JP4021565B2 - Lubrication device for injection molding machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lubrication device for an injection molding machine.
[0002]
[Prior art]
Conventionally, in an injection molding machine, a resin heated and melted in a heating cylinder is injected at a high pressure into a cavity space of a mold apparatus, and cooled and solidified in the cavity space. Thus, a molded product can be obtained.
[0003]
The injection molding machine has a mold clamping device and an injection device, and the mold clamping device includes a fixed platen and a movable platen, and the mold clamping cylinder moves the movable platen forward and backward to close the mold, mold clamping, and mold opening. Do.
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 molten resin, and a screw is rotatable in the heating cylinder and is advanced and retracted. Arranged freely. The resin is injected from the injection nozzle by moving the screw forward, and the resin is measured by moving the screw backward.
[0004]
By the way, in the injection molding machine having the above-described configuration, the screw is advanced without being rotated in the injection process, and the screw is retracted while being rotated in the measurement process. 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. A bearing is provided for rotatably supporting the shaft.
[0005]
Then, grease is sealed in the bearing, and the bearing is lubricated by the grease.
[0006]
[Problems to be solved by the invention]
However, in the conventional injection molding machine, when the drive motor is driven at a high load, the grease in the bearing deteriorates due to a shearing stress applied thereto, or the grease increases as the temperature of the drive motor increases. As a result, the grease component will vaporize and the grease will flow out of the bearing. As a result, the bearing cannot be lubricated for a long time.
[0007]
An object of the present invention is to solve the problems of the conventional injection molding machine and to provide a lubrication device for an injection molding machine capable of lubricating a bearing for a long period of time even when a drive motor is driven at a high load. And
[0008]
[Means for Solving the Problems]
For this purpose, the lubrication device for an injection molding machine of the present invention includes a casing, a rotor shaft to which a rotor of a drive motor is fixed, and a bearing that rotatably supports the rotor shaft.
The casing is provided with a grease reservoir formed adjacent to the bearing, and a greasing hole for connecting the outer peripheral surface of the casing and the grease reservoir.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the 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 first cross-sectional view illustrating an injection device according to an embodiment of the present invention, and FIG. It is the 2nd sectional view showing.
[0011]
In FIG. 2, 12 is a heating cylinder, and the heating cylinder 12 has an injection nozzle 12a at the front end (left end in the figure). A screw 22 is disposed in the heating cylinder 12 so as to be rotatable and advance and retract.
The screw 22 has a screw head 22a at the front end, extends rearwardly (to the right in the figure) inside the heating cylinder 12, and is connected to a drive unit described later at the rear end (right end in the figure). A screw-like flight 23 is formed around the screw 22, and a groove 26 is formed by the flight 23.
[0012]
A resin supply port 29 is formed at a set position of the heating cylinder 12, and a hopper 30 is fixed to the resin supply port 29. The resin supply port 29 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 foremost position (left side in the drawing) in the heating cylinder 12. Is done.
[0013]
Therefore, when the driving unit is driven and the screw 22 is rotated (moved to the right in the drawing) during the measuring step, the pellet-shaped resin 33 in the hopper 30 falls and is heated. The inside of the groove 26 is advanced (moved to the left in the figure).
A heater (not shown) is disposed 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, the molten resin 33 for one shot is stored in front of the screw head 22a.
[0014]
Next, in the injection process, when the drive 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 and is not shown. The cavity of the mold device is filled.
Next, the drive unit will be described.
[0015]
In FIG. 3, reference numeral 11 denotes a drive unit case as a casing surrounding the drive unit, and the drive unit case 11 is fixed to the rear end (right end in the drawing) of the heating cylinder 12 (FIG. 2). The drive unit case 11 includes a front cover 13, a center frame 15, a rear cover 17, a front frame 41 that connects the front cover 13 and the center frame 15, and a rear frame 42 that connects the center frame 15 and the rear cover 17. Become. The front cover 13 and the front frame 41 are connected by the bolt b1, the front frame 41 and the center frame 15 are connected by the bolt b2, the center frame 15 and the rear frame 42 are connected by the bolt b3, and the rear frame 42 and the rear cover 17 are connected. It is fixed by bolts b4.
