JP3759722B2 - Molding device for injection molding machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mold clamping device used in an injection molding machine or a die-cast molding machine, and more particularly to an electrically driven mold clamping device.
[0002]
In this specification, “inner winding type” or “inner winding toggle type” means that the link member constituting the toggle mechanism bends toward the axis of the ball screw shaft, that is, the center of the machine when the mold is opened. It shall refer to the method to do. The “outer winding type” or “outer winding toggle type” refers to a method in which the link member bends away from the center of the machine when the mold is opened, contrary to the “inner winding type”. .
[0003]
[Prior art]
A toggle type mold clamping device is known as one of electrically driven mold clamping devices of an injection molding machine.
[0004]
FIG. 3 shows an internally wound toggle type mold clamping device which is an example of a conventional toggle type mold clamping device.
[0005]
In FIG. 3, a fixed platen 42, a movable platen 43, and an end housing 44 are sequentially arranged on a bed 41. The fixed platen 42 and the end housing 44 are connected at both ends of four tie bars 45 penetrating the movable platen 43. A half mold 46 is attached to each of the fixed platen 42 and the movable platen 43.
[0006]
The end housing 44 is provided with a mold opening / closing drive device 47, and the cross head 48, the movable plate 43, and the end housing 44 that move back and forth by the mold opening / closing drive device 47 are connected by a toggle mechanism 52. The toggle mechanism 52, the movable platen 43, and the end housing 44 are connected at positions close to the upper and lower ends.
[0007]
The mold opening / closing drive device 47 is composed of a ball nut 53 incorporated in the cross head 48 and a ball screw shaft 54, a screw mechanism for converting rotational motion into linear motion, an electric motor 55 for driving the screw mechanism, a belt -It is comprised from drive mechanisms, such as the pulley 56. FIG. The ball screw shaft 54 is supported only on the bearing case portion 57 side, and the ball nut 53 screwed with the ball screw shaft 54 is fixed only to the cross head 48. The ball screw shaft 54 is so-called cantilevered, and the tip of the ball screw shaft 54 that is screwed with the ball nut 53 is in a free state.
[0008]
Next, the operation will be described.
[0009]
In the inner winding toggle type mold clamping device, the cross head 48 is moved by the mold opening / closing drive device 47 and the toggle mechanism 52 is bent and extended. The toggle mechanism 52 extends in a direction away from the center of the machine when the mold is closed or clamped, and is bent toward the center of the machine when the mold is opened. Thereby, the mold 46 is closed, clamped, and opened. The toggle mechanism 52 enlarges the moving distance, speed, and force of the cross head 48 and transmits it to the movable platen 43.
[0010]
[Problems to be solved by the invention]
In the toggle type mold clamping device, the ball screw shaft is supported only on one side on the end housing side, and the other tip is not supported. For this reason, the ball screw shaft is easily deflected by the load due to the operation of the toggle mechanism and the load of the cross head, the ball nut and the like, and the unsupported tip is shaken.
[0011]
This deflection and runout imposes a moment load on the ball nut, which significantly reduces the life of the ball nut. In addition, since the ball screw shaft applies a large cantilever load to the bearing in the bearing case portion, the life of the bearing in the bearing case portion is also reduced.
[0012]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a mold clamping device that does not receive a moment load on a ball nut and a bearing that supports a ball screw shaft, and has a long life and high reliability.
[0013]
[Means for Solving the Problems]
A mold clamping device of an injection molding machine according to the present invention is a toggle type mold clamping device that opens and closes a mold by bending and stretching a toggle mechanism by electric drive, and is connected to an inner winding type toggle mechanism, A bearing that rotatably supports one end of a ball screw shaft that moves a cross head including a ball nut back and forth, a support bearing that rotatably supports a tip portion that is the other end of the ball screw shaft, and a bed A tie bar support coupled to an extension formed in a supported end housing, and a support plate fixed to the tie bar support and incorporating a support bearing .
[0014]
In the mold clamping device of the injection molding machine of the present invention configured as described above, since both ends of the ball screw shaft are rotatably supported by the bearing and the support bearing, respectively, the ball screw shaft is loaded when the mold is opened and closed. The load can be shared by both ends of the ball screw shaft. As a result, the load received by the bearing can be reduced, and the deflection of the ball screw shaft and the deflection of the tip can be prevented, so that it is difficult to apply a moment load to the ball nut.
[0015]
In the mold clamping device of the injection molding machine of the present invention , the tie bar support and the support plate may be integrated. Also, the inner winding type toggle mechanism of the mold clamping device of the injection molding machine of the present invention includes a first link member having one end pivotally attached to the outer end portion of the end housing, and both ends of the first link member. A second link member pivotally attached to the other end of the movable plate and the outer end of the movable platen, and a third link member having one end pivotally attached to an intermediate portion of the first link member and the other end pivotally attached to the crosshead. The link member may be included.
