JP6507580B2 - Toggle type clamping device - Google Patents

Description

  The present invention relates to a toggle type clamping device used for a die casting machine, an injection molding machine, etc., and more particularly to a rotational driving means such as an electric motor and a toggle type clamping device using a ball screw mechanism.

  Conventionally, die casting machines and injection molding machines are used to manufacture various molded articles. In these apparatuses, generally, a mold having a two-part structure is clamped, and a material for molding (metal in a molten state: molten metal or resin in a molten state) is injected into a mold cavity in the mold by an injection apparatus. After filling, it is cooled and solidified to manufacture a cast product or a resin molded product. A mold clamping device is used to perform the mold opening and closing operation and the mold clamping operation of the mold.

  The clamping device is roughly classified into a direct-pressure clamping device and a toggle-type clamping device. The former direct-pressure type clamping device can be made compact in size in the longitudinal direction of the device, but a mold opening / closing device for performing mold opening / closing operation is separately required.

  The latter toggle type clamping device moves the toggle link by moving the crosshead of the toggle link mechanism in the device longitudinal direction (mold opening and closing direction) by a linear actuator such as a hydraulic cylinder fixed to the rear surface side of the end platen. The movable platen is moved by bending and stretching, and a mold opening and closing operation is performed to move the movable mold fixed to the movable platen away from or approach the fixed mold fixed to the fixed platen. The toggle-type clamping device has a larger dimension in the longitudinal direction than the direct-pressure-type clamping device, but can also perform the clamping operation of the mold. Specifically, in the stretched state of the toggle link, the fixed mold and the movable mold are in the mold-matching state, and the tie bar for fixing the distance from the fixed platen to the end platen is stretched by a predetermined amount within the elastic deformation area. By adjusting the position of the end platen according to the thickness of the mold in the mold opening / closing direction so that the state is reached, the toggle link mechanism is made to be in the extended state, and the mold clamping force according to the amount of extension of the tie bar It can be applied to In addition, the toggle type clamping device can extend the toggle link mechanism by the driving force of the linear actuator which is sufficiently low with respect to the direct pressure type clamping device, and after the toggle link is in the extended state, The application of the mold clamping force to the mold can be continued without applying any power or driving force to the linear motion actuator.

  Furthermore, the toggle type clamping device has a movable platen with respect to a boost characteristic that can obtain an output larger than a force input to the cross head of the toggle link mechanism, or with respect to the movement amount of the cross head near the stretched state of the toggle link. The clamping force control and the mold opening and closing control that make use of the characteristic according to the toggle curve specific to the specifications such as the dimensions of the toggle link can be performed. It is characterized by In the present application, in order to indicate the moving direction and the end of the component in the mold opening and closing direction, the mold closing direction (side) is forward (forward) and the mold opening direction (side) is backward (back).

  As a mold clamping device for moving the crosshead of the toggle link mechanism by a hydraulic cylinder, for example, Patent Document 1 discloses a device having a cylinder 29 and a cylinder rod 30 as shown in FIG. 4 and FIG. An apparatus having a cylinder 31 and a cylinder rod 32 as shown in FIG. 5 is disclosed. 4 and 5, the thickness of the cylinder rod relative to the movable plate is drawn differently, but in FIG. 4 the thickness of the rod is drawn somewhat exaggerated for the sake of description, and in general It is about five thick.

  Patent Document 3 describes a die casting machine using a toggle type clamping device as shown in FIG. 3, and bending / expansion of the toggle link mechanism 18 is performed by a motor 23 for mold opening / closing and a motor 23 for mold opening / closing. The ball screw mechanism 22 converts the rotational driving force of the above into linear driving force in the mold opening and closing direction. Hereinafter, a configuration based on the mold opening / closing motor 23 and the ball screw mechanism 22 of the toggle type clamping device of the die casting machine of Patent Document 3 will be referred to as an electric cylinder of Patent Document 3.

Unexamined-Japanese-Patent No. 11- 198204 Japanese Patent Application Laid-Open No. 10-29232 Japanese Patent Application Publication No. 2007-136519

  In the toggle type clamping device of the die casting machine described in Patent Document 3, the mold opening / closing motor 23 and the screw shaft 22b of the ball screw mechanism 22 are connected by the drive pulley 24, the driven pulley 25 and the belt 26, and used for mold opening / closing. The screw shaft 22b is rotated by the rotational driving force of the motor 23, and thereby the driving force in the mold opening and closing direction is applied to the nut body 22a screwed to the screw shaft 22b.

  Further, the ball screw mechanism 22 is held by the holding cylinder 21, and the front end of the holding cylinder 21 is kept airtight with the connecting cylinder 28 connected to the front end of the nut 22a. The rear end side of the cylindrical body 21 is kept airtight by a pulley storage bracket 27 connected to the rear end of the holding cylindrical body 21. As described above, since the ball screw mechanism 22 is housed in the sealed structure formed by the holding cylinder 21 and the connection cylinder 28, there is no fear that metal ball, mist or the like adheres to the ball screw mechanism 21. Since the life can be achieved and the sound emitted from the ball screw mechanism 22 can be reduced, noise reduction can also be achieved. Further, there is no possibility that the lubricating oil of the ball screw mechanism 22 scatters around and contaminates the surrounding.

