JP2000052394A - Lubrication device for injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lubrication device for an injection molding machine capable of feeding easily grease to screwing sections. SOLUTION: A lubrication device for an injection molding machine is provided with a driving motor, a ball screw shaft 65, a ball nut 69 to be screwed with the ball screw shaft 65 and a rotation transmitting means for transmitting the rotation generated by driving the driving motor to either one of the ball screw shaft 65 and the ball nut 69. A grease feed line with its one end opened on a screwing section P2 between the ball screw shaft 65 and the ball nut 69 and the other end opened toward the outside of a device is formed on the ball screw shaft 65. A grease feed opening 111 is formed on the section opened to the outside of the grease feed line. Even when the ball nut 69 is set inside the driving motor or the ball nut 69 is rotated, a pipe can be connected easily with the grease feed opening 111 and a grease gun can be connected easily with the pipe.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubrication device for an injection molding machine.

[0002]

2. Description of the Related Art Conventionally, in an injection molding machine, a resin heated and melted in a heating cylinder is injected at a high pressure to fill a cavity space of a mold apparatus.
A molded product can be obtained by cooling and solidifying in the cavity space.

The injection molding machine has a mold clamping device and an injection device. The mold clamping device has a fixed platen and a movable platen, and a mold closing cylinder advances and retreats the movable platen to close, close, and close the mold. Open the mold. On the other hand, the injection device includes a heating cylinder that heats and melts the resin supplied from the hopper, and an injection nozzle that injects the melted resin, wherein a screw is rotatable in the heating cylinder and moves forward and backward. Arranged freely. Then, the resin is injected from the injection nozzle by moving the screw forward, and the resin is measured by moving the screw backward.

[0004] In the injection molding machine having the above-described structure, the screw is advanced without rotating in the injection step, and is retracted while rotating in the measuring step. In this case, a drive motor is used as a drive source, and the rotational motion generated by the drive motor is converted into a linear motion by, for example, a ball screw.

[0005] A lubricating device is provided for lubricating the ball screw, a greasing hole is formed in the ball nut, and the grease supplied from the greasing hole causes a gap between the ball nut and the ball screw shaft. Is lubricated.

[0006]

However, in the lubricating device of the conventional injection molding machine, when the ball screw is disposed inside the drive motor, when the ball nut is rotated, or the like, the screw is not used. Grease cannot be supplied to the joint. FIG. 2 is a conceptual diagram of a conventional lubrication device for an injection molding machine.

In the drawing, reference numeral 160 denotes a ball screw, 165
Is a ball screw shaft, 169 is a ball nut screwed with the ball screw shaft 165, P1 is the ball screw shaft 16
5 and a threaded portion between the ball nut 169. By rotating the ball screw shaft 165, the ball nut 169 can be moved in the axial direction. In addition, by rotating the ball nut 169, the ball screw shaft 165 can be moved in the axial direction.

Incidentally, in order to prevent a frictional force or galling from occurring when the ball screw shaft 165 and the ball nut 169 move relative to each other, the screwing portion P1 is always made of grease (not shown). Lubricated.
Further, grease is consumed as the relative movement between the ball screw shaft 165 and the ball nut 169 is repeated, so that grease is supplied to the threaded portion P1 periodically.

For this purpose, the ball nut 169 is
A greasing hole 171 communicating from the outer peripheral surface to the screw portion P1 is provided. A pipe 175 is connected to the greasing hole 171 via a nipple 180, and the pipe 175 and the grease gun 173 are selectively connected via a joint 174. Therefore, by operating the grease gun 173, grease can be injected and supplied to the screw portion P1.

However, when the ball screw 160 is disposed inside a drive motor (not shown), a pipe 175 is connected to the greasing hole 171 or a grease gun 173 is connected to the pipe 175. It becomes difficult.
When the ball nut 169 is rotated, it is not determined at which position in the circumferential direction of the ball nut 169 the greasing hole 171 is stopped.
It becomes difficult to connect the pipe 175 to the greasing hole 171.

Therefore, it becomes difficult to supply grease to the threaded portion P1. SUMMARY OF THE INVENTION It is an object of the present invention to provide a lubricating device for an injection molding machine capable of easily supplying grease to a threaded portion by solving the problems of the conventional lubricating device for an injection molding machine.

