CN116490302A - Injection device - Google Patents

Abstract

The present invention relates to an injection device (1) for injecting a molding material, comprising: a screw (13) which is driven to rotate around a rotation shaft (12) and is driven to advance and retreat in the axial direction; an injection motor (21) which is a driving source for advancing and retreating the screw (13); a motion conversion mechanism (41) which includes a screw shaft (42) that rotates together with the rotational motion of the injection motor (21) and a nut (43) that is provided with the screw shaft (42) on the inside, and converts the rotational motion of the injection motor (21) into linear motion in the axial direction; a metering motor (31) which is a rotation driving source of the screw (13); a driving force transmission member (51) connected to the screw (13) and transmitting a rotational driving force based on the rotational movement of the metering motor (31) and an advancing and retreating driving force based on the linear movement of the screw shaft (42) of the movement conversion mechanism (41) to the screw (13), respectively; and an axial force detection unit (61) for detecting an axial force acting on the screw (13) in the axial direction, wherein the axial force detection unit (61) comprises: an annular shaft force sensor (62) disposed so as to be rotatable relative to each other between the screw (13) and the driving force transmission member (51) around the rotation shaft (12) of the screw (13); and a rotation limiting member (63) that limits rotation of the shaft force sensor (62) with respect to rotation of the screw (13) and the driving force transmission member (51).

Description

Injection device

Technical Field

The present invention relates to an injection device for injecting a molding material using a screw, and more particularly, to a technique for improving the accuracy of detection of an axial force acting on the screw.

Background

An injection device for an injection molding machine mainly measures and injects molding materials such as resin materials using a screw that is rotationally driven by a measuring motor and is driven back and forth by an injection motor.

In general, at the time of metering, a predetermined amount of molding material is melted and sent to the front end side of the cylinder by rotation of a screw by a metering motor. Further, at the time of injection, a predetermined amount of molding material fed to the front end side of the cylinder at the time of metering is injected into the mold device by advancing a screw by an injection motor. Then, as the holding pressure, the screw may be further advanced by an injection motor so that a desired pressure acts on the molding material in the mold device.

When the injection motor of the injection device outputs a rotational motion as a rotational motor, a motion conversion mechanism is used to convert the rotational motion into a linear motion in the axial direction of the screw. For example, patent document 1 discloses an injection device including, as such a motion conversion mechanism, a screw shaft rotated by a rotational motion of an injection motor and a nut on which the screw shaft is disposed inside. A driving force transmission member for transmitting the rotational driving force from the metering motor and the advancing and retreating driving force in the axial direction transmitted from the injection motor via the motion conversion mechanism to the screw is disposed between the metering motor and the injection motor and the screw.

However, the injection device is provided with an axial force sensor that detects an axial force acting on the screw in the axial direction, for example, at the time of the pressure maintaining as a reaction force received by the screw from the molding material, and the like.

The axial force sensor does not rotate together with the screw, and the closer the mounting position is to the screw, the higher the accuracy of detecting the axial force is, which is preferable. However, in such an injection device in which the transmission path of the driving force from the injection motor and the metering motor to the screw is complicated as described above, it is not easy to mount the axial force sensor in the vicinity of the screw so as not to rotate.

In this regard, patent document 1 proposes an injection device having a "pressure detector disposed between the rotational movement shaft and the drive shaft", which has a "rotation restriction mechanism that restricts rotation of the pressure detector".

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open publication No. 2017-47576

Disclosure of Invention

Technical problem to be solved by the invention

In patent document 1, "pressure detector" is disposed between the rotational movement shaft and the drive shaft. From the viewpoint of further improving the detection accuracy of the axial force, there is room for improvement in the "pressure detector".

The present invention addresses such problems, and an object thereof is to provide an injection device capable of detecting an axial force acting on a screw with relatively high accuracy.

Means for solving the technical problems

An injection device capable of solving the above problems is an injection molding material, comprising: a screw driven to rotate about a rotation axis and driven to advance and retreat in an axial direction; an injection motor which is a driving source for advancing and retreating the screw; a motion conversion mechanism that includes a screw shaft that rotates together with a rotational motion of the injection motor and a nut that is provided with the screw shaft inside, and converts the rotational motion of the injection motor into a linear motion in the axial direction; the metering motor is a rotary driving source of the screw; a driving force transmission member connected to the screw, and configured to transmit a rotational driving force based on a rotational movement of the metering motor and an advancing and retreating driving force based on a linear movement of the screw shaft of the movement conversion mechanism to the screw, respectively; and an axial force detection unit that detects an axial force acting on the screw in the axial direction, the axial force detection unit including: an annular shaft force sensor disposed so as to be rotatable relative to each other between the screw and the driving force transmission member around the rotation shaft of the screw; and a rotation restriction member that restricts rotation of the shaft force sensor with respect to rotation of the screw and the driving force transmission member.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the injection device described above, the axial force acting on the screw can be detected with relatively high accuracy.

