JP2000210998A - Fixing structure of screw shaft in drive device for electromotive injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve the miniaturization of an apparatus and the reduction of material cost and processing cost and to certainly support the rotatory force and axial load acting on a screw shaft by reducing the diameter of the screw shaft to the attaching portion of the screw shaft. SOLUTION: In a screw shaft fixing structure, the screw portion 18b of the ball screw 18 fixed to a front plate 10 is screwed in the ball nut 38 supported on a pressure plate 12 in a freely rotatable manner. The shaft portion 18c of the ball screw 18 is inserted in the shaft attaching hole 10d of the boss part 10a of the front plate 10 and the ball screw 18 is fixed to the front plate 10 while the rotatory force and axial load acting on the ball screw 18 are supported by the friction type clamping element 37 mounted in a mounted hole 10e and an axial fixing means 36 consisting of the nut screwed onto the screw 18e formed to one end of the shaft portion 18c and the flange 18d provided to the other end of the shaft portion 18c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screw shaft fixing structure for a drive unit of an electric injection molding machine.
A drive nut provided on the other of the fixed member or the movable member is screwed into a screw shaft provided on one of the fixed member or the movable member, and the movable member is rotated with respect to the fixed member by rotating the drive nut with an electric motor. The present invention relates to a structure for fixing a screw shaft in a drive device of an electric injection molding machine which is moved to perform a required operation.

[0002]

2. Description of the Related Art An electric injection molding machine shown in FIG. 4 is known. The electric injection molding machine includes a fixed platen 2 on one side of a machine base 1, an end plate 4 connected to the fixed platen 2 by a tie bar 3, and a space between the fixed platen 2 and the end plate 4. A movable platen 6 that is guided by the tie bar 3 to move forward and backward with respect to the fixed platen 2, clamps the mold 5 with the fixed platen 2 and opens the mold, and a driving device 7 that moves the movable platen 6. A mold clamping device A comprising
Further, a heating cylinder 9 having an injection screw (operating member) 8 inserted into the other side on the machine base 1 so as to be rotatable in the circumferential direction and movably in the axial direction, and supports the heating cylinder 9. A front plate 10;
A pusher plate 12 supported via a guide bar 11 and rotatably supporting the injection screw 8, and a driving device 13 for moving the injection screw 8 forward and backward in the axial direction via the pusher plate 12. Apparatus B is provided.

The driving device 7 of the mold clamping device A is
A ball nut 16 rotatably supported by the end plate 4 is screwed into a ball screw 15 attached to a crosshead (movable member) 14 a of a toggle mechanism 14 connected to the end plate (fixed member) 4 and the movable platen 6. The crosshead 14 is moved in the axial direction of the ball screw 15 by rotating the ball nut 16 by an electric motor 17 via a transmission mechanism 17a such as a pulley or a belt.
The movable platen 6 is configured to be driven via the toggle mechanism 14.

The driving device 13 of the injection device B is
Conventionally, as shown in detail in FIG. 5, a pair of ball screws 18 (only one is shown in FIG. 5) is provided in a shaft mounting hole 10b formed in a boss portion (mounting portion) 10a of a front plate (fixing member) 10. The shaft portion 18a is inserted by a shaft portion 18a on one end side having a large diameter and is fastened to a mounting hole 10c formed in the shaft mounting hole 10b by a fastening means 19 for stopping the movement in the rotation direction and the axial direction. Are fixed to the front plate 10. And the ball screw 1
A ball nut (drive nut) 20 is screwed into the other end side of 8. The ball nut 20 is connected to a flange 22a on one end of a sleeve 22 rotatably supported by bearings 21 and 21 on the pusher plate (movable member) 12.

[0005] A fastening means 23 is attached to the sleeve 22.
The ball nut 20 is rotated by the electric motor 24 (see FIG. 4) fixed to the pusher plate 12 through the transmission mechanism 24a to rotate the pulley 23 fixed via the 10
The pusher plate 12 is configured to move closer to and away from the pusher plate. The movement of the pusher plate 12 causes the injection screw 8 to move forward and backward in the heating cylinder 9 in the axial direction, so that the injection operation of the molten resin or the retreat operation at the time of measurement is performed.

In the driving device 13 of the injection device B,
Boss portion 10a of front plate (fixing member) 10
In addition, as a fastening means 19 for stopping the movement in the rotation direction and the axial direction and fixing the shaft portion 18a of the ball screw 18, a friction type fastening element as shown in FIG. 6 is used.

