JP2003232426A - Driving force transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase capacity of a kinetic direction conversion part, to miniaturize a driving device and to reduce cost of the driving device. <P>SOLUTION: This driving force transmission device has a driving part and the kinetic direction conversion part furnished with a first conversion element and a second conversion element and to convert rotating motion to rectilinear motion. Additionally, one of the first and second conversion elements is a screw shaft, the other is more than two nuts, and a position of each of the nuts in the axial direction is regulated by a regulation mechanism part 81. In this case, as the screw shaft and the more than two nuts are screwed on each other and screw parts are respectively formed on them, the number of turns of the ball increases and consequently, it is possible to increase the capacity of the kinetic direction conversion part. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally, an electric injection molding machine, namely,
In an electric molding machine, a screw is rotatably and movably arranged in a heating cylinder of an injection device as a drive device, and the screw is rotated by driving a metering motor, or the injection motor is driven. The screw can be moved back and forth by driving the. Then, during the measuring step, when the screw is rotated, the resin supplied from the hopper into the heating cylinder is heated, melted and advanced, and stored in front of the screw head formed at the front end of the screw, Along with this, the screw is retracted. Further, when the screw is moved forward during the injection step, the resin accumulated in front of the screw head is injected from the injection nozzle and filled (filled) in the cavity space of the mold device. Subsequently, the resin filled in the cavity space is cooled and solidified to form a molded product.

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

In the figure, 11 is a heating cylinder, 12 is a screw arranged in the heating cylinder 11 so as to be rotatable and forward / backward (movable in the left-right direction in the figure), and 13 is a front end of the heating cylinder 11. It is an injection nozzle formed at the left end in the figure.

The rear end (right end in the figure) of the heating cylinder 11 is attached to a front injection support 31, and a rear injection support 32 is arranged at a predetermined distance from the front injection support 31. And the front injection support 3
A guide bar 33 is installed between 1 and the rear injection support 32, and a pressure plate 34 is arranged along the guide bar 33 so as to be movable back and forth. The front injection support 31 and the rear injection support 32 are fixed to a slide base (not shown) by bolts (not shown).

A drive shaft 35 is connected to the rear end of the screw 12, and the drive shaft 35
Are rotatably supported with respect to the pressure plate 34 by bearings 36 and 37. An electric metering motor 41 is arranged to rotate the screw 12, and pulleys 42 and 43 and a timing belt 44 are arranged between the metering motor 41 and the drive shaft 35. Therefore, by driving the measuring motor 41, the screw 12 can be rotated in the forward direction or the reverse direction.

A ball screw 47 composed of a ball screw shaft 45 and a ball nut 46 that are screwed together is disposed behind the pressure plate 34 (to the right in the drawing), and the ball screw 47 is provided. A movement direction conversion unit and a screw unit that convert the rotational motion into the linear motion are configured by. The ball screw shaft 45 is rotatably supported by the bearing 48 with respect to 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 electric injection motor 53 is arranged to move the screw 12 forward and backward, and pulleys 54 and 55 and a timing belt 56 are arranged between the injection motor 53 and the ball screw shaft 45. Therefore, by driving the injection motor 53 and rotating the ball screw shaft 45, the ball nut 46 and the pressure plate 34 are advanced and retracted, and the screw 12 is moved forward (moved to the left in the drawing) or retracted (to the right in the drawing). Can be moved to).

In the injection apparatus having the above construction, when the measuring motor 41 is driven to rotate the screw 12 in the forward direction during the measuring process, the resin dropped from the hopper is supplied into the heating cylinder 11 to cause the screw 12 to rotate. The screw 12 is moved backward in the groove formed on the outer peripheral surface, and the screw 12 is moved backward accordingly, and the resin is transferred to the screw head 27.
Is stored in front of (to the left in the figure).