  Here, in the toggle type clamping device of the die casting machine of Patent Document 3, the cross head 19 of the toggle link mechanism 18 is bent and extended by driving the cross head 19 of the toggle link mechanism 18 in the mold opening and closing direction. It is a linear motion in the mold opening and closing direction of the connecting cylinder 28 whose front end is fixed. The front end of the nut 22a is fixed to the rear end of the connecting cylinder 28. When the nut 22a is retracted by the rotational movement of the screw shaft 22b, the screw shaft 22b of the ball screw mechanism 22 is stored in the connecting cylinder 28. Be done.

  Therefore, the inner diameter of the connecting cylindrical body 28 becomes a diameter (diameter larger than the outer diameter of the screw shaft 22b) according to the outer diameter of the screw shaft 22b. In addition, since the connecting cylinder 28 is a linear moving shaft of a hollow structure, the crosshead 19 connected to the front end side is linearly moved in the mold opening and closing direction to bend and extend the toggle link mechanism 18, thereby not illustrated. A cross section coefficient and a cross section strength that can resist the driving force required to linearly move the movable platen and the movable mold in the mold opening and closing direction are required. The outer diameter of the connecting cylinder 28 as a hollow structure is determined based on the cross section coefficient and the cross section strength and the diameter according to the outer diameter of the screw shaft 22b (inner diameter of the connecting cylinder 28).

  In a toggle type clamping device that drives a crosshead with a hydraulic cylinder, the hydraulic cylinder is determined because the driving force (output) is determined so that the mold opening and closing operation is possible with the movable mold attached to the movable platen. The cylinder rod (solid shaft) of the hydraulic cylinder selected based on the driving force naturally has strength (section coefficient, cross-section strength, etc.) that can sufficiently resist the driving force. In the electric cylinder of Patent Document 3, at least the screw shaft 22b (solid shaft) of the ball screw mechanism 22 capable of transmitting the equivalent driving force in the linear direction is also required to have the same strength.

The electric cylinder of Patent Document 3 is different from the hydraulic cylinder in that the driving force is transmitted to the connecting cylinder 28 (hollow shaft) via the nut body 22a, but the driving force necessary for the mold opening / closing operation is the same. If so, it is difficult to make the screw shaft 22b of the electric cylinder of Patent Document 3 significantly smaller than the outer diameter of the cylinder rod of the hydraulic cylinder as in Patent Documents 1 and 2. Further, in view of the fact that a screw groove screwed with the nut body 22a is machined on the outer peripheral surface of the screw shaft 22b, and the cross section coefficient and the cross section strength of the screw shaft 22b are defined by the bottom outer diameter of the screw groove of the screw groove 21b. For example, the outer diameter of the screw shaft 22b of the electric cylinder of Patent Document 3 is at least as large as or larger than the cylinder rod of the existing hydraulic cylinder.

  Furthermore, the rear end side of the connecting cylindrical body 28 needs to have a connecting structure (flanging structure etc.) between the cylindrical bodies in accordance with the shape of the front end side of the connected nut body 22a. In order to ensure the strength against the driving force for linearly moving the cross head 19 in the mold opening and closing direction described above, the outer diameter of the connecting portion is larger than the outer diameter of the connecting cylindrical body 28 Become.

  Furthermore, by the rotational movement of the screw shaft 22b, the coupled cylindrical body 28 and the nut body 22a connected integrally move inside the holding cylindrical body 21 in the mold opening and closing direction. In the mold closing (clamping) state, the connection portion between the connected connecting cylinder 28 and the nut body 22 a is located on the front end side in the holding cylinder 21, so at least the front end side of the holding cylinder 21. The inner diameter, that is, the inner diameter of the mounting portion of the holding cylinder 21 on the rear surface side of the tail stock 20 (end platen) must be larger than the outer diameter of the connecting portion described above, as shown in FIG. It does not. In addition, the outer diameter and the shape of the mounting portion of the holding cylinder 21 on the rear surface side of the tail stock 20 are based on the inner diameter of the same portion as shown in FIG. The weight of the holding cylinder 21 has to be a diameter and a shape capable of securing strength and rigidity capable of being cantilevered.

  In the case of newly designing and manufacturing the toggle type clamping device based on the installation of the electric cylinder of Patent Document 3, the electric cylinder of Patent Document 3 has no problem regarding the installation. Here, in recent years, from the viewpoint of energy saving, in an existing die-cast machine or a toggle-type clamping device of an injection molding machine, a hydraulic cylinder for driving a crosshead of a toggle link mechanism as disclosed in Patent Documents 1 and 2 is an electric motor There is a demand to replace an electric actuator or the like such as the electric cylinder of Patent Document 3 which converts rotational movement into linear movement by combining the above and the ball screw mechanism.

