JP7250980B2 - Injection molding machine - Google Patents

Description

The present invention relates to an injection molding machine.

The electric injection molding machine described in Patent Document 1 includes a driven portion, an electric motor for operating the driven portion, and an electric motor disposed between the electric motor and the driven portion. and a motion direction converter for converting the rotary motion of the rotation into a linear motion.

WO2005/037519

An injection molding machine has various motors. A motor has a stator, a bearing held by the stator, and a rotor rotatably supported by the bearing.

Inside the rotor of the motor, a drive shaft that rotates and rectilinearly moves with the rotational motion of the rotor is sometimes provided. The drive shaft is for example splined to the rotor.

Conventionally, when the drive shaft is driven, the bearings of the motor vibrate greatly, causing problems due to impacts and the like.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a main object of the present invention is to provide an injection molding machine that suppresses vibration of a bearing of a motor when driving a drive shaft.

In order to solve the above problems, according to one aspect of the present invention,
a motor ;
a motion conversion mechanism for converting rotary motion of the motor into linear motion ;
The motor includes a stator, a bearing held by the stator, a rotor rotatably supported by the bearing, and biasing the bearing against the stator in a forward direction of the motion conversion mechanism. and a biasing member.

According to one aspect of the present invention, there is provided an injection molding machine that suppresses vibration of a bearing of a motor when driving a drive shaft.

It is a figure which shows the state at the time of completion of mold opening of the injection molding machine by one Embodiment. It is a figure which shows the state at the time of mold clamping of the injection molding machine by one Embodiment. FIG. 3 illustrates an injection device according to one embodiment;

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a state of an injection molding machine according to one embodiment when mold opening is completed. FIG. 2 is a diagram showing a state of the injection molding machine according to one embodiment at the time of mold clamping. As shown in FIGS. 1 and 2, the injection molding machine has a frame Fr, a mold clamping device 10, an injection device 40, an ejector device 50, and a control device 90.

First, the mold clamping device 10 and the ejector device 50 will be described. In the description of the mold clamping device 10 and the ejector device 50, the moving direction of the movable platen 13 when the mold is closed (right direction in FIGS. 1 and 2) is defined as the front, and the moving direction of the movable platen 13 when the mold is opened (FIG. 1 and The left direction in FIG. 2) will be described as the rear.

The mold clamping device 10 performs mold closing, mold clamping, and mold opening of the mold device 30 . The mold clamping device 10 is of a horizontal type, for example, and the mold opening/closing direction is horizontal. The mold clamping device 10 has a stationary platen 12 , a movable platen 13 , a toggle support 15 , tie bars 16 , a toggle mechanism 20 , a mold clamping motor 25 and a motion conversion mechanism 26 .

The fixed platen 12 is fixed with respect to the frame Fr. A stationary mold 32 is attached to the surface of the stationary platen 12 facing the movable platen 13 .

The movable platen 13 is movable relative to the frame Fr in the mold opening/closing direction. A guide 17 for guiding the movable platen 13 is laid on the frame Fr. A movable mold 33 is attached to the surface of the movable platen 13 facing the fixed platen 12 .

Mold closing, mold clamping, and mold opening are performed by moving the movable platen 13 forward and backward with respect to the fixed platen 12 . A mold device 30 is composed of the fixed mold 32 and the movable mold 33 .

The toggle support 15 is connected to the stationary platen 12 with a gap therebetween, and is placed on the frame Fr so as to be movable in the mold opening/closing direction. The toggle support 15 may be movable along a guide laid on the frame Fr. The guide of the toggle support 15 may be shared with the guide 17 of the movable platen 13 .

In this embodiment, the fixed platen 12 is fixed to the frame Fr, and the toggle support 15 is movable relative to the frame Fr in the mold opening/closing direction. 12 may be movable relative to the frame Fr in the mold opening/closing direction.

A tie bar 16 connects the fixed platen 12 and the toggle support 15 with a space therebetween. A plurality of tie bars 16 may be used. Each tie bar 16 is parallel to the mold opening/closing direction and extends according to the mold clamping force. At least one tie bar 16 is provided with a clamping force detector 18 . The mold clamping force detector 18 detects the mold clamping force by detecting the distortion of the tie bars 16 and sends a signal indicating the detection result to the control device 90 .

