JP4820502B2 - Direct pressure electric mold clamping device for injection molding machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mold clamping device of an injection molding machine, and more particularly to a structure of an electric direct pressure type mold clamping device that transmits a driving force of a driving source to a moving die plate without using a toggle link mechanism.
[0002]
[Prior art]
FIG. 10 shows a schematic configuration of a conventional direct pressure electric mold clamping device.
[0003]
A fixed die plate 3 and a back plate 32 are disposed at both ends of the base 1 so as to face each other. A moving die plate 4 is disposed in front of the back plate 32 so as to face the fixed die plate 3. A fixed mold 5 is held on the front surface of the fixed die plate 3, and a movable mold 6 is held on the front surface of the movable die plate 4.
[0004]
The back plate 32 and the fixed die plate 3 are connected by four tie rods 37. Through holes are formed at the four corners of the movable die plate 4, and each tie rod 37 passes through each of these through holes. The movable die plate 4 slides along these tie rods 37 and can move in the front-rear direction (that is, the mold clamping direction and the mold opening direction).
[0005]
Further, a sliding plate 13 is attached to the base 1 in a range in which the moving die plate 4 moves, and the leg portion 4 a of the moving die plate 4 slides on the sliding plate 13.
[0006]
The movable die plate 4 is connected to the front surface of the back plate 32 via a ball screw 40. The load cell 45 is fixed to the back surface of the movable die plate 4, and the tip of the ball screw screw shaft 41 is fixed to the back surface side of the load cell 45. The ball screw nut 42 is rotatably supported by the back plate 32 via a bearing 47.
[0007]
A motor 50 is accommodated below the base 1. A pulley 52 is attached to the end face of the ball screw nut 42 (end face on the moving die side), and a pulley 51 is attached to the shaft of the motor 50. A timing belt 53 is stretched between the pulley 51 and the pulley 52. The screw shaft 41 is driven in the axial direction by rotating the nut 42 using the motor 50, so that the movable die plate 4 moves in the front-rear direction along the tie rod 37.
[0008]
As described above, in the conventional direct pressure electric mold clamping device, the mold clamping and mold opening operations are performed by driving the movable die plate 4 using the ball screw 40.
[0009]
(Problems of conventional direct pressure mold clamping devices)
In the conventional apparatus, since the screw shaft 41 of the ball screw moves backward together with the movable die plate 4 when the mold is opened, it is necessary to secure an empty space behind the back plate 32. This has contributed to an increase in the overall length of the apparatus. Further, the movable die plate 4 is twisted by the rotational force of the ball screw 40, and the fixed mold 5 and the movable mold 6 are displaced.
[0010]
[Problems to be solved by the invention]
The present invention has been made in view of the problems of the conventional direct pressure type electric mold clamping apparatus as described above, and an object of the present invention is to shorten the overall length of the apparatus and obtain an accurate mold clamping force. Another object of the present invention is to provide a direct pressure type electric mold clamping device capable of suppressing unnecessary twisting of a mold or the like.
[0011]
[Means for Solving the Problems]
A direct pressure electric mold clamping device of an injection molding machine according to the present invention includes a base, a fixed die plate that is disposed on the base and holds a fixed mold, and is opposed to the fixed die plate. A movable die plate to be held, a linear guide mechanism provided on the base for guiding the movement of the movable die plate, a backup plate for directly connecting the movable die plate from the back side, a fixed die plate, and the backup plate A plurality of ball screws whose tips are rotatably connected to the fixed die plate and whose nuts are fixed to the backup plate, and the screw shafts of the plurality of ball screws are synchronized with each other. And a motor for rotating the motor.