[0016]
Further, a metering motor 44 as a first drive motor is provided at the front part (left part in the figure) of the drive part case 11, and an injection is provided as a second drive motor at the rear part (right part in the figure). Motors 45 are disposed on the same axis. The metering motor 44 includes a stator 46 fixed to the front frame 41 and an annular rotor 47 disposed on the inner peripheral side of the stator 46, and the injection motor 45 is fixed to the rear frame 42. And a ring-shaped rotor 49 disposed on the inner peripheral side of the stator 48.
[0017]
The rotor 47 is rotatably supported with respect to the drive unit case 11. For this purpose, a hollow first rotor shaft 56 as a first rotating body is fitted and fixed to the rotor 47, and the front end (left end in the figure) of the first rotor shaft 56 is fixed by a bearing 51. The rear end of the front frame 41 is supported by the center frame 15 by a bearing 52.
[0018]
Meanwhile, the rotor 49 is rotatably supported with respect to the drive unit case 11. For this purpose, a hollow second rotor shaft 57 as a second rotating body is fitted and fixed to the rotor 49, the front end of the second rotor shaft 57 is fixed to the center frame 15 by the bearing 53, and the rear end is a bearing. 54 is supported by the rear frame 42.
[0019]
By the way, in the measuring motor 44, by supplying a current having a predetermined frequency to the stator 46, the screw 22 (FIG. 2) can be moved backward. For this purpose, the sleeve 18 is disposed 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 a bolt 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 to the front end of the first spline shaft 63. The screw 22 is fixed. In this case, the first spline nut 62 and the first spline shaft 63 constitute a first driving force transmission means, which restricts relative motion in the rotational direction and allows relative motion in the axial direction. The The first spline shaft 63 has a length corresponding to the stroke of the screw 22.
[0020]
Therefore, when the measuring motor 44 is driven to rotate the rotor 47, the rotation of the rotor 47 is applied to the screw 22 via the first rotor shaft 56, the sleeve 18, the first spline nut 62, and the first spline shaft 63. Then, the screw 22 is rotated. Then, the resin 33 moves forward (moves to the left in the figure) while the resin 33 is melted in the groove 26, and the screw 22 moves backward (moves to the right in the figure) by the back pressure generated as the resin 33 advances. )
[0021]
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 having a predetermined frequency to the stator 48, the screw 22 can be moved forward without rotating. For this purpose, 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 periphery of the bearing retainer 64. The ball screw shaft 65 is supported rotatably with respect to 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 through the bearing retainer 64. A rear cap 77 is fixed to the rear cover 17 via an annular load meter 75 via a bolt b 6, and the second shaft portion 65 b of the ball screw shaft 65 is fixed to the rear cap 77 by a bearing 67. Supported. The rear cap 77 is provided with an absolute value pulse encoder 85 via a bracket 86. The absolute value pulse encoder 85 is connected to the second shaft portion 65b and functions as a first rotational speed detection means, detects the rotational speed of the ball screw shaft 65, that is, the rotational speed of the injection motor, and It functions as a position detection means, and detects the position of the screw 22 based on the number of rotations of the injection motor.
[0022]
A ball nut 69 is disposed in the second rotor shaft 57 so as to be able to advance and retreat. The ball nut 69 and the ball screw shaft 65 are screwed together to constitute a motion direction conversion means. Accordingly, 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, and the rotational motion is converted into a linear motion, causing the ball nut 69 to advance and retract. A stopper 19 is fixed to the front end of the ball screw shaft 65 with a bolt b13 so that the ball screw shaft 65 does not come off from the ball nut 69.
[0023]
In addition, a sleeve-like second spline shaft 71 is fixed to the front end of the ball nut 69 by a bolt b11 and fixed to the center frame 15 so that the ball nut 69 does not rotate with the ball screw shaft 65. The second spline nut 76 and the second spline shaft 71 are spline-connected. In this case, the second spline nut 76 and the second spline shaft 71 constitute the second driving force transmission means, the relative motion in the rotational direction is restricted, and the relative motion in the axial direction is allowed. The second spline shaft 71 has a length corresponding to the stroke of the screw 22.
