JP6784630B2 - Injection device and molding machine - Google Patents

Description

The present disclosure relates to an injection device for injecting a molding material in a liquid or solid-liquid coexisting state into a mold and a molding machine provided with the injection device. The molding machine is, for example, a die casting machine or a plastic injection molding machine.

As an injection device for pushing a molding material into a mold by a plunger, an injection device in which the driving force of the plunger is obtained not by a hydraulic cylinder but by an electric motor, that is, a fully electric injection device is known. Further, as such an all-electric injection device, there is also known one having a plurality of electric motors and switching the electric motor to be used as the injection process progresses (for example, Patent Document 1).

In Patent Document 1, two electric motors, two ball screw mechanisms for inputting rotations of the two electric motors, a member driven by one of the two ball screw mechanisms and abutting on the rear end of the plunger, and a plunger. An injection device having a one-way clutch interposed between the two ball screw mechanisms and the other is disclosed. In Patent Document 1, one of the two electric motors is for low-speed injection and the other is for high-speed injection. Further, the two ball screw mechanisms are provided in parallel with each other and in parallel with the plunger.

JP-A-2007-210000

The technique of Patent Document 1 lacks specificity. For example, it is unclear how to retract the plunger. Therefore, it is desired to provide an injection device and a molding machine capable of suitably transmitting the driving force of a plurality of electric motors to the plunger.

The injection device according to one aspect of the present disclosure is an injection device that advances a plunger to push out a molding material into a mold, and is a first linear motion that is coaxially connected to a first electric motor and a rear end of the plunger. A first transmission unit that includes a member and the first linear motion member is driven in the axial direction of the plunger by a driving force of the first electric motor, a rotary second electric motor, and the first linear motion member are inserted. A second transmission unit that includes a second linear motion member and converts the rotation of the second electric motor into a linear motion of the second linear motion member in the axial direction of the plunger, and the second linear motion member from the second linear motion member. (1) It has a connecting portion that allows and prohibits transmission of a driving force to a linear motion member.

In one example, the second transmission unit has a nut to which the rotation of the second electric motor is transmitted, and a screw shaft as the second linear motion member that is screwed into the nut.

In one example, the first electric motor is rotary, and the first transmission unit is coaxial with the plunger, which converts the rotation of the first electric motor into a linear motion of the first linear motion member in the axial direction of the plunger. The first linear motion member includes a screw shaft or a nut of the screw mechanism.

In one example, the injection device engages with the first linear motion member in a direction around the axis, prohibits the rotation of the first linear motion member around the axis, and of the first linear motion member. It further has a detent portion that allows movement in the axial direction, and the screw shaft as the second linear motion member engages with the first linear motion member in the axial direction and rotates around the axis. Rotation is prohibited and axial movement is allowed.

In one example, the first electric motor is a rotary type, and the first transmission unit converts the rotation of the first electric motor into a linear motion of the first linear motion member in the axial direction of the plunger, and the second electric motor. The amount of movement of the second linear motion member by one rotation of the first electric motor is smaller than the amount of movement of the first linear motion member by one rotation of the first electric motor.

In one example, the injection device further comprises a control device that controls the first electric motor and the second electric motor so as to perform injection by the driving force of the first electric motor and increase the pressure by the driving force of the second electric motor. Have.

In one example, the connecting portion is interposed between the outer peripheral surface of the first linear motion member and the inner peripheral surface of the second linear motion member with respect to the second linear motion member of the first linear motion member. It includes a one-way clutch that allows relative forward movement while prohibiting relative backward movement.

In one example, the one-way clutch has an inner rack held by the first linear motion member, an outer rack held by the second linear motion member, and one of the inner rack and the outer rack to the other. The inner rack has a plurality of first teeth that are arranged in the axial direction of the plunger and are inclined rearward, and the outer rack has an elastic member to be urged. , Arranged in the axial direction of the plunger, and having a plurality of second teeth that are inclined forward and can mesh with the plurality of first teeth.

In one example, the first linear motion member is hollow.

In one example, the injection device further includes a cylinder type shock absorber that comes into contact with a member fixed to the first linear motion member when the first linear motion member advances to a predetermined position.

In one example, the molding machine includes the injection device, a mold clamping device for molding the mold, and an extrusion device for extruding a molded product from the mold.

The molding machine according to one aspect of the present disclosure includes the above-mentioned injection device, a mold-clamping device for mold-clamping a mold, and an extrusion device for extruding a molded product from the mold.

According to the above configuration, the driving force of a plurality of electric motors can be suitably transmitted to the plunger.

The schematic diagram which shows the main part structure of the die casting machine which has the injection apparatus which concerns on embodiment of this disclosure. FIG. 6 is a schematic cross-sectional view showing a main configuration of the injection device of FIG. FIG. 3A is a cross-sectional view taken along the line IIIa-IIIa of FIG. 2, and FIG. 3B is a cross-sectional view taken along the line IIIb-IIIb of FIG. FIG. 4A is a cross-sectional view showing an example of the configuration of the one-way clutch of the injection device of FIG. 2, and FIG. 4B is a cross-sectional view showing another example of the configuration of the one-way clutch of FIG. The figure for demonstrating the operation of the injection apparatus of FIG. 6 (a) to 6 (d) are schematic views showing a main configuration of an injection device according to a modified example.

(Overall configuration of die casting machine)
FIG. 1 is a side view showing a configuration of a main part of the die casting machine 1 according to the embodiment of the present disclosure, including a cross-sectional view in part.

The die casting machine 1 injects a molten metal material (molten metal) into a mold 101 (a space such as a cavity Ca; the same applies hereinafter) and solidifies the molten metal in the mold 101 to perform die casting. It manufactures products (molded products). The metal is, for example, aluminum or an aluminum alloy. It is also possible to use a solid-liquid coexisting metal instead of the molten metal.

The mold 101 includes, for example, a fixed mold 103 and a moving mold 105. In the description of the present embodiment, for convenience, the cross section of the fixed mold 103 or the moving mold 105 is shown by one type of hatching, but these molds may be of a direct carving type or a nested type. It may be a thing. Further, the fixed mold 103 and the moving mold 105 may be combined with a core or the like.

The die casting machine 1 has, for example, a machine main body 3 that performs a mechanical operation for molding, and a control unit 5 that controls the operation of the machine main body 3.

The machine main body 3 includes, for example, a mold clamping device 7 that opens and closes and clamps the mold 101, an injection device 9 that injects molten metal into the mold 101, and a fixed mold 103 or a moving mold 105 for a molded product. It has an extrusion device 11 that extrudes from (moving die 105 in FIG. 1). In the machine main body 3, various known configurations other than the injection device 9 (for example, the configuration of the mold clamping device 7 and the extrusion device 11) are basically (excluding the portion related to the attachment of the injection device 9). It may be similar to the configuration.

In the molding cycle, the mold clamping device 7 moves the moving mold 105 toward the fixed mold 103 to close the mold. Further, the mold clamping device 7 applies a mold clamping force corresponding to the extension amount of the tie bar (reference numeral omitted) to the mold 101 to perform mold clamping. A cavity Ca having the same shape as the molded product is formed in the mold 101 that has been molded. The injection device 9 injects and fills the molten metal into the cavity Ca. The molten metal filled in the cavity Ca is deprived of heat by the mold 101, cooled, and solidified. As a result, a molded product is formed. After that, the mold clamping device 7 moves the moving mold 105 away from the fixed mold 103 to open the mold. At this time or thereafter, the extruder 11 extrudes the molded product from the moving die 105.

The control unit 5 includes, for example, a control device 13 (FIG. 2) that performs various calculations and outputs a control command, a display device 15 that displays an image, and an input device 17 that receives an operator's input operation. There is. From another viewpoint, the control unit 5 has, for example, a control panel (not shown) having a power supply circuit, a control circuit, and the like, and an operation unit 19 as a user interface.