The mold clamping force detector 18 is not limited to the strain gauge type, and may be of piezoelectric type, capacity type, hydraulic type, electromagnetic type, etc., and its mounting position is not limited to the tie bar 16 either.

The toggle mechanism 20 is arranged between the movable platen 13 and the toggle support 15 and moves the movable platen 13 relative to the toggle support 15 in the mold opening/closing direction. The toggle mechanism 20 is composed of a crosshead 21, a pair of link groups, and the like. Each link group has a first link 22 and a second link 23 that are connected with pins or the like so as to be bendable and stretchable. The first link 22 is swingably attached to the movable platen 13 with pins or the like, and the second link 23 is swingably attached to the toggle support 15 with pins or the like. A second link 23 is attached to the crosshead 21 via a third link 24 . When the crosshead 21 is advanced and retracted with respect to the toggle support 15 , the first link 22 and the second link 23 are bent and retracted, and the movable platen 13 is advanced and retracted with respect to the toggle support 15 .

The configuration of the toggle mechanism 20 is not limited to the configuration shown in FIGS. 1 and 2. FIG. For example, although the number of nodes in each link group is five in FIGS. may be

A mold clamping motor 25 is attached to the toggle support 15 and operates the toggle mechanism 20 . The mold clamping motor 25 advances and retreats the crosshead 21 with respect to the toggle support 15 , thereby bending and stretching the first link 22 and the second link 23 to advance and retreat the movable platen 13 with respect to the toggle support 15 . The mold clamping motor 25 is directly connected to the motion conversion mechanism 26, but may be connected to the motion conversion mechanism 26 via a belt, pulley, or the like.

The motion conversion mechanism 26 converts rotary motion of the mold clamping motor 25 into linear motion of the crosshead 21 . The motion conversion mechanism 26 includes a threaded shaft and a threaded nut that screws onto the threaded shaft. Balls or rollers may be interposed between the screw shaft and the screw nut.

The mold clamping device 10 performs a mold closing process, a mold clamping process, a mold opening process, etc. under the control of the control device 90 .

In the mold closing process, the mold clamping motor 25 is driven to advance the crosshead 21 at a set speed to the mold closing completion position, thereby advancing the movable platen 13 and bringing the movable mold 33 into contact with the fixed mold 32 . The position and speed of the crosshead 21 are detected using the encoder 25a of the mold clamping motor 25, for example. The encoder 25a detects the rotation of the mold clamping motor 25 and sends a signal indicating the detection result to the control device 90. FIG.

In the mold clamping process, the mold clamping motor 25 is further driven to further advance the crosshead 21 from the mold closing completion position to the mold clamping position, thereby generating a mold clamping force. A cavity space 34 is formed between the movable mold 33 and the fixed mold 32 during mold clamping, and the injection device 40 fills the cavity space 34 with a liquid molding material. A molded product is obtained by solidifying the filled molding material. A plurality of cavity spaces 34 may be provided, in which case a plurality of molded products can be obtained at the same time.

In the mold opening step, the mold clamping motor 25 is driven to retract the crosshead 21 at a set speed to the mold opening completion position, thereby retracting the movable platen 13 and separating the movable mold 33 from the fixed mold 32 . After that, the ejector device 50 ejects the molded product from the movable mold 33 .

Although the mold clamping device 10 of this embodiment has the mold clamping motor 25 as a drive source, the mold clamping motor 25 may be replaced by a hydraulic cylinder. Further, the mold clamping device 10 may have a linear motor for mold opening and closing and an electromagnet for mold clamping.

The ejector device 50 ejects the molded product from the mold device 30 . The ejector device 50 has an ejector motor 51 , a motion converting mechanism 52 and an ejector rod 53 .

The ejector motor 51 is attached to the movable platen 13 . The ejector motor 51 is directly connected to the motion conversion mechanism 52, but may be connected to the motion conversion mechanism 52 via a belt, pulley, or the like.

The motion conversion mechanism 52 converts rotary motion of the ejector motor 51 into linear motion of the ejector rod 53 . The motion conversion mechanism 52 includes a threaded shaft and a threaded nut that screws onto the threaded shaft. Balls or rollers may be interposed between the screw shaft and the screw nut.

The ejector rod 53 can move back and forth through the through hole of the movable platen 13 . A front end portion of the ejector rod 53 contacts a movable member 35 that is disposed inside the movable mold 33 so as to move back and forth. The front end of the ejector rod 53 may or may not be connected to the movable member 35 .