In the injection process, the injection motor 5 is also used.
When the screw 12 is moved forward by driving the screw 3, the resin accumulated in front of the screw head 27 becomes
It is injected from 3 and filled in the cavity space of a mold device (not shown). At this time, a backflow prevention device is arranged around the screw head 27 so that the resin stored in front of the screw head 27 does not backflow.

[0010]

However, in the conventional electric molding machine, when it is desired to increase the capacity for converting the movement direction of the ball screw 47, the ball screw 47 is accommodated in the ball nut 46 in principle. The number of windings of the ball may be increased. For example, even if two ball nuts are connected via a spacer and the number of windings of the ball is doubled, the load distribution applied to the ball becomes non-uniform. The capacity of the screw 47 cannot be doubled. That is, it is not possible to increase the capacity of the ball screw 47 by the number of windings of the ball.

When two ball nuts are connected via a spacer, a large load cell is required to detect the output generated by the threaded portion, which not only increases the size of the injection device but also increases the size of the injection device. The cost of the device increases.

According to the present invention, the problems of the conventional electric molding machine can be solved, the capacity of the motion direction converting portion can be increased, the driving device can be downsized, and the cost of the driving device can be reduced. It is an object of the present invention to provide a driving force transmission device that can do the above.

[0013]

To this end, in the driving force transmission device of the present invention, a drive section, a first conversion element rotated by driving the drive section, and the first conversion element. A second conversion element that is screwed together, and a motion direction conversion unit that converts rotational motion into linear motion.

One of the first and second conversion elements is a screw shaft, and the other is two or more nuts that are screwed with the screw shaft to form a screw portion. .

The position of each nut in the axial direction is
It is adjusted by the adjusting mechanism section.

In another drive force transmitting apparatus of the present invention,
Furthermore, a load detection unit that detects the output generated by each screw unit is provided.

In still another driving force transmission device of the present invention, each of the nuts and the movable pressing member are connected via each output member. The load detection unit is arranged between each output member and the moving pressure member.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this case, an example in which the present invention is applied to an injection device as a drive device will be described, but the present invention can also be applied to a mold clamping device and an ejector device.

FIG. 1 is a conceptual view of an injection device according to the first embodiment of the present invention, FIG. 3 is a sectional view of a ball screw unit according to the first embodiment of the present invention, and FIG. 4 is a first view of the present invention. 3 is a side view of the ball screw unit in the embodiment of FIG.

In the figure, reference numeral 11 denotes a heating cylinder as a cylinder member, and a screw (not shown) as an injection member is rotatably and forwardly and backwardly disposed in the heating cylinder 11. The rear end (the right end in FIG. 1) of the heating cylinder 11 is attached to the front injection support 31, and the center injection support 38 is arranged at a predetermined distance from the front injection support 31, and the center injection support 38 is further separated from the center injection support 38 by a predetermined distance. And the rear injection support 61 is disposed. A guide bar 33 is installed between the front injection support 31 and the central injection support 38, and a pressure plate 34 as a moving and pressing member moves back and forth along the guide bar 33 (moves in the left-right direction in FIG. 1). Arranged freely. The front injection support 31, the center injection support 38 and the rear injection support 61 are integrally connected and fixed to the slide base 62 by bolts (not shown).

A drive shaft 35 is connected to the rear end of the screw, and the drive shaft 35 is attached to the pressure plate 34 by a bearing (not shown).
It is rotatably supported with respect to. Then, in order to rotate the screw, an electric metering motor (not shown) serving as a first drive unit is provided, and a pulley and a timing belt (not shown) are provided between the metering motor and the drive shaft 35. One rotation transmission unit is provided. Therefore, the screw can be rotated in the forward direction or the reverse direction by driving the measuring motor. In this embodiment, an electric metering motor is used as the first drive unit, but a hydraulic motor can be used instead of the electric metering motor.