[0012]
Further, the direct pressure electric mold clamping device of the injection molding machine of the present invention includes a base, a fixed die plate arranged on the base and holding a fixed mold, and opposed to the fixed die plate. A movable die plate for holding a mold, a linear guide mechanism provided on the base for guiding the movement of the movable die plate, a backup plate disposed behind the movable die plate, the movable die plate, and the backup An elastic member that connects between the plates and can be expanded and contracted with respect to the clamping direction, and is disposed between the movable die plate and the backup plate, and one end of the elastic member is fixed, and the movable die plate is moved from the back side. a spring receiving member for directly connecting, connected between the fixed die plate and the backup plate, the fixing tip of the screw shaft Is rotatably connected to Lee plate, a plurality of ball screws the nut is fixed to the backup plate, the screw shaft of said plurality of ball screws, and a motor for rotating in synchronization with each other, the spring receiving member wherein It is characterized by straddling the screw shafts of a plurality of ball screws .
[0013]
In the present invention, the linear guide mechanism is preferably a linear guide.
[0014]
In the present invention, the linear guide mechanism is preferably a V-groove.
[0015]
In the direct pressure type electric mold clamping device of the present invention, by rotating the screw shaft of the ball screw, the backup plate moves in the axial direction of the ball screw, whereby the movable die plate moves in the front-rear direction, and the mold clamping is performed. Or mold opening operation is performed. At this time, since the screw shaft of the ball screw only rotates and does not move in the axial direction, it is not necessary to secure an empty space for the backward movement of the screw shaft behind the device. Therefore, the overall length of the apparatus can be shortened as compared with the conventional direct pressure type electric mold clamping apparatus.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2 show a schematic configuration of a first embodiment of a direct pressure electric mold clamping device of an injection molding machine according to the present invention. 1 is a front view, and FIG. 2 is a cross-sectional view parallel to the axial direction of the apparatus. In the figure, 3 is a fixed die plate, 4 is a moving die plate, 5 is a fixed die, 6 is a moving die, 2 is a backup plate, 10 is a ball screw, 11 is a screw shaft of the ball screw, and 12 is a nut of the ball screw. .
[0017]
A fixed die plate 3 and a support plate 7 are disposed at both ends of the base 1 so as to face each other. A movable die plate 4 is disposed in front of the fixed die plate 3 so as to face the fixed die plate 3. A fixed mold 5 is held on the front surface of the fixed die plate 3, and a movable mold 6 is held on the front surface of the movable die plate 4. The moving die plate 4 can slide on the base 1.
[0018]
FIG. 3 shows a left side view of the movable die plate 4. Through holes are formed in two corners of the movable die plate 4 at diagonal positions, and the screw shaft 11 of the ball screw 10 passes through these through holes. The sliding surface at the bottom of the movable die plate 4 is connected to the base 1 via a linear guide mechanism provided on the base 1, for example, a linear guide 30. The linear guide 30 includes a linear guide rail 30b provided on the base 1 and a slider 30a attached to the bottom of the movable die plate 4 and sandwiching the guide rail 30b from both side surfaces. Thus, the movable die plate 4 can slide linearly along the guide rail 30b together with the slider 30a.
[0019]
1 and 2, the backup plate 2 is disposed between the support plate 7 and the movable die plate 4. The backup plate 2 can move in the front-rear direction (left-right direction in the figure) on the base 1. The nuts 12 of the ball screw 10 are fixed to the two corners of the backup plate 2 that are diagonal to each other. A screw shaft 11 of the ball screw 10 passes through the backup plate 2 via a nut 12. A tip end portion (right end side in the figure) of the screw shaft 11 is rotatably connected to the fixed die plate 3. A rear end portion (left end side in the figure) of the screw shaft 11 is rotatably supported by the support plate 7 via a bearing 19 and penetrates the support plate 7. A movable die plate 4 is connected to the front surface of the backup plate 2 via a load cell 15.
[0020]
A motor 20 is accommodated below the base 1. A pulley 22 is attached to the rear end portion (left end side in the figure) of the screw shaft 11 of each ball screw, and a pulley 21 is attached to the shaft of the motor 20. As described later, a timing belt 23 is bridged between the pulley 21 and each pulley 22.