The ejector device 50 performs an ejection process under the control of the control device 90 .

In the ejecting step, the ejector motor 51 is driven to advance the ejector rod 53 at a set speed, thereby advancing the movable member 35 and ejecting the molded product. Thereafter, the ejector motor 51 is driven to retract the ejector rod 53 at a set speed, thereby retracting the movable member 35 to its original position. The position and speed of the ejector rod 53 are detected using the encoder 51a of the ejector motor 51, for example. The encoder 51a detects rotation of the ejector motor 51 and sends a signal indicating the detection result to the control device 90. FIG.

Next, the injection device 40 will be described. In the description of the injection device 40, unlike the description of the mold clamping device 10, etc., the moving direction of the screw 43 during filling (the left direction in FIGS. and the right direction in FIG. 2) will be described as the rear.

The injection device 40 is installed on a slide base Sb that can move back and forth with respect to the frame Fr, and can move back and forth with respect to the mold device 30 . The injection device 40 touches the mold device 30 and fills the cavity space 34 in the mold device 30 with the molding material. A molded article is obtained by cooling and solidifying the molding material filled in the cavity space 34 . The injection device 40 has, for example, a cylinder 41 , a nozzle 42 , a screw 43 , a cooler 44 , a metering motor 45 , an injection motor 46 , a pressure detector 47 , a heater 48 and a temperature detector 49 .

The cylinder 41 heats the molding material supplied inside from the supply port 41a. A supply port 41 a is formed in the rear portion of the cylinder 41 . A cooler 44 such as a water-cooled cylinder is provided on the outer periphery of the rear portion of the cylinder 41 . A heater 48 such as a band heater and a temperature detector 49 are provided on the outer periphery of the cylinder 41 ahead of the cooler 44 .

The cylinder 41 is divided into a plurality of zones in the axial direction of the cylinder 41 (horizontal direction in FIGS. 1 and 2). A heater 48 and a temperature detector 49 are provided for each zone. For each zone, the controller 90 controls the heater 48 so that the temperature detected by the temperature detector 49 becomes the set temperature.

A nozzle 42 is provided at the front end of the cylinder 41 and pressed against the mold device 30 . A heater 48 and a temperature detector 49 are provided around the nozzle 42 . The controller 90 controls the heater 48 so that the detected temperature of the nozzle 42 becomes the set temperature.

The screw 43 is arranged in the cylinder 41 so as to be rotatable and advanceable. When the screw 43 is rotated, the molding material is sent forward along the helical groove of the screw 43 . The molding material is gradually melted by the heat from the cylinder 41 while being sent forward. The screw 43 is retracted as the liquid molding material is fed forward of the screw 43 and accumulated at the front of the cylinder 41 . After that, when the screw 43 is advanced, the molding material in front of the screw 43 is injected from the nozzle 42 and filled in the mold device 30 .

A metering motor 45 rotates the screw 43 .

The injection motor 46 advances and retreats the screw 43 . Rotational motion of the injection motor 46 is converted into linear motion of the screw 43 by a motion conversion mechanism such as a ball screw.

The pressure detector 47 is provided in the force transmission path between the injection motor 46 and the screw 43 and detects the load acting on the pressure detector 47 . Pressure detector 47 sends a signal indicating the detection result to controller 90 . The detection result of the pressure detector 47 is used for controlling and monitoring the pressure that the screw 43 receives from the molding material, the back pressure against the screw 43, the pressure that the screw 43 acts on the molding material, and the like.

The injection device 40 performs a filling process, a holding pressure process, a weighing process, etc. under the control of the control device 90 .

In the filling process, the injection motor 46 is driven to advance the screw 43 at a set speed, and the liquid molding material accumulated in front of the screw 43 is filled into the cavity space 34 in the mold device 30 . The position and speed of the screw 43 are detected using the encoder 46a of the injection motor 46, for example. The encoder 46a detects rotation of the injection motor 46 and sends a signal indicating the detection result to the control device 90. FIG. When the position of the screw 43 reaches the set position, switching from the filling process to the holding pressure process (so-called V/P switching) is performed. The set speed of the screw 43 may be changed according to the position of the screw 43, time, and the like.

After the position of the screw 43 reaches the set position in the filling process, the screw 43 may be temporarily stopped at the set position, and then the V/P switching may be performed. Immediately before the V/P switching, instead of stopping the screw 43, the screw 43 may be moved forward or backward at a slow speed.