Drawings

Fig. 1 is a cross-sectional view along the axial direction of an injection device according to an embodiment of the present invention.

Fig. 2 is a sectional view showing an enlarged main portion of the injection device of fig. 1.

Fig. 3 is a sectional view showing a state in which the screw is advanced in the injection device of fig. 2.

Fig. 4 is a cross-sectional view showing an injection device according to another embodiment.

Fig. 5 is an enlarged sectional view showing a connection portion of a screw and a driving force transmission member of the injection device of fig. 1.

Fig. 6 is a sectional view showing a connection portion between a screw and a driving force transmission member of an injection device according to still another embodiment.

Fig. 7 is a sectional view showing a step of removing the axial force detecting portion in the injection device of fig. 1.

Fig. 8 is a sectional view showing a step subsequent to that of fig. 7.

Fig. 9 is a sectional view showing a step subsequent to that of fig. 8.

Fig. 10 is a sectional view showing a step subsequent to that of fig. 9.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The injection device 1 illustrated in fig. 1 is configured to inject a molding material into a mold device in an injection molding machine, for example, on a slide base 101 of a moving device that moves the injection device 1 forward and backward. In the present embodiment, the injection device 1 includes: a screw 13 that is driven to rotate around a rotation shaft 12 inside the cylinder 11 and is driven to advance and retreat in the axial direction (left-right direction in fig. 1); an injection motor 21 as a driving source for advancing and retreating the screw 13; and a metering motor 31 as a rotation driving source of the screw 13. The rotational driving force from the metering motor 31 and the forward and reverse driving forces from the injection motor 21 are transmitted to the screw 13 via the driving force transmission paths, respectively.

(screw)

The screw 13 has a rotary shaft 12 extending from the inside of the metering motor 31 into the cylinder 11, and a helical flight is provided around a screw main body 13a thereof, and the screw main body 13a is mainly located in the cylinder 11. The screw distal end portion 13b in the cylinder 11 is tapered toward the front side in the axial direction, and the screw proximal end portion 13c is located inside the metering motor 31 and connected to the driving force transmission path.

Here, the direction along the rotation axis 12 of the screw 13 is referred to as an axial direction, and the axial direction corresponds to the left-right direction in fig. 1. In the axial direction of the screw 13, the screw tip portion 13b side (left side in fig. 1) is regarded as the front side, and the screw base portion 13c side (right side in fig. 1) is regarded as the rear side.

(injection motor and metering motor)

The injection motor 21 and the metering motor 31 are disposed, for example, on the rear side in the axial direction of the screw 13, and supported by an injection motor support member 22 and a metering motor support member 32 standing on the slide base 101. The injection motor support member 22 and the metering motor support member 32 are coupled to each other by rods 24, 25, etc. at a plurality of locations around the metering motor 31, for example.

The injection motor 21 and the metering motor 31 each output rotational motion as a rotary motor, and each can include: rotors 21a, 31a as rotors; the stators 21b and 31b as stators include coils arranged on the outer peripheral sides of the rotors 21a and 31a; and stator frames 21c, 31c having stators 21b, 31b mounted on inner surfaces thereof. Further, bearing portions 21d and 31d may be provided between the rotors 21a and 31a and the stator frames 21c and 31 c. An encoder 25b is provided on a rear end surface of the stator frame 21c of the injection motor 21, and the encoder 25b is coupled to the rotor 21a via a shaft 25a to detect rotation of the rotor 21 a.

The metering motor 31 is located on the front side than the injection motor 21 in the axial direction of the screw 13, and is provided so that the driving force transmission path passes through the inside thereof.

(drive force transmitting path)

In the injection device 1 of this embodiment, the driving force transmission path is mainly configured to include: a motion conversion mechanism 41 that converts the rotational motion of the injection motor 21 into linear motion in the axial direction of the screw 13; and a driving force transmission member 51 connected to the screw base end portion 13c of the screw 13, and transmitting to the screw 13a rotational driving force based on the rotational movement of the metering motor 31 and a forward and backward driving force based on the linear movement converted by the movement conversion mechanism 41, respectively.

Wherein the motion converting mechanism 41 includes: the screw shaft 42 rotates together with the rotational movement of the injection motor 21; and a nut 43, on the inner side of which a screw shaft 42 is disposed. In this example, the nut 43 is fixedly attached to the cylinder 22a, and the cylinder 22a connects the stator frame 21c of the injection motor 21 and the injection motor support member 22.