  Even for a hydraulic cylinder for crosshead drive of a toggle type clamping device which does not require a large driving force at the time of clamping with respect to a direct pressure type clamping device, a movable platen and movable mold which are heavy items are desired. In order to cause the mold opening and closing operation at the speed, the hydraulic oil of an amount and pressure necessary to drive the hydraulic cylinder must be discharged from the hydraulic pump at a predetermined timing. The power consumption of the electric motor for driving the hydraulic pump at the time of mold opening / closing operation is during the operation cycle of the die casting machine or the injection molding machine together with the injection device for filling the mold cavity with a predetermined amount of molten metal or molten resin at a predetermined pressure. Occupy the top of the power consumption of

  However, in the existing die-cast machine or toggle mold clamping device of an injection molding machine in which the drive means of the cross head is a hydraulic cylinder as shown in FIGS. 4 and 5, the cross head side is a solid shaft of the hydraulic cylinder. A connection structure with the cylinder rod end is formed in accordance with the outer diameter and the shape of a certain cylinder rod end. Further, on the rear surface side of the end platen (tail stock), a connection structure with the rod side flange is formed in accordance with the outer diameter and the shape of the rod side flange of the hydraulic cylinder.

  Therefore, in the toggle type clamping device in which the drive means of the cross head is a hydraulic cylinder as shown in FIGS. 4 and 5, when replacing the hydraulic cylinder with the electric cylinder of Patent Document 3, first, a solid shaft of the hydraulic cylinder It is difficult to directly connect the connecting cylinder 28 of Patent Document 3 having a diameter that is clearly larger than the outer diameter of the end of the cylinder rod to the crosshead. And even if a spacer, an adapter, etc. are newly manufactured and attachment itself to the crosshead of the connection cylinder 28 of patent document 3 becomes possible, processing is carried out from the back side of an end platen (tail stock) to the front side Since the through hole for the cylinder rod of the hydraulic cylinder is processed according to the outer diameter and shape of the cylinder rod end which is a solid shaft, the connecting cylinder of Patent Document 3 having an outer diameter larger than that is processed. It can not penetrate the body 28.

  Therefore, additional processing is required to expand the inner diameter of the through hole of the end platen. In addition, by attaching a spacer, an adapter, etc. to the cross head side, the retreat limit position of the cross head (during movement / mold opening operation of the cross head to the end platen side) becomes forward than before replacement. If this happens, there is a problem that it becomes difficult to secure the maximum mold opening before replacement.

  The attachment of the end platen (tail stock) of the electric cylinder of Patent Document 3 to the rear surface side is the same, and the front end of the holding cylinder 21 of Patent Document 3 is clearly larger than the outer diameter and shape of the rod side flange of the hydraulic cylinder. It is difficult to attach the side directly to the back side of the end platen. As described above, even if attachment of the electric cylinder of Patent Document 3 becomes possible by attaching the spacer, adapter, etc. to the rear side of the end platen, the thickness of the spacer, adapter, etc. in the mold opening / closing direction, the end The amount of protrusion of the motorized cylinder from the rear side of the platen increases, and the moment in the vertical direction acting on the entire mounting portion of the motorized cylinder, which is a cantilever support, also increases. The electric cylinder of Patent Document 3 in this state is formed on the premise of mounting of the rod side flange of the hydraulic cylinder, which is smaller than the outer diameter and shape of the required mounting portion of the holding cylinder 21 of Patent Document 3 It is difficult to install in a state where sufficient strength and rigidity are secured

  The present invention has been made in view of the above-mentioned problems, and a toggle type clamping device for driving a crosshead by a hydraulic cylinder is easily modified to use an electric motor as a rotational drive source and a crosshead by a ball screw mechanism. It is an object of the present invention to provide a toggle type clamping device for driving

  In order to solve the above problems, a toggle-type mold clamping device according to the present invention comprises an end platen, a toggle link mechanism for mold opening and closing supported by the end platen, and a front end penetrating the end platen. A ball screw mechanism comprising a screw shaft fixed to the cross head of the toggle link mechanism, and a nut body screwed to the screw shaft and converting the applied rotational driving force into a linear driving force, an electric motor, A rotational movement transmitting means connected to the rotational shaft of the electric motor for transmitting the rotational movement of the electric motor, and driving the crosshead of the toggle link mechanism in the mold opening / closing direction by the ball screw mechanism; In a toggle type clamping device that performs opening and closing operation and clamping operation, the ball screw mechanism is housed inside and the front end is fixed to the rear surface side of the end platen. A tubular holding member and a rear end of a nut body of the ball screw mechanism are fixed, and at least a part of a screw shaft of the ball screw mechanism is accommodated and rotatably supported on the rear end side of the holding member. A hollow member is further provided, and the hollow member is rotationally driven by the electric motor via the rotational motion transmitting means, and the nut body is rotationally driven by the rotational driving of the hollow member. The screw shaft is driven in the mold opening and closing direction by the rotational drive of the motor, and the crosshead fixed to the front end of the screw shaft is driven in the mold opening and closing direction.

