JP2001221304A - Power transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a responsibility of a driving part by reducing a moment of inertia of a transmission mechanism. SOLUTION: This power transmission is provided with a driving means generating rotations by driving, a transmitted body held rotatably, and a multistage deceleration mechanism 82 decelerating the rotations generated by driving the driving means in multi stages and transmitting the rotations to the transmitted body. The multistage deceleration mechanism 82 is equipped with plural deceleration parts decelerating the transmitted rotations in a predetermined reduction gear ratio, and an intermediate transmission shaft 84 transmitting the rotations among the each deceleration part. The each deceleration part is provided with a driving side rotor and a driven side rotor. The reduction gear ratio at the each deceleration part can be reduced; therefore, a diameter of the driven side rotor can be made larger than a diameter of the driving side rotor enough to obtain the reduction gear ratio. Thus, a moment of inertia of the driven side rotor can be reduced, and a moment of inertia of the multistage deceleration mechanism 82 can be reduced sufficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission.

[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 is obtained by cooling and solidifying in the cavity space.

For this purpose, 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 movable platen is moved forward and backward by a mold clamping cylinder to form a mold device. Close, close and open the mold.

FIG. 2 is a conceptual diagram of a conventional injection device, and FIG. 3 is a conceptual diagram of a conventional power transmission device. FIG. 3 shows a power transmission device for injection.

In FIG. 1, reference numeral 10 denotes an injection device, and 12 denotes a heating cylinder. The heating cylinder 12 includes a hopper 30 and an injection nozzle 12a, and heats and melts the resin supplied from the hopper 30. The heating cylinder 12
Inside, a screw 22 is rotatably disposed and is capable of moving forward and backward (moving in the left-right direction in FIG. 2). Then, the screw 22 is moved forward (moved to the left in FIG. 2).
By doing so, the resin stored in front of the screw head 22a (left side in FIG.
The resin can be measured by injecting from 2a and moving backward (moving rightward in FIG. 2).

Therefore, in the injection device 10,
A drive unit 13 for rotating and moving the screw 22 forward and backward is provided behind the heating cylinder 12 (to the right in FIG. 2). In the drive unit 13, the rear end (the right end in FIG. 2) of the heating cylinder 12 is attached to the front injection support 31, and the rear injection support 32 is disposed at a predetermined distance from the front injection support 31. . A guide bar 40 is installed between the front injection support 31 and the rear injection support 32,
A pressure plate 34 is provided along the guide bar 40 so as to be able to advance and retreat.

A drive shaft 35 is connected to the rear end of the screw 22, and the drive shaft 35 is connected to pressure plates 34 by bearings 36 and 37.
Is rotatably supported with respect to. And screw 2
In order to rotate the motor 2, an electric measuring motor 41 is disposed, and a first transmission mechanism 57 including pulleys 42 and 43 and a timing belt 44 is disposed between the measuring motor 41 and the drive shaft 35. Is established. Therefore, by driving the measuring motor 41, the screw 22 can be rotated in the forward or reverse direction.

A ball screw 47 composed of a ball screw shaft 45 and a ball nut 46 screwed to each other is provided behind the pressure plate 34. The ball screw 47 rotates the linear motion. Is converted to The ball screw shaft 45 is rotatably supported by the bearing 48 on the rear injection support 32, and the ball nut 46 is fixed to the pressure plate 34 via the plate 51 and the load cell 52. Further, an injection motor 53 is provided for moving the screw 22 forward and backward.
A second transmission mechanism 58 including pulleys 54 and 55 and a timing belt 56 is disposed between the second transmission mechanism 58 and the ball screw shaft 45. Therefore, the injection motor 53 is driven,
By rotating the ball screw shaft 45, the ball nut 46 and the pressure plate 34 can be moved, and the screw 22 can be moved forward or backward. In addition,
The metering motor 41 and the injection motor 53 are formed by servo motors.

When a small injection motor 53 is used, for example, to reduce the size of the injection molding machine, the propulsive force for moving the screw 22 forward or backward is reduced accordingly. Therefore, the injection motor 5
The rotation generated by driving the motor 3 is reduced to increase the thrust.

For this purpose, the diameter d1 of the pulley 54 and the diameter d2 of the pulley 55 are set to satisfy d1 <d2.