The screw shaft 42 is spline-coupled to an inner peripheral surface of the cylindrical rotary member 23 provided on an inner peripheral side of the rotor 21a of the injection motor 21, for example, by a screw shaft base end portion 42a, and is rotatable in the nut 43 by a rotational motion generated by the injection motor 21, and can advance forward or retract backward in the axial direction. A key 42b is provided on the outer peripheral surface of the screw shaft base end portion 42a, and a key groove corresponding thereto is provided on the inner peripheral surface of the cylindrical rotating member 23. Thereby, the rotational movement of the injection motor 21 is converted into a linear movement in the axial direction.

However, the motion conversion mechanism is not limited to the illustrated motion conversion mechanism in which the screw shaft 42 is spline-coupled to the tubular rotary member 23 on the injection motor 21 side, as long as the motion conversion mechanism includes the screw shaft and the nut and can convert the rotational motion of the injection motor 21 into the linear motion.

The driving force transmission member 51 is configured as follows, for example. In the present embodiment, as shown in fig. 2, the driving force transmission member 51 disposed inside the metering motor 31 includes: a tubular body 52 surrounding a periphery of a screw shaft tip 42c of the screw shaft 42 protruding axially forward from the nut 43; and a front end wall portion 53 provided to cover an opening portion on the axially front side of the tubular body portion 52.

The screw shaft distal end portion 42c can be coupled to the rear side in the axial direction of the distal end wall portion 53 of the driving force transmission member 51 via a bearing 54 such as a self-aligning thrust roller bearing or another thrust bearing. Thereby, the screw shaft tip portion 42c can relatively rotate with respect to the driving force transmission member 51. Here, the inner ring of the bearing 54 is attached to the screw shaft front end portion 42c, and the outer ring of the bearing 54 is attached to the front end wall portion 53. Further, a key 52a is provided on the outer peripheral surface of the cylindrical body 52 of the driving force transmission member 51, and is fitted into a key groove on the inner peripheral surface of the rotor 31a of the metering motor 31, whereby the cylindrical body 52 is spline-coupled with the rotor 31 a.

On the other hand, the screw 13 is connected to the front side in the axial direction of the front end wall portion 53 of the driving force transmission member 51 via the screw base end portion 13 c.

When the driving force transmission member 51 is configured as described above, the driving force transmission member 51 can be rotated together with the rotational movement of the metering motor 31, and the driving force transmission member 51 can be linearly moved in accordance with the linear movement of the screw shaft 42 of the movement conversion mechanism 41 independently of the rotation. Thereby, the rotational driving force based on the rotational movement of the metering motor 31 and the advancing and retreating driving force based on the linear movement of the screw shaft 42 of the movement conversion mechanism 41 are effectively transmitted to the screw 13 connected to the driving force transmission member 51, respectively.

(axial force detection section)

However, when injection molding is performed by the injection molding machine, in the injection device 1, the screw 13 is rotated by the metering motor 31, and the molding material is melted and simultaneously fed to the front end side of the cylinder 11 to be metered, and then the screw 13 is advanced by the injection motor 21, so that the molding material on the front end side of the cylinder 11 is injected into the mold device. Then, the screw 13 is further advanced by the injection motor 21, and the pressure is maintained so that a predetermined pressure acts on the molding material in the mold device.

In such pressure maintaining and the like, it is necessary to detect an axial force acting on the screw 13 in the axial direction. In order to detect the axial force acting on the screw 13, the injection device 1 is provided with an axial force sensor.

The axial force sensor may be provided at a position on the rear side in the axial direction of the driving force transmission path, for example, at a position of the cylinder 22a or the like between the injection motor 21 and the injection motor support member 22. However, at this time, the axial force is transmitted from the screw 13 to the axial force sensor via the driving force transmission member 51 of the driving force transmission path, which is particularly capable of spline-coupling with the metering motor 31 side, and the accuracy of detecting the axial force is lowered by the influence of the sliding resistance between the metering motor 31 side and the driving force transmission member 51 or the like. Alternatively, if the axial force sensor is provided between the drive force transmission member 51 and the screw shaft distal end portion 42c, the axial force detected by the axial force sensor may include the same sliding resistance or the like of the drive force transmission member 51, and thus, a highly accurate detection result may not be obtained to a desired extent. Therefore, the axis force sensor is preferably disposed at a position closer to the screw 13.

On the other hand, in the vicinity of the screw 13, when the screw 13 and the driving force transmission member 51 that transmits the rotational driving force by the metering motor 31 rotate, the accuracy of detecting the axial force by the axial force sensor decreases when the axial force sensor rotates together with the rotation.

In this case, in the illustrated embodiment, the axial force detection unit 61 that detects the axial force acting on the screw 13 in the axial direction includes: a washer-type or other annular shaft force sensor 62 disposed so as to be rotatable relative to each other between the screw 13 and the driving force transmission member 51 around the rotation shaft 12 of the screw 13; and a rotation restriction member 63 that restricts rotation of the shaft sensor 62 with respect to rotation of the screw 13 and the driving force transmission member 51.