The control device 13 is provided, for example, in a control panel and an operation unit 19 (not shown). The control device 13 may be appropriately divided or dispersed. For example, the control device 13 includes a lower control device for each of the mold clamping device 7, the injection device 9, and the extrusion device 11, and a higher control device that performs control such as synchronizing between the lower control devices. It may be configured.

The display device 15 and the input device 17 are provided in, for example, the operation unit 19. The operation unit 19 is provided, for example, in a fixed portion of the mold clamping device 7. The display device 15 is composed of, for example, a touch panel including a liquid crystal display or an organic EL display. The input device 17 is composed of, for example, a mechanical switch and the touch panel described above.

When focusing on the injection device 9 of the die casting machine 1, the control unit 5 may be regarded as a control unit of the injection device 9. The same applies to the components of the control unit 5 (for example, the control device 13).

(Configuration of injection device)
The injection device 9 has, for example, a sleeve 21 that leads into the mold 101, a plunger 23 that is slidable in the sleeve 21, and a drive unit 25 that drives the plunger 23. In the description of the injection device 9, the mold 101 side (left side of the paper in FIG. 1) may be referred to as the front, and the opposite side may be referred to as the rear, and terms such as forward or backward may be used according to this definition. is there.

The sleeve 21 is, for example, a tubular member connected to the fixed mold 103, and a supply port 21a for receiving the molten metal into the sleeve 21 is opened on the upper surface thereof. The plunger 23 has a plunger tip 23a that can slide in the sleeve 21 in the front-rear direction, and a plunger rod 23b whose tip is fixed to the plunger tip 23a.

When the mold clamping of the mold 101 is completed by the mold clamping device 7, one shot of molten metal is poured into the sleeve 21 from the supply port 21a by a hot water supply device (not shown). Then, when the plunger 23 slides forward in the sleeve 21 from the position shown in the drawing, the molten metal in the sleeve 21 is pushed out (injected) into the mold 101.

The drive unit 25 has a fixed portion (reference numeral omitted) and a movable portion (such as a connecting shaft 41 described later) that can move in the axial direction of the plunger 23 with respect to the fixed portion. The fixing portion is fixed to, for example, the injection frame 69. The injection frame 69 is fixed to, for example, a fixed die plate 7a holding the fixing mold 103 in the mold clamping device 7. The movable part is connected to the plunger 23.

(Overall configuration of drive unit)
FIG. 2 is a schematic view showing a specific configuration of the injection device 9 (drive unit 25). Most of FIG. 2 is basically a cross-sectional view seen from above. However, FIG. 2 may be regarded as a side view.

The drive unit 25 is, for example, a fully electric type, and includes an injection electric motor 27, an injection transmission unit 29 for transmitting the driving force of the injection electric motor 27 to the plunger 23, a piezoelectric motive 31, and a piezoelectric motive 31. It has a pressure boosting transmission unit 33 for transmitting the driving force of the above to the plunger 23, and a connection unit 35 for connecting and disconnecting the pressure boosting transmission unit 33 and the plunger 23.

The injection motor 27 and the injection transmission unit 29 are mainly used for low-speed injection and high-speed injection (injection in a narrow sense). The pressure-increasing motive 31 and the pressure-increasing transmission unit 33 are mainly used for pressure-increasing. When the plunger 23 is driven by these, the injection device 9 switches the electric motor that applies the driving force to the plunger 23 according to the progress of the process. The connecting portion 35 contributes to optimizing the switching operation.

In the present embodiment, the combination of the injection motor 27 and the injection transmission unit 29 and the combination of the piezoelectric motive 31 and the pressure increase transmission unit 33 have a common point regarding the principle of the mechanism adopted. There are relatively many overlapping explanations. Therefore, in the following, when the description is common to both, the injection motor 27 and the injection transmission unit 29 will be described, and the reference numerals of the piezoelectric motive 31 and the pressure increase transmission unit 33 may be added in parentheses. That is, the code (and name) before () may be replaced with the code in ().

(Electric motor)
The number of injection motors 27 (31) may be appropriately set. In the description of the present embodiment, an embodiment in which two injection motors 27 and one piezoelectric motive 31 are provided will be taken as an example.

The injection electric motor 27 (31) is composed of, for example, a rotary electric motor, and although not particularly shown, the injection motor 27 (31) comprises a stator that constitutes one of the field magnet and the armature, and a stator that constitutes the other of the field magnet and the armature. It has a rotor that rotates with respect to. The injection motor 27 (31) may be of an appropriate type, for example, it may be a DC motor, an AC motor, a synchronous motor, or an induction motor. It may be an electric motor.

The injection motor 27 (31) may be equipped with a brake. In the following description, the state in which the injection motor 27 (31) is stopped may be a torque-free state, a state in which the position is controlled at a fixed position, or a brake is used. It may be in the state where it is set, and it may be appropriately selected from these.

The injection motor 27 (31) is configured as, for example, a servomotor. That is, the injection motor 27 (31) has a rotation sensor 27s (31s) that detects the rotation, and feedback control of the rotation speed is performed by a servo driver (not shown) based on the detection value of the rotation sensor 27s (31s). Be done. The rotation sensor 27s (31s) is, for example, an encoder that outputs a number of pulses according to the amount of rotation.

Further, the servo driver of the piezoelectric motive 31 can detect, for example, the current flowing through the piezoelectric motive 31 and perform torque feedback control based on the detected value. The servo driver of the injection motor 27 may also be capable of such torque feedback control.

The injection motor 27 (31) may be configured by a low inertia motor. That is, the injection electric motor 27 (31) may be composed of an electric motor in which the inertia of the rotor is relatively small with respect to the rated torque. It should be noted that the low-inertia motor is often described as a low-inertia motor in its catalog or specifications, and it is possible to specify whether or not the low-inertia motor is a low-inertia motor based on the description. Generally, a low inertia motor is configured such that the rotor diameter is relatively small with respect to the axial length of the rotor. However, it is also known that low inertia is realized by optimizing the magnet material, rotor diameter, iron core shape, product thickness, and the like.

The specifications of the injection motor 27 and the piezoelectric motive 31 may be the same as each other, but in the present embodiment, they are different from each other. For example, the injection motor 27 has a higher rated rotation speed and a lower rated torque than the piezoelectric motive 31.

The arrangement of the injection motor 27 (31) may be appropriately set. In the illustrated example, the injection motor 27 (31) is arranged in parallel with the plunger 23 (even if the position in the axial direction does not overlap with the plunger 23, it is expressed in this way for convenience). , Its output shaft is pointing backwards. Further, the injection motor 27 and the piezoelectric motive 31 are arranged so as not to overlap each other in the front-rear direction (advance / retreat direction of the plunger 23). Further, the two injection motors 27 are arranged in parallel with each other so that the positions in the vertical direction (the direction penetrating the paper surface, which may be the horizontal direction) are different from each other.

(Transmission part)
The injection transmission unit 29 (33), for example, has an injection transmission mechanism 37 (55) that transmits the rotation of the injection motor 27 (31) and an injection that converts the rotation from the winding transmission mechanism 37 (55) into a linear motion. It has a screw mechanism 39 (pressure boosting screw mechanism 57).

Further, in addition to the above, the injection transmission unit 29 is connected to the plunger 23 and has a connecting shaft 41 that transmits the linear motion of the injection screw mechanism 39 to the plunger 23. The linear motion of the pressure boosting screw mechanism 57 is transmitted to the connecting shaft 41 via the connecting portion 35.

(Rolling transmission mechanism)
The winding transmission mechanism 37 (55) is, for example, a pulley / belt mechanism, which is a pulley 43 (59) fixed to the output shaft of the injection motor 27 (31) and a belt 45 hung on the pulley 43 (59). (61) and an injection nut 47 (pressure boosting nut 63) to which the belt 45 (61) is hung and also used for the injection screw mechanism 39 (57). The belt 45 (61) may be, for example, a toothed belt or a toothless belt. The winding transmission mechanism 37 (55) may be of a type other than the pulley / belt mechanism, such as the sprocket / chain mechanism.