Similarly, for example, a small weighing motor 41
Is used, the rotational force when rotating the screw 22 is reduced accordingly. Therefore, the rotation generated by driving the weighing motor 41 is reduced to increase the rotational force.

For this purpose, the diameter d3 of the pulley 42 and the diameter d4 of the pulley 43 are set so that d3 <d4. The weighing motor 41 and the first transmission mechanism 5
7 and the drive shaft 35 constitute a first power transmission device, and the injection motor 53, the second transmission mechanism 58, and the ball screw shaft 45 constitute a second power transmission device.

[0013]

However, in the conventional second power transmission device, the injection motor 53 is used.
In order to reduce the rotation generated by driving the pulley 55, the diameter d2 of the pulley 55 needs to be sufficiently larger than the diameter d1 of the pulley 54 as shown in FIG. Becomes extremely large,
The moment of inertia of the second transmission mechanism 58 also becomes extremely large. Therefore, the injection motor 53 is started to rotate the ball screw shaft 45 to move the screw 22 forward or backward, or to stop the injection motor 53 to stop the ball screw shaft 4.
The start / stop time required for stopping the screw 5 and stopping the screw 22 becomes extremely long, and the driving unit 13
Responsiveness is reduced.

In the first power transmission device as well, the diameter d4 of the pulley 43 is reduced in order to reduce the rotation generated by driving the measuring motor 41.
Since the diameter must be sufficiently larger than the diameter d3, the moment of inertia of the pulley 43 becomes extremely large, and the moment of inertia of the first transmission mechanism 57 also becomes extremely large. Therefore, the start-up and rotation necessary to start the measuring motor 41 to rotate the screw 22 and to stop the measuring motor 41 to stop the screw 22 are performed.
The stop time becomes extremely long, and the responsiveness of the drive unit 13 decreases.

The present invention solves the above-mentioned problems of the conventional power transmission device, reduces the moment of inertia of the transmission mechanism,
It is an object of the present invention to provide a power transmission device that can increase the response of a driving unit.

[0016]

For this purpose, in the power transmission device of the present invention, a drive means for generating rotation by being driven, a driven body rotatably supported, and a drive means for driving the drive means And a multi-stage deceleration mechanism for transmitting the generated rotation to the driven body by decelerating the rotation in multiple stages.

The multi-stage speed reduction mechanism includes a plurality of speed reduction units for reducing the transmitted rotation at a predetermined reduction ratio, and an intermediate transmission shaft for transmitting rotation between the respective reduction units. In addition, each of the reduction units includes a driving-side rotator and a driven-side rotator.

In another power transmission device of the present invention, the driving-side rotator and the driven-side rotator are connected via a transmission.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic view of a drive unit of an injection device according to an embodiment of the present invention, FIG. 4 is a sectional view of a main part of the injection device according to the embodiment of the present invention, and FIG. It is a conceptual diagram of a power transmission device. Note that FIG. 5 shows a power transmission device for injection.

In FIG. 4, reference numeral 12 denotes a heating cylinder as a cylinder portion, and a front end of the heating cylinder 12 (FIG. 4).
The injection nozzle 12a is disposed at the left end of the drawing). In the heating cylinder 12, a screw 22 as an injection member is disposed rotatably and freely reciprocating (moving in the left-right direction in FIG. 4).

The screw 22 has a screw head 22a at the front end, extends rearward (to the right in FIG. 4) in the heating cylinder 12, and is connected to the drive unit 61 at the rear end (right in FIG. 4). Can be 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 predetermined position of the heating cylinder 12, a hopper 30 is provided at the resin supply port 29, and the resin 33 accommodated in the hopper 30 The resin is supplied into the heating cylinder 12 through the resin supply port 29. The resin supply port 29 is located at a position corresponding to the rear end (the right end in FIG. 4) of the groove 26 when the screw 22 is located at the forefront (left side in FIG. 4) in the heating cylinder 12. Formed.