The friction type fastening element includes an outer race 19a having a pair of tapered portions on both sides of the inner surface of the cylinder so that both ends have a large diameter, and a pair of outer races 19a having opposite ends on both sides of the outer surface of the cylinder. Inner race 19 with a taper
b, a plurality of screw holes 19c formed between the one end side of the outer race 19a and the inner race 19b and having a taper on the inner and outer surfaces matching the taper of the outer race 19a and the inner race 19b, and penetrating the end face and formed at appropriate intervals in the circumferential direction. A first tapered ring 19d having the outer race 19a and the inner race 19b has a taper on the inner and outer surfaces between the other ends of the outer race 19a and the inner race 19b. A second taper ring 19f having a plurality of bolt holes 19e formed corresponding to the screw holes 19c; and a screw hole of the first taper ring 19d passing through the bolt holes 19e of the second taper ring 19f. 19c bolt 19g. The outer race 19a and the inner race 19b are provided with slits penetrating in the radial direction over the entire length in the axial direction.

The inner and outer diameters of the outer race 19a and the inner race 19b are enlarged and reduced by tightening and loosening the bolt 19g, and the shaft portion 18a of the ball screw 18 fitted to the inner race 19b.
And the front plate 10 in which the outer race 19a is fitted in the mounting hole 10c of the boss 10a, can be integrally connected by frictional force, or the connection can be released.

In FIG. 4, reference numeral 25 denotes an electric motor for rotating the injection screw 8 via a transmission mechanism 26 such as a pulley or a belt, which is fixed to the pusher plate 12. 27 is a ball screw shaft 2 screwed into a ball nut 28 provided on the front plate 10
9 is an electric motor for nozzle touch for rotating 9 and moves the injection device B forward and backward with respect to the fixed platen 2. Reference numeral 30 denotes an ejector provided in the mold clamping device A, which drives an ejector plate 33 via a screw mechanism 32 in which a ball nut is screwed into a ball screw shaft by an electric motor 31 to operate an ejector pin 34. It has become.

[0010]

As described above, in the driving device 13 of the injection device B, when performing the injection operation of the molten resin by the injection screw 8 or the retreat operation at the time of measurement,
Boss portion 10a of front plate (fixing member) 10
The ball nut 18 is fixed to the ball screw 18 fixed to
Is rotated to move the pusher plate 12, but the pusher plate 12 receives a reaction force due to the operation of the injection screw 8, and this acts as a rotational force and an axial load on the ball screw 18 via the ball nut 20. Works.

Therefore, the conventional driving device 13 includes the frictional fastening element as the fastening means 19 for fastening the ball screw 18 to the boss portion 10a of the front plate (fixing member) 10 with the rotational force and the axial load. It takes both sides,
In order to obtain a large frictional force necessary to support this, the diameter of the mounting hole 10c of the boss portion 10a and the shaft portion 18a of the ball screw 18 must be increased to use a large size. .

For this reason, the diameter of the shaft portion 18a of the ball screw 18 becomes considerably larger than the diameter required for the screw portion 18b, so that the number of processing steps for the ball screw 18 and the shaft mounting hole 10b increases, and extra processing cost is required. In addition, there is a problem that the material is wasted, and the problem is more remarkable when the ball screw 18 is long. Also, since the friction type fastening element (fastening means) 19 is large, the boss 10a to which it is attached is mounted.
However, there is a problem that the size of the injection device B and the entire machine becomes large.

Therefore, the present invention eliminates the need for using a large friction type fastening element for fixing the screw shaft by stopping the movement in the rotation direction and the axial direction with respect to the fixed member or the movable member. An object of the present invention is to provide a fixing structure of a screw shaft in a drive unit of an electric injection molding machine that can reduce materials and processing costs. Another object of the present invention is to provide a drive unit for an easy-to-manufacture electric injection molding machine capable of reducing the size of a fixing member for fixing a screw shaft or a mounting portion of a movable member, and reducing the size of a machine or parts thereof. And a screw shaft fixing structure.

