JP5738924B2 - Electric injection molding machine motor - Google Patents

Description

  The present invention relates to a motor for an electric injection molding machine, and although not limited thereto, the present invention relates to a motor for an electric injection molding machine suitable for an injection motor for driving a screw in an axial direction.

  As is well known in the art, the injection device is generally composed of a heating cylinder and a screw provided in the heating cylinder so as to be driven in the rotational direction and the axial direction. In an electric injection molding machine in which each device is driven by a motor, the screw is rotated by a plasticizing motor and is driven in the axial direction by the injection motor. Incidentally, the injection motor is provided in a predetermined drive mechanism behind the screw. However, in many electric injection molding machines, the injection motor is disposed on the side as viewed from the axis of the screw. For example, a ball screw mechanism is provided at the rear end portion of the screw so as to be coaxial with the axis of the screw, and the ball screw and the screw are integrally coupled. However, the injection motor is provided on the side of the ball screw mechanism. That is, it is arranged on the side as viewed from the screw shaft. This injection motor rotates a ball nut via a power transmission mechanism such as a pulley and a belt, whereby the screw is driven in the axial direction. However, there is a disadvantage when the injection motor is arranged on the side as seen from the screw shaft. Since the power of the injection motor is transmitted from the side to the screw, an offset load acts on the screw in a direction perpendicular to the axis, and an offset load perpendicular to the rotation axis acts on the injection motor as well. Such an unbalanced load affects control and causes deterioration. In addition, power transmission needs to go through a power transmission mechanism such as a pulley and a belt, which leads to energy loss. The injection performed by driving the screw in the axial direction requires a large output, and the injection motor is a relatively high output motor, so the influence is great.

JP 2001-88180 A JP 2012-5290 A JP 2012-75699 A JP 2012-178925 A

  In order to eliminate such disadvantages, an electric injection molding machine in which an injection motor is arranged coaxially with a screw shaft is well known, and has been proposed in Patent Document 1, for example. In the electric injection molding machine described in Patent Document 1, a screw is driven in the axial direction by a ball screw mechanism, and a ball nut is fixed to a rear end portion of the screw via a predetermined structure. The ball screw is arranged coaxially with the screw. The rotation shaft of the injection motor is formed integrally with such a ball screw. Alternatively, the rear end portion of the ball screw is the rotation shaft of the injection motor. Therefore, when the injection motor is rotated, the ball screw is rotated and the screw is driven in the axial direction. In the electric injection molding machine described in Patent Document 1, since the screw and the injection motor are arranged coaxially, the eccentric load in the direction perpendicular to the axis does not act on the screw or the injection motor, and the power transmission mechanism Energy loss will be minimal.

  The injection motor is composed of a stator and a rotor as in the conventional motor, and these are put in a predetermined casing. The casing is also intended for dust protection, safety, and shielding of magnetic field lines. In such a casing, a bearing such as a bearing that rotatably supports the rotor is also provided. For example, in the electric injection molding machine described in Patent Document 1, a bearing for an injection motor is provided in the casing. Although Patent Documents 2 to 4 are not directly related to the present invention, various motors are also described in these documents. Patent Document 2 describes a motor used in a construction machine, and this motor is provided with two bearings in a casing for rotatably supporting a rotor. Patent Document 3 describes a motor for a sewing machine, and the rotor is supported like a cantilever by a single bearing. The bearing is provided integrally with the casing, and one end face of the bearing faces the outside of the casing and the other end face faces the inside of the casing. Therefore, it can be said that it is provided in the casing substantially. Patent Document 4 describes a direct drive motor, and the rotor of this motor is supported by a single bearing. This bearing is also provided in the casing.

  In the electric injection molding machine described in Patent Document 1, since the injection motor is provided coaxially with the screw, an offset load perpendicular to the axis does not act on the screw or the shaft of the injection motor, and the control is affected. Does not occur or deteriorates easily. Since no power transmission mechanism such as a pulley or belt is required, energy loss is small. Therefore, it is excellent. However, there are also problems to be solved. Specifically, there are problems with bearings for injection motors. Since the rotor needs to be rotatably supported, the bearing can be regarded as an essential part for the injection motor, but mechanical loss of the bearing, that is, energy loss due to friction cannot be ignored. There is also a problem of deterioration. The injection motor is a high-output motor, and the electric power supplied at the time of driving is large. Since injection is performed at a predetermined frequency, a large amount of heat is generated from the rotor or stator coil, resulting in a high temperature. Accordingly, the inside of the casing is exposed to a high temperature, and the lubricating oil of the bearing is likely to deteriorate early. Or bearing itself will deteriorate. There are also maintenance issues. When maintaining the bearing, it is necessary to remove the casing, which is complicated. These problems are conspicuous in an injection motor that requires high output, but also occur in other motors such as a mold clamping motor that drives a mold clamping device.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a motor for an electric injection molding machine that has a small energy loss, that is less susceptible to deterioration of lubricating oil and bearings, and that is easy to maintain. The purpose is to provide a motor.