In the holding pressure process, the injection motor 46 is driven to push the screw 43 forward with a set pressure to apply pressure to the molding material in the mold device 30 . The shortage of molding material due to cooling shrinkage can be replenished. The pressure of the molding material is detected using a pressure detector 47, for example. Pressure detector 47 sends a signal indicating the detection result to controller 90 .

In the holding pressure process, the molding material in the cavity space 34 is gradually cooled, and when the holding pressure process is completed, the entrance of the cavity space 34 is closed with the solidified molding material. This state is called a gate seal, and the backflow of molding material from the cavity space 34 is prevented. After the holding pressure process, the cooling process is started. In the cooling process, the molding material in the cavity space 34 is solidified. A weighing step may be performed during the cooling step to shorten the molding cycle.

In the weighing process, the weighing motor 45 is driven to rotate the screw 43 at a set number of revolutions, and the molding material is fed forward along the helical groove of the screw 43 . Along with this, the molding material is gradually melted. The screw 43 is retracted as the liquid molding material is fed forward of the screw 43 and accumulated at the front of the cylinder 41 . The number of rotations of the screw 43 is detected using an encoder 45a of the weighing motor 45, for example. The encoder 45a sends a signal indicating the detection result to the control device 90. FIG.

During the metering process, the injection motor 46 may be driven to apply a set back pressure to the screw 43 to limit its rapid retraction. The back pressure on the screw 43 is detected using a pressure detector 47, for example. Pressure detector 47 sends a signal indicating the detection result to controller 90 . When the screw 43 is retracted to the set position and a predetermined amount of molding material is accumulated in front of the screw 43, the metering process is completed.

The control device 90 has a CPU (Central Processing Unit) 91, a storage medium 92 such as a memory, an input interface 93, and an output interface 94, as shown in FIGS. The control device 90 performs various controls by causing the CPU 91 to execute programs stored in the storage medium 92 . The control device 90 also receives signals from the outside through an input interface 93 and transmits signals to the outside through an output interface 94 .

FIG. 3 is a diagram illustrating an injection device according to one embodiment. The injection device 40 has an injection frame 61, a metering drive shaft 62, an injection drive shaft 63, and the like, in addition to a cylinder 41, a screw 43, a metering motor 45, an injection motor 46, and the like.

The injection frame 61 is fixed to the slide base Sb. A threaded nut 65 is fixed to the injection frame 61 so as to be screwed onto the screw shaft 64 of the cylinder 41 , the metering motor 45 , the injection motor 46 , and the injection drive shaft 63 .

The injection frame 61 has, for example, a front support 61a, a rear support 61b provided behind the front support 61a, and a connecting rod 61c connecting the front support 61a and the rear support 61b. A cylinder 41 and a metering motor 45 are fixed to the front support 61a. An injection motor 46 and a screw nut 65 are fixed to the rear support 61b.

The weighing motor 45 has a stator 45b fixed to the injection frame 61, a bearing 45c held by the stator 45b, and a rotor 45d rotatably supported by the bearing 45c. A metering drive shaft 62 is arranged on the inner peripheral side of the rotor 45d to rotate and linearly move by the rotational motion of the rotor 45d.

The metering drive shaft 62 is spline-connected to the rotor 45d of the metering motor 45 and is rotationally restricted with respect to the rotor 45d. Specifically, the metering drive shaft 62 has a plurality of keys on its outer periphery at intervals in the circumferential direction, and the rotor 45d has a plurality of key grooves on its inner periphery into which the keys are slidably inserted. . Note that the number of keys and the number of key grooves may be one.

When the metering motor 45 is driven, the metering drive shaft 62 and the screw 43 rotate. Thereby, the molding material is sent forward along the spiral groove of the screw 43 . As the molding material is fed forward of the screw 43 and accumulated in the front portion of the cylinder 41, the screw 43 and metering drive shaft 62 are retracted. Therefore, when the metering motor 45 is driven, the metering drive shaft 62 rotates and retreats.

The injection motor 46 has a stator 46b fixed to the injection frame 61, a bearing 46c held by the stator 46b, and a rotor 46d rotatably supported by the bearing 46c. An injection drive shaft 63 is arranged on the inner peripheral side of the rotor 46d so as to rotate and linearly move due to the rotation of the rotor 46d.