Thus, the shaft force sensor 62 is located between the screw 13 and the driving force transmission member 51 on the axially forward side thereof and in the vicinity of the screw 13, and is therefore hardly affected by the sliding resistance of the driving force transmission member 51 in the driving force transmission path or the like when detecting the axial force from the screw 13. The rotation of the shaft sensor 62 with respect to the rotation of the screw 13 and the driving force transmission member 51 is regulated by the rotation regulating member 63. As a result, the axial force can be detected with high accuracy by the axial force sensor 62.

Here, the rotation restriction member 63 may restrict the rotation of the shaft force sensor 62 by, for example, connecting the shaft force sensor 62 to a member that does not rotate together with the screw 13 and the driving force transmission member 51. The rotation restricting member 63 illustrated in fig. 2 and 3 restricts rotation of the shaft force sensor 62, which may be caused by rotation of the screw 13 and the driving force transmission member 51, by connecting the shaft force sensor 62 to the metering motor supporting member 32.

More specifically, the metering motor support member 32 is provided with a slide hole 33, and the rotation restricting member 63 is inserted into and disposed in the slide hole 33. The shape of the slide hole 33 for the rotation restricting member 63 can be appropriately determined in accordance with the shape of the rotation restricting member 63 so that the rotation restricting member 63 inserted therein can slide in the axial direction. As shown in the figure, the rotation restricting member 63 is formed in a cylindrical shape such as a cylinder surrounding the rotation shaft 12 of the screw 13. Alternatively, although not shown, the rotation restricting member 63 may be formed in one or more rod-like or plate-like shapes extending in the axial direction on the outer peripheral side of the rotary shaft 12 of the screw 13, or in a plurality of rod-like or plate-like shapes spaced apart from each other in the circumferential direction.

The rotation restricting member 63 is preferably slidable in the axial direction in the slide hole 33 of the metering motor supporting member 32, regardless of the shape thereof. Thus, for example, when the advancing and retreating driving force in the advancing direction is transmitted from the injection motor 21 to the screw 13 via the driving force transmission member 51, as shown in fig. 3, the rotation restriction member 63 can slide in the slide hole 33 and advance together with the shaft sensor 62 between the driving force transmission member 51 and the screw 13. When the forward and backward driving force in the backward direction is transmitted to the screw 13, the rotation restriction member 63 and the shaft sensor 62 are moved backward together with the driving force transmission member 51 and the screw 13, as shown in fig. 2. In this forward and backward movement, the slide hole 33 restricts the displacement of the rotation restricting member 63 inserted therein in the circumferential direction of the rotary shaft 12, and thus the rotation of the rotation restricting member 63 and the shaft force sensor is restricted.

In this case, as shown in fig. 3, the portion of the rotation restriction member 63 on the front side in the axial direction may protrude further toward the front side in the axial direction than the metering motor support member 32 by penetrating the metering motor support member 32, but the presence or absence of such a protrusion and the amount of the protrusion are preferably designed in consideration of the arrangement relation with the surrounding members. The illustrated slide hole 33 penetrates the metering motor supporting member 32 in the axial direction, but may be a slide hole that does not penetrate the metering motor supporting member in the axial direction.

The rotation restricting member is not limited to the rotation restricting member that connects the shaft sensor 62 to the metering motor supporting member 32 as described above. For example, in the axial force detecting portion 161 of the other embodiment shown in fig. 4, a rotation restricting member 163 for coupling the axial force sensor 162 to the stator frame 31c of the measuring motor 31 is provided.

As an example, the rotation restricting member 163 of fig. 4 has a shape including a cylindrical portion 163a extending in the axial direction from the shaft sensor 162 and a flange-like portion 163b extending from an end portion on the axially forward side of the cylindrical portion 163a to the outer peripheral side to the stator frame 31 c. The stator frame 31c is fixedly attached to the rear side in the axial direction of the measuring motor support member 32, and the rotation restricting member 163 can function to restrict the rotation of the shaft force sensor 62 by connecting the shaft force sensor 62 to the stator frame 31 c.

Here, for example, the cylindrical portion 163a of the rotation restriction member 163 is configured to be slidable in the axial direction with respect to the flange-like portion 163b, so that the shaft sensor 162 can advance or retract together with the driving force transmission member 51 and the screw 13 when the driving force for advancing or retreating is transmitted. The embodiment of fig. 4 can be substantially the same as the embodiments shown in fig. 2 and 3 with respect to the structure other than the rotation restricting member 163 of the axial force detecting portion 161. Instead of the rotation regulating member 163 including the cylindrical portion 163a and the flange-like portion 163b, a rod-like or plate-like rotation regulating member may be provided at one or more positions in the circumferential direction of the rotary shaft 12 and bent in the middle of the axial direction.