  Further, in the above-mentioned toggle type clamping device, the screw shaft is not subjected to screw processing in the portion projecting from the front end of the nut body in the maximum mold open state, and the penetrating portion of the end platen of the screw shaft It is preferable that the screw shaft further includes a first seal member which slides a non-threaded portion of the screw shaft and seals a penetrating portion of the end platen of the screw shaft.

  On the other hand, in the above-mentioned toggle type clamping device, the rear end of the hollow member is closed and it protrudes from the rear end of the holding member, and the projection from the rear end of the holding member of the hollow member and the rear end opening of the holding member And a second sealing member for sealing between the closing member and the projection of the hollow member.

  According to the present invention, a toggle type clamping device for driving a crosshead by a hydraulic cylinder is easily modified to provide a toggle type clamping device for driving a crosshead by a ball screw mechanism using an electric motor as a rotational drive source. It becomes possible.

It is an overview sectional view showing an outline about an example of a toggle type clamping device concerning the present invention. FIG. 2 is a cross-sectional view taken along line A-A of FIG. It is an outline sectional view showing the outline about an example of the conventional toggle type clamping device. It is a figure which shows the schematic about an example of the conventional hydraulic cylinder type | mold clamping apparatus. It is a figure which shows the schematic about an example of the conventional hydraulic cylinder type | mold clamping apparatus.

Hereinafter, a toggle-type mold clamping device according to the present invention will be described in detail with reference to the drawings.
As shown in FIG. 1, the toggle-type mold clamping device according to one embodiment of the present invention includes an end platen 4, a toggle link mechanism 2 for mold opening and closing supported by the end platen 4, and a front end 4. A ball screw which is formed of a screw shaft 6b penetrated and fixed to the cross head 3 of the toggle link mechanism 2 and a nut body 6a screwed with the screw shaft 6b and converts the applied rotational driving force into a linear driving force. A ball screw mechanism 6 is provided with a mechanism 6, an electric motor 7, and rotational movement transmitting means (8 to 10) connected to the rotational shaft of the electric motor 7 to transmit the rotational movement of the electric motor 7. In the toggle type clamping device 1 which drives the crosshead 3 of 2 in the mold opening / closing direction to perform the mold opening / closing operation and the mold clamping operation, the ball screw mechanism 6 is housed inside and the front end is the end platen The cylindrical holding member 5 fixed to the rear surface side of the ball screw mechanism 6 and the rear end of the nut body 6 a of the ball screw mechanism 6 store at least a part of the screw shaft 6 b of the ball screw mechanism 6 The hollow member 11 is further rotatably supported at the rear end side, and the hollow member 11 is rotationally driven by the electric motor 7 through the rotational motion transmitting means (8 to 10), and the hollow member 11 is The nut body 6a is rotationally driven by the rotational driving of the screw shaft 6b, the screw shaft 6b is driven in the mold opening and closing direction by the rotational driving of the nut body 6a, and the crosshead 3 fixed at the front end of the screw shaft 6b is driven in the mold opening and closing direction. It is characterized by A configuration based on the electric motor 7 and the ball screw mechanism 6 of the toggle type clamping device of the present invention with respect to the electric cylinder of Patent Document 3 will be hereinafter referred to as the electric cylinder of the present invention.

  In the toggle type clamping device 1 of the present embodiment, the rotational drive force of the electric motor 7 as the rotational drive source is first transmitted to the hollow member 11 through the rotational motion transfer means (8 to 10), and then the hollow member The torque is transmitted to the nut body 6a of the ball screw mechanism 6 through 11, and the screw shaft 6b is moved in the mold opening / closing direction by the rotational movement of the nut body 6a. Then, along with the movement of the screw shaft 6b in the mold opening / closing direction, the crosshead 3 connected to the front end of the screw shaft 6b is driven in the mold opening / closing direction, and the toggle link mechanism 2 bends and extends. Is done.

  The rear portion of the toggle link mechanism 2 is connected to the front side of the end platen 4 so as to be flexible and extensible. Although not shown in FIG. 1, the front of the toggle link mechanism 2 is connected to the rear surface side of the movable platen on which the movable mold is mounted so as to be bendable and extensible. Further, a fixed platen to which a fixed mold is attached is disposed to face the movable platen. In the present embodiment, the mold opening / closing direction is a direction in which the cross head 3 moves downward or upward in the drawing and the movable platen separates or approaches the fixed platen. Also, as described above, in order to indicate the moving direction or end of the component in the mold opening / closing direction, the mold closing direction (side) is advanced (forward), and the mold opening direction (side) is retracted (back) I assume. Specifically, the movement from the bottom to the top in the figure is the mold closing direction (forward / top in the figure front), and the motion from the top to the bottom is the mold opening direction (back / bottom in the figure back) In the end of the nut body 6a, the upper side in the drawing is the front end, and the lower side in the drawing is the rear end.