[0024]
Then, a bearing box 72 as a third driving force transmission means is fixed to the further front end of the second spline shaft 71 by a bolt b7, and a thrust bearing 73 is provided in front of the bearing box 72 (left side in the figure). A bearing 74 is disposed rearward (to the right in the drawing). In this case, the bearing box 72 constrains relative movement in the axial direction and allows relative movement in the rotational direction. Therefore, the first spline shaft 63 is supported by the thrust bearing 73 and the bearing 74 so as to be rotatable relative to the second spline shaft 71 and the ball nut 69.
[0025]
A rear end shaft 22b of the screw 22 is fixed to the front end of the first spline shaft 63 by bolts b8 and b9 via a first coupling 81 and a second coupling 82. The first coupling 81 is slid in the sleeve 18 as the screw 22 advances and retreats. In addition, 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 retreat limit position of the first spline shaft 63. Therefore, the axial dimension of the injection molding machine can be reduced.
[0026]
Reference numeral 84 denotes an encoder connected to the sleeve 18 via a gear train 87. The encoder 84 functions as a second rotational speed detection means, and determines the rotational speed of the sleeve 18, that is, the measuring motor rotational speed. To detect. Reference numeral 89 denotes a water cooling jacket, and the water cooling jacket 89 is fixed to the front cover 13 by bolts b10 and prevents heat from being transmitted from the rear end of the heating cylinder 12 to the front cover 13.
[0027]
Next, the operation of the drive unit having the above configuration 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 is applied to the ball screw shaft 65 via the second rotor shaft 57 and the bearing retainer 64. Then, 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. Accordingly, a thrust is generated in the ball nut 69, and the ball nut 69 is advanced.
[0028]
During this time, the metering motor 44 is not driven and the rotor 47 is in a stopped state. Accordingly, the first spline shaft 63 disposed in front of the ball nut 69 is advanced without rotating and advances the screw 22.
As described above, 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.
[0029]
Next, when a current is supplied to the stator 46 of the metering motor 44 in the metering step, the rotor 47 is rotated, and the rotation of the rotor 47 is performed via the first rotor shaft 56, the sleeve 18 and the first spline nut 62. Is transmitted to the first spline shaft 63, and the first spline shaft 63 is rotated. The rotation of the first spline shaft 63 is transmitted to the screw 22, and the screw 22 is rotated. Along with this, the resin 33 moves forward in the groove 26 while being melted, and the screw 22 is moved backward by the back pressure generated as the resin 33 advances.
[0030]
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.
The injection motor 45 is driven while controlling the back pressure of the resin 33 to be weighed, and the rotor 49 rotates the screw 22 in the backward direction. At this time, the load applied in the axial direction of the screw 22 or the like is detected by the load meter 75, and the back pressure can be calculated based on the load. In addition, a pressure sensor (not shown) may be provided in the heating cylinder 12, the pressure of the resin 33 in the heating cylinder 12 may be detected by the pressure sensor, and the back pressure may be calculated based on the pressure.
[0031]
By the way, in the injection molding machine having the above-described configuration, the first rotor shaft 56 is rotatably supported with respect to the drive unit case 11 by bearings 51 and 52, and is generated by driving the metering motor 44. The rotation is transmitted to the first rotor shaft 56, and is transmitted to the screw 22 through the first rotor shaft 56.
[0032]
In this case, since the weighing motor 44 is driven at a high load, if a grease-filled type bearing is used as the bearings 51 and 52, a shearing stress is applied to the sealed grease to deteriorate the grease, As the temperature of the motor 44 increases, the grease component of the grease vaporizes or the grease flows out of the bearing.
[0033]
In addition, since the measuring motor 44 is a hollow motor and the first rotor shaft 56 is supported by the bearings 51 and 52, the inner diameters of the bearings 51 and 52 are large. Therefore, the peripheral speed of the inner race (not shown) of the bearings 51 and 52 is increased, and the deterioration of the grease is accelerated.
Therefore, grease can be constantly supplied to the bearings 51 and 52. Therefore, as shown in FIG. 1, an annular recess 101 is formed in the front cover 13 adjacent to the bearing 51 in front of the bearing 51 disposed at the front end of the first rotor shaft 56. An annular recess 102 is formed in the center frame 15 adjacent to the bearing 52 behind the bearing 52 disposed at the rear end of the first rotor shaft 56.