[0014]

According to a first aspect of the present invention, a screw shaft is fixed to one of a fixed member and a movable member, and the other of the fixed member and the movable member. A drive nut screwed into the screw shaft is rotatably supported, and by rotating the drive nut by an electric motor, the movable member moves with respect to the fixed member to perform a required operation. In the fixing structure of the screw shaft in the drive device of the electric injection molding machine, the shaft of the screw shaft is inserted into a shaft mounting hole formed in a mounting portion of the fixed member or the movable member. hand,
Rotational movement is stopped by rotation fixing means mounted between the shaft mounting hole and the shaft, and the shaft is removably fixed to a flange fixed to the shaft and an end of the shaft. The movement in the axial direction is stopped by an axial fixing means including a fastening member, and the screw portion on the other end is screwed into the drive nut.

In the invention having the above structure, when the drive nut supported on the other of the fixed member and the movable member is rotated by the electric motor, the screw shaft fixed to one of the fixed member and the movable member is rotated. The movable member moves relative to the drive nut in the axial direction, the movable member moves relative to the fixed member, and the operating member provided on the movable member performs a required operation. According to the device having the above configuration, the rotational force and the axial load generated on the screw shaft in accordance with the required operation of the operating member provided on the movable member are fixed or movable by the rotation fixing means and the axial fixing means. Since it is securely supported by the member, and particularly, the axial load is firmly supported by the axial fixing means, the rotation fixing means only needs to support the rotational force alone, even if the driving device requires a large driving force. , Eliminating the need for specially sized objects.

In the apparatus having the above-mentioned structure, the fastening member in the axial fixing means is configured as a nut screwed to a screw formed on an outer periphery of an end of a shaft portion of the screw shaft. It can be configured as a split ring attached to an annular groove formed on the outer periphery of the shaft on the shaft end portion side. According to these configurations, the structure of the axial fixing means is simple and easy to manufacture, and the axial load generated on the screw shaft is more strongly supported.

Further, in the apparatus having the above-mentioned structure, the rotation fixing means includes an inner race, an outer race, and a pair of taper rings provided between the inner race and the outer race so as to face each other. The inner race and the outer race are expanded and contracted in the radial direction by being approached and separated from each other by bolts, and can be configured as a friction type fastening element for fixing the shaft portion of the screw shaft to the shaft mounting hole by frictional force. (Claim 4). According to this configuration, it is easy to machine the shaft mounting hole of the fixed member or the movable member to which the rotation fixing means is mounted, and it is also easy to fix and release the screw shaft to the shaft mounting hole by the rotation fixing means. is there.

Further, in the apparatus having the above-mentioned configuration, the rotation fixing means may include a spline hole provided in the mounting portion,
A spline shaft provided on a shaft portion of the screw shaft and fitted into the spline hole (claim 5); or
A key provided on one of the shaft mounting hole and the shaft of the screw shaft, and a key groove provided on the other of the shaft mounting hole and the shaft of the screw shaft to be fitted with the key. (Claim 6).

Further, in the apparatus having the above structure, the fixed member is a front plate for supporting a heating cylinder of the injection device, and the movable member is inserted into the heating cylinder so as to be rotatable and axially movable. The injection screw may be a pusher plate that presses the injection screw in the axial direction. According to this configuration, by moving the pusher plate with respect to the front plate, the injection screw of the injection device can be moved back and forth in the axial direction, and the injection operation or the retreat operation at the time of measurement can be performed.

Further, in the apparatus having the above structure, the fixed member is an end plate that supports one end of a toggle mechanism for moving a movable plate of the mold clamping device, and the movable member is
A crosshead of the toggle mechanism may be provided. According to this configuration, by moving the crosshead of the toggle mechanism with respect to the end plate, the movable plate of the mold clamping device is moved with respect to the fixed plate via the toggle mechanism, and the metal provided between them is provided. The mold can be closed and the mold can be opened.

[0021]

FIG. 1 is a block diagram showing an embodiment of the present invention.
This will be described with reference to FIG. The same components as those of the conventional device are denoted by the same reference numerals, and detailed description thereof will be omitted. The drawings show an embodiment in which the present invention is applied to a driving device of an injection device, and reference numeral 10 denotes a front plate (fixing member). A pair of boss portions (mounting portions) 10a (only 1 is shown in FIGS. 1 and 3) provided on both sides of the front plate 10 are provided with shaft mounting holes 10d penetrating in parallel to the axial direction of the heating cylinder 9. , The shaft mounting hole 10
A mounting hole 10e having a larger diameter than the shaft mounting hole 10d is provided on one end side (left side in the figure) of d.