In the case where the shaft force sensor 62 transmits/receives a signal and/or supplies power by wire, as shown by a broken line in fig. 2 and 3, the wiring 64 of the shaft force sensor 62 included in the shaft force detecting section 61 may extend so as to pass through the slide hole 33 along the rotation restricting member 63 from the shaft force sensor 62, for example, in the inside of the rotation restricting member 63 or the like. This can prevent the wiring 64 from being cut or broken by the rotation of the surrounding driving force transmission member 51 and the screw 13, and the advance and retreat displacement. In addition, in the shaft force sensor that performs wireless communication and noncontact power supply, such wiring may be omitted.

Since the driving force transmission member 51 is rotatable with respect to the shaft force sensor 62, as shown in an enlarged view in fig. 5, the bearing 55 can be interposed between the bearing and the shaft force sensor 62 by the front end wall portion 53, and can be coupled to the shaft force sensor 62. The bearing 55 effectively supports the shaft force sensor 62 in the axial direction from the rear of the shaft force sensor 62 to which the axial force is transmitted by the screw 13, and therefore a thrust bearing, a self-aligning thrust roller bearing which has aligning property and is not affected by an installation error or the like is more preferable.

The illustrated shaft force sensor 62 is provided with an outer annular portion 62a protruding to the rear side on the outer peripheral edge of the rear side surface in the axial direction. The front end wall portion 53 of the driving force transmission member 51 is provided with a central bulging portion 53a bulging toward the front side in the axial direction. The inner race of the bearing 55 is mounted between the front side surface of the front end wall portion 53 of the driving force transmission member 51 and the central bulging portion 53a, and the outer race is mounted between the rear side surface of the shaft force sensor 62 and the outer annular portion 62a. In this way, when the inner ring of the bearing 55 is attached to the front end wall portion 53 of the driving force transmission member 51 and the outer ring is attached to the shaft force sensor 62, the shaft force sensor 62 arranged as shown in the drawing is more reliably supported in the axial direction by the front end wall portion 53 of the driving force transmission member 51, and therefore the detection accuracy of the shaft force sensor 62 in the axial direction can be further improved.

However, in the illustrated example, a coupling cylindrical portion 53b extending in the axial direction is provided in the central bulging portion 53a of the front end wall portion 53 of the driving force transmission member 51. On the other hand, the rotary shaft 12 of the screw 13 is such that the shaft end 12a of the screw base end 13c is inserted into the coupling cylinder 53b. These coupling cylindrical portion 53b and shaft end portion 12a constitute a coupling portion for transmitting rotational driving force from the driving force transmission member 51 to the screw 13 as a connection portion between the screw 13 and the driving force transmission member 51.

In this embodiment, as shown in fig. 5, the screw 13 is provided with a connection flange 14 at the screw base end portion 13c, and the connection flange 14 is fixedly provided to the rotary shaft 12 and extends outward from the rotary shaft 12 to hold the coupling cylindrical portion 53b inside. For example, even when the screw 13 is moved backward (so-called suck-back) after the pressure maintaining, after the metering, or the like, the connection flange 14 functions to reliably connect the screw 13 and the driving force transmission member 51 in the axial direction so that the screw 13 is not greatly separated from the driving force transmission member 51.

The connection flange 14 may include, for example: the flange 15 is fitted into the rotary shaft 12 and coupled thereto, and is formed in a ring shape such as an annular ring; and an annular portion 16 fitted to the rear side of the flange portion 15 in the axial direction and surrounding the outer peripheral side of the connecting tube portion 53b. The flange portion 15 has an outer fitting portion 15a extending from the outer peripheral edge to the rear side in the axial direction and bent to the inner peripheral side, and the annular portion 16 has an inner fitting portion 16a extending from the inner peripheral edge to the front side in the axial direction and bent to the outer peripheral side, and the flange portion 15 and the annular portion 16 are fitted by these outer fitting portion 15a and inner fitting portion 16 a. In order to facilitate disassembly during maintenance of the axial force detecting portion 61 described later, the connecting flange 14 is preferably detachably attached to the rotary shaft 12 by forming the flange portion 15 from a plurality of detachable parts such as two.

In the case where the screw 13 has the connection flange 14 as described above, the shaft force sensor 62 can be positioned between the connection flange 14 of the screw 13 and the front end wall portion 53 of the driving force transmission member 51 around the shaft end portion 12a and the coupling cylindrical portion 53b.

At this time, by interposing the bearing 17 between the annular portion 16 of the connection flange 14 and the shaft force sensor 62, the screw 13 and the shaft force sensor 62 can be coupled to be rotatable relative to each other by the connection flange 14. For the same reasons as described above for the bearing 55 between the driving force transmission member 51 and the shaft force sensor 62, the bearing 17 between the connection flange 14 and the shaft force sensor 62 is preferably a thrust bearing, particularly a self-aligning thrust roller bearing.

