Thereby, the tie bar 18 moves in the direction along the central axis L, and the movable mold platen 15 is drawn toward the fixed mold platen 12 side.
When the cam member 31 is further rotated and the claw 64 reaches the terminal end 63b of the groove 63 as shown in FIG. 10C, the rotation of the cam member 31 is transmitted to the transmission plate 60 via the claw 64. 60 and the cam member 31 begin to rotate together. Then, the rolling element 32 provided between the transmission plate 60 and the flange portion 18a constituting the second-stage drive mechanism 30 moves along the cam body 34 formed on the transmission plate 60, and the transmission plate 60 The distance C4 between the tie bar 18 and the flange portion 18a of the tie bar 18 is reduced. As a result, the tie bar 18 moves in the direction along the central axis L, and the movable mold platen 15 is further drawn toward the fixed mold platen 12 side.

For example, as shown in FIG. 2, when the cam main body 34 of the cam member 31 is divided into four and the cam crest 35 is formed, the rotation angle of the cam member 31 is 90 ° at the maximum. On the other hand, by adopting a multistage configuration as shown in FIGS. 8 to 10, the cam member 31 constituting the first stage drive mechanism 30 is rotated by 90 ° at the maximum, and then further rotated. Thus, the transmission plate 60 constituting the second-stage drive mechanism 30 can be rotated, which makes it possible to substantially increase the amount of displacement (stroke) of the tie bar 18.
Of course, the drive mechanism 30 is not limited to two stages, and can be provided in multiple stages.

5 to 11, the cam main body 34 and the rolling element 32 are arranged on both sides of one cam member 31, but the present invention is not limited to this. Of course, FIG. The cam main body 34 and the rolling element 32 may be provided only on one side of the cam member 31 as in the configuration for explaining the operation principle shown in FIG. However, in that case, the operating direction of the tie bar 18 is only one direction, and a configuration for operating (or pressing) the tie bar 18 in the opposite direction is separately required.
In addition, as shown in FIG. 11, the cam body 34 and the rolling element 32 are not disposed on both sides of one cam member 31, but the cam member 31 and the rolling element 32 that form the cam body 34 are opposed to each other. Two sets may be provided in the direction, and each cam body 34 may be driven independently by the worm gear 42. In such a configuration, when the tie bar 18 is displaced in one direction (for example, the mold clamping direction), only one cam body 34 is rotationally driven, and when it is displaced in the other direction (for example, the mold opening direction), the other Only the cam body 34 is rotationally driven. Of course, you may provide two sets of the cam member 31 and the rolling element 32 which formed the cam main body 34 in the same direction.

Further, such a drive mechanism 30 is not limited to the tie bar 18 as long as the movable platen 15 can be displaced , and may be provided at other locations. For example, as shown in FIG. 12, the second movable mold platen 15B can be moved on the guide rail 14 between the fixed mold platen 12 and the first movable mold platen 15A driven by the drive cylinder 21. The drive mechanism 30 as described above may be provided between the first movable mold platen 15A and the second movable mold platen 15B. In this case, the movable mold 16 is attached to the second movable mold platen 15B.
In addition to this, as long as it does not depart from the gist of the present invention, the configuration described in the above embodiment can be selected or changed to another configuration as appropriate.

It is a figure for demonstrating schematic structure of the injection molding machine in this Embodiment. It is a figure for demonstrating the principle of operation of a drive mechanism. It is a figure which shows the example of the shape of a rolling element. It is a figure which shows the holder holding a rolling element. It is sectional drawing which shows the drive mechanism arrange | positioned at the one end side of a tie bar. It is a perspective developed view for showing the configuration of the drive mechanism. It is sectional drawing which shows the other example of a drive mechanism. It is sectional drawing which shows the example at the time of providing a drive mechanism in multistage. It is a perspective view which shows the structure for transmitting rotation between multistage drive mechanisms. It is a figure which shows the mode of operation | movement of a multistage drive mechanism. It is a figure which shows the other example of a multistage drive mechanism. It is a figure which shows the example which provided the drive mechanism in the other part of the injection molding machine.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Injection molding machine, 12 ... Fixed mold board, 13 ... Fixed mold, 15 ... Moving mold board (driven object), 16 ... Moving mold, 18 ... Tie bar, 18a ... Flange part, 20 ... Injection unit (injection) Part), 21 ... drive cylinder (platen movement mechanism), 30 ... drive mechanism (drive device), 31 ... cam member, 32 ... rolling element, 33 ... base member, 33a ... side surface (surface), 34 ... cam body ( Cam crest), 35 ... cam crest, 38 ... motor (drive source), 42 ... worm gear (drive gear), 60 ... transmission plate, L ... central axis