[0016]
Alternatively, the mold clamping device of the injection molding machine of the present invention is a toggle type mold clamping device for opening and closing the mold by bending and stretching the toggle mechanism by electric drive, and is connected to the outer winding type toggle mechanism. And a bearing for rotatably supporting one end of a ball screw shaft for moving a cross head including a ball nut forward and backward, a support bearing for rotatably supporting a tip portion which is the other end of the ball screw shaft, and a bed And a support plate that is coupled to extensions provided above and below the rear plate of the end housing that is supported on the support plate and that incorporates support bearings.
Further, the mold clamping device of an injection molding machine of the present invention, in the vicinity of the center of the rear plate and the support plate, the support member for supporting one end of the toggle mechanism but it may also be one that is fixed. Further, the toggle mechanism of the mold clamping device of the injection molding machine of the present invention includes a first link member having one end pivotally attached to the front upper and lower sides of the support member, and both ends of the first link member and the other end of the first link member. A second link member pivotally attached in the vicinity of the center of the movable platen; and a third link member having one end pivotally attached to an intermediate portion of the first link member and the other end pivotally attached to the cross head. It may be a thing. By adopting the externally wound toggle mechanism having such a configuration, the connection position of the toggle mechanism, the movable platen, and the end housing is positioned in the vicinity of the axis of the ball screw shaft, and thereby the point of action of the force can be Since it is in the vicinity of the mold mounting space range, the bending moment acting on the movable platen and the end housing can be reduced.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described based on examples with reference to the drawings.
(First embodiment)
FIG. 1 shows a side view of a mold clamping device of an injection molding machine according to a first embodiment of the present invention.
[0018]
The mold clamping device of the present embodiment is a so-called inner-wound toggle type mold clamping device, and has a configuration in which the tip of the ball screw shaft 14 is rotatably supported.
[0019]
In FIG. 1, on a bed 1, a fixed platen 2 fixed to the bed 1, an end housing 4, and four tie bars 5 that couple the fixed platen 2 and the end housing 4 at a predetermined interval; The movable platen 3 is provided so as to be slidable in the axial direction of the tie bars 5, and the drive mechanism 18 for sliding the movable platen 3 in the axial direction of the tie bars 5. A mold 6 is fixed to each of the fixed platen 2 and the movable platen 3.
[0020]
The drive mechanism 18 includes a toggle mechanism 12 that slides the movable platen 3 in the axial direction of the tie bar 5 by bending and stretching, and a mold opening / closing drive device 7 for bending and stretching the toggle mechanism 12.
[0021]
The toggle mechanism 12 includes a first link member 12a whose one end is pivotally attached to the outer end portion 4a of the end housing 4 via a pin 19e, and both ends of which are the other end of the first link member 12a and the movable platen 3. One end of the second link member 12b pivotally attached to the outer end portion 3a of the first link member 12a and the intermediate portion 12a 'of the first link member 12a via the pin 19b. The other end has a third link member 12c pivotally attached to the crosshead 8 via a pin 19a.
[0022]
The mold opening / closing drive device 7 is a mechanism for converting rotational motion into linear motion, and includes a ball nut 13 incorporated in the cross head 8, a ball screw shaft 14 screwed into the ball nut 13, and a ball screw shaft. An electric motor 15 for rotating the motor 14, a bearing case 17 having a bearing (not shown) that rotatably supports one end of the ball screw shaft 14, and a belt for transmitting the driving force of the electric motor 15 to the ball screw shaft 14. A pulley 16, a support bearing 11 that rotatably supports the tip 14 a that is the other end of the ball screw shaft 14, a support plate 10 in which the support bearing 11 is incorporated, and a tie bar support 9 that fixes the support plate 10. And have. The tie bar support 9 is fixed to an extension 5 a of the outer edge portion of the end housing 4. The support plate 10 and the tie bar support 9 may have an integral structure.
[0023]
Thus, both ends of the ball screw shaft 14 of the mold clamping device of the present embodiment are rotatably supported by the bearing in the bearing case portion 17 and the support bearing 11.
[0024]
Next, the operation will be described.
[0025]
In the mold clamping device of this embodiment, the cross head 10 is moved back and forth by the mold opening / closing drive device 7 so that the toggle mechanism 12 is bent and stretched. When closing or clamping the mold, the ball nut 13 is advanced in the direction of arrow a. As a result, the toggle mechanism 12 opens in the a ₁ direction, and the moving distance, speed, and force of the crosshead 10 are expanded and transmitted to the movable platen 3, and the mold 6 is closed and clamped. Further, when the mold opening of the mold 6, on the contrary, to close the toggle mechanism 12 in b ₁ direction by retracting the ball nut 13 in the direction of arrow b. Thus, in the case of the inner winding toggle type, the first link member 12a and the second link member 12b are linear in a state where the mold closing and clamping are completed, and the first link member is opened when the mold is opened. The 12a and the second link member 12b are bent toward the axis of the ball screw shaft 14, that is, are bent so as to be wound inside.