In order to more reliably transmit the axial force from the connection flange 14 to the shaft force sensor 62, it is preferable that the inner ring of the bearing 17 between the connection flange 14 and the shaft force sensor 62 is attached to the shaft force sensor 62, and the outer ring of the bearing 17 is attached to the annular portion 16 of the connection flange 14. In this example, an inner ring of the bearing 17 is mounted between the front side surface of the shaft force sensor 62 in the axial direction and an inner annular portion 62b provided on the inner peripheral edge of the front side surface and protruding toward the front side. A cylindrical protruding portion 16b protruding toward the rear side in the axial direction is formed on the outer edge of the annular portion 16 of the connection flange 14, and the outer ring of the bearing 17 is supported by the cylindrical protruding portion 16 b.

In the illustrated embodiment, the shaft force sensor 62 supports the bearing 17 between it and the connection flange 14 by the inner annular portion 62b, and supports the bearing 55 between it and the front end wall portion 53 of the driving force transmission member 51 by the outer annular portion 62a. Thus, the annular shaft sensor is located on the inner peripheral side of the portion connected to the connecting flange 14 of the screw 13 via the bearing 17, and the portion connected to the front end wall portion 53 of the driving force transmission member 51 via the bearing 55.

Here, it is preferable that the shaft end portion 12a of the screw 13, the connection flange 14, and the coupling cylindrical portion 53b be relatively displaceable in the axial direction so that the axial force transmitted from the screw 13 to the connection flange 14 via the rotation shaft 12 is more reliably transmitted to the shaft force sensor 62 between the connection flange 14 and the front end wall portion 53.

Specifically, for example, keys and key grooves may be provided on the outer peripheral surface of the shaft end portion 12a and the inner peripheral surface of the coupling cylindrical portion 53b, and keys and key grooves may be provided on the outer peripheral surface of the coupling cylindrical portion 53b and the inner peripheral surface of the annular portion 16 of the connection flange 14, respectively, and may be spline-coupled. Here, minute gaps C1 and C2 are provided in the axial direction between the end face of the shaft end 12a and the bottom face of the coupling cylindrical portion 53b and between the peripheral face of the opening of the coupling cylindrical portion 53b and the connecting flange 14, respectively. As a result, the screw 13 can be displaced in the axial direction by a plurality of relative displacements with respect to the driving force transmission member 51, and the axial force acting on the screw 13 can be effectively transmitted to the shaft force sensor 62 between the connection flange 14 and the driving force transmission member 51, so that the shaft force sensor 62 can detect the axial force with higher accuracy.

In the case where the screw 13 does not have the connecting flange 14 as described above, as in the embodiment shown in fig. 6, the shaft force transmission flange 214 may be fixedly provided at the screw base end portion 13c of the rotary shaft 12 of the screw 13. The shaft force transmission flange 214 is coupled to the shaft force sensor 62 via the bearing 17 so as to be rotatable relative to each other. In fig. 6, the shaft end portion 12a and the coupling cylindrical portion 53b are coupled by splines, and clearances C1, C2 are provided between the shaft end portion 12a and the coupling cylindrical portion 53b and between the shaft force transmission flange 214 and the coupling cylindrical portion 53b, respectively, whereby axial force is effectively transmitted from the screw 13 to the shaft force sensor 62 via the shaft force transmission flange 214. The embodiment of fig. 6 has substantially the same structure as the above-described embodiment, except that the connecting flange 14 is replaced with an axial force transmitting flange 214. The shaft force transmission flange 214 and the like are preferably configured by two or more detachable members, and are thereby detachably attached to the rotary shaft 12.

However, as in the embodiments shown in fig. 1 to 3, 5 and 6, when the rotation restricting member 63 of the axial force detecting portion 61 connects the axial force sensor 62 to the measuring motor supporting member 32, the sensor connecting portion of the measuring motor supporting member 32 to which the axial force sensor 62 is connected by the rotation restricting member 63 may be integrally formed with the motor supporting portion that supports the measuring motor 31. However, in order to facilitate maintenance of the axial force detection unit 61 as described later, it is preferable that the sensor coupling unit 32b of the measuring motor support member 32 is configured to be separable from the motor support unit 32a having a frame shape or the like, and to be detachable from the motor support unit 32a, as in the illustrated embodiment. In this case, as described above, the sensor coupling portion 32b of the slide hole 33 may be provided, and may be formed in a cylindrical shape or the like taking into consideration the rod-like, plate-like, cylindrical shape or the like of the rotation restriction member 63.

As shown in fig. 1, the measuring motor support member 32 is detachably attached to a cylinder support portion 32c on the front side in the axial direction of a motor support portion 32a such as a frame, and the cylinder support portion 32c is provided with a hole portion 32d through which the screw 13 passes. Although not shown, a cooler using water cooling or the like may be provided near a supply port of the cylinder support portion 32c for supplying the molding material into the cylinder 11.