The injection drive shaft 63 is spline-connected to the rotor 46d of the injection motor 46 and is rotationally restricted with respect to the rotor 46d. The injection drive shaft 63 includes a threaded shaft 64 on which a threaded nut 65 is fixed to the injection frame 61 . Therefore, when the injection motor 46 is driven, the injection drive shaft 63 advances and retreats while rotating. Balls or rollers may be interposed between the screw shaft 64 and the screw nut 65 .

The front end of injection drive shaft 63 is rotatably supported by bearing 66 held by metering drive shaft 62 . The outer ring of the bearing 66 is fixed to the inner peripheral side of the cylindrical metering drive shaft 62 , and the inner ring of the bearing 66 is fixed to the outer peripheral side of the injection drive shaft 63 . As a result, transmission of rotary motion from the injection drive shaft 63 to the metering drive shaft 62 can be prevented. When the injection motor 46 is driven to advance and retreat the injection drive shaft 63 while rotating, the metering drive shaft 62 and the screw 43 advance and retreat.

By the way, when the injection motor 46 is driven, the rotor 46d and the injection drive shaft 63 are in contact with each other in the tangential direction of the rotational movement, and the injection drive shaft 63 moves linearly with respect to the rotor 46d. The child 46d and the bearing 46c are about to be dragged.

Therefore, the stator 46b of the injection motor 46 has a front wall surface 46e that presses the front bearing 46c (hereinafter simply referred to as the "front bearing 46c") of the two bearings 46c, and a and a rear wall surface 46f that presses the rear side bearing 46c (hereinafter simply referred to as the "rear side bearing 46c") from behind. The front wall surface 46e and the rear wall surface 46f can limit the movement of the bearing 46c to both front and rear sides.

However, in order to ensure the ease of assembly of the injection motor 46, the distance W1 between the front wall surface 46e and the rear wall surface 46f is slightly smaller than the distance W2 between the front end surface of the front side bearing 46c and the rear end surface of the rear side bearing 46c. set large.

Therefore, the injection motor 46 has a biasing member 46g that biases the bearing 46c to one side in the axial direction with respect to the stator 46b. The biasing member 46g may abut against the outer ring of the bearing 46c instead of the inner ring of the bearing 46c so as not to rotate.

A spring such as a coil spring is used as the biasing member 46g. A plurality of springs may be arranged symmetrically around the center line of the bearing 46c, or one spring may be provided along the entire circumferential direction of the bearing 46c. Incidentally, the spring may be a disc spring or the like.

A rubber plate or the like can also be used as the biasing member 46g. A plurality of rubber plates may be arranged symmetrically about the center line of the bearing 46c, or one rubber plate may be provided along the entire circumferential direction of the bearing 46c. In the latter case, the shape of the rubber plate may be ring-shaped.

For example, when the biasing force of the biasing member 46g is forward, there is no gap between the front bearing 46c and the front wall surface 46e as shown in FIG. The bearing 46c does not move forward. Further, the rearward movement of the bearing 46c can be restricted by the forward biasing force. Therefore, the vibration of the bearing 46c can be suppressed, and problems caused by the vibration, such as damage to the encoder 46a and generation of impact noise due to impact, can be suppressed.

The biasing force of the biasing member 46g may be directed backward. In this case, since there is no gap between the rear side bearing 46c and the rear wall surface 46f, the bearing 46c does not move rearward even if a rearward thrust force acts on the bearing 46c. In addition, the forward movement of the bearing 46c can be restricted by the backward biasing force. In this case as well, the vibration of the bearing 46c can be suppressed, and problems caused by the vibration, such as damage to the encoder 46a and generation of impact noise due to impact, can be suppressed.

The injection motor 46 may have a ring-shaped member 46h between the bearing 46c and the biasing member 46g. The biasing force of the biasing member 46g acts on the bearing 46c via the ring-shaped member 46h. The ring-shaped member 46h can disperse the biasing force in the entire circumferential direction.

The direction of the thrust force acting on the bearing 46c is the direction of linear movement of the injection drive shaft 63. As shown in FIG. In the filling process, since the injection drive shaft 63 is advanced while being rotated, forward thrust force acts on the bearing 46c. On the other hand, in the weighing process, since the injection drive shaft 63 is rotated and retracted, a rearward thrust force acts on the bearing 46c.

