JP2000061984A - Nozzle touch mechanism for injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fit a ball screw precisely without requiring skill. SOLUTION: A ball screw 6 is comprised of a fall screw shaft 8 and a ball nut 9 engaging with each other. The ball nut 9 is fitted to a sleeve 17 integrally, engages a first bearing 20 comprising small-diameter ball bearings, second and third bearings 21, 22, comprising large-diameter angular ball bearings and a fourth bearing 23 comprising small-diameter ball bearings in turn with the periphery of the sleeve 17, holds them by a fastening nut 19 and a flange part 18, and is assembled integrally as a nut unit. The fourth bearing 23 is engaged with the small diameter part 12 of a nut fitting hole 10, the second and third bearings 21, 22 are engaged with the large diameter part 13 of the nut fitting hole, and a bearing pressing member 24 is bolt-bonded to the rear wall of a heating cylinder housing so that the second and third bearing 21, 22 are pressed to the front wall of the large diameter part 13 of the nut fitting hole to be fitted integrally to the heating cylinder housing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nozzle touch mechanism of an injection molding machine, and more particularly, to a nozzle touch of an injection molding machine in which a nozzle is brought into contact with or separated from a fixed mold by using a ball screw. Regarding the improvement of the mechanism.

[0002]

2. Description of the Related Art In a nozzle touch mechanism of an injection molding machine, a fixed platen of a mold clamping device and a heating cylinder housing of an injection device are drivingly connected with each other by a ball screw, and the ball screw is driven by a driving mechanism so that the heating cylinder is used during injection. Various types are known in which the housing is advanced to bring the nozzle into pressure contact with the fixed mold, and after the injection, the heating cylinder housing is retracted to separate the nozzle from the fixed mold. By the way, the ball screw is composed of a ball screw shaft and a ball nut, one of which is attached to the fixed platen while the other is attached to the heating cylinder housing so as not to move in the axial direction, and one is fixed and the other is rotatably provided. As shown in FIGS. 4 to 6, the ball nut is rotatably attached to the heating cylinder housing.

The nozzle touch mechanism shown in FIGS. 4 to 6 is applied to an in-line screw type injection molding machine. The front end of the nozzle touch mechanism is fixed to the fixed platen 51 and the heating cylinder housing 5 is used.
Two sets of ball screws 58 consisting of a ball screw shaft 59 inserted into a nut mounting hole 56 formed in 2 and a ball nut 60 screwed into the ball screw shaft 59 and rotatably mounted in the nut mounting hole 56. Equipped with each ball nut 6
The heating cylinder housing 52 is moved forward and backward by rotating 0 by the drive mechanism 65, and the nozzle 54 of the heating cylinder 53 attached to the heating cylinder housing 52 is fixed to a fixed mold (not shown).
It comes in contact with and separates from. In this nozzle touch mechanism, each ball nut 60 has a flange portion 61 at the front end, and a tightening nut 62 is engaged at the rear end side of the ball nut 60. The nuts are attached via two tapered roller bearings 63 and 64. It is attached to the hole 56. That is, in the middle of the nut mounting hole 56, as shown in FIG.
Is provided, the front tapered roller bearing 63 is sandwiched between the flange portion 61 of the ball nut and the front surface of the bearing projection 57, and the rear tapered roller bearing 64 is provided on the rear surface of the bearing projection 57 and the tightening nut 62 of the ball nut. It is sandwiched between and.
As a result, each ball nut 60 is attached to the heating cylinder housing 52 so as to be rotatable and not rattling in the axial direction.