FIG. 1 shows a maximum mold opening state where a movable platen (not shown) is separated from the fixed platen by a maximum distance. In this state, the crosshead 3 and the screw shaft 6b are in the retracted limit position, and the toggle link mechanism 2 is in the maximum bending state.

  With regard to the mold opening and closing operation, in the present embodiment, the toggle link mechanism 2 is bent and extended using the electric motor 7 as a rotational drive source to perform the mold opening and closing operation. By employing, for example, a servomotor as the electric motor 7, it is possible to control the driving force and the mold opening position with high accuracy compared to the case of a hydraulic cylinder, and in particular, the expansion foam molding method in an injection molding machine and an injection press The (compression) molding method and the like are suitable for an injection molding method including a step of opening the movable mold from the mold clamped for a minute distance before and after the operation of the injection device and holding the position.

  The rotational drive force of the electric motor 7 is transmitted to the ball screw mechanism 6 via a rotational motion transmission means described later. As described later, the ball screw mechanism 6 includes a screw shaft 6b which is not screwed at the front end side including the penetrating portion of the end platen 4, and a nut body 6a which is screwed to the screw shaft 6b. The ball screw mechanism 6 is accommodated in a cylindrical holding member 5 whose front end is fixed to the rear surface side of the end platen 4.

  The rotational motion transmission means of the present embodiment includes a drive pulley 8 attached to the output shaft of the electric motor 7, and a driven pulley 9 attached to the projecting portion of the hollow member 11 projecting from the rear end of the holding member 5; And a belt 10 for transmitting the rotation 8 of the pulley to the driven pulley 9. The configuration of the rotational motion transmitting means of the present invention is not limited to this embodiment, and may be a gear and a chain, or only a gear.

  The hollow member 11 is rotatably supported on the rear end side of the holding member 5 by a bearing or the like. Therefore, when the electric motor 7 is driven, its rotational drive force is transmitted to the hollow member 11 via the drive / driven pulley and the belt. Then, the hollow member 11 and the nut body 6 a fixed to the front end of the hollow member 11 integrally rotate. By the rotational movement of the nut body 6a, the screw shaft 6b moves in the mold opening / closing direction, and the crosshead 3 fixed to the front end of the screw shaft 6b is driven in the mold opening / closing direction, and the mold opening / closing operation of the mold is performed.

  Here, in the present embodiment, the front end portion of the screw shaft 6b is fixed to the cross head 3 by the coupling 3a having a two-part split structure. The screw shaft 6b does not rotate with respect to the coupling 3a by the key 3b fixed by bolts 3c at two positions in the diameter direction of the screw shaft 6b and a key groove (not shown) formed on the inner peripheral surface of the coupling 3a. As fixed.

  It is preferable to provide an appropriate sliding gap that allows the sliding of the front end of the screw shaft 6b with respect to the coupling 3a for the gap between the key 3b and the key groove. For example, in a toggle type clamping device in which the mold opening and closing direction is horizontal, in the mold closed (clamping) state in which the cross head 3 is at the forward limit position, the loads of links in the stretched toggle link mechanism act in the vertical direction. Therefore, the vertical position of the crosshead 3 is slightly lower than that in the backward limit position. When the front end of the screw shaft 6b and the crosshead 3 are completely fixed, the front end of the screw shaft 6b is also slightly lowered at the forward limit position of the crosshead. The load acts. At this time, if the vertical sliding of the front end portion of the screw shaft 6b with respect to the coupling 3a is allowed within a predetermined range, the generation of such an eccentric load can be suppressed. Further, the method of fixing the front end of the screw shaft 6b to the crosshead 3 is not limited to the coupling 3a, but the front end of the screw shaft 6b with respect to the crosshead 3 as described above in any form. It is preferable to adopt a configuration that allows the sliding of the parts.

  As described above, the feature of the present invention is that the nut body 6a is immobile in the mold opening / closing direction inside the holding member 5 in order to rotate the nut body 6a via the hollow member 11 instead of the screw shaft of the ball screw mechanism. And the screw shaft 6b passing through the end platen 4 is moved in the mold opening and closing direction to drive the crosshead fixed directly to the front end thereof.

  That is, in this embodiment having the above features, the outer diameter of the screw shaft 6b of the ball screw mechanism 6 is the same as that of the hydraulic cylinder when the driving force required to linearly move the movable platen and the movable mold in the mold opening and closing direction is the same. The outer diameter of the end of the cylinder rod is substantially the same, and at least the outer diameter of the screw shaft of the ball screw mechanism does not have to be so large that attachment to the crosshead becomes difficult.