A ball screw unit 63 is arranged between the pressure plate 34 and the rear injection support 61. The ball screw unit 63 includes a common ball screw shaft 64, which is rotatably arranged, and the ball screw shaft 64.
And the first and second ball nuts 65 and 66, which are screwed together and are arranged at a predetermined distance in the axial direction, and are arranged between the first ball nut 65 and the pressure plate 34. The first output member 71, the second ball nut 66, and the second ball nut 66 disposed between the pressure plate 34.
The output member 72 and the adjustment mechanism section 81 are provided. And
The first output member 71 has a rear end (right end in FIG. 3).
Is attached to the flange portion 68 of the first ball nut 65 by the bolt b1, and the front end (the left end in FIGS. 1 and 3) is attached to the pressure plate 34 via the load cell 82 as the first load detecting portion. A rear end of the second output member 72 is attached to the flange portion 69 of the second ball nut 66 via the adjusting mechanism portion 81, and a front end of the second output member 72 is pressed via a load cell 83 as a second load detecting portion. It is attached to the plate 34.

The ball screw shaft 64 has a threaded portion 73 formed in the main portion on the front side (left side in FIGS. 1 and 3) in the axial direction, and a shaft portion 74 formed near the rear end.
It is rotatably supported on the pressure plate 34 by the first ball nut 65 on the front side and on the rear injection support 61 by the bearing 75 on the rear end. The ball screw shaft 64 and the first ball nut 65 convert the rotary motion into the linear motion, and the first motion direction conversion unit and the first ball screw unit as the first screw unit are the ball screw shaft 64 and the first ball screw unit. The second ball nut 66 serves as a second motion direction converting portion for converting rotational movement into linear movement and a second screw portion serving as a second screw portion.
Of the ball screw part, the ball screw shaft 64 constitutes a screw shaft and a first conversion element, and the first and second ball nuts 65 and 66 constitute a first and second nut and a second conversion element. To be done.

Further, an electric injection motor 53 as a second drive portion is arranged to move the screw forward and backward, and a drive pulley 54 and a driven pulley 54 are provided between the injection motor 53 and the shaft portion 74. 55, and a second rotation transmission portion including a timing belt 56 stretched between the drive pulley 54 and the driven pulley 55. Therefore, the first and second ball nuts 65, 66 are driven by driving the injection motor 53 and rotating the ball screw shaft 64.
It is possible to move the pressure plate 34 and the pressure plate 34 to move the screw back and forth. At this time, the output generated by the first and second ball screw parts is the load cell 8
2, 83 is detected as an emission output, and the load cell 8
The sensor outputs of Nos. 2 and 83 are sent to a control unit (not shown). The emission output control processing means (not shown) of the control unit performs the emission output control processing and controls the emission output based on the sensor output. The ball screw unit 63 and the injection motor 53 constitute a driving force transmission device.
Further, in the present embodiment, the electric injection motor 53 is used as the second drive unit, but a hydraulic motor may be used instead of the electric injection motor 53.

Then, the first and second ball nuts 6 are
The adjusting mechanism 81 is provided to adjust the relative positions of the shafts 5, 66 in the axial direction. The adjusting mechanism 81
Is a flange 8 formed at the rear end of the second output member 72.
5 is provided with an annular adjusting plate 86 disposed so as to oppose to each other, and the vicinity of the inner peripheral edge of the adjusting plate 86 and the flange portion 69 are fixed by a bolt b2. Further, screw holes 87 are formed through the adjusting plate 86 at a plurality of positions in the circumferential direction of the adjusting plate 86, and the screw holes 87 and the cylindrical adjusting bolt b3 as an adjusting member are screwed together. To be The tip (left end in FIG. 3) of the threaded portion of the adjusting bolt b3 is flattened and brought into contact with the flange 85. Then, a fixing bolt b4 as a fixing member is arranged so as to penetrate through each of the adjusting bolts b3, and is attached to the flange 85.