The shaft mounting hole 10d is formed to have a smaller diameter than the mounting hole 10b of the conventional device. The shaft mounting hole 10d has one end having a diameter corresponding to the rotational force and the axial load. The shaft portion 18c is inserted with the other end side flange 18d in contact with the other end surface of the boss portion 10a. A screw 18e is formed at an end of the shaft portion 18c of the ball screw 18, and a nut (fastening member) 35 which is in contact with one end surface of the boss 10a is screwed into the screw 18e. 18c constitutes an axial fixing means 36, and the axial fixing means 36 prevents the ball screw 18 from moving relative to the boss 10a in the axial direction. The flange 18d may be configured by fixing a ring formed separately to the ball screw 18c.

The mounting hole 10e is provided with a friction type fastening element (rotation fixing means) 37 having a structure similar to that of the friction type fastening element (fastening means) 19 of the conventional device and having a smaller size. Mounted, said frictional fastening element 37
Accordingly, the relative rotation of the ball screw 18 in the circumferential direction with respect to the boss 10a is prevented. In addition,
The nut 35 is provided with a short shaft portion 35a that fits into the mounting hole 10e.
8c is kept parallel to the mounting hole 10e, and the fastening state by the friction type fastening element is kept good.

On the other hand, the screw portion 18b of the ball screw 18
It is screwed into a ball nut (drive nut) 38 rotatably supported by a pusher plate (movable member) 12. The support structure of the ball nut 38 with respect to the pusher plate 12 is as follows. That is, through holes 12c having bearing mounting holes 12a and 12b are provided in boss portions on both sides of the pusher plate 12 (only one side is shown in FIGS. 1 and 2), and the bearing mounting holes 12a and 12b are provided.
b, large and small diameter bearings 39a, 39b are mounted respectively. The one ball nut body 38a located in the through hole 12c is rotatably supported by the pusher plate 12 by being inserted into the bearings 39a and 39b.

In the ball nut body 38a, another ball nut body 38b abuts the flange 40 on one end side of the ball nut body 38b with an adjusting member 41 interposed therebetween, and is integrally connected by bolts 40a. The other end surface 4 of the ball nut body 38a opposite to the flange 40
2, a plurality of screw holes 43 are formed at appropriate intervals in the circumferential direction.

A bearing holding collar 44 having a hole through which the ball screw 18 passes is brought into contact with the other end surface 42,
It is fixed to the ball nut body 38a by a bolt 45 that passes through the bearing holding collar 44 and is screwed into the screw hole 43. The bearing holding collar 44 has an outer peripheral portion,
A flange portion 44a is provided which projects toward the other end of the ball nut body 38a and is fitted to the other end, and is positioned on the same axis as the ball nut body 38a. Further, the bearing holding collar 44 has a flange portion 44a.
Of the inner ring of the small-diameter bearing 39b via the adjustment ring 46, and the flange 40 of the large-diameter bearing 39a, together with the flange 40 abutting on the outer end surface of the inner ring of the large-diameter bearing 39a.
The axial movement of the ball nut body 38a relative to the ball nut 39b is prevented.

An oil seal (seal member) 47 a is provided on the inner periphery of the cover 47 for closing the bearing mounting hole 12 b attached to the pusher plate 12, which is in sliding contact with the outer periphery of the bearing holding collar 44. Large diameter bearing 3
A plurality of holes 48 are provided in the bottom of the bearing mounting hole 12a for mounting the 9a at appropriate intervals in the circumferential direction, and a preload is applied to each of the bearings 39a and 39b by a compression spring 49 housed in the hole 48. I have. An oil seal 50a that slides on the outer periphery of the flange 40 is also attached to the inner periphery of the cover 50 that closes the bearing attachment hole 12a. As described above, the ball nut 38 includes a ball nut body 38a and a ball nut body 38b.
A pulley 23 attached to the electric motor 24 is connected to the electric motor 24 via a transmission mechanism 24a such as a belt. Other configurations are the same as those of the conventional device.

When the electric motor 24 rotates, the ball nut 38 rotates through the pulley 23 in the same manner as in the conventional apparatus, whereby the pusher plate 12 moves the heating cylinder with respect to the front plate 10. 9 moves back and forth in the axial direction.
An injection screw (operating member) 8 supported by 2 moves forward and backward in the heating cylinder 9 in the axial direction thereof. In the injection step, the injection screw 8 moves forward and the molten resin in the heating cylinder 9 is injected into the cavity of the mold 5 clamped by the mold clamping device A, and is rotated by the electric motor 25 in the measuring step. The injection screw 8 is retracted, and the molten resin is measured in the heating cylinder 9 in front of the injection screw 8.