The rotation of the injection motor 27 (31) is sequentially transmitted to the pulley 43 (59), the belt 45 (61) and the injection nut 47 (63), and is input to the injection screw mechanism 39 (57). The winding transmission mechanism 37 (55) contributes to improving the degree of freedom in the arrangement of the injection motor 27 (31) with respect to the injection screw mechanism 39 (57), for example. The diameter of the pulley 43 (59) and the diameter of the injection nut 47 (63) may be the same, or one may be larger than the other. That is, the winding transmission mechanism 37 (55) may or may not contribute to deceleration or acceleration.

In the illustrated example, in the injection transmission unit 29, the diameter of the injection nut 47 is substantially the same as the diameter of the pulley 43. On the other hand, in the pressure boosting transmission unit 33, the diameter of the pressure boosting nut 63 is larger than the diameter of the pulley 59. Therefore, the pressure boosting nut 63 is driven with a torque larger than the torque generated by the pressure boosting motive 31.

In the injection transmission unit 29, two belts 45 are hung on the injection nut 47, and the driving force of the two injection motors 27 is transmitted. However, an injection nut 47 may be provided for each injection motor 27. In the control of the two injection motors 27, tandem control may be performed. Further, only one injection motor 27 may be provided.

(Screw mechanism)
The injection screw mechanism 39 (57) has an injection nut 47 (63) described above and an injection screw shaft 49 (pressure-increasing screw shaft 65) screwed into the injection nut 47 (63). In addition, in FIG. 2, the state when the pressure-increasing screw shaft 65 is advanced by the two-dot chain line is also shown.

The injection nut 47 (63) is allowed to rotate around the axis and is restricted from moving in the axial direction. On the other hand, the injection screw shaft 49 (65) is restricted from rotating around the shaft and is allowed to move in the axial direction. Therefore, when the rotation of the injection motor 27 (31) is transmitted to the injection nut 47 (63), the injection screw shaft 49 (65) moves in the axial direction thereof.

Allowance of axial rotation of the injection nut 47 (63) and restriction of axial movement are made, for example, by supporting the injection nut 47 (63) with an appropriate bearing. The rotation of the injection screw shaft 49 (65) around the shaft is regulated by the connecting shaft 41 as described later. However, in addition to or instead of restricting rotation by the connecting shaft 41, rotation may be regulated by a general method such as a spline groove.

The injection screw mechanism 39 (57) may be a ball screw mechanism in which a ball is interposed between the injection nut 47 (63) and the injection screw shaft 49 (65), or a sliding screw mechanism in which the ball is not interposed. You may. For example, the injection screw mechanism 39 may be a ball screw mechanism, and the booster screw mechanism 57 may be a sliding screw mechanism. The injection screw mechanism 39 (57) may be a single-threaded screw type having one screw groove, or may be a multi-threaded screw type having two or more screw grooves.

The injection screw shaft 49 has a hollow shape (cylindrical shape) as shown by a dotted line. As a result, for example, the weight of the injection screw shaft 49 is reduced. However, the injection screw shaft 49 may be solid (cylindrical). The pressure boosting screw shaft 65 is hollow so that the connecting shaft 41 can be inserted therethrough.

The injection screw mechanism 39 (57) is arranged coaxially with, for example, the plunger 23. Specifically, for example, the axes of the injection nut 47 (63) and the injection screw shaft 49 (65) are located on the extension of the axis of the plunger 23.

(Connecting shaft)
The connecting shaft 41 is coaxially connected to the rear end of the plunger 23 and is coaxially fixed to the front end of the injection screw shaft 49. Therefore, when the injection screw shaft 49 moves in the axial direction, the plunger 23 moves in the axial direction. Further, as will be described later, the booster screw shaft 65 is connected to the connecting shaft 41 at an appropriate time by the connecting portion 35. Therefore, when the booster screw shaft 65 moves in the axial direction in the state where the connection is made, the plunger 23 moves in the axial direction.

The connecting shaft 41 is a shaft-shaped member extending linearly, and its cross-sectional shape is substantially constant over the entire length. The cross-sectional shape of the connecting shaft 41 (the shape of the outer edge of the cross section) is, for example, non-circular, as will be described in detail later. However, the cross-sectional shape of the connecting shaft 41 may be circular. As shown by the dotted line in FIG. 2, the connecting shaft 41 is, for example, hollow (see also FIGS. 3 (a) and 3 (b)). However, the connecting shaft 41 may be solid.

When the linear motion member 53, the connecting shaft 41, or the injection screw shaft 49 is hollow, it does not have to be hollow over the entire length, and a solid portion (for example, an end portion or an intermediate position) is partially formed. It may exist. Each of the linear motion member 53, the connecting shaft 41, or the injection screw shaft 49 is hollow, for example, at least half or two-thirds or more of the length.

The connection shaft 41 and the plunger 23 are connected by, for example, a coupling 51. The coupling 51 has, for example, a spacer interposed between the flange provided at the rear end of the plunger rod 23b and the flange provided at the front end of the connecting shaft 41, although not particularly designated. , Has a case-like portion for accommodating these flanges and spacers.

The connection shaft 41 and the injection screw shaft 49 may be fixed by being integrally formed thereof, or by being separately formed and connected by a coupling, a screw or the like. You may.

Since the connecting shaft 41 and the injection screw shaft 49 are maintained fixed to each other at least during the molding cycle, they may be regarded as one member. In the following, both may be referred to as a linear motion member 53. In the present embodiment, the linear motion member 53 has an axial shape as a whole and is coaxially connected to the plunger 23. In the description of the present embodiment, a part of the linear motion member 53 is regarded as an injection screw shaft 49, but the entire linear motion member 53 may be regarded as a screw shaft of the injection screw mechanism 39.

(Relative relationship between injection transmission section and booster transmission section)
The linear motion member 53 of the injection screw mechanism 39 is inserted through the booster screw shaft 65. Therefore, they are arranged concentrically. The entire linear motion member 53 may be regarded as the screw shaft of the injection screw mechanism 39, and the screw shafts may be regarded as being concentrically arranged.

Comparing the injection transmission unit 29 and the pressure boosting transmission unit 33, for example, the amount of movement of the injection screw shaft 49 (plunger 23) by one rotation of the injection motor 27 is that of the pressure boosting screw shaft 65 by one rotation of the piezoelectric motive 31. Greater than the amount of movement. Therefore, for example, the injection transmission unit 29 can easily move the injection screw shaft 49 at a relatively high speed, and the pressure boosting transmission unit 33 can easily transmit a relatively large force to the pressure boosting screw shaft 65.

The above difference may be realized by the difference in reduction ratio in the winding transmission mechanism 37 and 55, and / or by the difference in the leads of the injection screw mechanism 39 and the pressure boosting screw mechanism 57. May be good. For example, the lead of the injection screw mechanism 39 is larger than the lead of the pressure boosting screw mechanism 57.

Further, when the injection screw mechanism 39 and the pressure boosting screw mechanism 57 are compared, the diameter of the pressure boosting screw mechanism 57 (for example, the effective diameter or the valley diameter of the male screw. The same applies to the injection screw mechanism 39) is the diameter of the injection screw mechanism 39. Has been made larger than. Further, the length of the injection screw shaft 49 (the length of the portion where the screw groove is actually formed. The same applies to the pressure boosting screw shaft 65) is longer than the length of the pressure boosting screw shaft 65. From another point of view, the stroke of the injection screw mechanism 39 is longer than the stroke of the booster screw mechanism 57.

(Stopping rotation)
A structure for restricting the rotation of the injection screw shaft 49 and the booster screw shaft 65 around the axis will be described with reference to FIGS. 3 (a) and 3 (b). FIG. 3A is a cross-sectional view taken along the line IIIa-IIIa of FIG. 2, and FIG. 3B is a cross-sectional view taken along the line IIIb-IIIb of FIG.