[0021]
FIG. 4 (left side view) shows details of a connecting portion between the motor 20 and the screw shaft 11. A pulley 22 is attached to the rear end portion of the screw shaft 11 of each ball screw, and a pulley 21 is attached to the shaft of the motor 20. A timing belt 23 is bridged between the pulley 21 and each pulley 22.
[0022]
FIG. 5 shows a partial detailed view of the ball screw 10. This figure corresponds to the EE cross section of FIG. A nut 12 of the ball screw 10 is fixed to the backup plate 2. A screw shaft 11 of the ball screw 10 passes through the backup plate 2 via a nut 12. A tip end portion (right end side in the figure) of the screw shaft 11 of the ball screw 10 is rotatably connected to the front surface of the fixed die plate 3 via a bearing 17 and a fixing member 18. A rear end portion (left end side in the figure) of the screw shaft 11 is rotatably supported by the support plate 7 via a bearing 19 and penetrates the support plate 7. The pulley 22 described above is attached to the rear end portion of the screw shaft 11.
[0023]
Each nut 12 is driven in the axial direction by rotating each screw shaft 11 using the motor 20. That is, the plurality of ball screws 10 are driven in synchronization with each other. As a result, the backup plate 2 moves in the front-rear direction along the screw shaft 11. As the backup plate 2 moves, the moving die plate 4 connected to the front surface of the backup plate 2 also moves. As described above, the mold clamping and mold opening operations are performed by driving the ball screw 10.
[0024]
At the time of mold clamping, the ball screw 10 is driven to move the movable die plate 4 forward relative to the fixed die plate 3, thereby bringing the mold surfaces of the fixed mold 5 and the movable mold 6 into contact with each other. At this time, the reaction force of the mold clamping force (compressive load generated on the mold surface) is transmitted to the screw shaft 11 of the ball screw through the load cell 15 and the backup plate 2 in this order.
[0025]
As described above, in the direct pressure type electric mold clamping device of the present invention, the screw shaft 11 of the ball screw 10 only rotates and does not move in the axial direction. Therefore, an empty space for retreating the screw shaft 11 is provided at the rear of the device. There is no need to reserve. Therefore, the overall length of the apparatus can be shortened as compared with the conventional direct pressure type electric mold clamping apparatus.
[0026]
Further, in the direct pressure type electric mold clamping device of the present invention, as shown in FIG. 3, the movable die plate 4 is slid by a linear guide 30 provided on the base 1. As described above, since the slider 30a of the linear guide 30 sandwiches the guide rail 30b from both sides, the movable die plate 4 does not move except in the sliding direction along the guide rail 30b. Therefore, unlike the case where a smoother is used for the sliding surface, the torsional moments generated in both directions of rotation generated in the backup plate 2 by the forward and reverse rotation 60 of the ball screw 11 and transmitted to the moving die plate 4 via the load cell 15 It can be received by the linear guide 30. As a result, the following effects occur. 1) Since there is no twist (rotation) and lateral displacement of the moving die plate 4, an accurate clamping force can be obtained. 2) Since the moving mold 6 does not rotate in accordance with the moving die plate 4, the two molds 5, 6 are not displaced, the mold is not rubbed, and the mold is not rubbed. Life span is extended. Further, since the moving mold 6 does not rotate, it becomes possible to mold a precision molded product.
[0027]
Instead of using the above-described linear guide 30 as the above-described linear guide mechanism, as shown in FIG. 6, a linear guide groove 70 (for example, a V-groove) provided on the surface of the base 1 and the movable die plate 4 You may use the member 80 which has the convex part (for example, V-shaped cross section) attached to the bottom part and corresponding to the guide groove 70. FIG. The movable die plate 4 can be slid linearly along the guide groove 70 by inserting and sliding the convex portion of the member 80 into the guide groove 70. Also in this case, the torsional moment generated by the rotation 60 of the ball screw 11 can be received by the guide groove 70, so that the above-described accurate mold clamping force can be obtained.