[0012]

For this purpose, in the lubricating device for an injection molding machine according to the present invention, a drive motor, a ball screw shaft, a ball nut screwed to the ball screw shaft, and the drive motor are provided. A rotation transmitting means for transmitting the rotation generated by the driving to one of the ball screw shaft and the ball nut.

[0013] The ball screw shaft is provided with a greasing passage, one end of which opens into a threaded portion between the ball screw shaft and the ball nut, and the other end of which opens outward. In another lubrication device for an injection molding machine according to the present invention, the rotation transmitting means transmits the rotation of the drive motor to a ball screw shaft. In still another lubrication device for an injection molding machine of the present invention, the rotation transmitting means transmits the rotation of the drive motor to a ball nut.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a cross-sectional view of a main part of a driving unit according to an embodiment of the present invention, FIG. 3 is a first cross-sectional view showing an injection device according to an embodiment of the present invention, and FIG. 4 is an injection device according to an embodiment of the present invention. FIG. 5 is a second sectional view showing

In FIG. 3, reference numeral 12 denotes a heating cylinder. The heating cylinder 12 has an injection nozzle 12a at a front end (left end in the figure). A screw 22 is disposed in the heating cylinder 12 so as to be rotatable and advance / retreat. The screw 22 has a screw head 22a at the front end, extends rearward (to the right in the figure) inside the heating cylinder 12, and has a rear end (right end in the figure).
Is connected to a driving unit described later. A spiral flight 23 is formed around the screw 22, and the flight 23 forms a groove 26.

A resin supply port 29 is formed at a set position of the heating cylinder 12.
The hopper 30 is fixed to 9. The resin supply port 29 is
When the screw 22 is located at the most forward position (left side in the drawing) in the heating cylinder 12, it is formed at a position corresponding to the rear end (right end in the drawing) of the groove 26.

Therefore, when the driving unit is driven to move backward (moving to the right in the drawing) while rotating the screw 22 during the weighing step, the pellet-shaped resin 33 in the hopper 30 falls down. It enters the heating cylinder 12 and moves forward (moves to the left in the figure) in the groove 26. A heater (not shown) is provided around the heating cylinder 12 so that the heating cylinder 12 can be heated by the heater and the resin 33 in the groove 26 can be melted. Therefore, when the screw 22 is rotated backward by a predetermined amount, one shot of the melted resin 33 is stored in front of the screw head 22a.

Next, in the injection step, when the driving unit is driven to advance the screw 22 without rotating, the resin 33 stored in front of the screw head 22a is injected from the injection nozzle 12a. It is filled in a cavity space of a mold device (not shown). Next, the driving unit will be described.

In FIG. 4, reference numeral 11 denotes a drive unit case surrounding the drive unit. The drive unit case 11 is fixed to the rear end (right end in the figure) of the heating cylinder 12 (FIG. 3).
The drive unit case 11 includes a front cover 13, a center frame 15, a rear cover 17, and the front cover 1.
The front frame 41 connects the center frame 3 to the center frame 15 and the rear frame 42 connects the center frame 15 to the rear cover 17. Then, the front cover 13 and the front frame 41 are bolted to each other.
1, the front frame 41 and the center frame 1
5 by the bolt b2, and the center frame 15 and the rear frame 42 by the bolt b3.
2 and the rear cover 17 are fixed by bolts b4, respectively.

A metering motor 44 is provided at a front portion (left portion in the drawing) of the driving portion case 11, and an injection motor 45 as a driving motor is provided at a rear portion (right portion in the drawing).
Are arranged on the same axis. The weighing motor 44
Is a stator 4 fixed to the front frame 41
6, and an annular rotor 47 disposed on the inner peripheral side of the stator 46. An injection motor 45 is fixed to the rear frame 42, and a stator 48.
And an annular rotor 49 disposed on the inner peripheral side of the rotor.

The rotor 47 is rotatably supported by the drive unit case 11. For this purpose, a hollow first rotor shaft 56 is fitted (fixed) into the rotor 47 and fixed, and the front end (left end in the figure) of the first rotor shaft 56 is attached to the front frame 41 by the bearing 51 and the rear end. Are supported on the center frame 15 by the bearings 52, respectively.