When an injection operation of the molten resin by the injection screw 8 or a retreat operation at the time of measurement is performed, the operation of the injection screw 8 with respect to the ball screw 18 fixed to the boss portion 10a of the front plate 10 is performed. The accompanying reaction force,
It acts as a rotational force and an axial load via the ball nut 38. The axial load is securely supported by the boss 10a by axial fixing means 36 constituted by the nut 18 screwed to the screw 18e of the shaft 18c of the ball screw 18 and the flange 18d of the ball screw 18. Is done. The rotation force is applied to the nut 35 and the flange 18d by tightening the nut 35 of the axial fixing means 36.
The boss 10a is formed by a frictional force generated between the boss 10a and the boss 10a and a frictional fastening element 37 as a rotation fixing means.
Supported by Therefore, unlike the conventional device, the axial load does not act on the friction type fastening element 37, and the frictional force is applied. Therefore, even if the friction type fastening element 37 is of a relatively small size (capacity), The rotation force can be reliably supported.

In the above embodiment, the ball screw 1
8 with the boss 10a of the front plate 10
The fastening member of the axial fixing means 36 for stopping the axial movement and fixing the screw to the end of the shaft portion 18c is a screw 18e.
Was formed, and the nut 35 was screwed into this.
Instead, as shown in FIG. 3, an annular groove 18f is formed in the outer periphery of the end portion of the shaft portion 18c of the screw shaft 18, and the ring-shaped members divided into a plurality are integrally tightened by bolts or the like. The split ring 51 to be connected may be mounted in the annular groove 18f.

In the above, the wall surface on one end side (left side in the figure) of the annular groove 18f is formed as a tapered surface 18g inclined so as to decrease in diameter toward the opposite wall surface side.
When one end of the inner peripheral surface of the first ring is formed as a tapered surface 51a that matches the tapered surface 18g, the split ring 51 is
f, the split ring 51 is formed by the tapered surface 18g and the tapered surface 51a.
To prevent the ball screw 18 from moving in the axial direction with respect to the boss 10a, so that the axial fixing can be performed more firmly.

In the above-described embodiment, the rotation fixing means includes an outer race 19a and an inner race 19b, and tapered rings 19d and 19f therebetween.
A friction type fastening element 37 of a type in which the shaft portions 18c of the ball screw shaft 18 are fixed to the shaft mounting holes 10d by frictional force by moving the bolts 19g closer to and away from each other with bolts 19g, and by frictional force. However, the friction type fastening element is not limited to the above-mentioned type, and other types may be employed.

Further, in the above-described embodiment, the rotation fixing means employs a friction type fastening element 37. Instead of this, a spline hole is provided in the boss portion 10a and the shaft of the ball screw 18 is provided. The portion 18c may be provided with a spline shaft fitted into the spline hole. Further, a key provided on one of the boss 10a and the shaft 18c, and a key groove provided on the other of the boss 10a and the shaft 18c to be fitted with the key are provided. You can also. With this configuration, the ball screw 18 can be securely fixed to the boss portion 10a without relying on the frictional force, by forcibly stopping the rotational force through the contact of the mechanical portion.

In the above embodiment, when the ball nut 38 is mounted on the pusher plate 12 via the bearings 39a and 39b, the bearing for preventing the axial movement of the ball nut body 38a with respect to the bearings 39a and 39b. The holding collar 44 is attached to the ball nut body 38a.
Is formed so as to be in contact with the other end surface 42 of the ball nut body 38a, so that it is not necessary to machine a screw for screwing the bearing holding nut on the outer peripheral portion on the other end side of the ball nut body 38a, and machining is easy, The distance between the bearings 39a and 39b can be increased.

Therefore, the ball nut body 3 having the above configuration
The support structure 8 is preferable because the load borne by the bearings 39a and 39b can be reduced and the ball nut body 38a can be reliably supported. However, in the present invention, the support structure for rotatably supporting the ball nut with respect to the pusher plate 12 is not limited to that of the above-described embodiment, but is optional. The structure of the ball nut 20 of the conventional device shown in FIG. It can be configured similarly to the support structure for the pusher plate 12.

Further, in the above embodiment, the present invention is applied to the injection device B in which the ball screw 18 is fixed to the front plate 10 and the ball nut 38 is rotatably supported on the pusher plate 12. On the contrary, the ball screw 18 is fixed to the pusher plate 12,
The present invention may be applied to an injection device in which the ball nut 38 is rotatably supported on the front plate 10.