  Further, if the outer diameter of the cylinder rod end of the hydraulic cylinder and the outer diameter of the screw shaft 6b of the ball screw mechanism 6 are substantially the same, the screw shaft 6b can be penetrated through the existing through holes of the end platen 4 The additional processing of the same through hole is unnecessary. Furthermore, it is not necessary to arrange a spacer, adapter or the like having a large thickness in the mold opening / closing direction on the cross head 3 side, as the retraction distance of the cross head 3 can not be secured as before replacement. By arranging an adapter or the like having the same outer diameter and shape as the cylinder rod end of the hydraulic cylinder, the front end of the screw shaft 6b can be easily connected to the cross head 3 side.

  Furthermore, since the screw shaft 6b penetrates the end platen 4 and moves in the mold opening and closing direction, the inner diameter of at least the front end side of the holding member 5, that is, the inside of the mounting portion of the holding member 5 on the rear surface side of the end platen 4 Only the screw shaft 6 b of the ball screw mechanism 6 moves in the mold opening and closing direction. Therefore, the outer diameter and shape of the front end side of the holding member 5 can be made to conform to the outer diameter and shape of the rod side flange of the hydraulic cylinder, and the mounting portion of the hydraulic cylinder on the rear surface side of the end platen 4 The front end side of the holding member 5 can be easily attached.

  As described above, according to the electric cylinder of the present invention, it is easy to use the toggle type clamping device for driving the crosshead by the hydraulic cylinder as the toggle type clamping device for driving the crosshead by the ball screw mechanism using the electric motor as a rotational drive source. Can be remodeled.

Next, other features of the toggle type clamping device according to the present embodiment will be described.
As shown in FIG. 1, in the screw shaft 6b of the ball screw mechanism 6 of the present embodiment, the portion protruding forward from the nut body 6a is not screwed. This is the maximum mold open state shown in FIG. 1 in which the movable platen (not shown) is separated from the fixed platen by the maximum distance, and in this state, the cross head 3 is at the retracted limit position and the toggle link mechanism 2 is maximally bent. In the state, that is, the state in which the screw shaft 6b is moved to the rearmost position (retraction limit position), it is necessary to apply screw processing for screwing the nut body 6a to the range projecting forward from the nut body 6a in this state Because there is no

  The screw shaft 6b and the nut body 6a in the maximum mold opening state and the mold clamping state are provided at the front end of the screwed portion or the rear end of the non-threaded portion of the screw shaft 6b. It is desirable that a stopper ring 14 be attached to prevent the screw shaft 6b from moving forward and backward beyond the positional relationship of Such a stopper ring minimizes breakage of the sliding portion including the ball screw mechanism 6 in the case where control abnormality or the like occurs due to a defect in the electric motor 7 or a sensor required for control or an error in the control program. Not only to limit, but also to prevent falling off of the nut body 6a from the screw shaft 6b of the ball screw mechanism 6 during assembly, and to specify a mechanical position reference of origin setting of an encoder (not shown) for controlling the electric motor 7. The case is also valid.

  As in the present embodiment, the penetrating portion of the end platen 4 of the screw shaft 6b is caused to slide by the non-threaded portion of the screw shaft 6b (the unthreaded portion) sliding. In the same way as the penetration part of a general linear motion shaft, seal members such as bush (bearing metal) and dust seal or oil seal that support the linear motion of the linear motion shaft (unprocessed portion of screw shaft 6b) It can be arranged.

  As in the present embodiment, when the first seal member 12b for preventing intrusion of contamination or the like is disposed on the bush 12a disposed in the through portion of the end platen 4 of the screw shaft 6b, mold closing (mold tightening ), The grease or dust, etc., of the toggle link mechanism 2 falls on the front side recess of the end platen 4 and the unthreaded portion of the screw shaft 6b which protrudes into the toggle link mechanism 2 in the extended state. Even if it adheres, the penetration | invasion of those contamination etc. in the holding member 5 can be suppressed.

  In addition, as shown in FIG. 1, the ball screw shaft 6b is in the forward limit position and the reverse limit position both in the forward limit position (mold closed (clamping) state) and in the reverse limit position (maximum mold open state). The linear motion is always supported at two points where the distance does not change at the front in the bush 12a of the penetrating portion of the end platen 4 and at the rear in the nut body 6a at any position during the movement between them. Therefore, the accuracy of the linear motion of the ball screw shaft 6b is high relative to the electric cylinder of Patent Document 3, and a stable high-precision mold opening / closing operation becomes possible, and balls or sliding in the nut body 6a of the ball screw mechanism 6 It is possible to suppress uneven wear of parts.

  Furthermore, in the present embodiment, the rear end of the hollow member 11 accommodating the rear end side of the screw shaft 6b in the mold open state is the end cap 13 which doubles as a fixing component to the rear end side of the hollow member 11 of the driven pulley 9. Although it is closed, it is not limited to this as long as the airtightness of the opening at the rear end of the hollow member 11 can be maintained, and a hollow member with a bottom may be used. However, in such a case, it is preferable that the driven pulley 9 be fixed to the rear end of the hollow member 11 with a ring screw or the like. Further, in the present embodiment, the closing member 12c for closing between the protrusion from the rear end of the holding member 5 of the hollow member 11 and the rear end side opening of the holding member 5, the closing member 12c and the hollow member 11 A second seal member 12d is disposed to seal between the protrusion and the protrusion.