On the other hand, the rotor 49 is also provided in the drive unit case 11.
Is rotatably supported with respect to. Therefore, the rotor 4
9, a hollow second rotor shaft 57 is fitted and fixed, and the front end of the second rotor shaft 57 is supported by the center frame 15 by the bearing 53 and the rear end thereof is supported by the rear frame 42 by the bearing. By the way, in the weighing motor 44, by supplying a current of a predetermined frequency to the stator 46, the screw 22 can be moved backward while rotating. For this purpose, the sleeve 18 is provided on the inner periphery of the front part of the first rotor shaft 56, and the front end of the sleeve 18 and the front end of the first rotor shaft 56 are fixed by bolts b5. Further, a first spline nut 62 is fixed to the rear end of the sleeve 18 by a bolt b12, and the first spline nut 62 and the first spline shaft 63 are spline-connected.
The screw 22 is fixed to the front end of the screw. in this case,
The first spline nut 62 and the first spline shaft 63
Thus, the first driving force transmitting means is constituted, the relative movement in the rotational direction is restricted, and the relative movement in the axial direction is allowed. The first spline shaft 63 has a length corresponding to the stroke of the screw 22.

Therefore, when the measuring motor 44 is driven to rotate the rotor 47, the rotation of the rotor 47 is performed via the first rotor shaft 56, the sleeve 18, the first spline nut 62 and the first spline shaft 63. The power is transmitted to the screw 22 to rotate the screw 22.
Then, the resin 33 moves forward (moves leftward in the figure) while being melted in the groove 26, and the screw 22 moves backward (moves rightward in the figure) due to the back pressure generated as the resin 33 moves forward. Let me do.

At this time, since the first spline nut 62 and the first spline shaft 63 are spline-connected, the first spline shaft 63 is retracted relatively to the first spline nut 62. On the other hand, in the injection motor 45, by supplying a current of a predetermined frequency to the stator 48, the screw 22 can be advanced without rotating. For this purpose, an annular bearing retainer 64 as a rotation transmitting means is fixed to the rear end of the second rotor shaft 57, and the first shaft portion 65a of the ball screw shaft 65 is fitted into the inner periphery of the bearing retainer 64. Fixed. The ball screw shaft 65 is rotatably supported by the drive unit case 11. That is, the ball screw shaft 65 is supported on the rear cover 17 by the bearing 66 and the thrust bearing 68 via the bearing retainer 64.
A rear cap 77 is fixed to the rear cover 17 with a bolt b6 across an annular load meter 75,
A second shaft portion 65 b of the ball screw shaft 65 is supported by a rear cap 77 by a bearing 67. An absolute value pulse encoder 85 is provided on the rear cap 77 via a bracket 86. The absolute value pulse encoder 85 is connected to the second shaft 65b to
Functions as a rotation speed detecting means for detecting the rotation speed of the ball screw shaft 65, that is, the rotation speed of the injection motor, and also functions as a screw position detection means, based on the rotation speed of the injection motor. Is detected. In the present embodiment, the bearing retainer 64 transmits the rotation of the injection motor 45 to the ball screw shaft 65, but may transmit the rotation to the ball nut.

A ball nut 69 is provided in the second rotor shaft 57 so as to be able to advance and retreat, and the ball nut 69 and the ball screw shaft 65 are screwed together to constitute a movement direction changing means. Therefore, the rotation of the rotor 49 is transmitted to the ball screw shaft 65 via the second rotor shaft 57 and the bearing retainer 64,
The rotation is converted to a linear motion, and the ball nut 69 is moved forward and backward. The stopper 19 is fixed to the front end of the ball screw shaft 65 by a bolt b13 so that the ball screw shaft 65 does not come off the ball nut 69.

In order to prevent the ball nut 69 from rotating together with the ball screw shaft 65, a sleeve-shaped second spline shaft 71 is fixed to the front end of the ball nut 69 by a bolt b11.
The second spline nut 76 fixed to 5 and the second spline shaft 71 are spline-connected. In this case, the second
The spline nut 76 and the second spline shaft 71 constitute a second driving force transmitting means, and the relative movement in the rotation direction is restricted, and the relative movement in the axial direction is allowed. The second spline shaft 71 has a length corresponding to the stroke of the screw 22.

Further, a bearing box 72 as a third driving force transmitting means is fixed to the further front end of the second spline shaft 71 by a bolt b7, and a thrust bearing is provided forward (leftward in the drawing) in the bearing box 72. 73, and a bearing 74 is disposed rearward (rightward in the figure). In this case, the bearing box 72 restricts the relative movement in the axial direction, and allows the relative movement in the rotation direction. Therefore,
The first spline shaft 63 has a thrust bearing 73
The bearing 74 supports the second spline shaft 71 and the ball nut 69 so as to be relatively rotatable.