Further, in an injection apparatus of a type in which a rear plate (fixed member) is connected to a front plate 10 by a guide bar, and a pusher plate (movable member) 12 which moves along the guide bar is provided therebetween. The present invention may be applied to a configuration in which a ball screw 18 is fixed to one of the rear plate and the pusher plate 12 and a ball nut 38 is rotatably supported on the other.

In the driving device 7 of the mold clamping device A,
A ball screw 18 is fixed to a crosshead (movable member) 14a of the toggle mechanism 14, and an end plate (fixed member) 4 is fixed.
The present invention may be applied to a configuration in which a ball nut 38 is rotatably supported. Further, the movable plate 6 is connected to the toggle mechanism 1.
In a direct pressure type mold clamping device that is driven directly without the intervention of a ball screw 4, a ball screw 18 is fixed to one of a movable platen (movable member) and an end plate (fixed member), and a ball nut 38 is rotatable to the other. The present invention may be applied to a supported configuration.

In the ejector 30 attached to the mold clamping device A, the ball screw 18 is fixed to an ejector plate (movable member) 33 having an ejector pin 34, and the ball nut 38 is rotated on the movable platen or a member fixed thereto. Freely supported, and a ball nut 38
The present invention can be applied to a configuration in which is rotated. Further, in the above embodiment, the screw shaft and the drive nut screwed into the screw shaft are constituted by the ball screw 18 and the ball nut 38. However, instead of these, a screw shaft having a square screw or a trapezoidal screw is used. And a suitable nut.

[0040]

As described above, according to the first aspect of the present invention, the screw shaft screwed into the drive nut rotatably supported on one of the movable member and the fixed member has the shaft at one end thereof. Part is inserted into a shaft mounting hole formed in the mounting part of the fixed member or the movable member, and the rotation in the rotation direction is stopped by rotation fixing means mounted between the shaft mounting hole and the shaft part, The axial movement is stopped by an axial fixing means including a flange fixed to the shaft and a fastening member detachably fixed to an end of the shaft.

Therefore, the rotational force and the axial load generated on the screw shaft in accordance with the required operation of the operating member provided on the movable member are applied to the fixed member or the movable member by the rotation fixing means and the axial fixing means, respectively. Since it is securely supported, and especially the axial load is strongly supported by the axial fixing means, the rotation fixing means needs to support only a small rotational force reduced by the additional frictional force by the axial fixing means. ,
Even if the driving device requires a large driving force, it is not necessary to use a specially large driving device. For this reason, the screw shaft does not need to make the diameter of the shaft portion inserted into the mounting portion of the fixed member or the movable member larger than the screw portion, and the maximum diameter of the screw shaft can be smaller than that of the conventional device. Therefore, the material and processing cost can be reduced, and the size of the mounting portion of the fixed member or the movable member can be reduced, so that the machine or its parts can be reduced in size and its manufacture is easy.

According to the second and third aspects of the present invention, a nut screwed onto a screw formed on the outer periphery of the end of the shaft of the screw shaft, or the outer periphery of the screw shaft on the shaft end side. The split ring mounted on the annular groove formed as described above functions as a fastening member in the axial fixing means, and can more strongly support the axial load generated on the screw shaft. The structure of the axial fixing means is simple and easy to manufacture, and the device can be easily assembled and removed.

According to the fourth aspect of the present invention, the friction type fastening element as the rotation fixing means expands and contracts the inner race and the outer race, and the shaft end of the screw shaft is fixed to the fixed member or the movable member. Since it is fixed to the shaft mounting hole of the mounting part, no special processing is required for the shaft end and the shaft mounting hole of the screw shaft. The fixing of the screw shaft by the rotation fixing means and the release thereof can be easily performed.

According to the fifth and sixth aspects of the present invention, the rotation fixing means applies the rotational force acting on the screw shaft by the abutment of the mechanical part by the spline or key and the spline hole or key groove. Since the screw shaft is forcibly stopped, the shaft end of the screw shaft can be more securely fixed to the shaft mounting hole in the rotation direction.