[0028]
If the load cell 15 shown in FIGS. 1 and 2 can be omitted, the movable die plate 4 can be directly connected to the front surface of the backup plate 2. In that case, the backup plate 2 and the movable die plate 4 can also be configured integrally. When the load cell 15 is omitted, the twist due to the rotation of the ball screw 10 absorbed between the load cell 15 and the movable die plate 4 and between the load cell 15 and the backup plate 2 is not absorbed. The effect of using the linear guide 30 as the guide 4 is even greater.
[0029]
Further, the screw shaft 11 of the ball screw can also function as a tie rod (37; FIG. 10) in a conventional mold clamping device. In this way, the configuration of the apparatus can be simplified.
[0030]
Preferably, the fixed die plate 3 and the backup plate 2 are connected by two ball screws 10, and these ball screws 10 are arranged in the horizontal direction with the central axes of the fixed mold 5 and the movable mold 6 as the center. Placed at an oblique position.
[0031]
If the two ball screws 10 are arranged in this way, and if these ball screws 10 also function as tie rods, the number of parts arranged around the mold is reduced, so that the mold can be easily accessed. .
[0032]
7 and 8 show a schematic configuration of a second embodiment of the direct pressure type electric mold clamping device according to the present invention. 7 is a front view, and FIG. 8 is a cross-sectional view in a direction parallel to the axial direction of the apparatus.
[0033]
A fixed die plate 3 and a support plate 7 are disposed at both ends of the base 1, and a moving die plate 4 is disposed in front of the fixed die plate 3 so as to face the fixed die plate 3. A fixed die plate 3 holds a fixed mold 5, and a movable die plate 4 holds a movable mold 6. A backup plate 2 is disposed between the support plate 7 and the movable die plate 4. The moving die plate 4 and the backup plate 2 can slide on the base 1. A screw shaft 11 of the ball screw 10 passes through the backup plate 2 through a nut 12 of the ball screw 10 fixed to the backup plate 2. The tip end portion (right end side in the drawing) of the screw shaft 11 is rotatably connected to the fixed die plate 3, and the rear end portion (left end side in the drawing) of the screw shaft 11 rotates on the support plate 7 via the bearing 19. It is supported freely and penetrates the support plate 7. A movable die plate 4 is connected to the front surface of the backup plate 2 via four coil springs (elastic members) 9 and the like. A motor 20 is accommodated below the base 1. A pulley 22 is attached to the rear end of each screw shaft 11, and a pulley 21 is attached to the shaft of the motor 20, and a timing belt 23 is bridged between the pulley 21 and each pulley 22.
[0034]
Similar to the first embodiment, as shown in FIG. 3, the screw shaft 11 of the ball screw 10 penetrates through holes at two corners of the movable die plate 4, and the movable die plate 4 is provided on the base 1. The base 1 is slid by a linear guide mechanism, for example, a linear guide 30 including a slider 30a and a guide rail 30b.
[0035]
The connecting portion between the motor 20 and the screw shaft 11 is the same as that shown in FIG.
[0036]
FIG. 9 shows details of a connection portion between the backup plate 2 and the movable die plate 4. A spring receiving member 8 is attached to the back surface of the movable die plate 4 with a load cell 15 interposed therebetween. The backup plate 2 and the spring receiving member 8 are connected via four coil springs 9.
[0037]
Also in the direct pressure type electric mold clamping device of the present embodiment, the nuts 12 are driven in the axial direction by rotating the screw shafts 11 with each other using the motor 20, whereby the backup plate 2 is connected to the screw shaft 11. Are moved in the front-rear direction with respect to the fixed die plate 3. As the backup plate 2 moves, the moving die plate 4 connected to the front surface of the backup plate 2 via the coil spring 9 also moves together with the backup plate 2. Thus, mold clamping and mold opening operations are performed by driving the ball screw 10.
[0038]
Thus, in this embodiment as well, as in the first embodiment, the screw shaft 11 of the ball screw 10 only rotates and does not move in the axial direction. There is no need to keep it behind. Therefore, the overall length of the apparatus can be shortened as compared with the conventional direct pressure type electric mold clamping apparatus.