A rear end shaft 22b of the screw 22 is connected to a front end of the first spline shaft 63 via a first coupling 81 and a second coupling 82.
8, fixed by b9. The first coupling 8
1 is the sleeve 18 as the screw 22 advances and retreats.
The inside can be moved. At the rear end of the first spline shaft 63, a concave portion 63a is formed at the retreat limit position of the first spline shaft 63 so as not to interfere with the head of the bolt b13. Therefore, the axial dimension of the injection molding machine can be reduced.

An encoder 84 is connected to the sleeve 18 via a gear train 87.
Functions as a second rotational speed detecting means, and the sleeve 18
, Ie, the rotation speed of the metering motor.
Reference numeral 89 denotes a water-cooled jacket, which is fixed to the front cover 13 by bolts b10, and is connected to the front cover 1 from the rear end of the heating cylinder 12.
3 to prevent heat from being transmitted.

Next, the operation of the driving section having the above configuration will be described. First, in the injection step, when a current is supplied to the stator 48 of the injection motor 45, the rotor 49 is rotated, and the rotation of the rotor 49 is controlled by the second rotor shaft 5.
7 and the ball screw shaft 6 via the bearing retainer 64
5 and the ball screw shaft 65 is rotated.
At this time, since the second spline nut 76 fixed to the center frame 15 and the second spline shaft 71 are spline-connected, the ball nut 69 does not rotate. Therefore, a thrust is generated in the ball nut 69, and the ball nut 69 is advanced.

During this time, the weighing motor 44 is not driven, and the rotor 47 is stopped. Therefore, the first spline shaft 63 disposed in front of the ball nut 69
Is advanced without rotating, the screw 2
Advance 2 In this manner, the rotational motion generated by the injection motor 45 is converted into a linear motion by the ball screw shaft 65 and the ball nut 69. As a result, the resin 33 stored in front of the screw 22 can be injected from the injection nozzle 12a.

Next, in the measuring step, the measuring motor 4
When the current is supplied to the stator 46 of No. 4, the rotor 47 is rotated, and the rotation of the rotor 47 is transmitted to the first spline shaft 63 via the first rotor shaft 56, the sleeve 18, and the first spline nut 62, The first spline shaft 63 is rotated. Then, the rotation of the first spline shaft 63 is transmitted to the screw 22, and the screw 22 is rotated. Accordingly, the groove 2
6, the resin 33 moves forward while being melted.
The screw 22 is caused to retreat by a back pressure generated with the advance of the screw.

At this time, since the first spline nut 62 and the first spline shaft 63 are spline-connected, the first spline shaft 63 is relatively retracted with respect to the first spline nut 62. The injection motor 45 is driven while controlling the back pressure of the resin 33 to be measured, and the rotor 49 is rotated in a direction to retract the screw 22. At this time, the load applied to the screw 22 or the like in the axial direction is detected by the load meter 75, and the back pressure can be calculated based on the load. Further, a pressure sensor (not shown) is provided in the heating cylinder 12, and the heating cylinder 1 is controlled by the pressure sensor.
It is also possible to detect the pressure of the resin 33 inside 2 and calculate the back pressure based on the pressure.

Next, the ball screw 101 including the ball screw shaft 65 and the ball nut 69 will be described. FIG.
As shown in FIG. 5, an annular bearing retainer 64 is fixed to the rear end of the second rotor shaft 57, and the first shaft portion 65a of the ball screw shaft 65 is fitted and fixed to the inner periphery of the bearing retainer 64. You. Further, a second shaft portion 65 b of the ball screw shaft 65 is supported by a rear cap 77 by a bearing 67. Then, a screw portion 65c of the ball screw shaft 65 and a screw portion formed on the inner periphery of the ball nut 69 are screwed.

Accordingly, the rotational motion of the second rotor shaft 57 is transmitted to the ball screw shaft 65 via the bearing retainer 64 and is converted into a linear motion by the ball screw 101, thereby moving the ball nut 69 in the axial direction. Can be done. By the way, the ball screw shaft 65
In order to prevent the generation of frictional force or galling when the ball nut 69 and the ball nut 69 move relative to each other, the threaded portion P2 between the ball screw shaft 65 and the ball nut 69 is always lubricated with grease. Is done. In addition, grease is consumed as the relative movement between the ball screw shaft 65 and the ball nut 69 is repeated, so that the threaded portion P2 is periodically
Is supplied with grease.