As described above, the connecting shaft 41 has a non-circular cross-sectional shape (the shape of the outer edge of the cross section). Specifically, for example, the cross-sectional shape of the connecting shaft 41 is a shape obtained by cutting a part of a circle with a straight line (41f). From another viewpoint, the outer shape of the connecting shaft 41 is a shape in which a flat surface 41f is provided on the outer peripheral surface of the cylinder. The number and position of the plane 41f may be appropriately set. In the illustrated example, two planes 41f facing each other are provided. The width of the plane 41f may be appropriately set, and the length of the plane 41f may be provided as much as necessary for sliding described later.

As shown in FIGS. 2 and 3A, the detent member 67 is in contact with the plane 41f. The detent member 67 is provided so as not to be movable in any direction, for example. Specifically, for example, the detent member 67 is fixed to the injection frame 69. Therefore, the connection shaft 41 is restricted from rotating around the axis, and is allowed to move in the axial direction with sliding with respect to the detent member 67.

The shape of the portion of the detent member 67 that abuts on the flat surface 41f may be an appropriate shape. In the illustrated example, the portion that comes into contact with the plane 41f is made flat. In the illustrated example, the detent member 67 is provided for each plane 41f and does not come into contact with a portion of the connecting shaft 41 other than the plane 41f. However, the detent member 67 may be a single tubular member and may be configured to abut on a portion of the connecting shaft 41 other than the flat surface 41f (see the cross-sectional shape of the booster screw shaft 65 described later). ).

As shown in FIGS. 2 and 3B, a part of the inner peripheral surface of the booster screw shaft 65 is in contact with the plane 41f. Therefore, the pressure boosting screw shaft 65 is restricted from rotating about the axis with respect to the connecting shaft 41, and is allowed to move in the axial direction accompanied by sliding with the connecting shaft 41. As described above, the connection shaft 41 is regulated by the detent member 67 for (absolute) rotation, so that the pressure boosting screw shaft 65 is shafted by the detent member 67 via the connection shaft 41. Rotation around is regulated.

The shape of the portion of the booster screw shaft 65 that abuts on the flat surface 41f may be an appropriate shape. In the illustrated example, the portion that comes into contact with the plane 41f is made flat. Further, the booster screw shaft 65 may or may not be in contact with a portion of the connecting shaft 41 other than the flat surface 41f (in the illustrated example).

(Connection part)
As shown in FIG. 2, the connecting portion 35 has an inner portion 35a provided on the linear motion member 53 (connecting shaft 41) and an outer portion 35b provided on the pressure boosting screw shaft 65. .. As shown in the drawing, when the plunger 23 and the linear motion member 53 are located at the retracted limit, the inner portion 35a is separated rearward from the outer portion 35b. Then, as the linear motion member 53 advances, the inner portion 35a is located inside the outer portion 35b, and the inner portion 35a and the outer portion 35b can be coupled to each other.

FIG. 4A is a cross-sectional view showing an example of the configuration of the connecting portion 35. In this figure, a state in which the inner portion 35a is located in the outer portion 35b is shown. The left side of the paper surface is the front side (mold 101 side) as in FIG. Vs indicates the speed of the booster screw shaft 65, and Vf indicates the speed of the connecting shaft 41.

The connecting portion 35 includes, for example, a straight-ahead one-way clutch 71 (hereinafter, may be simply referred to as “clutch 71”) and a releasing portion 73 for deactivating the clutch 71.

The clutch 71 is configured to allow the connecting shaft 41 to move forward relative to the pressure boosting screw shaft 65 while prohibiting the relative retreat. Specifically, for example, the clutch 71 includes an inner rack 75 held by the connecting shaft 41, an outer rack 77 held by the booster screw shaft 65, and an elastic member 79 that urges the outer rack 77. have.

The inner rack 75 has a plurality of teeth 75a arranged in the axial direction of the connecting shaft 41 on the surface facing the outer rack 77. The plurality of teeth 75a are serrated to be inclined rearward. For example, the tooth 75a has an inclined surface in the front and a vertical surface (may be an inverted inclined surface or a steeply inclined surface) in the rear. The inner rack 75 is immovable with respect to the connecting shaft 41 in the axial and radial directions thereof. For example, the inner rack 75 is fixed to the connecting shaft 41 by a screw (reference numeral omitted). The inner rack 75 may be integrally formed with the connecting shaft 41.

The outer rack 77 has a plurality of teeth 77a arranged in the axial direction of the booster screw shaft 65 on the surface facing the inner rack 75. The plurality of teeth 77a are serrated to be inclined forward. For example, the tooth 77a has an inclined surface at the rear and a vertical surface (may be an inverted inclined surface or a steep inclined surface) at the front. The outer rack 77 is held so as to be movable in the axial direction and radially (for example, in the vertical direction or the horizontal direction) with respect to the booster screw shaft 65. Specifically, for example, the outer rack 77 has a portion that is slidably accommodated in a space formed in the pressure boosting screw shaft 65 in the radial direction.

The elastic member 79 is composed of, for example, a spring such as a leaf spring or a spiral winding spring, and is interposed between the outer rack 77 and the booster screw shaft 65. Then, the elastic member 79 urges the outer rack 77 to the inner rack 75 with respect to the booster screw shaft 65.

Therefore, when the connecting shaft 41 advances relative to the booster screw shaft 65 (Vf> Vs), the inclined surface of the teeth 75a of the inner rack 75 and the inclined surface of the teeth 77a of the outer rack 77 slide. As it moves, the outer rack 77 is pushed toward the booster screw shaft 65 against the urging force of the elastic member 79. As a result, the relative advance of the connecting shaft 41 with respect to the booster screw shaft 65 is allowed.

On the other hand, when the booster screw shaft 65 advances relative to the connecting shaft 41 (Vf <Vs), the vertical plane of the teeth 75a of the inner rack 75 and the vertical plane of the teeth 77a of the outer rack 77 are in relation to each other. It fits. As a result, the relative advance of the booster screw shaft 65 with respect to the connecting shaft 41 is prohibited.

Note that FIGS. 2 and 4A exemplify an embodiment in which the inner rack 75 and the outer rack 77 are provided in the direction in which the plane 41f is provided when the connecting shaft 41 is viewed in the axial direction. There is. However, the inner rack 75 and the outer rack 77 may be provided in a direction different from the direction in which the plane 41f is provided.

The release portion 73 is composed of, for example, an electromagnet, is located on the outside of the outer rack 77 (the side opposite to the side facing the inner rack 75), and is fixed to the booster screw shaft 65. Then, when the release portion 73 is energized, the release portion 73 attracts the outer rack 77, which is at least partially made of a magnetic material, against the urging force of the elastic member 79. As a result, the clutch 71 is in a non-operating state (a state in which both forward and backward movement of the connecting shaft 41 with respect to the booster screw shaft 65 is allowed). The number and position of the release portions 73 may be appropriately set.

FIG. 4B is a cross-sectional view showing another example of the configuration of the connecting portion 35. FIG. 4B is a diagram corresponding to FIG. 4A. Here, for convenience, the same reference numerals as those in FIG. 4A are used.

In the example of FIG. 4A, the outer rack 77 of the inner rack 75 and the outer rack 77 is made movable in the radial direction. On the other hand, in the example of FIG. 4B, the inner rack 75 is movable in the radial direction. Along with this, the elastic member 79 and the release portion 73 are provided on the connecting shaft 41. Others are the same as in FIG. 4 (a).

(Support structure of drive unit)
As shown in FIG. 2, the drive unit 25 has a support member 81 for supporting the injection screw mechanism 39 and the like, for example. Although the support member 81 is shown by one hatch in FIG. 2, the support member 81 may be configured by combining a plurality of members. The support member 81 is, for example, configured in a housing shape as a whole and is fixed to the injection frame 69.

The support member 81 houses, for example, an injection screw mechanism 39 and a pressure boosting screw mechanism 57. A cover 83 covering the injection screw shaft 49 projecting rearward from the support member 81 is fixed behind the support member 81. The entire support member 81 and cover 83 may be regarded as the support member.

The support member 81 supports the injection nut 47 and the pressure boosting nut 63 via an appropriate bearing. Further, for example, the main body portion (stator) of the injection motor 27 located outside the support member 81 is fixed to the support member 81. The piezoelectric motive 31 is fixed to, for example, the injection frame 69.