Then, during the measuring step, the screw 22
Is rotated, the resin 3 contained in the hopper 30 is rotated.
3 is supplied into the heating cylinder 12, is advanced in the groove 26 (moves to the left in FIG. 4), and is heated and melted during that time and is stored in front of the screw head 22a. At this time, the screw 22 is moved backward (moved rightward in FIG. 3) by the pressure of the melted resin 33. Subsequently, when the screw 22 is advanced during the injection step, the resin 33 stored in front of the screw head 22a is injected from the injection nozzle 12a and is filled in a cavity space of a mold device (not shown). At this time, a check ring (not shown) is provided around the screw head 22a so that the resin stored in front of the screw head 22a does not flow backward.

A drive unit 61 for rotating the screw 22 and moving it forward and backward is provided behind the heating cylinder 12 (to the right in FIG. 1).
In the driving unit 61, the rear end (the right end in FIG. 1) of the heating cylinder 12 is attached to the front injection support 62, and a rear injection support (not shown) is provided at a predetermined distance from the front injection support 62. You. A bar 63 is installed between the front injection support 62 and the rear injection support.

A drive shaft (adapter) 64 is connected to the rear end of the screw 22. The drive shaft 64 is rotatably supported by a bearing 65 on a pressure plate 66 as a support member. Then, in order to rotate the screw 22, the first
And a drive pulley (not shown) as a drive side rotating body and a driven as a driven side rotary body between the metering motor and the drive shaft 64. A first transmission mechanism including a side pulley 67 and a timing belt (not shown) is provided. Therefore, the screw 22 can be rotated in the forward or reverse direction by driving the weighing motor. Note that an electric servomotor can be used as the weighing motor. Further, a hydraulic motor can be used instead of the electric weighing motor.

Further, a ball screw 73 as a movement direction changing means comprising a ball screw shaft 71 and a ball nut 72 screwed to each other is provided so as to penetrate the front injection support 62, and is provided by the ball screw 73. Rotational motion is converted to linear motion. And the ball nut 7
2 has a mounting flange 74 through which it is mounted to the front injection support 62. Also,
The ball screw shaft 71 extends through the front injection support 62 to form a driven body, and includes bearings 75 to 7.
7 rotatably supports the pressure plate 66. The bearings 75 and 77 are composed of radial bearings, and the bearing 76 is composed of a thrust bearing. In addition, the bearing 7 in the ball screw shaft 71 is used.
A small-diameter portion 71a having a reduced diameter is formed in a portion adjacent to 6, the split flange 80 is fixed to the small-diameter portion 71a, and the split flange 80 and the bearing 76 are brought into contact. A plate 78 is fixed to the rear end (the right end in FIG. 1) of the ball screw shaft 71.
8 and the pressure plate 66 are connected via the rod 79, the plate 101 and the rod 102.

Further, an injection motor 81 as a second driving means is provided for moving the screw 12 forward and backward, and between the injection motor 81 and the ball screw shaft 71.
A multi-stage reduction mechanism 82 as a second transmission mechanism is provided. The multi-stage reduction mechanism 82 reduces the rotation generated by driving the injection motor 81 in multiple stages, and increases the propulsive force when the screw 12 advances and retreats. Therefore, by driving the injection motor 81 and rotating the ball screw shaft 71, the ball screw shaft 71 and the pressure plate 66 can be moved, and the screw 12 can be moved forward or backward. A power transmission device is constituted by the injection motor 81, the multi-stage reduction mechanism 82, and the ball screw shaft 71.

Next, the multi-stage reduction mechanism 82 will be described.

The injection motor 81 is mounted on the upper end of the pressure plate 66, and the drive shaft 83 of the injection motor 81 is projected forward (to the left in FIG. 1). The rotation generated by driving the injection motor 81 is reduced by a multi-stage reduction mechanism 82 and transmitted to the ball screw shaft 71.

To this end, the multi-stage reduction mechanism 82 includes a plurality of reduction units connected to each other, that is, in this embodiment, a first-stage reduction unit 82a, a second-stage reduction unit 82b, and a first-stage reduction unit 82b. An intermediate transmission shaft 84 that transmits rotation between the second-stage reduction unit 82a and the second-stage reduction unit 82b is provided. A synchronous transmission unit 8 for synchronizing and rotating the ball screw shafts 71 with the second stage reduction unit 82b.
2c are connected.

