JP3439127B2 - Lubrication device for injection molding machine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating 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 device.
A molded product can be obtained by cooling and solidifying in the cavity space.

The injection molding machine includes a mold clamping device and an injection device. The mold clamping device includes a fixed platen and a movable platen, and a mold clamping cylinder advances and retracts the movable platen to close the mold and clamp 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, and a screw is rotatably and forwards and backwards in the heating cylinder. Arranged freely. Then, the screw is moved forward to inject the resin from the injection nozzle, and the screw is moved backward to measure the resin.

By the way, in the injection molding machine having the above construction, the screw is moved forward without rotating in the injection process, and is retracted while rotating in the measuring process. In this case, a drive motor is used as the drive source, and the rotary motion generated by the drive motor is converted into a linear motion by, for example, a ball screw.

A lubrication device is provided to lubricate 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. The threaded portion of the is lubricated.

[0006]

However, in the conventional lubrication device for an injection molding machine, when the ball screw is disposed inside the drive motor, 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 figure, 160 is a ball screw and 165.
Is a ball screw shaft, 169 is a ball nut screwed with the ball screw shaft 165, and P1 is the ball screw shaft 16
5 and the ball nut 169. By rotating the ball screw shaft 165, the ball nut 169 can be moved in the axial direction. Further, the ball screw shaft 165 can be moved in the axial direction by rotating the ball nut 169.

By the way, in order to prevent a frictional force or a 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, since the grease is consumed as the relative movement of the ball screw shaft 165 and the ball nut 169 is repeated, the grease is regularly supplied to the threaded portion P1.

Therefore, the ball nut 169 is
A greasing hole 171 that communicates with the screwed portion P1 from the outer peripheral surface is provided. Further, 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 jetted and supplied to the screw portion P1.

However, when the ball screw 160 is disposed inside a drive motor (not shown), a pipe 175 may be connected to the greasing hole 171 or a grease gun 173 may be connected to the pipe 175. It will be difficult.
Further, 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 solve the problems of the conventional lubrication device for an injection molding machine, and to provide a lubrication device for an injection molding machine, which can easily supply grease to a threaded portion.

[0012]

Therefore, in a lubrication device for an injection molding machine of the present invention, a drive motor, a ball screw shaft, a ball nut screwed with the ball screw shaft, and the drive motor are provided. Rotation transmitting means for transmitting the rotation generated by driving to the ball screw shaft.

The ball screw shaft is provided with a greasing passage, one end of which opens at a threaded portion between the ball screw shaft and the ball nut and the other end of which opens toward the outside.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 is a sectional view of an essential part of a drive unit according to an embodiment of the present invention, FIG. 3 is a first 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. It is a second cross-sectional view showing.

In FIG. 3, reference numeral 12 is a heating cylinder, and the heating cylinder 12 has an injection nozzle 12a at the front end (the left end in the drawing). A screw 22 is disposed in the heating cylinder 12 so as to be rotatable and movable back and forth. The screw 22 has a screw head 22a at the front end, extends rearward (rightward in the drawing) in the heating cylinder 12, and has a rear end (right end in the drawing).
Will be connected to a drive unit described later. A spiral flight 23 is formed around the screw 22, and a groove 26 is formed by the flight 23.

A resin supply port 29 is formed at a set location of the heating cylinder 12, and the resin supply port 2
The hopper 30 is fixed to the unit 9. The resin supply port 29 is
The screw 22 is formed at a position corresponding to the rear end portion (right end portion in the drawing) of the groove 26 in a state where the screw 22 is placed at the most front (left side in the drawing) inside the heating cylinder 12.

Therefore, when the driving portion is driven and the screw 22 is retracted (moved to the right in the drawing) while rotating the screw 22 in the measuring step, the pellet-shaped resin 33 in the hopper 30 falls. It enters the heating cylinder 12 and is advanced (moved to the left in the drawing) in the groove 26. Further, a heater (not shown) is arranged around the heating cylinder 12, and the heater can heat the heating cylinder 12 to melt the resin 33 in the groove 26. Therefore, when the screw 22 is rotated and retracted by a predetermined amount, one shot of the melted resin 33 is stored in front of the screw head 22a.

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

In FIG. 4, 11 is a drive unit case surrounding the drive unit, and 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 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 15 and the center frame 15, and the rear frame 42 connects the center frame 15 and the rear cover 17. Then, the front cover 13 and the front frame 41 are attached to the bolt b.
1, the front frame 41 and the center frame 1
5 by a bolt b2, and the center frame 15 and the rear frame 42 by a bolt b3.
2 and the rear cover 17 are fixed by bolts b4.