For this purpose, a greasing hole 102 is formed substantially in the center of the threaded portion 65c so as to open to the threaded portion P2 and extends in the radial direction, and a greasing hole 103 is formed in communication with the greasing hole 102. Is done. In addition, even if the ball nut 69 moves in the axial direction of the ball screw shaft 65,
It is always formed where the ball nut 69 is interposed. The greasing hole 103 extends in the ball screw shaft 65 in the axial direction, passes through the screw portion 65c and the first shaft portion 65a, and communicates with the greasing holes 104 and 105 at substantially the center of the second shaft portion 65b. . The greasing holes 104 and 105 are opened toward the reservoir 106 formed in the rear cap 77 so as to face the second shaft portion 65b.

Further, inside the rear cap 77, a greasing hole 108 communicating with the reservoir 106 and extending in the radial direction, and extending in the axial direction communicating with the greasing hole 108, the rear end face of the rear cap 77 ( (Right end face in the figure) is opened outward to form a greasing hole 109. Therefore, a pipe (not shown) can be connected to the greasing hole 109, and the pipe can be connected to a grease gun (not shown) as a grease supply source via a joint or the like. In this case, when the grease is sprayed and supplied to the greasing hole 109 by operating the grease gun, the grease passes through the greasing holes 109 and 108 in order and accumulates in the reservoir 10.
6 and is supplied to the threaded portion P2 through the greasing holes 104 to 102 in order. A grease tank (not shown) may be used as a grease supply source, and grease may be supplied from the grease tank via a pipe. In that case, a valve is provided at a predetermined portion of the pipe to selectively supply grease.

The ball nut 69 is used for the injection motor 4.
5, since the greasing hole 109 is formed on the outer peripheral surface of the injection molding machine, it is easy to connect a pipe or connect a grease gun to the pipe. The greasing holes 102 to 105, 108, 109
The reservoir 106 constitutes a greasing path. Therefore, grease can be easily supplied to the screw portion P2.

In this embodiment, the ball nut 6
9 is not rotated, but even when applied to a lubricating device of an injection molding machine in which a ball nut is rotated, the greasing hole 109 is located at a fixed position regardless of the rotation of the ball nut 69. This makes it easy to connect the pipe to the greasing hole 109. It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified based on the gist of the present invention, and they are not excluded from the scope of the present invention.

[0040]

As described above in detail, according to the present invention, in a lubricating device for an injection molding machine, a drive motor, a ball screw shaft, a ball nut screwed to the ball screw shaft, A rotation transmitting unit configured to transmit rotation generated by driving the drive motor to one of the ball screw shaft and the ball nut.

The ball screw shaft is provided with a greasing passage, one end of which opens into a threaded portion between the ball screw shaft and the ball nut, and the other end of which opens toward the outside of the device. You. In this case, a greasing hole is formed in a portion of the greasing passage that is open to the outside. Therefore, even if the ball nut is provided inside the drive motor, or even if the ball nut is rotated, it is necessary to connect a pipe to the greasing hole or connect a grease gun to the pipe. It will be easier.

As a result, grease can be easily supplied to the threaded portion.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a driving unit according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram of a conventional lubrication device for an injection molding machine.

FIG. 3 is a first sectional view showing the injection device according to the embodiment of the present invention.

FIG. 4 is a second sectional view showing the injection device according to the embodiment of the present invention.

[Explanation of symbols]

 45 Injection motor 64 Bearing retainer 65 Ball screw shaft 69 Ball nut 102-105, 108, 109 Greasing hole 106 Reservoir P2 Threaded part

Claims (3)

[Claims] 1. A drive motor, (b) a ball screw shaft, (c) a ball nut screwed onto the ball screw shaft, and (d) a drive motor that is generated by driving the drive motor. (E) the ball screw shaft has one end connected to a threaded portion between the ball screw shaft and the ball nut. A lubrication device for an injection molding machine, wherein a lubrication passage that opens and the other end opens to the outside is provided. 2. The lubricating device for an injection molding machine according to claim 1, wherein said rotation transmitting means transmits the rotation of the drive motor to a ball screw shaft. 3. The lubricating device for an injection molding machine according to claim 1, wherein the rotation transmitting means transmits the rotation of the drive motor to a ball nut.