  Here, it is possible to maintain the airtightness in the holding member 5 by the first seal member 12b and the end cap 13 as described above, the closing member 12c and the second seal member 12d described above. Become.

  In the present invention, since the nut body 6a rotates, it is difficult to apply grease to the outer peripheral surface of the nut body 6a to perform grease lubrication. However, since grease piping has already been installed on the link shaft of each link in toggle link mechanism 2, one line of piping is branched from the grease piping in the vicinity of cross head 3, and holes are made in the axial direction from the front end of screw shaft 6b. By communicating with the outer peripheral surface processed and threaded, grease lubrication of the ball screw mechanism 6 becomes possible.

  On the other hand, in the present embodiment, since it is possible to maintain the airtightness in the holding member 5, it is relatively expensive and does not employ grease lubrication which requires modification of the grease piping of the existing toggle link mechanism. Also, the ball screw mechanism 6 can be lubricated by forming an oil bath in the holding member 5. Select a lubricating oil (lubricant) with a viscosity and properties suitable for lubrication of the ball screw mechanism 6, and soak the amount so that the lower part of the outer peripheral surface of the unthreaded portion of the screw shaft 6b is slightly immersed in the holding member 5 Level). The nut body 6a does not move in the mold opening / closing direction and rotates, so that the part immersed in the lubricating oil of the nut body 6a linearly moves in that state, and the lubricating oil is vigorously stirred to lubricate by oxidation etc. It does not accelerate the deterioration of oil.

  Further, although the screw shaft 6b linearly moves, since the lower side of the outer peripheral surface of the unmachined portion is only slightly immersed, the unmachined portion does not cause the lubricating oil to be vigorously stirred. On the other hand, since the outer peripheral surface of the threaded portion is threaded, a slight amount of agitation of the lubricating oil occurs. However, in the mold opening and closing operation, for protection of the mold mating surface and suppression of impact at the time of mold alignment (during mold closing), and for prevention of breakage of cast products and resinous material in the mold at mold open time, The mold opening / closing speed between the rear of the mold alignment position and the mold alignment position ahead of the mold alignment position by a predetermined distance is sufficiently reduced. Therefore, the high speed moving time of the screw shaft 6b in the operation cycle, which is concerned about the stirring of the lubricating oil by the screw processing part, is slight, and does not accelerate the deterioration of the lubricating oil due to oxidation or the like.

  Furthermore, when making the inside of the holding member into an oil bath, bearings that rotatably support the nut body 6a in the holding member 5, the first seal member 12b that seals the front and back of the holding member 5, and the second seal member 12d Since the lower part of the above is always immersed in the lubricating oil, it is expected that the good lubrication state of the bearings can be maintained for a long time, and the drying deterioration of the sealing members can be suppressed.

  FIG. 2 is a cross-sectional view taken along the line A-A of FIG. A screw-in type oil gauge 15 for confirming the level of lubricating oil (lubricant) is disposed on the side of the holding member 5 and, in the upper part, the pressure change in the holding member 5 is particularly An air breather 16 is disposed to filter the air drawn into the holding member 5 when the pressure drops. The air breather 16 can also be used as a lubricating oil filler. Further, as shown in FIG. 1, a drain plug 17 is bored at the lowermost position of the holding member 5. Although not shown, if a level sensor is disposed separately from the oil gauge 15, the level control of the lubricating oil is easy. The arrangement position of these members is not limited to that shown in FIG. 1. For example, apart from the air breather 16, a sealing portion with a plug is provided on the upper portion of the holding member 5, and it is You can also In FIG. 2, the level of the lubricating oil injected into the holding member 5 is also shown as an example.

  As in the present embodiment, in the case of adopting a form in which the inside of the holding member 5 is formed into an oil bus for lubricating the ball screw mechanism 6 in the holding member 5, not only the lubrication of the ball screw mechanism 6 can be facilitated easily, but also a hollow member The good lubrication state of the bearings that rotatably support 11 can be maintained for a long time, and the effect of suppressing the drying deterioration of the seal members can be expected. In addition, when the toggle type clamping device for driving the cross head with a hydraulic cylinder is converted into a toggle type clamping device for driving the cross head by a ball screw mechanism using an electric motor as a rotational drive source, The ball screw mechanism and other internal lubrication can be completed. Therefore, there is no need to remodel the existing toggle type clamping device or the lubricating device of the other parts of the die cast machine or the injection molding machine which performs the mold opening / closing operation and the mold clamping operation by this toggle type clamping device.