A metering motor 44 is provided in the front part (left part in the figure) of the drive part case 11, and an injection motor 45 as a drive motor in the rear part (right part in the figure).
Are arranged on the same axis as each other. The weighing motor 44
Is a stator 4 fixed to the front frame 41
6, and an annular rotor 47 arranged on the inner peripheral side of the stator 46, and the injection motor 45 is a stator 48 fixed to the rear frame 42, and the stator 48.
It is composed of an annular rotor 49 arranged on the inner peripheral side.

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

On the other hand, the rotor 49 is also the drive unit case 11
It is rotatably supported with respect to. Therefore, the rotor 4
A hollow second rotor shaft 57 is fitted and fixed to the shaft 9. 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 54. By the way, in the metering motor 44, by supplying a current of a predetermined frequency to the stator 46, the screw 22 can be retracted while rotating. Therefore, the sleeve 18 is arranged on the inner periphery of the front portion 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 the bolt b5. Further, a first spline nut 62 is fixed to the rear end of the sleeve 18 by a bolt b12, the first spline nut 62 and the first spline shaft 63 are spline-connected, and the first spline shaft 63 is provided.
The screw 22 is fixed to the front end of the. in this case,
The first spline nut 62 and the first spline shaft 63
And constitute the first driving force transmission means, restrain relative movement in the rotational direction, and allow relative movement in the axial direction. The first spline shaft 63 has a length corresponding to the stroke of the screw 22.

Therefore, when the metering motor 44 is driven to rotate the rotor 47, the rotor 47 is rotated via the first rotor shaft 56, the sleeve 18, the first spline nut 62 and the first spline shaft 63. It is transmitted to the screw 22 to rotate the screw 22.
Then, the resin 33 moves forward (moves leftward in the drawing) while being melted in the groove 26, and the screw 22 moves backward (moves rightward in the drawing) due to the back pressure generated as the resin 33 moves forward. To be made.

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 relative 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 moved forward without rotating. Therefore, 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 with respect to the rear cover 17 by the bearing 66 and the thrust bearing 68 via the bearing retainer 64.
Then, a rear cap 77 is fixed to the rear cover 17 with a bolt b6 with an annular load meter 75 interposed therebetween.
The second shaft portion 65b of the ball screw shaft 65 is supported by the bearing 67 with respect to the rear cap 77. An absolute value pulse encoder 85 is mounted on the rear cap 77 via a bracket 86. The absolute value pulse encoder 85 is connected to the second shaft portion 65b and has a first
Of the ball screw shaft 65, that is, the rotation speed of the injection motor, and the screw position detection means. The position of the screw 22 is determined based on the rotation speed of the injection motor. To detect. In this embodiment, the bearing retainer 64 transmits the rotation of the injection motor 45 to the ball screw shaft 65, but it can also transmit the rotation to the ball nut.

A ball nut 69 is arranged in the second rotor shaft 57 so as to be able to move forward and backward, and the ball nut 69 and the ball screw shaft 65 are screwed together to form a movement direction converting 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 rotary motion is converted into a linear motion to move the ball nut 69 back and forth. A 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 from the ball nut 69.

A second sleeve-shaped spline shaft 71 is fixed to the front end of the ball nut 69 by a bolt b11 so that the ball nut 69 does not rotate together with the ball screw shaft 65.
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 compose a second driving force transmission means, restrain the relative movement in the rotational direction, and allow the relative movement in the axial direction. The second spline shaft 71 has a length corresponding to the stroke of the screw 22.

A bearing box 72 as a third driving force transmitting means is fixed to the front end of the second spline shaft 71 by means of a bolt b7, and a thrust bearing is provided in the front of the bearing box 72 (to the left in the figure). 73, and bearings 74 are arranged at the rear (right side in the figure). In this case, the bearing box 72 restrains 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.
Also, the bearing 74 supports the second spline shaft 71 and the ball nut 69 in a relatively rotatable manner.

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

Reference numeral 84 is an encoder connected to the sleeve 18 via a gear train 87.
Functions as a second rotation speed detection unit, and the sleeve 18
The number of rotations of, that is, the number of rotations of the measuring motor is detected.
Further, 89 is a water cooling jacket, which is fixed to the front cover 13 by bolts b10, and is provided from the rear end of the heating cylinder 12 to the front cover 1
Prevent heat transfer to the 3.

Next, the operation of the drive unit having the above structure will be described. First, in the injection process, 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 causes the second rotor shaft 5 to rotate.
7 through the bearing retainer 64 and the ball screw shaft 6
5, 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, thrust is generated in the ball nut 69, and the ball nut 69 is advanced.

During this time, the metering motor 44 is not driven and the rotor 47 is in a stopped state. Therefore, the first spline shaft 63 disposed in front of the ball nut 69.
Is advanced without rotating and the screw 2
Move 2 forward. In this way, the rotary 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 accumulated in the front of the screw 22 can be injected from the injection nozzle 12a.