(shock absorber)
As shown in FIG. 2, the injection device 9 has a shock absorber 85 provided in the injection frame 69.

The shock absorber 85 is, for example, a cylinder type, and has a cylinder portion (reference numeral omitted), a piston (not shown) that slides in the cylinder portion, and a piston rod that extends from the piston to the outside of the cylinder portion (reference numeral omitted). And a spring (not shown) arranged in the cylinder portion. The spring urges the piston toward the piston rod with respect to the cylinder portion. Although not shown in particular, the cylinder portion has a cylinder body on which the piston slides and an outer shell portion that covers the outside thereof. Of the two cylinder chambers partitioned by the piston in the cylinder body, the cylinder chamber on the side opposite to the piston rod is, for example, via an orifice, between the cylinder chamber on the piston rod side and between the cylinder body and the outer shell. It leads to the gap of. These spaces are filled with a working fluid (eg, oil).

In the shock absorber 85, the cylinder portion of the shock absorber 85 is fixed to the injection frame 69 in a state where the piston rod is directed to the rear in the axial direction of the plunger 23. The shock absorber 85 may be provided on a member other than the injection frame 69 as long as it is provided so as not to be movable.

On the other hand, the coupling 51 is formed with a contact portion 51a that comes into contact with the shock absorber 85 (the piston rod thereof) when the plunger 23 advances to a predetermined position. The contact portion 51a may be provided on a member other than the coupling 51 as long as it is provided on a member that moves together with the plunger 23.

(Control device)
Although not particularly shown, the control device 13 includes, for example, a CPU, a ROM, a RAM, and an auxiliary storage device. Then, various functional units are constructed by the CPU executing the program stored in the ROM and / or the auxiliary storage device. Then, the control device 13 outputs various control commands based on signals from various devices in the die casting machine 1 (injection device 9).

The signals are input to the control device 13, for example, the input device 17, the rotation sensors 27s and 31s, the position sensor 87 for detecting the position of the plunger 23 (FIG. 2), and the force applied to the molten metal by the plunger 23. It is a force sensor 89 (FIG. 2) for detecting.

The control device 13 outputs a signal to, for example, a display device 15, a driver (not shown) that supplies electric power to the injection motor 27, a driver (not shown) that supplies electric power to the piezoelectric motive 31, and a release unit 73. It is a driver (not shown) to be supplied.

The position sensor 87 constitutes, for example, a linear encoder together with a scale portion (not shown). For example, the position sensor 87 is fixedly provided at a position facing the front end of the connecting shaft 41 located at the backward limit. On the other hand, the scale portion is provided on the connecting shaft 41 and extends in the axial direction thereof. Then, the position sensor 87 indirectly detects the position of the plunger 23 by detecting the position of the scale portion that moves with the movement of the connecting shaft 41. The position sensor 87 or the control device 13 can detect the speed by differentiating the detected position.

The force sensor 89 is configured to include, for example, a load cell located between the plunger 23 (strictly speaking, the spacer of the coupling 51) and the connecting shaft 41. The load cell is, for example, a strain gauge type. The control device 13 can identify the force applied to the plunger 23 and the pressure applied to the molten metal based on the detection signal from the force sensor 89.

(Operation of injection device)
FIG. 5 is a diagram for explaining the operation of the injection device 9.

The upper graph of FIG. 5 shows changes over time such as injection speed and injection pressure. In this graph, the horizontal axis shows the elapsed time, and the vertical axis shows the magnitude of velocity and pressure. The line with the sign of Vf indicates the speed of the connecting shaft 41, as in FIG. 4A. Since the connecting shaft 41 is connected to the plunger 23, from another point of view, the line with the Vf sign indicates the injection speed (the speed of the plunger 23). The lines labeled with Vs indicate the speed of the booster screw shaft 65, as in FIG. 4A. The line Lp indicates the injection pressure (the pressure applied to the molten metal by the plunger 23).

The timing chart at the bottom of FIG. 5 shows the presence / absence of driving of the injection motor 27 and the piezoelectric motive 31. “ON” in the figure is a state in which these electric motors generate a driving force. “OFF” in the figure is, for example, a state in which torque is free, a state in which position control to a fixed position is performed, or a state in which the brake is operating.

The injection device 9 performs low-speed injection (t0 to t1), high-speed injection (t1 to t3), pressure increase (t4 to t5), and pressure holding (t5) in this order. That is, in the initial stage of injection, the injection device 9 advances the plunger 23 at a relatively low speed in order to prevent air from being entrained in the molten metal, and then fills the molten metal without delaying the solidification of the molten metal. The plunger 23 is advanced at a relatively high speed from the viewpoint of. After that, in order to eliminate sink marks on the molded product, the injection device 9 increases the pressure of the molten metal in the cavity by the force in the forward direction of the plunger 23, and further maintains the increased pressure to wait for the molded product to solidify. .. Specifically, it is as follows.

(Just before injection start: just before t0)
Immediately before the start of injection, the injection device 9 is in the state shown in FIGS. 1 and 2. That is, the plunger 23 (linear motion member 53) and the pressure boosting screw shaft 65 are stopped at an initial position such as a retreat limit. From another point of view, the injection motor 27 and the piezoelectric motive 31 are stopped. The release unit 73 is not energized, for example.

(Low speed injection: t0 to t1)
When the mold clamping of the fixed mold 103 and the moving mold 105 is completed and a predetermined low-speed injection start condition such as the molten metal being supplied to the sleeve 21 is satisfied, the control device 13 rotates the injection motor 27 and causes the plunger. Move 23 forward. That is, low-speed injection is performed by the driving force of the injection motor 27.

The speed of the plunger 23 is controlled by adjusting the rotation speed of the injection motor 27. Specifically, the control device 13 feedback-controls the rotation speed of the injection motor 27 based on the detected value of the position sensor 87. The speed feedback control here may be based on the deviation of the speed itself of the plunger 23, or based on the deviation between the target position set with respect to the elapsed time in a predetermined time interval and the current position. It may be a thing (a thing that substantially realizes speed feedback by position feedback that is performed from moment to moment).

The speed of the plunger 23 (low speed injection speed _VL ) in low speed injection is, for example, less than 1 m / s. The specific value of the low-speed injection speed _VL may be appropriately set by the operator. The control device 13 receives the input of the value via the input device 17.

During the low speed injection, the piezoelectric motive 31 is stopped, for example. This stop is, for example, a state in which the position is controlled at a fixed position or a state in which the brake is used. As a result, even if the connecting shaft 41 slides on the booster screw shaft 65, the movement of the booster screw shaft 65 is surely suppressed. However, the stop may be in a torque-free state. Even in this case, the booster screw shaft 65 can be stopped by the resistance of the booster screw mechanism 57 itself.

(High-speed injection: t1 to t3)
The control device 13 determines whether or not the position of the plunger 23 has reached a predetermined high-speed switching position in the low-speed injection. The determination may be made as appropriate. For example, the control device 13 determines whether or not the detection position of the position sensor 87 has reached a predetermined high-speed switching position, or determines whether or not a predetermined time has elapsed from the start of injection.

Then, when the control device 13 determines that the high-speed switching position has been reached, the rotation speed of the injection motor 27 is increased so that the speed of the plunger 23 is higher than that at the time of low-speed injection. The continuation of the feedback control of the injection speed is the same as that of the low speed injection.

Further, the control device 13 controls the pressure-increasing motive 31 so as to advance the pressure-increasing screw shaft 65 at an appropriate time (t2) after the start of high-speed injection, for example. The speed Vs of the booster screw shaft 65 at this time is slower than the speed Vf (injection speed in high-speed injection) of the linear motion member 53.

Therefore, even if the inner rack 75 located behind the outer rack 77 at the start of injection reaches the outer rack 77, the relative advance of the inner rack 75 with respect to the outer rack 77 is allowed. That is, the plunger 23 is still advanced by the driving force of the injection motor 27, and the driving of the pressure boosting screw shaft 65 by the piezoelectric boosting motive 31 basically does not affect the speed of the plunger 23.