  In the present invention, the motor of the electric injection molding machine is configured such that the bearing is disposed outside the casing. That is, the bearing that rotatably supports the rotation shaft of the motor is disposed outside the casing that houses the rotor and the stator.

That is, in order to achieve the object, the invention according to claim 1 is a motor that drives an apparatus that constitutes an electric injection molding machine and includes a ball screw mechanism, and the motor is A rotating shaft is formed integrally with the ball screw of the ball screw mechanism, and when the rotating shaft is rotated, a ball nut screwed with the ball screw is driven in the axial direction, and the rotating shaft is freely rotatable. The bearing supported by the motor is configured as a motor of an electric injection molding machine characterized in that it is provided outside the casing that houses the rotor and stator of the motor.
According to a second aspect of the present invention, in the motor according to the first aspect, the bearing is also used as a bearing of the ball screw, and is configured as a motor of an electric injection molding machine.
According to a third aspect of the present invention, in the motor according to the first or second aspect, the device is an injection device, the motor is an injection motor that drives a screw in an axial direction, the screw shaft and the injection The motor is configured as a motor of an electric injection molding machine characterized in that the rotation shaft of the motor is arranged coaxially.
According to a fourth aspect of the present invention, in the motor according to any one of the first to third aspects, the rotary shaft is supported in a cantilevered manner by the bearing. Configured as

As described above, the present invention is a motor that drives an apparatus that constitutes an electric injection molding machine and includes a ball screw mechanism, and the motor has a rotating shaft that is integrated with a ball screw of the ball screw mechanism. When the rotating shaft is rotated, the ball nut screwed with the ball screw is driven in the axial direction, and the bearing that rotatably supports the rotating shaft accommodates the rotor and stator of the motor. It is provided outside the casing. Therefore, the bearing is not exposed to the high temperature in the casing, and the lubricating oil hardly deteriorates and the bearing itself hardly deteriorates. And since it is provided in the outer side of a casing, the maintenance of a bearing is also easy. According to another invention, the bearing is also used as a ball screw bearing. Therefore, the number of bearings can be reduced. As a result, energy loss due to friction of the bearing can be reduced and efficiency is increased. According to another invention, the motor is an injection motor that drives the screw in the axial direction, and the screw shaft and the rotation shaft of the injection motor are arranged coaxially. The injection motor is a motor that requires a high output and becomes high in temperature, and the deterioration of the lubricating oil and the bearing are likely to occur. However, since the bearing is provided outside the casing according to the present invention, the deterioration of the lubricating oil and the bearing It is possible to surely prevent the deterioration. Since the screw shaft and the rotating shaft of the motor are arranged coaxially, neither the screw nor the rotating shaft is subjected to an offset load perpendicular to the axial direction. Therefore, control is stabilized and deterioration can be suppressed. According to another invention, since the rotating shaft of the motor is supported in a cantilever manner by the bearing, only one bearing is required. Energy loss due to bearing friction can be minimized.

BRIEF DESCRIPTION OF THE DRAWINGS It is a front view which shows the injection apparatus in a partial cross section of the electric injection molding machine provided with the motor which concerns on embodiment of this invention.

  Embodiments of the present invention will be described below. As shown in FIG. 1, an injection device 1 according to an embodiment of the present invention includes a heating cylinder 2, a screw 3 provided in the heating cylinder 2 and capable of driving in the rotational direction and the axial direction, It is comprised from the drive mechanism 4 etc. which drive the screw 3. FIG. An injection nozzle is provided at the front end of the heating cylinder 2 and a hopper 6 for supplying an injection material is provided at the rear end. A heater is wound around the outer peripheral surface, but FIG. 1 shows the injection nozzle and the heater. Absent.

  The injection device 1 includes a predetermined support structure, that is, a front support base 8 provided behind the heating cylinder 2, a rear support base 9 provided behind the front support base 8, and a front support base 8. It is supported by a support mechanism comprising guide bars 11, 11,... This support mechanism can be said to be a part of the drive mechanism 4. That is, the drive mechanism 4 includes a front support base 8, a rear support base 9, guide bars 11, 11,..., A slide disc 12 that is guided by these guide bars 11 and slides, a plasticizing mechanism 13, and an injection. And a mechanism 14. The screw 3 has a shaft passing through the front support base 8 near the rear, and a rear end portion thereof is rotatably supported by the slide board 12. The plasticizing mechanism 13 includes a plasticizing motor 16 provided on the slide disk 12, a drive pulley 17 provided on the rotating shaft of the plasticizing motor 16, and a driven fixed to the shaft behind the shaft of the screw 3. The pulley 18 is composed of a timing belt 20 that is wound around the driving pulley 17 and the driven pulley 18. Therefore, when the plasticizing motor 16 is driven, power is transmitted in order to the driving pulley 17, the timing belt 20, and the driven pulley 18 to rotate the screw 3, and the plasticizing process can be performed in the injection apparatus 1 as conventionally known. it can.