Next, in the weighing process, the weighing motor 4
When a 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
While the resin 33 is being melted in the inside of 6
The screw 22 is retracted by the back pressure generated by the forward movement 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. Then, 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 the direction of retracting the screw 22. At this time, the load meter 75 detects the load applied in the axial direction of the screw 22 and the like, and the back pressure can be calculated based on the load. In addition, a pressure sensor (not shown) is arranged in the heating cylinder 12, and the heating cylinder 1 is operated by the pressure sensor.
It is also possible to detect the pressure of the resin 33 in 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. Figure 1
As shown in FIG. 7, an annular bearing retainer 64 is fixed to the rear end of the second rotor shaft 57, and the first shaft portion 65 a of the ball screw shaft 65 is fitted and fixed to the inner circumference of the bearing retainer 64. It The second shaft portion 65b of the ball screw shaft 65 is supported by the bearing 67 with respect to the rear cap 77. Then, the threaded portion 65c of the ball screw shaft 65 and the threaded portion formed on the inner circumference of the ball nut 69 are screwed together.

Therefore, the rotational movement of the second rotor shaft 57 is transmitted to the ball screw shaft 65 via the bearing retainer 64 and converted into a linear movement by the ball screw 101, so that the ball nut 69 is moved in the axial direction. Can be made. By the way, the ball screw shaft 65
In order to prevent 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 constantly lubricated with grease. To be done. Further, since grease is consumed as the relative movement of the ball screw shaft 65 and the ball nut 69 is repeated, the threaded portion P2 is regularly used.
The grease is supplied to the.

To this end, a greasing hole 102 is formed in the threaded portion P2 at substantially the center of the threaded portion 65c and extends in the radial direction. A greasing hole 103 is formed in communication with the greasing hole 102. To be done. The greasing hole 102 is provided 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, and communicates with the greasing holes 104 and 105 at substantially the center of the second shaft portion 65b through the screw portion 65c and the first shaft portion 65a. . Then, the greasing holes 104 and 105 are opened toward a reservoir 106 formed inside the rear cap 77 so as to face the second shaft portion 65b.

Further, in the rear cap 77, a greasing hole 108 which communicates with the reservoir 106 and extends in the radial direction, and an axial direction which communicates with the greasing hole 108 and extends in the axial direction are formed. A greasing hole 109 is formed by opening it toward the outside at the right end surface in the figure). Therefore, a pipe (not shown) can be connected to the greasing hole 109, and the pipe and a grease gun (not shown) as a grease supply source can be connected via a joint or the like. In this case, when the grease gun is operated to supply the grease to the greasing hole 109, the grease passes through the greasing holes 109 and 108 in order to store the grease.
6, and further supplied to the screwing 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 the grease may be supplied from the grease tank through a pipe. In that case, a valve is arranged to selectively supply grease to a predetermined portion of the pipe.

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

In the present embodiment, the ball nut 6
Although 9 is not rotated, even when applied to a lubricating device of an injection molding machine in which a ball nut is rotated, the greasing hole 109 is placed at a fixed position regardless of the rotation of the ball nut 69. It becomes easy to connect a pipe to the greasing hole 109. It should be noted that the present invention is not limited to the above-described embodiments, and various modifications can be made based on the spirit 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 the lubrication device of the injection molding machine, the drive motor, the ball screw shaft, and the ball nut screwed with the ball screw shaft, Rotation transmitting means for transmitting the rotation generated by driving the drive motor to the ball screw shaft.

The ball screw shaft is provided with a greasing passage, one end of which opens at a threaded portion between the ball screw shaft and the ball nut and the other end of which opens toward the outside of the apparatus. It In this case, a greasing hole is formed in a portion of the greasing passage that is open toward the outside. Therefore, even if the ball nut is disposed inside the drive motor, or even if the ball nut is rotated, it is not possible 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 drawings]

FIG. 1 is a cross-sectional view of a main part of a drive 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 cross-sectional view showing the injection device according to the embodiment of the present invention.

FIG. 4 is a second cross-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 screw part

Claims (2)

(57) [Claims] 1. (a) a drive motor; (b) a ball screw shaft; (c) a ball nut screwed with the ball screw shaft; and (d) generated by driving the drive motor. Rotation transmitting means for transmitting the rotation to the ball screw shaft, and (e) one end of the ball screw shaft is opened at a threaded portion between the ball screw shaft and the ball nut, and the other end is formed. A lubricating device for an injection molding machine, characterized in that a greasing passage opening to the outside is provided. 2. A driving motor; (b) a ball screw shaft; and (c) a ball nut screwed onto the ball screw shaft.
And has a, (d) to the ball screw shaft, one end of the ball screw shaft and ball
Opening in the threaded portion between the nut and the other end, and the other end faces the reservoir.
A lubrication device for an injection molding machine, which is characterized in that a greasing hole that opens as a result is formed .