The intermediate transmission shaft 84 is passed through the upper end of the pressure plate 66, and a bracket 88 is attached to the pressure plate 66, and a cover 89 is attached to the bracket 88. The intermediate transmission shaft 8
4 is rotatably supported by a bearing 85 provided on a pressure plate 66, a bearing 86 provided on a bracket 88, and a bearing 87 provided on a cover 89. The ball screw shaft 71 and the intermediate transmission shaft 84 are made to protrude forward and backward from the pressure plate 66. Further, the first-stage reduction portion 82a and the second
The step reduction portion 82 b is disposed with the pressure plate 66 interposed therebetween.

In the first-stage speed reducer 82a, a drive-side pulley 91 as a drive-side rotating body is fixed to the front end of the drive shaft 83, and the front end surface of the pressure plate 66 of the intermediate transmission shaft 84 (FIG. 1). (A left end surface of the pulley) is fixed to a driven pulley 92 as a driven rotary body, and the pulleys 91 and 92 are connected via a timing belt 93 as a transmission body. Then, in the second-stage reduction portion 82b, the intermediate transmission shaft 84
The drive-side pulley 94 as a drive-side rotating body is fixed at a position close to the rear end face (the right end face in FIG. 1) of the pressure plate 66, and is close to the rear end face of the pressure plate 66 of the upper ball screw shaft 71. A driven side pulley 95 as a driven side rotating body is fixed, and the pulleys 94 and 95 are connected via a timing belt 96 as a transmission body. Further, in the synchronous transmission portion 82c, a drive side pulley 97 as a drive side rotating body is fixed at a position corresponding to the rear end face of the pulley 95 in the upper ball screw shaft 71, and the lower ball screw shaft 7
The driven pulley 98 as a driven rotating body is fixed at a position corresponding to the pulley 97 in FIG.
7, 98 are connected via a timing belt 99 as a transmission body. Incidentally, reference numeral 100 denotes a second-stage reduction unit 82b.
And a similar roller (not shown) is also provided in the synchronous transmission portion 82c.

Further, the first-stage speed reducer 82a and the second
A predetermined reduction ratio γ1 is set in each of the speed reduction portions 82b.
1, pulleys 91, 9 so that the rotation is decelerated at γ12.
4 is formed by a small-diameter pulley, and pulleys 92, 95
Is formed by a large diameter pulley.

When the diameters of the pulleys 91, 92, 94, and 95 are d11 to d14, γ11 = d12 / d11> 1 γ12 = d14 / d13> 1 d11 = d13 d12 = d14. The diameters d11 and d13 can be different, and the diameters d12 and d14 can be different.

In the driving unit 61 having the above-described structure, when the driving shaft 83 is rotated by driving the injection motor 81, the rotation of the driving shaft 83 is controlled by the pulley 91,
The speed is reduced and transmitted to the intermediate transmission shaft 84 via the timing belt 93 and the pulley 92, and the rotation of the intermediate transmission shaft 84 is controlled by the pulley 94, the timing belt 96, and the pulley 95.
And transmitted to the ball screw shaft 71.

Accordingly, a large reduction ratio γ13 γ13 = γ11 × γ12 can be obtained by the entire multi-stage speed reduction mechanism 82. As a result, the driving force for moving the screw 12 forward or backward can be increased.

In this case, the reduction ratio γ13 can be represented by the product of the reduction ratio γ11 of the first-stage reduction unit 82a and the reduction ratio γ12 of the second-stage reduction unit 82b.
11, γ12 can be made smaller than the reduction ratio γ13. Therefore, the diameters d12, d14 of the pulleys 92, 95
From the diameters d11 and d13 of the pulleys 91 and 94
Since it is only necessary to increase the value as needed to obtain 1, γ12, the moment of inertia of the pulleys 92 and 95 can be reduced. By the way, the moment of inertia generated by rotating a rotating body such as the pulleys 92 and 95 is proportional to the square of the diameter of the rotating body. Therefore, when the diameters d12 and d14 of the pulleys 92 and 95 are reduced, the inertia moment of the multi-stage reduction mechanism 82 can be sufficiently reduced.