Also, the magnitude of the thrust force acting on the bearing 46c is proportional to the product of the coefficient of friction and the tangential force. The tangential force is proportional to the injection motor 46 torque. Therefore, the greater the torque of the injection motor 46, the greater the tangential force and the greater the thrust force.

Generally, the torque of the injection motor 46 during the metering process is less than the torque of the injection motor 46 during the filling process. Therefore, the rearward thrust force acting on the bearing 46c during the weighing process is less than the forward thrust force acting on the bearing 46c during the filling process.

Therefore, the biasing member 46g may bias the bearing 46c in the injection direction (here, forward) with respect to the stator 46b. This is because the forward biasing force is for countering the backward thrust force, and the backward thrust force is smaller than the forward thrust force.

The biasing member 46g may be installed, for example, behind the rear bearing 46c in a more compressed state than in its natural state, and bias the bearing 46c forward by its elastic restoring force. The biasing member 46g may be installed in front of the front side bearing 46c in a state extended from its natural state, and bias the bearing 46c forward by its elastic restoring force.

From the viewpoint of durability of the biasing member 46g, the biasing member 46g may be used in a compressed state. On the other hand, from the viewpoint of ease of assembly of the injection motor 46, the biasing member 46g may be used in an extended state. The injection motor 46 is assembled with the encoder 46a facing downward, and the lower parts are assembled before the upper parts. By delaying the order of assembly of the biasing member 46g, it is easy to secure a clearance for assembly.

The biasing force of the biasing member 46g may be set larger than the thrust force acting on the bearing 46c in the direction opposite to the biasing force. The bearing 46c does not move forward and backward. In order to reduce the necessary biasing force as much as possible, the biasing member 46g may bias the bearing 46c toward the stator 46b in the ejection direction (here, forward). This is because, as described above, the forward biasing force is to counteract the rearward thrust force, and the rearward thrust force is smaller than the forward thrust force.

Although the front wall surface 46e is provided in front of the front bearing 46c in this embodiment, it may be provided in front of the rear bearing 46c. Further, the rear wall surface 46f is provided behind the rear bearing 46c in this embodiment, but may be provided behind the front bearing 46c. Moreover, although the number of bearings 46c is two in this embodiment, it may be one, or may be three or more.

By the way, when the metering motor 45 is driven, the rotor 45d and the metering drive shaft 62 move linearly with respect to the rotor 45d while the rotor 45d and the metering drive shaft 62 come into contact with each other in the tangential direction of the rotational motion. The child 45d and the bearing 45c are about to be dragged.

Therefore, the stator 45b of the metering motor 45 has a front wall surface 45e that presses the front bearing 45c (hereinafter simply referred to as the "front bearing 45c") of the two bearings 45c, and a and a rear wall surface 45f that presses the rear side bearing 45c (hereinafter simply referred to as "rear side bearing 45c") from behind. The front wall surface 45e and the rear wall surface 45f can limit the movement of the bearing 45c to both the front and rear sides.

However, in order to ensure the ease of assembly of the metering motor 45, the distance W3 between the front wall surface 45e and the rear wall surface 45f is slightly smaller than the distance W4 between the front end surface of the front bearing 45c and the rear end surface of the rear bearing 45c. set large.

Therefore, the weighing motor 45 has a biasing member 45g that biases the bearing 45c to one side in the axial direction with respect to the stator 45b. The biasing member 45g may abut against the outer ring of the bearing 45c instead of the inner ring of the bearing 45c so as not to rotate.

A spring such as a coil spring is used as the biasing member 45g. A plurality of springs may be arranged symmetrically about the center line of the bearing 45c, or one spring may be provided along the entire circumferential direction of the bearing 45c. Incidentally, the spring may be a disc spring or the like.

A rubber plate or the like can also be used as the biasing member 45g. A plurality of rubber plates may be arranged symmetrically about the center line of the bearing 45c, or one rubber plate may be provided along the entire circumferential direction of the bearing 45c. In the latter case, the shape of the rubber plate may be ring-shaped.

For example, when the biasing force of the biasing member 45g is directed rearward, there is no gap between the rear side bearing 45c and the rear wall surface 45f as shown in FIG. , the bearing 45c does not move rearward. In addition, the forward movement of the bearing 45c can be restricted by the backward biasing force. Therefore, the vibration of the bearing 45c can be suppressed, and problems caused by the vibration, such as damage to the encoder 45a and generation of impact noise due to impact, can be suppressed.