The injection device 1 is disassembled as described below, for example, when the shaft force sensor 62 is replaced or other maintenance of the shaft force detecting unit 61 is performed. First, the cylinder support portion 32c is removed from the motor support portion 32a of the metering motor support member 32 together with the cylinder 11, thereby exposing the screw 13 as shown in fig. 7.

Next, the rotation restricting member 63 is slid in the slide hole 33, and at the same time, as shown in fig. 8, the sensor coupling portion 32b is detached from the motor support portion 32a of the metering motor support member 32.

As a result, the screw base end portion 13c is made accessible, and therefore, the flange portion 15 of the connection flange 14 on the screw base end portion 13c is detached from the screw 13, the connection between the screw 13 and the driving force transmission member 51 is released, and the shaft end portion 12a of the rotary shaft 12 of the screw 13 is pulled out from the connection cylindrical portion 53b of the driving force transmission member 51, and the state shown in fig. 9 is achieved.

Then, the shaft force sensor 62 and the rotation restricting member 63 of the shaft force detecting portion 61 can be removed by removing the remaining annular portion 16 and the bearing 17 of the connecting flange 14. This brings the state shown in fig. 10.

When such a decomposition is performed, the axial force detecting portion 61 can be extracted from the metering motor 31, the driving force transmitting member 51, and the injection motor 21 side portions without being separated. Therefore, according to this embodiment, as described above, by disposing the axial force detection portion 61 in the vicinity of the screw 13 in the injection device 1, it is possible to relatively quickly and easily perform maintenance of the axial force detection portion 61 while improving the detection accuracy of the axial force. After the injection device 1 is disassembled in this way, the assembly can be performed by performing the steps reverse to the above steps.

(Cylinder body)

The cylinder 11 is provided with a screw 13 inside thereof, and melts a molding material supplied from a supply port, not shown, into the inside by heating and rotation of the screw 13. A heater 18 for heating the molding material inside is disposed around the cylinder 11.

The cylinder 67 has a nozzle 19 having a smaller inner and outer diameter on the front side in the axial direction, and a heater 18 is also disposed around the nozzle 19.

(action of injection device)

The injection device 1 as described above is mounted on an injection molding machine, and can perform the following operations at the time of injection molding.

In the above-described metering step, a mold closing step of closing a mold device, not shown, to a mold closed state is performed in a state in which a predetermined amount of molding material has been metered and placed in the cylinder 11.

Then, the steps are sequentially performed: a filling step of injecting a molding material into the mold device by advancing the screw 13, and filling the molding material into the cavity in the mold device; and a pressure maintaining step of further advancing the screw 13 to maintain the molding material located inside the nozzle 19 of the cylinder 11 at a predetermined pressure.

Then, a cooling step of cooling the molding material filled in the mold device to solidify the molding material is performed, thereby obtaining a molded product. At this time, a metering step is performed in which the molding material separately supplied into the cylinder 11 is melted by heating by the heater 18 while being conveyed toward the nozzle 19 of the cylinder 11 by the rotation of the screw 13, and a predetermined amount of the molding material is disposed in the nozzle 19.

The cooling step is followed by a take-out step in which the mold device is opened to be in an open state, and the molded article is taken out from the mold device by an ejector or the like.

Symbol description

1-injection device, 11-cylinder, 12-rotation shaft, 12 a-shaft end, 13-screw, 13 a-screw main body, 13 b-screw front end, 13 c-screw base end, 14-connection flange, 214-shaft force transmission flange, 15-flange portion, 15 a-outside fitting portion, 16-annular portion, 16 a-inside fitting portion, 16 b-cylindrical protruding portion, 17-bearing, 18-heater, 19-nozzle, 21-injection motor, 31-metering motor, 21a, 31 a-rotor, 21b, 31 b-stator, 21c, 31 c-stator frame, 21d, 31 d-bearing portion, 22-injection motor supporting member, 22 a-cylinder, 23-cylindrical rotating member, 24, 25-rod, 25 a-shaft portion, 25 b-encoder, a 32-meter motor support, a 32 b-sensor coupling, a 32 c-cylinder, a 32 d-hole, a 33-slide hole, a 41-motion conversion mechanism, a 42-screw shaft, a 42 a-screw shaft base, a 42 b-key, a 42 c-screw shaft tip, a 43-nut, a 51-drive force transmission member, a 52-cylindrical body, a 52 a-key, a 53-tip wall, a 53 a-center boss, a 53 b-coupling cylinder, 54, 55-bearings, 61, 161-axial force detection portions, 62, 162-axial force sensors, 62 a-outer annular portions, 62 b-inner annular portions, 63, 163-rotation members, 163 a-cylindrical portions, 163 b-flange-shaped portions, 64-wiring, 67-cylinder, 101-sliding base, C1 and C2-clearance.