Therefore, the adjusting bolt b3 is rotated and moved forward and backward with respect to the adjusting plate 86 (moved in the left-right direction in FIG. 3), and the fixing bolt b4 is fixed with the sensor outputs of the load cells 82 and 83 equalized. By tightening, the relative positions of the first and second ball nuts 65, 66 in the axial direction can be adjusted. As a result, the distribution of the force transmitted from the ball screw shaft 64 to the first and second ball nuts 65 and 66 can be adjusted. In the present embodiment, the second output member 7
The adjusting mechanism 81 is arranged between the second ball nut 66 and the second ball nut 66, but the adjusting mechanism 81 is arranged between the first output member 71 and the first ball nut 65. It can also be installed.

Thus, the ball screw unit 63
, The common ball screw shaft 64 and the first and second ball nuts 65 and 66 are screwed together, and the first and second ball nuts 65 and 66 are screwed together.
Since the second ball nuts 65 and 66 are fixed to the pressure plate 34 via the first and second output members 71 and 72 and the load cells 82 and 83, the first and second ball screw portions are connected in series. Will be done. Therefore, the number of turns of the ball is increased, and the capacity for converting the movement directions of the first and second ball screw portions can be increased.

Further, since the adjusting mechanism 81 can adjust the relative positions of the first and second ball nuts 65 and 66 in the axial direction, the first and second balls can be adjusted. It is possible to make the load distribution on the ball uniform in the threaded portion.

Since the outputs of the first and second ball screw portions can be detected by the load cells 82 and 83, respectively, it is not necessary to dispose a large load cell and the injection apparatus can be downsized. In addition, the cost of the injection device can be reduced.

Next, a second embodiment of the present invention will be described. In addition, about the thing which has the same structure as 1st Embodiment, the description is abbreviate | omitted by giving the same code | symbol.

FIG. 5 is a sectional view of a ball screw unit according to the second embodiment of the present invention.

In the figure, reference numeral 181 denotes an adjusting mechanism section,
The adjustment mechanism portion 181 includes a male screw portion 185 formed at the rear end (right end in the figure) of the second output member 72, an adjusting plate 86 arranged to face the rear end of the male screw portion 185, and A cylindrical body 188 that is rotatably attached to the adjusting plate 86 and has an internal thread portion 189 formed on the inner peripheral surface thereof.
The male screw portion 185 and the female screw portion 189 are screwed together.

Then, in order to selectively prevent the relative rotation between the adjusting plate 86 and the cylindrical body 188, a retaining screw b6.
However, in order to selectively prevent the rotation of the tubular body 188 with respect to the second output member 72, the set screws b7 are respectively provided as fixing members.

Therefore, the set screws b6 and b7 are loosened, the tubular body 188 is rotated, and the adjusting plate 86 is moved back and forth (moved in the left-right direction in the drawing) to load cells as the first and second load detectors. By tightening the set screws b6 and b7 in a state where the sensor outputs of 82 and 83 are equalized, the first and second ball nuts 65 and 66 as the first and second nuts and the second conversion element are tightened. The relative position in the axial direction of can be adjusted.

Next, a third embodiment of the present invention will be described. In addition, about the thing which has the same structure as 1st Embodiment, the description is abbreviate | omitted by giving the same code | symbol.

FIG. 6 is a sectional view of the ball screw unit according to the third embodiment of the present invention, and FIG. 7 is a side view of the ball screw unit according to the third embodiment of the present invention.

In the figure, 281 is an adjusting mechanism section,
The adjusting mechanism portion 281 is provided with an adjusting plate 186 that is slidably movable with respect to a flange 85 formed at the rear end of the second output member 72. A plurality of long grooves 191 having a fan shape.
A fixing screw b8 is disposed on the flange 85 so as to penetrate through the flange 85.

Therefore, the retaining screws b8 are loosened, the second ball nut 66 is rotated, and the sensor outputs of the load cells 82 and 83 as the first and second load detecting portions are equalized. By tightening the screw b8, the relative positions in the axial direction of the first and second nuts and the first and second ball nuts 65 and 66 as the second conversion element can be adjusted.