The biasing force of the biasing member 45g may be forward. In this case, since there is no gap between the front side bearing 45c and the front wall surface 45e, the bearing 45c does not move forward even if a forward thrust force acts on the bearing 45c. Further, the rearward movement of the bearing 45c can be restricted by the forward biasing force. In this case as well, the vibration of the bearing 45c can be suppressed, and problems caused by the vibration, such as damage to the encoder 45a and generation of impact noise due to impact, can be suppressed.

The metering motor 45 may have a ring-shaped member 45h between the bearing 45c and the biasing member 45g. The biasing force of the biasing member 45g acts on the bearing 45c via the ring-shaped member 45h. The ring-shaped member 45h can disperse the biasing force in the entire circumferential direction.

The present invention may be applied to only one of the injection motor 46 and the metering motor 45.

In this embodiment, the injection device 40 is of the in-line screw type, and the screw 43 corresponds to the injection member described in claims. Incidentally, the injection device 40 may be of a pre-plastic type.

A pre-plastic injection apparatus supplies molding material melted in a plasticizing cylinder to an injection cylinder, and injects the molding material from the injection cylinder into a mold apparatus. A screw is rotatably and reciprocally arranged in the plasticizing cylinder, and a plunger is reciprocally arranged in the injection cylinder. In the case of the pre-plastic method, the plunger corresponds to the injection member described in the claims.

Although the embodiments and the like of the injection molding machine have been described above, the present invention is not limited to the above-described embodiments and the like. Improvements are possible.

The present invention is applicable to the ejector device 50 as well. The ejector motor 51 has a stator fixed to the movable platen 13, a bearing held by the stator, and a rotor rotatably supported by the bearing. An ejector drive shaft may be arranged on the inner peripheral side of the rotor to rotate and linearly move by the rotational motion of the rotor.

The ejector drive shaft is spline-connected to the rotor of the ejector motor 51 and is rotationally restrained with respect to the rotor. The ejector drive shaft includes the threaded shaft of the motion conversion mechanism 52 , and a threaded nut screwed onto the threaded shaft is fixed to the movable platen 13 . Therefore, when the ejector motor 51 is driven, the ejector drive shaft advances and retreats while rotating.

A front end portion of the ejector drive shaft is rotatably supported by a bearing held by a bearing holder. As a result, transmission of rotational motion from the ejector drive shaft to the bearing holder can be prevented. When the ejector motor 51 is driven to move the ejector drive shaft forward and backward while rotating, the bearing holder moves forward and backward. A rear end portion of an ejector rod 53 is connected to the bearing holder, and the ejector rod 53 advances and retreats together with the bearing holder.

By the way, when the ejector motor 51 is driven, the rotor and the ejector drive shaft are in contact with each other in the tangential direction of the rotary motion, and the ejector drive shaft moves linearly with respect to the rotor. tries to be dragged.

Therefore, the ejector motor 51 may have a biasing member that biases the bearing axially to one side with respect to the stator, similarly to the injection motor 46 . Vibration of the bearing of the ejector motor 51 can be suppressed when driving the ejector drive shaft.

Further, the ejector motor 51 may further have a ring-shaped member arranged between the bearing and the biasing member, similar to the injection motor 46 . The biasing force of the biasing member acts on the bearing via the ring-shaped member.

The direction of the thrust force acting on the bearing of the ejector motor 51 is the linear motion direction of the ejector drive shaft. When the ejector drive shaft is rotated to advance the ejector rod 53, a forward thrust force acts on the bearing. On the other hand, when the ejector drive shaft is rotated to retract the ejector rod 53, a backward thrust force acts on the bearing.

Also, the magnitude of the thrust force acting on the bearing of the ejector motor 51 is proportional to the product of the coefficient of friction and the tangential force. The tangential force is proportional to the torque of the ejector motor 51 . Therefore, the greater the torque of the ejector motor 51, the greater the tangential force and the greater the thrust force.

When the ejector rod 53 is retracted, the torque of the ejector motor 51 is smaller than when the ejector rod 53 is moved forward while separating the molded product from the mold device 30 . Therefore, the rearward thrust force acting on the bearing of the ejector motor 51 when the ejector rod 53 moves backward is smaller than the forward thrust force acting on the bearing of the ejector motor 51 when the ejector rod 53 moves forward.