[0039]
Also in the direct pressure type electric mold clamping device of the present embodiment, as shown in FIG. 3, the moving die plate 4 is slid using the linear guide 30 provided on the base 1. The generated torsional moment can be received by the linear guide 30 and an effect such as obtaining an accurate mold clamping force is produced. Further, as described above with reference to FIG. 6, instead of using the linear guide 30, a moving die plate is used by using a guide groove 70 provided on the surface of the base 1 and a member 80 having a convex portion inserted into the guide groove 70. The same effect can be obtained by sliding 4.
[0040]
Also in this embodiment, similarly to the first embodiment, when the load cell 15 shown in FIGS. 8 and 9 can be omitted, the movable die plate 4 can be directly connected to the front surface of the spring receiving member 8. . In that case, the spring receiving member 8 and the movable die plate 4 can also be configured integrally. When the load cell 15 is omitted, the twist caused by the rotation of the ball screw 10 absorbed between the load cell 15 and the movable die plate 4 and between the load cell 15 and the spring receiving member 8 is not absorbed. The effect of using the linear guide 30 for guiding the plate 4 is further increased.
[0041]
In the present embodiment, when the mold surfaces of the fixed mold 5 and the movable mold 6 are in contact with each other during mold clamping, the reaction force of the mold clamping force is the load cell 15, the spring receiving member 8, the coil spring 9, and It is transmitted to the screw shaft 11 of the ball screw through the backup plate 2 in order. As a result, the screw shaft 11 elastically extends and at the same time the coil spring 9 contracts.
[0042]
Here, by appropriately designing the spring constant of the coil spring 9, it is possible to cause the coil spring 9 to generate a large elastic deformation compared to the extension of the screw shaft 11. Thus, unlike the case where the reaction force is received by only four tie rods (the total cross-sectional area is large and therefore the rigidity is high) at the time of clamping, the allowance for elongation when the reaction force acts can be increased. Therefore, when the mold surfaces of the fixed mold 5 and the movable mold 6 come into contact with each other, the mold clamping force can be gradually increased. In addition, the resolution of the mold clamping force is improved. As a result, it is possible to prevent the occurrence of overshoot of the mold clamping force and increase the accuracy of the mold clamping force. Moreover, since it is possible to prevent an excessive load from acting on the components of the mold clamping device, it is possible to extend the life of those components.
[0043]
【The invention's effect】
According to the direct pressure type electric mold clamping apparatus of the present invention, when the mold is clamped and opened, the screw shaft of the ball screw only rotates and does not move in the axial direction. There is no need to keep it behind. Therefore, the overall length of the device can be shortened as compared with the conventional direct pressure type electric clamping device.
[0044]
The moving die plate is slid by using a linear guide provided on the base, or the moving die plate is slid along a guide groove provided on the surface of the base. Since the twist (rotation) and displacement of the plate are eliminated, it is possible to improve mold clamping accuracy, protect the mold and extend its life, and achieve stable precision molding.
[0045]
In addition, the fixed die plate and the backup plate are connected by two ball screws, and these ball screws are arranged at an oblique position with respect to the horizontal direction with the central axis of the fixed die and the moving die as the center. By making these ball screws also function as tie rods, the number of parts arranged around the mold, such as the number of rods, is reduced, so that access to the mold is facilitated.
[0046]
In addition, since a plurality of ball screws are used, a load such as a mold clamping force can be dispersed, so that the size of the ball screw can be reduced.
[0047]
In addition, the fixed die plate and the backup plate are coupled using a ball screw, and the movable die plate is connected to the front surface of the backup plate via an elastic member, so that the mold clamping force can be reduced when the mold surface is in contact with the mold surface. You can make it stand up slowly. In addition, the resolution of the mold clamping force is improved. As a result, it is possible to prevent the occurrence of overshoot of the mold clamping force during mold clamping and to increase the accuracy of the mold clamping force. Along with this, it is possible to prevent an excessive load from acting on the component parts of the mold clamping device, so that the service life of those component parts can be extended.