The speed-increasing motive 31 is, for example, speed-controlled during high-speed injection. The speed control may be open control or feedback control based on the detection value of the rotation sensor 31s. Like the injection motor 27, the feedback control may be based on the deviation of the speed itself, or may substantially provide speed feedback by controlling the position from moment to moment.

(Deceleration injection: t3 to t4)
When the molten metal is filled in the cavity Ca to some extent, the plunger 23 receives a reaction force from the filled molten metal and is decelerated, while the injection pressure rises sharply. The operation of each part is the same as that at the time of high-speed injection. However, deceleration control may be performed to control the rotation speed of the injection motor 27 to decrease.

(Pressure increase: t4 to t5)
As the injection speed decreases as described above, the speed Vf of the linear motion member 53 decreases to the speed Vs of the booster screw shaft 65 (t4). As a result, the outer rack 77 is engaged with the inner rack 75 from the rear, and the driving force of the piezoelectric motive 31 is transmitted to the plunger 23. That is, the pressure is increased by the driving force of the piezoelectric motive 31.

The above-mentioned drive start time t2 of the piezoelectric motive 31 is appropriately set as long as the speed Vs can reach a desired value before the speed Vf of the linear motion member 53 drops to the speed Vs of the pressure boosting screw shaft 65. May be set.

The injection motor 27 may be in a torque-free state at an appropriate time, for example, after the plunger 23 is decelerated (after t3) or after the speed Vf drops to the speed Vs (after t4). Alternatively, the injection motor 27 may be continuously driven even after the speed Vf drops to the speed Vs, and may contribute to pressure increase or the like. Alternatively, the injection motor 27 may be driven to such an extent that the injection screw mechanism 39 or the like does not become a load for increasing the pressure (to the extent that it does not contribute to the increasing pressure).

In the pressure increase, the torque increase motive 31 is, for example, torque controlled. Specifically, for example, the control device 13 performs feedback control of the torque of the booster motive 31 so as to obtain a desired step-up curve based on the detected value of the force sensor 89. The timing of switching from the speed control before the start of the pressure increase to the torque control after the start of the pressure increase may be appropriately set near the time point t4. For example, the control device 13 determines whether or not the speed Vf has decreased to the speed Vs based on the detection values of the rotation sensor 27s (or the position sensor 87) and the rotation sensor 31s, and switches when it is determined that the speed Vf has decreased. Do.

When the driving force of the piezoelectric motive 31 is transmitted to the plunger 23, the injection pressure rises and the injection pressure reaches the final pressure P (t5). On the other hand, the injection speed becomes 0 when the cavity Ca is completely filled with the molten metal.

(Attachment of shock absorber: t3 to t5)
The coupling 51 comes into contact with the shock absorber 85 after the injection speed starts to decrease and before the injection pressure reaches the final pressure. As a result, for example, the generation of so-called surge pressure is suppressed.

(Holding pressure: t5-)
The control device 13 maintains a state in which the injection pressure is the final pressure P. Specifically, the control device 13 continues the torque control of the piezoelectric boosting motor 31 (and the injection motor 27) following the pressure boosting. The retreat of the plunger 23 may be restricted by using the brake of the piezoelectric booster 31 and / or the injection motor 27, or by using other brakes (not shown), and the pressure may be held.

(Extrusion follow-up and plunger retreat)
After that, although not particularly shown, when the molten metal solidifies, the control device 13 ends the holding pressure, causes the mold clamping device 7 to open the mold, and pushes out the molded product from the fixed mold 103 by the extrusion device 11. At this time, the control device 13 may control the driving force for pushing out the biscuit by the plunger 23 so that the injection motor 27 and / or the piezoelectric motive 31 is generated. That is, extrusion tracking may be performed.

After the holding pressure is completed, or when extrusion tracking is completed, the control device 13 retracts the plunger 23 to the initial position. Specifically, for example, the control device 13 energizes the release unit 73 to deactivate the clutch 71. Then, the control device 13 rotates the injection motor 27 in the direction of retracting the injection screw shaft 49, and rotates the piezoelectric booster 31 in the direction of retracting the booster screw shaft 65.

As described above, in the present embodiment, the injection device 9 for advancing the plunger 23 and pushing the molding material into the mold 101 includes an injection motor 27, an injection transmission unit 29, and a rotary pressure-increasing piezoelectric motive 31. It has a pressure transmission unit 33 and a connection unit 35. The injection transmission unit 29 includes a linear motion member 53 coaxially connected to the rear end of the plunger 23, and the linear motion member 53 is driven in the axial direction of the plunger 23 by the driving force of the injection motor 27. The pressure boosting transmission unit 33 includes a pressure boosting screw shaft 65 through which the linear motion member 53 is inserted, and converts the rotation of the pressure boosting motor 31 into a linear motion of the pressure boosting screw shaft 65 in the axial direction of the plunger 23. The connecting portion 35 can allow and prohibit the transmission of the driving force from the booster screw shaft 65 to the linear motion member 53.

Therefore, for example, the plunger 23 can be reciprocally driven by the injection motor 27, and the plunger 23 can be driven by the piezoelectric booster 31 as needed. Further, for example, since a transmission path (pressure boosting transmission unit 33) from the piezoelectric motive 31 to the linear motion member 53 is provided separately from the transmission path from the injection motor 27 to the linear motion member 53, the injection motor The speed transmission ratios leading up to the plunger 23 can be made different from each other between the 27 and the increased piezoelectric motive 31. Further, for example, in the path from the piezoelectric motive 31 to the plunger 23, the connecting portion 35 cuts off the transmission of force immediately before the plunger 23, so that a clutch is engaged between the piezoelectric motive 31 and the pressure boosting transmission 33. The moment of inertia for the injection motor 27 can be reduced as compared with the case where it is provided. Further, since the linear motion member 53 fixed to the plunger 23 is inserted into the pressure boosting screw shaft 65, for example, the engagement between the pressure boosting screw shaft 65 and the linear motion member 53 is axially 2 It is possible to reduce the possibility that an unnecessary moment is generated between the pressure boosting screw shaft 65 and the linear motion member 53 in a plan view or a side view.

In the present embodiment, the pressure boosting transmission unit 33 has a pressure boosting nut 63 to which the rotation of the pressure boosting motive 31 is transmitted, and a pressure boosting screw shaft 65 screwed into the pressure boosting nut 63.

Therefore, for example, the linear motion member 53 is inserted through the booster screw shaft 65 that receives an axial force from the outer peripheral surface. As a result, for example, the distance between the axial force applied to the booster screw shaft 65 and the linear motion member 53 is short, and it becomes easy to reduce an unnecessary moment in a side view or a plan view generated between the two. Further, for example, it is not necessary to provide two pressure boosting screw shafts 65 with the linear motion member 53 sandwiched between them to balance them. Further, for example, as compared with the case where the pressure boosting screw shaft 65 and the linear motion member 53 are provided in series, it is possible to avoid applying a force to one end of the pressure boosting screw shaft 65 and / or increase. Since the diameter of the pressure screw shaft 65 is secured, the possibility that the pressure screw shaft 65 buckles is reduced.

In the present embodiment, the injection motor 27 is a rotary type, and the injection transmission unit 29 has an injection screw mechanism 39 that converts the rotation of the injection motor 27 into a linear motion of the linear motion member 53 in the axial direction of the plunger 23. There is. The linear motion member 53 includes an injection screw shaft 49 of the injection screw mechanism 39, which is coaxially arranged with the plunger 23.

Therefore, for example, the linear motion member 53 immediately after the rotation of the injection motor 27 is converted into a linear motion is directly connected to the plunger 23. As a result, for example, as compared with the embodiment in which the injection screw shaft 49 is arranged in parallel with the connecting shaft 41 and the two are connected (see FIG. 6D described later), only the mass of the member required for the connection is obtained. , The moment of inertia for the injection motor 27 can be reduced. From another point of view, it is not necessary to provide and balance the two injection screw shafts 49 with the connecting shaft 41 interposed therebetween, as in the case of the booster screw shaft 65 described above (see FIG. 6D).