  The injection mechanism 14 includes a ball screw mechanism 21 and an injection motor 22 that drives the ball screw mechanism 21. A ball nut 23 of the ball screw mechanism 21 is provided on the back surface side of the slide board 12 via a spacer 25, and the ball screw 24 is disposed so as to be coaxial with the axis of the screw 3. Since the ball screw 24 is screwed with the ball nut 23, the ball screw 24 rotates and protrudes beyond the ball nut 23 in the axial direction. However, since the spacer 25 is provided, the ball screw 24 does not hit the slide board 12. The ball screw 24 penetrates the rear support base 9, and no thread is cut in the rear part that penetrates. The rear portion where the thread is not cut is a rotating shaft 24a of the injection motor 22 described below.

  The injection motor 22 includes a rotor 27 provided on the rotary shaft 24a, a stator 28 disposed around the rotor 27, and a casing 29 that houses these. The stator 28 is fixed in the casing 29, and the casing 29 is fixed to the rear support 9. When this injection motor 22 is driven, the ball screw 24 rotates and the ball nut 23 is driven in the axial direction. As a result, the screw 3 is driven in the axial direction, and the injection process can be performed in the injection apparatus 1 as is well known in the art.

  The present embodiment is characterized by a bearing that rotatably supports the rotary shaft 24a of the injection motor 22. Also in the present embodiment, the bearing 31 of the injection motor 22 is a bearing, and the bearing 31 is provided in the vicinity of the rear support base 9, that is, outside the casing 29. That is, there is no bearing in the casing 29. Since the bearing 31 is provided at such a position, the bearing 31 is not exposed to the high temperature in the casing 29. Therefore, the bearing 31 and the lubricating oil are unlikely to deteriorate. Further, since the bearing 31 is provided outside the casing 29, maintenance of the bearing 31 is facilitated. The bearing 31 also serves as a bearing for the ball screw 24, and supports the rotary shaft 24a of the injection motor 22 in a cantilever shape. Therefore, in this embodiment, a minimum number of bearings is sufficient. As a result, energy loss due to friction in the bearing 31 can be minimized. An encoder 33 that detects the rotation angle is provided at the rear end of the rotation shaft 24a of the injection motor 22.

  This embodiment can be variously modified. For example, in the above description, the rotary shaft 24a has been described as being cantilevered so as to be rotatably supported by one bearing 31, but a bearing is also provided on the other end side of the rotary shaft 24a, You may make it support from both. Such other bearing is also preferably provided outside the casing 29. In this embodiment, one ball screw mechanism 21 and one injection motor 22 are provided, but two or more of these may be provided. More specifically, two ball screw mechanisms 21 and 21 are provided in parallel to the slide board 12, and the rotation shafts 24a and 24a of the injection motors 22 and 22 are fixed to the ball screws 24 and 24, respectively. The screw 3 is arranged between the two ball screws 24, 24. When the two injection motors 22 are driven in synchronization, the screw 3 can be driven in the axial direction. The injection motor 22 according to the present embodiment can be applied to other devices such as a mold clamping device. In the case of a mold clamping device including a toggle mechanism, it is necessary to drive the cross head in the axial direction by a ball screw mechanism. A motor having a structure similar to the injection motor 22 according to the present embodiment can be applied to the mold clamping motor provided in the ball screw of this ball screw mechanism.

DESCRIPTION OF SYMBOLS 1 Injection device 2 Heating cylinder 3 Screw 4 Drive mechanism 8 Front support stand 9 Back support stand 11 Guide bar 12 Slide board 16 Plasticizing motor 21 Ball screw mechanism 22 Injection motor 23 Ball nut 24 Ball screw 24a Rotating shaft 27 Rotor 28 Stator 29 Casing 31 bearing

Claims (4)

A motor that drives an apparatus that constitutes an electric injection molding machine and includes a ball screw mechanism , wherein the motor has a rotation shaft formed integrally with a ball screw of the ball screw mechanism, and the rotation shaft The ball nut screwed with the ball screw is driven in the axial direction when the shaft is rotated, and the bearing that rotatably supports the rotating shaft houses the rotor and stator of the motor. A motor for an electric injection molding machine, characterized in that the motor is provided outside the casing.   The motor according to claim 1, wherein the bearing is also used as a bearing for the ball screw.   The motor according to claim 1 or 2, wherein the device is an injection device, the motor is an injection motor that drives a screw in an axial direction, and the shaft of the screw and the rotation shaft of the injection motor are arranged coaxially. A motor for an electric injection molding machine.   The motor of any one of Claims 1-3 WHEREIN: The said rotating shaft is supported by the said bearing in the shape of a cantilever, The motor of the electric injection molding machine characterized by the above-mentioned.

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