[Brief description of the drawings]
FIG. 1 is a front view showing a schematic configuration of a first embodiment of a direct pressure electric mold clamping device of the present invention.
FIG. 2 is an axial sectional view showing a schematic configuration of the first embodiment of the direct pressure type electric mold clamping device of the present invention.
FIG. 3 is a left side view showing one embodiment of a moving die plate of the present invention.
FIG. 4 is a diagram showing details of a connecting portion between a motor and a screw shaft according to the present invention.
5 is a partial detail view of the ball screw according to the present invention, corresponding to a cross section taken along the line EE in FIG. 4;
FIG. 6 is a left side view showing another embodiment of the moving die plate of the present invention.
FIG. 7 is a front view showing another schematic configuration of the second embodiment of the direct pressure type electric mold clamping device of the present invention.
FIG. 8 is an axial sectional view showing a schematic configuration of a second embodiment of the direct pressure type electric mold clamping device of the present invention.
FIG. 9 is a detailed view of a connecting portion between the backup plate and the moving die plate of the present invention.
FIG. 10 is a diagram showing a schematic configuration of a conventional direct pressure type electric mold clamping device.
[Explanation of symbols]
1 ... Base,
2 ... Backup plate,
3 ... fixed die plate,
4 ... Moving die plate,
4a ... Moving die plate legs,
5 ... fixed mold,
6 ... Moving mold,
7 ... Support plate,
8 ... Spring receiving member,
9: coil spring (elastic member),
10, 40 ... Ball screw,
11, 41... Screw shaft of ball screw,
12, 42 ... ball screw nuts,
13 ... slip board,
15, 45 ... load cells,
17, 19, 47 ... bearings,
18: fixing member,
20, 50 ... motor,
21, 22, 51, 52 ... pulley,
23, 53 ... timing belt,
30 ... Linear guide,
30a ... slider,
30b ... guide rail,
32 ... back plate,
37 ... tie rod,
60: Direction of rotation of the ball screw,
70: guide groove,
80 ... convex member.

Claims (4)

Base and
A fixed die plate arranged on the base for holding a fixed mold;
A moving die plate that is placed opposite the fixed die plate and holds the moving mold;
A linear guide mechanism provided on the base for guiding the movement of the movable die plate;
A backup plate that connects the moving die plate directly from the back side;
A plurality of ball screws that connect between the fixed die plate and the backup plate, the tip of the screw shaft is rotatably connected to the fixed die plate, and the nut is fixed to the backup plate;
A motor for rotating the screw shafts of the plurality of ball screws in synchronization with each other;
A direct pressure type electric mold clamping device for an injection molding machine. Base and
A fixed die plate arranged on the base for holding a fixed mold;
A moving die plate that is placed opposite the fixed die plate and holds the moving mold;
A linear guide mechanism provided on the base for guiding the movement of the movable die plate;
A backup plate located behind the moving die plate;
An elastic member that connects between the movable die plate and the backup plate and can be expanded and contracted with respect to the clamping direction;
A spring receiving member disposed between the moving die plate and the backup plate, one end of the elastic member being fixed, and connecting the moving die plate directly from the back;
A plurality of ball screws that connect between the fixed die plate and the backup plate, the tip of the screw shaft is rotatably connected to the fixed die plate, and the nut is fixed to the backup plate;
A motor that rotates the screw shafts of the plurality of ball screws in synchronization with each other ;
The direct pressure type electric mold clamping apparatus of an injection molding machine, wherein the spring receiving member extends over screw shafts of the plurality of ball screws .   3. The direct pressure type electric mold clamping device for an injection molding machine according to claim 1, wherein the linear guide mechanism is a linear guide.   The direct pressure type electric mold clamping apparatus for an injection molding machine according to claim 1 or 2, wherein the linear guide mechanism is a V-groove.

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