Claims (6)

A mold driving device that holds a fixed mold and a movable mold facing each other and moves the movable mold with respect to the fixed mold,
A stationary mold plate for holding the stationary mold;
A movable mold plate that holds the movable mold so as to face the fixed mold and is capable of moving back and forth in a direction of moving away from the fixed mold plate;
A drive mechanism for moving the movable platen relative to the fixed platen,
The drive mechanism is
A base member rotatably held around an axis parallel to a direction in which the movable platen is moved;
A drive source for rotating the base member about the axis;
On the surface of the base member, a cam crest formed continuously in an annular shape in a plane perpendicular to the axis, and having a predetermined cam profile;
It is held in a rotatable state between the cam crest and the movable platen side, and is displaced in the axial direction by the cam profile of the cam crest when the base member rotates around the axis. Rolling elements to
A tie bar that connects the fixed mold plate and the movable mold plate with one end fixed to one of the fixed mold plate and the movable mold plate;
With
The drive mechanism is provided between the tie bar and the other of the fixed mold plate and the movable mold plate,
The cam crest is formed by continuously forming a plurality of cam crests having the same cam profile in the circumferential direction,
A plurality of the rolling elements are provided corresponding to each of the cam peaks,
The die driving device is characterized in that the rolling element has a barrel shape, a truncated cone shape, or a spherical shape.   The mold drive apparatus according to claim 1, further comprising a mold platen movement mechanism that moves the movable mold plate with respect to the fixed mold plate with a stroke larger than that of the drive mechanism. The mold driving apparatus according to claim 1 , wherein the driving source is a motor. Gear teeth are formed on the outer periphery of the base member,
4. The mold driving device according to claim 1 , wherein the driving source drives and rotates the base member by driving a driving gear that meshes with the gear teeth. 5. 5. The mold driving device according to claim 1 , wherein the cam crest and the rolling elements corresponding to the cam crest are provided in multiple stages in the axial direction. An injection molding machine that forms a molded product by injecting resin between a fixed mold and a movable mold,
A stationary mold plate for holding the stationary mold;
A movable mold plate that holds the movable mold so as to face the fixed mold and is capable of moving back and forth in a direction of moving away from the fixed mold plate;
A drive mechanism for moving the movable mold plate relative to the fixed mold plate;
An injection part for injecting resin into a cavity formed between the fixed mold and the movable mold;
With
The drive mechanism is
A base member rotatably held around an axis parallel to a direction in which the movable platen is moved;
A drive source for rotating the base member about the axis;
On the surface of the base member, a cam crest formed continuously in an annular shape in a plane perpendicular to the axis, and having a predetermined cam profile;
It is held in a rotatable state between the cam crest and the movable platen side, and is displaced in the axial direction by the cam profile of the cam crest when the base member rotates around the axis. Rolling elements to
A tie bar that connects the fixed mold plate and the movable mold plate with one end fixed to one of the fixed mold plate and the movable mold plate;
With
The drive mechanism is provided between the tie bar and the other of the fixed mold plate and the movable mold plate,
The cam crest is formed by continuously forming a plurality of cam crests having the same cam profile in the circumferential direction,
A plurality of the rolling elements are provided corresponding to each of the cam peaks,
The shape of the rolling element is any one of a barrel shape, a truncated cone shape, and a spherical shape.

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