According to the seventh and eighth aspects of the present invention, in each of the above inventions, the front plate supporting the heating cylinder of the injection device and the end plate of the mold clamping device are fixed members, and the injection screw of the injection device is provided. Since the movable member is a pusher plate for supporting the cross head of a toggle mechanism for driving the movable plate of the mold clamping device, the injection screw of the injection device as an operating member and the movable plate of the mold clamping device are reliably driven. Thus, the required operation can be smoothly performed by the operating member.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a main part of an embodiment in which the present invention is applied to a driving device of an injection device in an electric injection molding machine.

FIG. 2 is a longitudinal sectional view showing an embodiment in which the present invention is applied to a driving device of an injection device in an electric injection molding machine.

FIG. 3 is a sectional view showing a main part of another embodiment in which the present invention is applied to a driving device of an injection device in an electric injection molding machine.

FIG. 4 is an overall view of an electric injection molding machine.

FIG. 5 is a longitudinal sectional view showing a screw shaft fixing structure in a driving device of an injection device of a conventional electric injection molding machine.

FIG. 6 is a longitudinal sectional view showing an example of a friction type fastening element.

[Explanation of symbols]

Reference Signs List 8 Injection screw (operating member) 9 Heating cylinder 10 Front plate (fixing member) 10a Boss portion (mounting portion) 10d Shaft mounting hole 10e Mounting hole 12 Pusher plate (movable member) 18 Ball screw (screw shaft) 18b Screw portion 18c Shaft Part 18d Flange 18e Screw 18f Annular groove 18g Tapered surface 35 Nut (fastening member) 36 Axial fixing means 37 Friction type fastening element (Rotation fixing means) 38 Ball nut (Drive nut) 51 Split ring 51a Tapered surface

Claims (8)

[Claims] A screw shaft is fixed to one of a fixed member and a movable member, and a drive nut screwed into the screw shaft is rotatably supported on the other of the fixed member and the movable member. By rotating the nut by an electric motor, the movable member is moved with respect to the fixed member, and a required operation is performed. The screw shaft has a shaft portion on one end side inserted into a shaft mounting hole formed in a mounting portion of the fixed member or the movable member, and a rotation fixing device mounted between the shaft mounting hole and the shaft portion. The movement in the rotation direction is stopped by the means, and the movement in the axial direction is stopped by the axial fixing means including a flange fixed to the shaft and a fastening member detachably fixed to an end of the shaft. And the other end Fixing structure of the screw shaft in the driving device of an electric injection molding machine screw portion is characterized in that it is screwed to the drive nut. 2. The electric type according to claim 1, wherein the fastening member in the axial fixing means is a nut screwed on a screw formed on an outer periphery of an end portion of a shaft portion of the screw shaft. A structure for fixing a screw shaft in a drive unit of an injection molding machine. 3. The electric injection according to claim 1, wherein the fastening member in the axial fixing means is a split ring mounted in an annular groove formed on an outer periphery of a shaft end of the screw shaft. A structure for fixing a screw shaft in a driving device of a molding machine. 4. The rotation fixing means includes an inner race, an outer race, and a pair of tapered rings provided between the inner race and the outer race and opposed to each other. The frictional fastening element for expanding and contracting the inner race and the outer race in the radial direction, and fixing the shaft portion of the screw shaft to the shaft mounting hole by frictional force. 4. A screw shaft fixing structure in the drive device for the electric injection molding machine according to any one of the above items. 5. The rotation fixing means comprises a spline hole provided in the mounting portion, and a spline shaft provided in a shaft portion of the screw shaft and fitted in the spline hole. 4. A fixing structure of a screw shaft in a drive device of an electric injection molding machine according to any one of 1, 2, and 3. 6. A key provided on one of the shaft mounting hole and the shaft of the screw shaft, and the rotation fixing means is provided on the other of the shaft mounting hole and the shaft of the screw shaft. The screw shaft fixing structure according to any one of claims 1, 2, and 3, wherein the key shaft is fitted with the key groove. 7. The fixing member is a front plate that supports a heating cylinder of the injection device, and the movable member is configured such that the injection screw rotatably and axially movably inserted into the heating cylinder. 7. The screw shaft fixing structure in a drive device for an electric injection molding machine according to claim 1, wherein the screw shaft is a pusher plate that presses in the axial direction. 8. The apparatus according to claim 1, wherein the fixing member is an end plate that supports one end of a toggle mechanism for moving a movable plate of the mold clamping device, and the movable member is a crosshead of the toggle mechanism. Item 7. A fixing structure for a screw shaft in a drive device for an electric injection molding machine according to any one of Items 1 to 6.