[0026]
As described above, in the mold clamping device of the present embodiment, since both ends of the ball screw shaft 14 are supported by the bearing in the bearing case portion 17 and the support bearing 11, the ball screw shaft is opened and closed when the mold 6 is opened and closed. The load applied to 14 can be shared by both ends of the ball screw shaft 14. Thereby, the load which the bearing in the bearing case part 17 receives can be made small compared with the load which the bearing which conventionally supported the ball screw shaft cantilevered. Furthermore, since the deflection of the ball screw shaft 14 and the deflection of the tip end portion 14a can be prevented, it is difficult to apply a moment load to the ball nut 13. Therefore, the mold clamping device of this embodiment can extend the life of the bearing and the ball nut 13.
(Second Embodiment)
FIG. 2 shows a side view of a mold clamping device of an injection molding machine according to the second embodiment of the present invention.
[0027]
The mold clamping device according to the present embodiment is a so-called externally wound toggle type mold clamping device.
[0028]
In FIG. 2, a fixed plate 22, a movable plate 23, and an end housing 24 are sequentially arranged on a bed 21. The stationary platen 22 and the end housing 24 are connected at both ends of four tie bars 25 penetrating the movable platen 23. Half molds 26 are attached to the fixed platen 22 and the movable platen 23, respectively.
[0029]
The end housing 24 includes a rear plate 30a on which a mold opening / closing drive device 27 is provided, and a support plate 30 coupled to an extension 24a that extends forward from the upper and lower outer edges of the rear plate 30a.
[0030]
A guide bar 28a that supports the cross head 28 so as to be movable back and forth is fixed at a vertically symmetrical position between the rear plate 30a and the support plate 30. A support member 38 is fixed near the center of the rear plate 30a and the support plate 30.
[0031]
The cross head 28, the movable platen 23, and the end housing 24 are connected by a toggle mechanism 32.
[0032]
The toggle mechanism 32 includes a first link member 39a, one end of which is pivotally attached to the upper and lower sides of the support member 38 via pins 29e, and one end of the first link member 39c, 29d. The other end of 39a and the second link member 39b pivotally attached to the clevis respectively provided in the vicinity of the center of the movable plate 23, and one end pivoted to the intermediate portion 39c ′ of the first link member 39a via a pin 29b. The third link member 39c is attached to the clevis provided on the cross head 28 through the pin 29a. As described above, the toggle mechanism 32, the movable platen 23, and the end housing 24 in the outer winding type are generally connected at positions closer to the axis of the ball screw shaft 34 than in the inner winding type.
[0033]
The mold opening / closing drive device 27 includes a screw mechanism that converts a rotational motion of a ball nut 33 and a ball screw shaft 34 incorporated in the cross head 28 into a linear motion, an electric motor 35 that drives the screw mechanism, a belt and a pulley. 36 and other drive mechanisms.
[0034]
A support bearing 31 is attached to the tip 34 a of the ball screw shaft 34, and the bearing 21 is incorporated in the center of the support plate 30.
[0035]
Next, the operation will be described.
[0036]
In the outer-winding toggle type mold clamping device, the cross head 28 is moved by the mold opening / closing drive device 27 and the toggle mechanism 32 is bent and stretched. When the mold mechanism is closed and clamped, the first link member 39a and the second link member 39b are linearly extended by extending toward the axis of the ball screw shaft 34, while the mold is opened. Then, it bends away from the axis of the ball screw shaft 34, that is, outward. As a result, the mold 26 is closed, clamped, and opened. The toggle mechanism 32 expands the moving distance, speed, and force of the cross head 28 and transmits it to the movable platen 23.
[0037]
Since the connecting position of the toggle mechanism 32, the movable platen 23, and the end housing 24 is close to the axis of the ball screw shaft 34, and the point of action of the force is in the vicinity of the mounting space range of the mold 26, the movable platen 23, end The bending moment acting on the housing 24 can be reduced.