Claims (16)

1. An injection device for injecting a molding material, comprising:

a screw driven to rotate about a rotation axis and driven to advance and retreat in an axial direction;

an injection motor which is a driving source for advancing and retreating the screw;

a motion conversion mechanism that includes a screw shaft that rotates together with a rotational motion of the injection motor and a nut that is provided with the screw shaft inside, and converts the rotational motion of the injection motor into a linear motion in the axial direction;

the metering motor is a rotary driving source of the screw;

a driving force transmission member connected to the screw, and configured to transmit a rotational driving force based on a rotational movement of the metering motor and an advancing and retreating driving force based on a linear movement of the screw shaft of the movement conversion mechanism to the screw, respectively; a kind of electronic device with high-pressure air-conditioning system

An axial force detection unit for detecting an axial force acting on the screw in the axial direction,

the axial force detection unit includes: an annular shaft force sensor disposed so as to be rotatable relative to each other between the screw and the driving force transmission member around the rotation shaft of the screw; and a rotation restriction member that restricts rotation of the shaft force sensor with respect to rotation of the screw and the driving force transmission member.

2. The injection device of claim 1, wherein,

the injection device comprises a metering motor supporting member for supporting a metering motor,

the rotation restriction member is connected to the weighing motor support member so that the weighing motor support member can be displaced in the axial direction while being restricted from rotating.

3. The injection device of claim 2, wherein,

the metering motor supporting member has a slide hole for the rotation limiting member,

the rotation restricting member is configured to be inserted into the slide hole in a slidable manner along the axial direction.

4. An injection device according to claim 3, wherein,

the rotation restricting member is in the form of one or more rods or plates extending in the axial direction on the outer peripheral side of the rotation shaft of the screw, or in the form of a tube surrounding the circumference of the rotation shaft of the screw.

5. The injection device according to claim 3 or 4, wherein,

the axial force detecting portion has a wiring extending from the axial force sensor along the rotation restricting member through the slide hole.

6. The injection device according to any one of claims 2 to 5, wherein,

the metering motor supporting member has:

a motor support unit for supporting the weighing motor; a kind of electronic device with high-pressure air-conditioning system

And a sensor coupling unit which is coupled to the shaft force sensor via a rotation restricting member and is detachable from the motor support unit.

7. The injection device according to any one of claims 1 to 6, wherein,

the driving force transmission member has:

a cylindrical body portion surrounding the periphery of the leading end portion of the screw shaft; a kind of electronic device with high-pressure air-conditioning system

A front end wall portion provided in the opening portion on the front side in the axial direction of the tubular body portion.

8. The injection device of claim 7, wherein,

the driving force transmission member is connected to the shaft force sensor via a bearing through the front end wall portion so as to be rotatable relative to the shaft force sensor.

9. The injection device of claim 8, wherein,

the bearing between the front end wall portion of the driving force transmission member and the shaft force sensor is a thrust bearing.

10. An injection device according to claim 8 or 9, wherein,

an inner ring of a bearing between the front end wall portion of the driving force transmission member and the shaft force sensor is attached to the front end wall portion of the driving force transmission member, and an outer ring of the bearing is attached to the shaft force sensor.

11. The injection device according to any one of claims 8 to 10, wherein,

the coupling part of the connection part of the screw and the driving force transmission member includes: a coupling cylindrical portion extending in the axial direction from a front end wall portion of the driving force transmission member; and a shaft end part which is provided at the screw base end part of the rotary shaft and is inserted into the connecting cylinder part,

the screw has a connecting flange at a screw base end portion, the connecting flange being detachably attached to the rotary shaft and holding the connecting tube portion inside,

the shaft force sensor is located between the connection flange of the screw and the front end wall portion of the driving force transmission member around the shaft end portion and the connection tube portion.

12. The injection device of claim 11, wherein,

the shaft end portion and the connecting flange are relatively displaceable in the axial direction, and an axial force acting on the screw is transmitted to a shaft force sensor between the connecting flange of the screw and a front end wall portion of the driving force transmission member.

13. An injection device according to claim 11 or 12, wherein,

the screw is connected to the shaft force sensor via a bearing via the connecting flange so as to be rotatable relative to the shaft force sensor.

14. The injection device of claim 13, wherein,

the bearing between the connecting flange of the screw and the shaft force sensor is a thrust bearing.

15. An injection device according to claim 13 or 14, wherein,

the annular shaft force sensor is located on the inner peripheral side of a connection portion connected to the connecting flange of the screw via a bearing, and is located on the inner peripheral side of the connection portion connected to the front end wall portion of the driving force transmission member via the bearing.

16. The injection device according to any one of claims 13 to 15, wherein,

an inner ring of a bearing between the connection flange of the screw and the shaft force sensor is mounted to the shaft force sensor, and an outer ring of the bearing is mounted to the connection flange.