[0034]
Further, the flange portion 18a of the sleeve 18 is fixed to the front end of the first rotor shaft 56, the annular seal member 103 is fixed to the outer peripheral surface of the flange portion 18a, and the seal lip 104 of the seal member 103 is It slides on the vertical wall of the recess 101. As a result, the recess 101 is sealed by the sleeve 18 and the seal member 103, and a grease reservoir 111 is formed. An annular seal member 105 is fixed to the outer peripheral surface of the rear end of the first rotor shaft 56, and the seal lip 106 of the seal member 105 is slid with the vertical wall of the recess 102. As a result, the recess 102 is sealed by the seal member 105 to form a grease reservoir 112. Since the grease reservoirs 111 and 112 are both formed in an annular shape, they are suitable for supplying grease to the large bearings 51 and 52.
[0035]
Further, a greasing hole 114 for connecting the outer peripheral surface of the front cover 13 and the grease reservoir 111 is formed. A pipe (not shown) is connected to the greasing hole 114 via a nipple, and the pipe and a grease gun (not shown) as a grease supply source are connected via a joint. Therefore, by operating the grease gun, grease can be injected and supplied to the bearing 51.
[0036]
Further, a greasing hole 116 for connecting the outer peripheral surface of the front cover 13 and the grease reservoir 112 is formed. The pipe is connected to the greasing hole 116 via a nipple, and the pipe and the grease gun are connected via a joint. Therefore, the grease can be sprayed and supplied to the bearing 52 by operating the grease gun.
[0037]
As a result, even when the weighing motor 44 is driven with a high load, the bearings 51 and 52 can be sufficiently supplied with grease, and the bearings 51 and 52 can be lubricated for a long period of time. The durability of can be improved.
A grease tank (not shown) can be used as a grease supply source, and the grease can be supplied from the grease tank via the pipe. In that case, a valve for selectively supplying grease is disposed at a predetermined portion of the pipe.
[0038]
In the present embodiment, the lubrication device for supplying grease to the bearings 51 and 52 that rotatably supports the first rotor shaft 56 has been described. However, the bearing that rotatably supports the second rotor shaft 57. 53 and 54 can be supplied with grease in the same manner.
In addition, this invention is not limited to the said embodiment, It can change variously based on the meaning of this invention, and does not exclude them from the scope of the present invention.
[0039]
【The invention's effect】
As described above in detail, according to the present invention, in the lubrication device for an injection molding machine, the casing, the rotor shaft to which the rotor of the drive motor is fixed, and the bearing that rotatably supports the rotor shaft are provided. Have.
The casing is provided with a grease reservoir formed adjacent to the bearing, and a greasing hole for connecting the outer peripheral surface of the casing and the grease reservoir.
[0040]
In this case, even when the drive motor is driven with a high load, the bearing can be sufficiently supplied with grease, and the bearing can be lubricated for a long period of time, so that the durability of the bearing can be improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a main part of a drive unit in an embodiment of the present invention.
FIG. 2 is a first cross-sectional view showing an injection apparatus according to an embodiment of the present invention.
FIG. 3 is a second cross-sectional view showing the injection apparatus in the embodiment of the present invention.
[Explanation of symbols]
11 Drive unit case 44 Weighing motor 45 Injection motors 47 and 49 Rotors 51 to 54 Bearing 56 First rotor shaft 57 Second rotor shaft 111 and 112 Grease reservoir 114 and 116 Grease hole

Claims (2)

(A) a casing;
(B) a rotor shaft to which the rotor of the drive motor is fixed ;
(C) having a bearing that rotatably supports the rotor shaft ;
(D) The casing is provided with a grease reservoir formed adjacent to the bearing, and a greasing hole for connecting the outer peripheral surface of the casing and the grease reservoir. Lubrication device. The lubrication device for an injection molding machine according to claim 1, wherein the grease reservoir is sealed by a seal member that rotates with the rotation of the rotor shaft and is slid with respect to the casing .

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