In the present embodiment, the injection device 9 engages with the linear motion member 53 in the axial direction thereof, prohibits the linear motion member 53 from rotating around the axis, and moves the linear motion member 53 in the axial direction. It has a detent member 67 that allows the above. The pressure-increasing screw shaft 65 engages with the linear motion member 53 in the axial direction, so that the axial rotation is prohibited and the axial movement is allowed.

Therefore, the linear motion member 53 that transmits the driving force of the injection motor 27 to the plunger 23 contributes to the detent of the booster screw shaft 65. From another viewpoint, the detent member 67 is also used as both a detent for the linear motion member 53 and a detent for the booster screw shaft 65. Thereby, for example, the structure can be simplified. Such a detent structure is possible because the linear motion member 53 is inserted into the pressure boosting screw shaft 65 (concentric structure).

In the present embodiment, the injection motor 27 is a rotary type, and the injection transmission unit 29 converts the rotation of the injection motor into a linear motion of the linear motion member 53 in the axial direction of the plunger 23. The amount of movement of the pressure boosting screw shaft 65 by one rotation of the piezoelectric booster 31 is smaller than the amount of movement of the linear motion member 53 by one rotation of the injection motor 27.

Therefore, for example, the drive system including the linear motion member 53 tends to move the plunger 23 at a relatively high speed, and the drive system including the pressure boosting screw shaft 65 through which the linear motion member 53 is inserted has a relatively large force. Is easy to give to the plunger 23. On the other hand, since the linear motion member 53 is inserted through the pressure boosting screw shaft 65 and connected to the plunger 23, the linear motion member 53 is relatively long and the pressure boosting screw shaft 65 has a relatively large diameter. growing. Further, in low-speed injection and high-speed injection (injection in a narrow sense), the moving distance of the plunger 23 is relatively long, and the pressure boosting exerts a relatively large force on the plunger 23. From the above, for example, the drive unit 25 suitable for injection (narrow sense) and pressure boosting is realized as a whole.

In the present embodiment, the connecting portion 35 is interposed between the outer peripheral surface of the linear motion member 53 and the inner peripheral surface of the pressure boosting screw shaft 65, and the linear motion member 53 advances relative to the pressure boosting screw shaft 65. Includes a one-way clutch 71 that allows relative retreat while allowing for.

Therefore, for example, as described with reference to FIG. 5, when the speed Vf of the linear motion member 53 drops to the speed Vs of the booster screw shaft 65, the booster screw shaft 65 automatically and smoothly moves linearly. Engage with member 53. In other words, for example, it is not necessary to accurately control the relative speed between the linear motion member 53 and the booster screw shaft 65, and it is not necessary to control the timing at which the two are coupled. Further, since the clutch 71 is interposed between the outer peripheral surface of the linear motion member 53 and the inner peripheral surface of the booster screw shaft 65, it is unnecessary for the transmission of force between the two as described above. It is possible to reduce the risk of generating a large moment and the risk of buckling.

In the present embodiment, the one-way clutch 71 has an inner rack 75 held by the linear motion member 53, an outer rack 77 held by the pressure boosting screw shaft 65, and one of the inner rack 75 and the outer rack 77 as the other. It has an elastic member 79 that urges the clutch. The inner rack 75 is arranged in the axial direction of the plunger 23 and has a plurality of teeth 75a inclined rearward. The outer rack 77 is arranged in the axial direction of the plunger 23 and has a plurality of teeth 77a that are inclined forward and can mesh with the plurality of teeth 75a.

Therefore, for example, instead of engaging one claw with a plurality of teeth as in a general ratchet mechanism (this embodiment is also included in the technique according to the present disclosure), a plurality of teeth 75a and a plurality of teeth 77a Engage with. As a result, for example, the load applied to one tooth 75a and one tooth 77a is reduced, and a relatively large force can be transmitted from the booster screw shaft 65 to the linear motion member 53. As a result, it becomes easy to apply the technique of the present disclosure to a large die casting machine.

In the present embodiment, the linear motion member 53 is hollow.

Therefore, for example, the moment of inertia for the injection motor 27 or the piezoelectric motive 31 can be reduced. As a result, for example, the rise in speed at the time of switching from low-speed injection to high-speed injection can be made steep. As a result, the quality of the molded product can be improved.

In the present embodiment, the injection device 9 further includes a cylinder type shock absorber 85 that comes into contact with the coupling 51 fixed to the linear motion member 53 when the linear motion member 53 advances to a predetermined position.

Therefore, for example, it is possible to alleviate the impact generated between the start of deceleration of injection and the completion of pressure increase. That is, the generation of so-called surge pressure can be suppressed. As a result, for example, the possibility that the impact is transmitted to the electric drive system is reduced. Unlike the hydraulic drive system, the electric drive system does not have the effect of shock mitigation by compressing the hydraulic oil, so that the protection effect of the shock absorber 85 is effective.

In the above embodiment, the injection electric motor 27 is an example of the first electric motor. The injection transmission unit 29 is an example of the first transmission unit. The linear motion member 53 is an example of the first linear motion member. The piezoelectric motive 31 is an example of a second electric motor. The pressure boosting transmission unit 33 is an example of the second transmission unit. The booster screw shaft 65 is an example of the second linear motion member. The coupling 51 is an example of a member fixed to the first linear motion member that comes into contact with the shock absorber.

(Modification example)
The injection apparatus according to various modifications will be described with reference to FIGS. 6 (a) to 6 (d). 6 (a) to 6 (d) are views schematically showing a driving unit of the injection device. In the following, the differences from the embodiments will be mainly described. Unless otherwise specified, the same as in the embodiment may be used. Further, in the following, the same or similar configurations as those in the embodiment may be designated by the reference numerals of the embodiments.

The injection device 201 of FIG. 6A has a rack and pinion mechanism 203 instead of the injection screw mechanism 39. The rack and pinion mechanism 203 has, for example, a rack 205 coaxially fixed to the rear end of the connecting shaft 41 and a pinion 207 that meshes with the rack 205. The rotation of the injection motor 27 is transmitted to the pinion 207. The connecting shaft 41 and the rack 205 form a linear motion member 209.

As described above, when the electric motor (injection electric motor 27 or the piezoelectric motive 31) is a rotary type, the mechanism for converting the rotation into a linear motion is not limited to the screw mechanism. Although not particularly shown, a link mechanism may be used in addition to the rack and pinion mechanism.

In the injection device 221 of FIG. 6B, the positional relationship between the injection screw mechanism 39 and the pressure boosting screw mechanism 57 in the front-rear direction is opposite to that of the embodiment. Specifically, the injection screw shaft 49 is connected to the rear end of the plunger 23, and the connection shaft 41 is connected to the rear end of the injection screw shaft 49 to form the linear motion member 223. The pressure boosting screw mechanism 57 is located behind the injection nut 47, and the linear motion member 223 is inserted therethrough. The inner portion 35a of the connecting portion 35 is located at the rear end of the connecting shaft 41.

Note that FIG. 6B illustrates an embodiment in which the injection screw shaft 49 is located in the booster screw shaft 65 at the initial position, and the booster screw shaft 65 is not detented depending on the connection shaft 41. ing. The detent of the booster screw shaft 65 may be made by, for example, a spline groove. However, as in the embodiment, the connecting shaft 41 may be located in the booster screw shaft 65 at the initial position and may be prevented from rotating by the connecting shaft 41.

In the injection device 231 of FIG. 6C, the members connected to the plunger 23 in the injection nut 47 and the injection screw shaft 49 are opposite to those of the embodiment. That is, the injection nut 47 constitutes a linear motion member 235 that is fixed to the connecting shaft 233 connected to the plunger 23 and inserted through the booster screw shaft 65. The injection screw shaft 49 is inserted through a hollow connecting shaft 233.