  On the other hand, in the electric cylinder of Patent Document 3, the nut body 22a in the holding cylinder 21 does not rotationally move but linearly moves in the mold opening and closing direction. When grease lubrication is adopted for the lubrication of the ball screw mechanism 22, a pipe for grease lubrication may be connected to the outer peripheral surface of the nut body 22a which linearly moves in the mold opening and closing direction. For that purpose, it is necessary to make piping connected with nut body 22a into flexible tube piping, and to make the connected tube piping follow according to linear motion of nut body 22a. However, it is very difficult to make the tube piping connected to the nut body 22a follow the linear movement of the nut body 22a in the space of the holding cylinder 21 as shown in FIG. Therefore, it is necessary to provide an opening in the longitudinal direction of the holding cylindrical body 21 and secure a follow-up space for tube piping. However, as described in Patent Document 3, in order to store the ball screw mechanism 22 in the holding cylinder 21, it is necessary to close the opening and to provide a cover or the like capable of securing a space following the tube piping. become.

  Here, also in the electric cylinder of Patent Document 3, since the holding cylinder 20 has a closed structure, lubrication by the oil bath is possible. However, when the oil amount (level) is such that the lower part of the outer peripheral surface of the screw shaft 22b is slightly immersed, the connection between the nut 22a having a larger outer diameter than the screw shaft 22b and the nut 22a and the connecting cylinder 28 The lower part of the part is deeply immersed in the lubricating oil and linearly moves in that state, so that the lubricating oil is vigorously stirred to cause the oil surface to wave and accelerate deterioration of the lubricating oil due to oxidation and the like. Therefore, it is difficult to check the level of the lubricating oil during the operation cycle and there is a problem that the frequency of replacement of the lubricating oil becomes high as compared with the case where the lubrication by the oil bath is adopted for the electric cylinder of the present invention.

  Although one embodiment of the present invention has been described above with reference to the drawings, the present invention is not limited to the present embodiment, and various modifications may be made without departing from the scope of the invention. It's too late. For example, although the embodiment has been described in which the nut body 6a of the ball screw shaft 6 is rotated via the hollow member 11 connected to the rear end side of the nut body 6a, the hollow member 11 is not used. The rear end of the nut body 6a of the ball screw mechanism 6 may be extended from the rear end of the holding member 5 so that the driven pulley can be attached thereto, and the driven pulley may be attached to the outer peripheral surface. Even in such a case, it is preferable to close the rear end of the nut body 6b.

Reference Signs List 1 toggle type clamping device 2 toggle link mechanism 3 cross head 3a coupling 3b key 3c bolt 4 end platen 5 holding member 6 ball screw mechanism 6a nut body 6b screw shaft 7 electric motor 8 drive pulley 9 driven pulley 10 belt 11 hollow member 12a bush 12b first seal member 12c closing member 12d second seal member 13 end cap 15 oil gauge 16 air breather 17 drain plug

Claims (3)

End platen,
A toggle link mechanism for mold opening and closing supported by the end platen;
A screw shaft having a front end penetrating the end platen and fixed to the cross head of the toggle link mechanism, and a nut body screwed to the screw shaft, converts an applied rotational driving force into a linear driving force Ball screw mechanism,
Electric motor,
Rotary motion transmission means connected to the rotary shaft of the electric motor for transmitting the rotary motion of the electric motor;
Equipped with
In the toggle type clamping device, the crosshead of the toggle link mechanism is driven in the mold opening and closing direction by the ball screw mechanism to perform the mold opening and closing operation and the clamping operation.
A cylindrical holding member that accommodates the ball screw mechanism and has a front end fixed to the rear surface of the end platen;
A hollow hollow member rotatably supported on the rear end side of the holding member while accommodating at least a portion of the screw shaft before Symbol ball screw mechanism,
And further
The nut body is fixed to the front end of the hollow member so as to be rotatable and axially immovable with the hollow member.
The hollow member is rotationally driven by the electric motor via the rotational motion transmitting means, and the nut body is rotationally driven by the rotational drive of the hollow member, and the screw shaft is in the mold opening and closing direction by the rotational drive of the nut body. to be driven, being configured for driving the cross head fixed to the front end of the front Symbol screw shaft in the mold opening and closing direction,
The screw shaft is supported in linear motion by the penetrating portion of the end platen and the nut body spaced apart from the penetrating portion.
A toggle type clamping device characterized by In the toggle type clamping device according to claim 1,
The screw shaft is not screwed at a portion projecting from the front end of the nut body in the maximum mold open state,
The through portion of the front Symbol end platen, together with said threaded is not subjected portion of the screw shaft slides,
Further seen including a first seal member for sealing between the through portion of the end platen and said screw shaft,
The screw shaft has a stopper ring at the front end of the threaded part or at the rear end of the non-threaded part
A toggle type clamping device characterized by The toggle type clamping device according to claim 1 or 2
The rear end of the hollow member is closed and protrudes from the rear end of the holding member,
A closing member for closing between the protrusion of the hollow member from the rear end of the holding member and the rear end side opening of the holding member;
A second sealing member for sealing between the closing member and the projecting portion of the hollow member;
Further seen including,
The rotational motion of the electric motor is transmitted to the protrusion of the hollow member via the rotational motion transmission means.
A toggle type clamping device characterized by

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