The drive mechanism 65 transmits the rotation of a drive shaft 67 of a motor with reduction gear (geared motor) 66 to one driven gear 69 via a drive gear 68 and to the other driven gear 69 via an idler gear 70. This is transmitted so that each driven gear 69 rotates in the same direction. Each driven gear 69
The ball nuts 60 are bolted to the rear end surface of the ball nuts 60 so that the ball nuts 60 can be integrally rotated. The idler gear 70 is an annular gear having outer peripheral teeth as shown in FIG. 5, and two upper and lower portions of the inner periphery are supported by a casting support metal 71 so as to mesh with each driven gear 69. In addition,
Reference numeral 55 in FIGS. 4 to 6 denotes a screw provided in the heating cylinder 53 so as to be rotatable and movable back and forth, and 72 denotes a nozzle touch position detector. The nozzle touch position detector 72 is composed of a slit plate 75 attached to the drive shaft 67 via a connecting shaft 73 and an auxiliary shaft 74, and a photo sensor 76 provided in front of the heating cylinder housing 52. Is measured to measure the amount of movement of the heating cylinder housing 52. The front side means the left direction of the heating cylinder housing 52 in FIG.

[0005]

The above-mentioned conventional nozzle touch mechanism has a problem that it requires skill to attach the ball nut 60. When mounting the ball nut 60, the front tapered roller bearing 63 is attached to the heating cylinder housing 5
From the front of 2, the rear tapered roller bearing 64 is inserted from the rear, and the tapered roller bearings 63 and 64 are mounted so as to abut the bearing projections 57 of the nut mounting holes. Then, the ball nut 60 is normally fitted to the tapered roller bearings 63 and 64 from the front of the heating cylinder housing 52, and a tightening nut 62 is screwed to the rear end side of the ball nut 60 for tightening. By the way, the ball nut 60 needs to be attached to the heating cylinder housing 52 so that there is no rattling in the axial direction, and therefore each tapered roller bearing 63,
64 must be mounted with an even clamping force so that it does not rattle in the axial direction. Further, in each of the tapered roller bearings 63 and 64, each inner race is moved by the operation of the tightening nut 62, and by this movement, the outer race is pressed against the bearing projection 57 via each roller, whereby the tightened state is obtained. Mounted. However, each tapered roller bearing 6
Since the inner races and outer races 3 and 64 do not always move under the same conditions, the tightening torque of the tightening nut 62 must be adjusted while performing various adjustment operations. Moreover, the ball nut 60 and each tapered roller bearing 6
3 and 64 are mounted in the nut mounting holes 57, and the above operations must be performed in a state where the tightened state of the tapered roller bearings 63 and 64 cannot be visually observed. As a result, the work of adjusting the tightening torque of the tightening nut 62 must depend on the intuition of the operator,
Since a high degree of skill is required, it is difficult for anyone to install it accurately.

There is also a problem that the ball screw replacement work is complicated and takes a long time. When removing the ball screw 58, the front end of the ball screw shaft 59 is removed from the fixed platen 51, the driven gear 69 and the tightening nut 62 are removed from the ball nut 60, and the ball nut 60 and the front tapered roller bearing 63 from the front of the heating cylinder housing 52. And by removing the rear tapered roller bearing 64 from the rear. In this way, the ball nut 60, the tightening nut 62 and the tapered roller bearings 63 and 64 are installed in the nut mounting hole 5
Since it has to be disassembled in 7 and removed from different directions, the removal work is complicated. In addition, the mounting work of the ball screw 60 requires a high degree of skill in mounting the ball nut 60 as described above, and the tapered roller bearing 6
3, 64, the ball nut 60, and the tightening nut 62 are sequentially assembled in the nut mounting hole 57, which is complicated. As described above, the ball screw 58
In each work of mounting and removing the
2, 63, 64, 69 must be assembled or disassembled in the nut mounting hole 57 sequentially, and the replacement work of the ball screw 58 is complicated and takes a long time.

Further, there is a problem that the environment around the drive mechanism 65 is polluted and the lubricating oil management of the drive mechanism 65 is complicated. An idler gear 70 provided between the driven gears 69 of the drive mechanism is guided and supported by a supporting metal, but it is necessary to apply grease to the supporting metal 71 in order to prevent abrasion and galling of the idler gear 70. ing. However, this grease adheres to the idler gear 71 and is scattered around by the rotation of the idler gear 71.
It is extremely polluting the surrounding environment. Further, since the grease is consumed so much that it is scattered, it is necessary to apply the grease frequently and in such a manner that it is difficult for the grease to be scattered, which makes the lubricating oil management complicated.