In each of the above-mentioned embodiments, the rotation generated by driving the injection motor 53 (FIG. 1) as the drive unit is applied to the screw shaft and the ball screw shaft 64 as the first conversion element. Transmitted to the ball screw shaft 6
The rotational movement of No. 4 causes the first and second ball nuts 65, 66 to move.
However, the rotational movement of the ball screw shaft can also be converted into a linear movement accompanied by the rotation of the ball screw shaft, that is, a rotational linear movement.
Further, the rotation generated by driving the injection motor 53 is transmitted to the ball nut to convert the rotational movement of the ball nut into the rotational linear movement of the ball nut or the linear movement of the ball screw shaft. It can also be converted.

In each of the above embodiments, in the ball screw unit 63, the ball screw shaft 64 and the first and second ball nuts 65 and 66 are screwed together. The shaft 64 and three or more ball nuts can be screwed together.

Further, in the above embodiment, the ball screw unit 63 is used, but
It is also possible to use a roller screw unit having a roller screw shaft as the screw shaft and a roller nut as the nut.

The present invention is not limited to the above-mentioned embodiments, but can be variously modified within the scope of the present invention, and they are not excluded from the scope of the present invention.

[0043]

As described above in detail, according to the present invention, in the driving force transmission device, the drive section, the first conversion element rotated by driving the drive section, and the first conversion element are provided. The second conversion element screwed with the first conversion element is provided, and the movement direction conversion unit converts the rotational movement into the linear movement.

One of the first and second conversion elements is a screw shaft, and the other is two or more nuts that are screwed with the screw shaft to form a screw portion. .

The position of each nut in the axial direction is
It is adjusted by the adjusting mechanism section.

In this case, since the screw shaft and the two or more nuts are screwed together to form the respective screw portions, the number of windings of the ball is increased and the capacity of the motion direction changing portion can be increased. .

Further, since the position of each nut in the axial direction is adjusted by the adjusting mechanism portion, it is possible to make the load distribution on the ball uniform in each screw portion.

In another driving force transmission device of the present invention,
Furthermore, a load detection unit that detects the output generated by each screw unit is provided.

In this case, since each output of each screw portion can be detected by the load detecting portion, it is not necessary to dispose a large load detecting portion, so that the driving device can be downsized and the driving device can be driven. The cost of the device can be reduced.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of an injection device according to a first embodiment of the present invention.

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

FIG. 3 is a cross-sectional view of the ball screw unit according to the first embodiment of the present invention.

FIG. 4 is a side view of the ball screw unit according to the first embodiment of the present invention.

FIG. 5 is a sectional view of a ball screw unit according to a second embodiment of the present invention.

FIG. 6 is a sectional view of a ball screw unit according to a third embodiment of the present invention.

FIG. 7 is a side view of a ball screw unit according to a third embodiment of the present invention.

[Explanation of symbols]

34 Pressure Plate 53 Injection motor 64 ball screw shaft 65, 66 First and second ball nuts 71, 72 First and second output members 81, 181, 281 Adjustment mechanism section 82, 83 load cell

Claims (3)

[Claims] 1. A drive unit, (b) a first conversion element rotated by driving the drive unit, and a second conversion element screwed with the first conversion element. And (c) one of the first and second conversion elements is a screw shaft, and the other is screwed with the screw shaft. A driving force transmission device comprising: two or more nuts each of which is made to form a threaded portion, and (d) the position of each nut in the axial direction is adjusted by the adjustment mechanism unit. 2. The driving force transmission device according to claim 1, further comprising a load detection section for detecting an output generated by each screw section. 3. The nuts and the moving pressure members are connected to each other through the output members, and (b) the load detection unit is provided between the output members and the moving pressure members. The driving force transmission device according to claim 2.