Since the injection nut 47 is fixed to the connection shaft 233 which is detented as in the embodiment, the rotation around the shaft is restricted and the movement in the axial direction is permitted. The injection screw shaft 49 is allowed to rotate around the shaft by a bearing (not shown) and its movement in the axial direction is restricted. The rotation of the injection motor 27 is transmitted to the injection screw shaft 49. The inner portion 35a of the connecting portion 35 is provided at an intermediate position in the axial direction on the connecting shaft 233.

In the injection device 241 of FIG. 6D, the injection screw mechanism 39 is not provided coaxially with the plunger 23, but is provided in parallel with the plunger 23. Specifically, for example, in a plan view, two injection screw mechanisms 39 are provided with the connecting shaft 41 interposed therebetween. In this modification, the injection nut 47 is fixed to the connecting shaft 41 as in the modification of FIG. 6C, and the injection nut 47 is fixed to the connecting shaft 41 via the connecting member 243. There is. The connecting shaft 41, the connecting member 243, and the injection nut 47 constitute a linear motion member 245 that is (partially) inserted into the booster screw shaft 65. The inner portion 35a of the connecting portion 35 is provided at an intermediate position in the axial direction on the connecting shaft 41.

The configurations of the embodiment and the modified example may be combined as appropriate. For example, in a configuration in which the booster screw mechanism 57 is located rearward as shown in FIG. 6B, a rack and pinion mechanism 203 may be provided instead of the injection screw mechanism 39 as shown in FIG. 6A. Further, for example, in a configuration in which the plunger 23 and the transmission mechanism (injection screw mechanism 39) are not coaxial as shown in FIG. 6D, a transmission mechanism other than the screw mechanism may be provided as shown in FIG. 6A. Alternatively, the injection screw shaft 49 may be fixed to the connecting member 243, and the injection screw shaft 49 may form a linear motion member as in the embodiment.

The present invention is not limited to the above embodiments and modifications, and may be implemented in various embodiments.

The molding machine (molding machine) is not limited to the die casting machine. For example, the molding machine may be another metal molding machine, an injection molding machine for molding a resin, or a molding machine for molding a material obtained by mixing wood powder with a thermoplastic resin or the like. There may be. Further, the molding machine is not limited to horizontal clamping horizontal injection, and may be, for example, vertical clamping vertical injection, horizontal clamping vertical injection, or vertical clamping horizontal injection. The molding material is not limited to a liquid material, and may be a solid-liquid coexisting material such as a semi-solidified metal or a semi-molten metal.

The injection is not limited to those having low-speed injection and high-speed injection, and may be, for example, one in which the injection speed is constant or continuously increases from the start of injection to the start of pressure increase.

The first electric motor is not limited to the rotary type motor, and may be a linear motor. In this case, the first transmission unit may be configured to include only the mover of the linear motor and the fixed first linear motion member. Further, the winding transmission mechanism for transmitting the rotation of the rotary first electric motor or the second electric motor may not be provided, and in addition to or in place of the winding transmission mechanism, another transmission mechanism such as a gear mechanism may be provided. It may be provided.

The division of roles between the first electric motor and the second electric motor may be appropriately set, and is not limited to the division of roles in which the first electric motor is used for injection (in a narrow sense) and the second electric motor is used for boosting pressure. For example, the first motor may be used for high speed injection and the second motor may be used for low speed injection and pressure boosting. Further, for example, contrary to the embodiment, the first electric motor may be used for boosting pressure and the second electric motor may be used for injection.

In the embodiment, the connecting shaft 41 and the injection screw shaft 49 are fixed to form a linear motion member 53 as the first linear motion member. However, the first transmission unit (injection transmission unit 29) includes, for example, a connection unit (separate from the connection unit 35) that connects and blocks the transmission of the driving force from the injection screw shaft 49 to the connection shaft 41. May be good. In other words, for example, the first linear motion member may be configured only by the connecting shaft 41.

The connection portion is not limited to the one including the one-way clutch. For example, in the embodiment, the teeth of the inner rack and the outer rack are not inclined forward or backward (a shape that does not allow the inner rack 75 to advance relative to the outer rack 77), and the booster screw shaft 65 is connected. The energization of the release portion 73 may be stopped at the timing when it should be connected to the shaft 41. Further, for example, the connecting portion may have a half nut that engages with the thread groove of the injection screw shaft 49.

Further, in the embodiment, the inner rack and the outer rack face each other when the linear motion member 53 advances to a predetermined position, but the inner rack directly faces each other regardless of the position of the linear motion member 53. It may be configured over a relatively long range of the moving member 53.

1 ... Die casting machine (molding machine), 9 ... Injection device, 23 ... Plunger, 27 ... Injection motor (1st electric motor), 29 ... Injection transmission unit (1st transmission unit), 31 ... Increased piezoelectric motive (2nd electric motor) , 33 ... Pressure boosting transmission unit (second transmission unit), 35 ... Connection unit, 53 ... Linear motion member (first linear motion member), 65 ... Pressure booster screw shaft (second linear motion member), 101 ... Mold ..

Claims (11)

An injection device that advances the plunger and pushes the molding material into the mold.
With the first electric motor
A first transmission unit including a first linear motion member coaxially connected to the rear end of the plunger, and the first linear motion member is driven in the axial direction of the plunger by a driving force of the first electric motor.
The second rotary motor and
A second transmission unit that includes a second linear motion member through which the first linear motion member is inserted and converts the rotation of the second electric motor into a linear motion of the second linear motion member in the axial direction of the plunger.
A connection portion capable of allowing and prohibiting transmission of a driving force from the second linear motion member to the first linear motion member,
The injection device that has. The second transmission unit
The nut to which the rotation of the second motor is transmitted and
The injection device according to claim 1, further comprising a screw shaft as the second linear motion member that is screwed into the nut. The first electric motor is a rotary type and
The first transmission unit has a screw mechanism coaxially arranged with the plunger, which converts the rotation of the first electric motor into a linear motion of the first linear motion member in the axial direction of the plunger.
The injection device according to claim 1 or 2, wherein the first linear motion member includes a screw shaft or a nut of the screw mechanism. Engagement with the first linear motion member in the axial direction, prohibiting the axial rotation of the first linear motion member, and allowing the first linear motion member to move in the axial direction. It also has a stop,
The screw shaft as the second linear motion member engages with the first linear motion member in the axial direction, rotation around the axis is prohibited, and movement in the axial direction is permitted. The injection device according to claim 3, wherein claim 2 is cited. The first electric motor is a rotary type and
The first transmission unit converts the rotation of the first electric motor into a linear motion of the first linear motion member in the axial direction of the plunger.
The amount of movement of the second linear motion member by one rotation of the second electric motor is smaller than the amount of movement of the first linear motion member by one rotation of the first electric motor according to any one of claims 1 to 4. The injection device described. Claims 1 to further include a control device that controls the first electric motor and the second electric motor so as to perform injection by the driving force of the first electric motor and increase the pressure by the driving force of the second electric motor. 5. The injection device according to any one of 5. The connecting portion is interposed between the outer peripheral surface of the first linear motion member and the inner peripheral surface of the second linear motion member, and is relative to the second linear motion member of the first linear motion member. The injection device according to any one of claims 1 to 6, which includes a one-way clutch capable of allowing forward movement and prohibiting relative backward movement. The one-way clutch
The inner rack held by the first linear motion member and
The outer rack held by the second linear motion member and
It has an elastic member that urges one of the inner rack and the outer rack to the other.
The inner rack is arranged in the axial direction of the plunger and has a plurality of first teeth that are inclined rearward.
The injection according to claim 7, wherein the outer rack is arranged in the axial direction of the plunger and has a plurality of second teeth that are inclined forward and can mesh with the plurality of first teeth. apparatus. The injection device according to any one of claims 1 to 8, wherein the first linear motion member is hollow. Any one of claims 1 to 9, further comprising a cylinder-type shock absorber that comes into contact with a member fixed to the first linear motion member when the first linear motion member advances to a predetermined position. The injection device described in. The injection device according to any one of claims 1 to 10.
A mold clamping device that clamps the mold and
An extruder that extrudes a molded product from the mold,
Molding machine that has.

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