In this case, since the reduction ratio γ13 is the product of the reduction ratio γ11 of the first-stage reduction unit 82a and the reduction ratio γ12 of the second-stage reduction unit 82b, the pulleys 91, 92, 9
4, 95, timing belts 93 and 96, and an intermediate transmission shaft 84 are required.
The number of elements that generate the moment of inertia increases by the amount of the intermediate transmission shaft 94 and the intermediate transmission shaft 84. Here, assuming that a value at which the moment of inertia increases by the amount of the pulleys 92 and 94 and the intermediate transmission shaft 84 is ΔM1 and a value at which the moment of inertia decreases by reducing the diameter d14 is ΔM2, the value ΔM
1, ΔM2 becomes ΔM1≪ΔM2. Therefore, the moment of inertia of the multi-stage reduction mechanism 82 can be sufficiently reduced. As a result, the injection motor 81 is activated to rotate the ball screw shaft 71 to move the screw 22 forward or backward, or to stop the injection motor 81 to stop the ball screw shaft 71 and stop the screw 22. The start / stop time required for the drive unit 61 can be shortened, and the responsiveness of the drive unit 61 can be increased.

In the present embodiment, pulleys 91 and 94 are used as driving-side rotating bodies, pulleys 92 and 95 are used as driven-side rotating bodies, and timing belts 93 and 96 are used as transmitting bodies. However, a drive-side gear is used as the drive-side rotator, a driven-side gear is used as the driven-side rotator, an idle gear is used as the transmission body, or a drive-side rotator is used as the drive-side rotator. It is also possible to use a sprocket, use a driven sprocket as the driven rotating body, and use a chain as the transmission. When the driving gear is used as the driving rotating body and the driven gear is used as the driven rotating body, the driving gear and the driven gear can be used without disposing the idle gear as necessary. It is also possible to directly mesh with the gear on the side.

In this embodiment, the ball screw shaft 71 is used as the driven member. However, a ball nut is used instead of the ball screw shaft 71, and the ball nut is rotated. Can also be communicated. In the present embodiment, the multi-stage reduction mechanism 82 is disposed between the injection motor 81 and the ball screw shaft 71.
4 can also be arranged. Furthermore, in the present embodiment, an example is described in which the multi-stage reduction mechanism 82 is applied to an injection device. However, the invention can be applied to a mold clamping device or an ejector mechanism.

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.

[0043]

As described in detail above, according to the present invention, in a power transmission device, a driving means for generating rotation by being driven, a rotatably supported driven body, And a multi-stage speed reduction mechanism for transmitting the rotation generated by driving the driving means to the driven body while reducing the speed in multiple stages.

The multi-stage speed reduction mechanism includes a plurality of speed reduction units for reducing the transmitted rotation at a predetermined reduction ratio, and an intermediate transmission shaft for transmitting rotation between the reduction units. In addition, each of the reduction units includes a driving-side rotator and a driven-side rotator.

In this case, since the reduction ratio in each reduction section can be reduced, the diameter of the driven-side rotating body may be made larger than the diameter of the driving-side rotating body as necessary to obtain the reduction ratio. Accordingly, the moment of inertia of the driven-side rotating body can be reduced, and the moment of inertia of the multi-stage reduction mechanism can be sufficiently reduced.

As a result, it is possible to reduce the starting and stopping time required for starting the driving means to rotate the driven body and for stopping the driving means to stop the driven body. The responsiveness of the unit can be increased.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a driving unit of an injection device according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram of a conventional injection device.

FIG. 3 is a conceptual diagram of a conventional power transmission device.

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

FIG. 5 is a conceptual diagram of a power transmission device according to an embodiment of the present invention.

[Explanation of symbols]

 71 Ball screw shaft 81 Injection motor 82 Multi-stage reduction mechanism 82a, 82b First-stage and second-stage reduction units 84 Intermediate transmission shafts 91, 92, 94, 95 Pulleys 93, 96 Taming belt

Claims (2)

[Claims] 1. A driving means for generating rotation by being driven, (b) a driven body rotatably supported, and (c) a driving means for driving the driving means. A multi-stage reduction mechanism for reducing the rotation in multiple stages and transmitting the rotation to the driven body, and (d) a plurality of reduction units for reducing the transmitted rotation at a predetermined reduction ratio; A power transmission device comprising: an intermediate transmission shaft for transmitting rotation between the reduction units; and (e) each of the reduction units includes a driving-side rotating body and a driven-side rotating body. 2. The power transmission device according to claim 1, wherein the driving-side rotator and the driven-side rotator are connected via a transmission.