The present invention has been made to solve the above-mentioned problems of the prior art. The object of the present invention is to perform injection molding in which the ball screw can be mounted accurately without requiring any skill, and the ball screw can be replaced easily and quickly. To provide a nozzle touch mechanism for a machine. Further, in the case of employing a plurality of ball screws, it is an object of the invention to provide a nozzle touch mechanism of an injection molding machine which can guide and support an idler gear installed between driven gears without oil.

[0009]

In order to solve the above-mentioned problems, in the present invention, the nut mounting hole is formed in a cylindrical shape having a small diameter portion at the front and a large diameter portion at the rear, and the bearing has a flange portion at the rear end. It is mounted on the outer circumference of the sleeve that has a front end and is designed to engage with the tightening nut, and is clamped between the tightening nut and the flange part for mounting, and the sleeve is rotatable and the sleeve flange part is rearward. The ball nut is integrally attached to the sleeve by sandwiching it in the axial direction by the front wall of the large diameter part of the nut mounting hole and the bearing pressing member mounted on the rear wall of the heating cylinder housing so as to project. . Thus, when the ball nut is mounted, the bearing can be previously assembled integrally with the sleeve, or the ball nut can be further integrated integrally with the sleeve to form a nut unit, and the nut unit can be mounted by mounting the nut unit into the nut mounting hole from the rear.
At that time, the inner race is attached to the flange of the sleeve by pressing it with a tightening nut, and the outer race is attached to the front wall of the large diameter part of the nut attaching hole by a bearing pressing member. There is no need to set a preload on. When removing the ball nut, the bearing and sleeve or the bearing, sleeve and ball nut are integrated as a nut unit.Therefore, by removing the bearing pressing member from the heating cylinder housing, this can also be moved backward from the nut mounting hole. Can be released.

The flange portion of the sleeve is preferably a driven gear and flange portion integrally formed with the driven gear of the drive mechanism. Accordingly, by mounting the bearing or the ball nut on the sleeve, the nut unit can be compactly assembled including the driven gear.

The bearing comprises a small diameter bearing, a large diameter bearing and a small diameter bearing which are mounted on the outer circumference of the sleeve in order from the flange side. The small diameter bearing on the tightening nut side is mounted on the small diameter portion of the nut mounting hole. The large-diameter bearing may be mounted on the large-diameter portion of the nut mounting hole, and the bearing pressing member may be mounted on the outer circumference of the small-diameter bearing on the flange side. At that time, it is preferable that the large-diameter bearing employs two Anguilura ball bearings or tapered roller bearings, which are assembled in opposite directions so as not to be displaced in the axial direction. By pressing the front wall of the large diameter portion of the mounting hole and pressing the bearing pressing member with the other bearing when retracting, the heating cylinder housing can be moved integrally with the ball nut without axial displacement.

In a nozzle touch mechanism using a plurality of ball screws, an idler gear consisting of an annular gear provided between driven gears is supported by deep groove ball bearings at two or more positions on the inner circumference, and the idler gear is supported by rolling contact. I'm supposed to get it. As a result, it is possible to prevent wear and galling of the idler gear without using a lubricant such as grease.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described in detail with reference to FIGS. FIG. 1 is a conceptual explanatory view of a nozzle touch mechanism applied to an inline-scrill type injection molding machine, and is a plan view showing a state in which the nozzle touch is partially cut. FIG. 2 is a view on arrow AA of FIG. 1 and shows a drive system of the nozzle touch mechanism. FIG. 3 is an enlarged view of a main part of FIG. 1, showing a ball nut mounting structure. 1-3, 1 is a fixed platen of the mold clamping device, which is a machine base (not shown)
It is fixedly installed on the upper side, and a fixed mold (not shown) is attached to the left side surface in FIG. Reference numeral 2 denotes a heating cylinder housing of the injection device, which is a fixed platen 1 on a machine base (not shown).
It is installed to face and retreat freely. 3 is a heating cylinder,
A nozzle 4 is provided at the tip, and a screw 5 is rotatably and reciprocally arranged inside. The rear end is inserted and fixed in the heating cylinder housing 2 so that the nozzle 4 at the tip faces the fixed platen 1. The heating cylinder housing 2 is held and is moved back and forth integrally with the heating cylinder housing 2. The left side of the heating cylinder housing 2 in FIG. 1 is the front.