[0038]
Also, in the externally wound toggle type mold clamping device of this embodiment, both ends of the ball screw shaft 34 are supported by the bearing in the bearing case portion 37 and the support bearing 31, respectively, as in the first embodiment. The load applied to the ball screw shaft 34 when the mold 26 is opened and closed can be shared by both ends of the ball screw shaft 34. Thereby, the load which the bearing in the bearing case part 37 receives can be made small compared with the load which the bearing which conventionally supported the ball screw shaft cantilevered. Furthermore, since the deflection of the ball screw shaft 34 and the deflection of the tip end portion 34a can be prevented, it is difficult to apply a moment load to the ball nut 33. Therefore, the mold clamping device of this embodiment can also extend the life of the bearing and the ball nut 33.
[0039]
【The invention's effect】
As described above, according to the present invention, since both ends of the ball screw shaft are supported by the bearing and the support bearing, the load applied to the ball screw shaft when the mold is opened and closed can be shared by both ends. it can. As a result, the load received by the bearing can be reduced, the deflection of the ball screw shaft and the deflection of the tip can be prevented, and the moment load is hardly applied to the ball nut. Therefore, the life of the bearing, the ball nut, and the ball screw shaft can be increased.
[Brief description of the drawings]
FIG. 1 is a side view of an inner winding toggle type mold clamping device according to a first embodiment of the present invention.
FIG. 2 is a side view of an outer winding toggle type mold clamping device in a second embodiment of the present invention.
FIG. 3 is a side view of an example of a conventional inner winding toggle type mold clamping device.
[Explanation of symbols]
1, 21 Beds 2, 22 Fixed platen 3, 23 Movable platen 3a Outer end 4, 24 End housing 4a End housing outer end 5, 25 Tie bar 5a, 24a Extension 6, 26 Mold 7, 27 Open / close drive device 8, 28 Crosshead 9 Tie bar support 10, 30 Support plate 11, 31 Support bearing 12, 32 Toggle mechanism 12a, 39a First link member 12a ', 39c' Intermediate portion 12b, 39b Second link member 12c, 39c Third link member 13, 33 Ball nut 14, 34 Ball screw shaft 14 a, 34 a Tip portion 15, 35 Electric motor 16, 36 Belt pulley 17, 37 Bearing case portion 18 Drive mechanism 19 a, 19 b, 19 c, 19 d, 19 e, 29a, 29b, 29c, 29d, 29e Pin 21 Bearing 28a Guide bar 30a Rear Rate 38 support members

Claims (6)

In a toggle type injection molding machine mold clamping device that opens and closes the mold by bending and stretching the toggle mechanism by electric drive,
A bearing connected to an internally wound toggle mechanism ( 12 ) and rotatably supporting one end of a ball screw shaft ( 14 ) for moving a crosshead ( 8 ) having a ball nut ( 13 ) back and forth;
A support bearing ( 11 ) that rotatably supports the tip ( 14a ) that is the other end of the ball screw shaft ( 14 );
A tie bar support (9) coupled to an extension (5a) formed on an end housing (4) supported on the bed (1), and the support bearing (11) fixed to the tie bar support (9). And a support plate (10) in which is incorporated) a mold clamping device of an injection molding machine. The mold clamping device for an injection molding machine according to claim 1 , wherein the tie bar support (9) and the support plate (10) are of an integral structure. The toggle mechanism (12) includes a first link member (12a) having one end pivotally attached to an outer end (4a) of the end housing (4), and both ends of the first link member (12a). ) And the second link member (12b) pivotally attached to the outer end (3a) of the movable plate (3), and the intermediate portion (12a ′) of the first link member (12a). The mold clamping apparatus for an injection molding machine according to claim 1 or 2 , further comprising a third link member (12c) having one end pivotally attached and the other end pivotally attached to the crosshead (8). In a toggle type injection molding machine mold clamping device that opens and closes the mold by bending and stretching the toggle mechanism by electric drive,
A bearing connected to an externally wound toggle mechanism (32) and rotatably supporting one end of a ball screw shaft (34) for moving a cross head (28) provided with a ball nut (33) back and forth;
A support bearing (31) that rotatably supports the tip (34a), which is the other end of the ball screw shaft (34);
A support plate (30) which is coupled to extensions (24a) provided above and below a rear plate (30a) of an end housing (24) supported on a bed (21) and incorporates the support bearing (31). And a mold clamping device for an injection molding machine. The injection molding machine according to claim 4 , wherein a support member (38) for supporting one end of the toggle mechanism (32) is fixed near the center of the rear plate (30a) and the support plate (30). Mold clamping device. The toggle mechanism (32) includes a first link member (39a) having one end pivotally mounted on the upper and lower sides of the support member (38), and both ends at the other end of the first link member (39a). And one end pivotally attached to the second link member (39b) pivotally mounted in the vicinity of the center of the movable plate (23) and the intermediate portion (39c ′) of the first link member (39a), and the other end is the aforementioned The mold clamping device for an injection molding machine according to claim 5 , further comprising a third link member (39c) pivotally attached to the cross head (28).

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