Therefore, the biasing member may bias the bearing of the ejector motor 51 toward the stator of the ejector motor 51 in the ejection direction (here, forward). This is because the forward biasing force is for countering the backward thrust force, and the backward thrust force is smaller than the forward thrust force.

The present invention can also be applied to the mold clamping device 10 . The mold clamping motor 25 has a stator fixed to the toggle support 15, a bearing held by the stator, and a rotor rotatably supported by the bearing. A mold clamping drive shaft may be arranged on the inner peripheral side of the rotor so as to rotate and linearly move due to the rotary motion of the rotor.

The mold clamping drive shaft is spline-connected to the rotor of the mold clamping motor 25 and is rotationally restrained with respect to the rotor. The mold clamping drive shaft includes the threaded shaft of the motion conversion mechanism 26 , and a threaded nut screwed onto the threaded shaft is fixed to the toggle support 15 . Therefore, when the mold clamping motor 25 is driven, the mold clamping drive shaft advances and retreats while rotating.

A front end portion of the mold clamping drive shaft is rotatably supported by a bearing held by the crosshead 21 . As a result, transmission of rotary motion from the mold clamping drive shaft to the crosshead 21 can be prevented. When the mold clamping motor 25 is driven to rotate the mold clamping drive shaft to advance and retreat, the crosshead 21 advances and retreats, and the movable platen 13 advances and retreats.

By the way, when the mold clamping motor 25 is driven, the mold clamping drive shaft moves linearly with respect to the rotor while the rotor and the mold clamping drive shaft are in contact with each other in the tangential direction of the rotational movement. The child or bearing will be dragged.

Therefore, like the injection motor 46, the mold clamping motor 25 may have a biasing member that biases the bearing to one side in the axial direction with respect to the stator. Vibration of the bearing of the mold clamping motor 25 can be suppressed when driving the mold clamping drive shaft.

Also, the mold clamping motor 25 may further have a ring-shaped member arranged between the bearing and the biasing member, similar to the injection motor 46 . The biasing force of the biasing member acts on the bearing via the ring-shaped member.

The mold clamping device 10 of the above embodiment is a horizontal type in which the mold opening/closing direction is horizontal, but may be a vertical type in which the mold opening/closing direction is vertical. A vertical mold clamping device has a lower platen, an upper platen, a toggle support, a tie bar, a toggle mechanism, a mold clamping motor, and the like. One of the lower platen and the upper platen is used as a fixed platen and the other as a movable platen. A lower mold is attached to the lower platen, and an upper mold is attached to the upper platen. A mold device is composed of the lower mold and the upper mold. The lower mold may be attached to the lower platen via a rotary table. A toggle support is disposed below the lower platen. The toggle mechanism is arranged between the toggle support and the lower platen, and raises and lowers the lower platen relative to the toggle support. A mold clamp motor operates a toggle mechanism. The tie bars are vertically parallel and pass through the lower platen to connect the upper platen and the toggle support.

10 Mold clamping device 12 Fixed platen 13 Movable platen 25 Mold clamping motor 30 Mold device 32 Fixed mold 33 Movable mold 40 Injection device 41 Cylinder 43 Screw 45 Metering motor 45b Stator 45c Bearing 45d Rotor 45g Biasing member 46h Ring Shaped member 46 Injection motor 46b Stator 46c Bearing 46d Rotor 46g Biasing member 46h Ring-shaped member 50 Ejector device 51 Ejector motor 53 Ejector rod 62 Metering drive shaft 63 Injection drive shaft 90 Control device

Claims (4)

a motor ;
a motion conversion mechanism for converting rotary motion of the motor into linear motion ;
The motor includes a stator, a bearing held by the stator, a rotor rotatably supported by the bearing, and biasing the bearing against the stator in a forward direction of the motion conversion mechanism. and a biasing member. The motion conversion mechanism has a screw shaft and a screw nut screwed onto the screw shaft,
2. The injection molding machine according to claim 1, wherein said screw shaft rotates and advances and retreats as said motor rotates. the motor is an injection motor for advancing and retreating the injection member,
a drive shaft arranged on the inner peripheral side of the rotor and to which the rotary motion of the injection motor is transmitted;
The drive shaft includes the screw shaft,
3. The injection molding machine according to claim 2, wherein said advance direction is a direction in which molding material is injected by said injection member. 4. The injection molding machine of claim 3, wherein the drive shaft is splined to the rotor.

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