In the nozzle touch mechanism shown in FIGS. 1 to 3, the fixed platen 1 and the heating cylinder housing 2 are drivingly connected by two sets of ball screws 6, and each ball screw 6 is driven by a driving mechanism 7. . Each ball screw 6 is composed of a ball screw shaft 8 and a ball nut 9 which are screwed together, and two sets are provided symmetrically on both sides of the heating cylinder 3. Each ball screw shaft 8 has a nut mounting hole 1 provided in the heating cylinder housing 2.
0 extends through the heating cylinder 3 in parallel, and the front end is attached to the fixed platen 1 by a mounting plate 11 so as not to rotate. The nut mounting holes 10 are for mounting the ball nuts 9. Two nut mounting holes 10 are provided symmetrically and in parallel on both sides of the heating cylinder 3 in the heating cylinder housing 2, and a step having a small diameter portion 12 at the front and a large diameter portion 13 at the rear. A circular hole 15 through which the ball screw shaft 8 is inserted is formed in the front wall 14 that closes the front of the small diameter portion 12 and has a cylindrical shape.

The ball nut 9 is rotatably mounted in the nut mounting hole 10 so as to rotate by being screwed onto the ball screw shaft 8. That is, the ball nut 9 has a flange portion 16 at the rear end, and the flange portion 16 is bolted to the flange portion 18 at the rear end of the sleeve 17 and is integrally attached to the sleeve 17. The flange portion 18 of the sleeve has outer peripheral teeth and also serves as a driven gear that meshes with a drive gear 26 of a drive mechanism described later, that is, a so-called driven gear integrally formed as a driven gear and flange portion. . A tightening nut 19 is provided on the outer circumference of the front end of the sleeve 17.
A first bearing 20 formed of a ball bearing having a small diameter in order from the flange portion 18 side.
Second and third bearings 2 consisting of large-diameter Anguilura ball bearings
No. 1, 22 and a fourth bearing 23 composed of a small-diameter ball bearing are fitted to each other, and the inner race of each bearing 20, 21, 22, 23 is held by the tightening nut 19 and the flange portion 18 in the axial direction to form a sleeve. It is attached integrally to 17. The sleeve 17 is mounted in the nut mounting hole 10 such that the tightening nut 19 side is on the front side and the flange portion 18 projects from the rear side. In the bearings 20, 21, 22.23 mounted on the outer circumference of the sleeve 17, the fourth bearing 23 on the tightening nut 19 side is attached to the small diameter portion 12 of the nut mounting hole, and the second and third bearings 21, 22 are attached. The first bearing 20 on the flange portion 18 side is fitted in the large diameter portion 13 of the nut mounting hole so as to project from the rear end of the nut mounting hole 10. A bearing pressing member 24 is fitted on the outer periphery of the first bearing 20 on the side of the flange portion 18, and the bearing pressing member 24 is bolted to the rear wall of the heating cylinder housing 2. A pressing portion is formed on the inner peripheral side of the bearing pressing member 24 so as to project forward, and this pressing portion engages with the rear end of the nut mounting hole 10 and contacts the outer race of the second bearing 21. The second and third bearings 21 and 22 are axially sandwiched by the front wall of the large diameter portion 13 of the nut mounting hole. The second
The third bearings 21 and 22 are mounted in opposite directions as shown in FIG. 3, and the rear second bearing 21 when the ball nut 9 moves forward and the front third bearing 2 when the ball nut 9 moves backward.
2 is responsible for the axial force. Further, the bearing pressing member 24 has an annular integral structure,
It may have a divided structure. As described above, since the ball nut 9 is mounted in the nut mounting hole 10 so as to be freely rotatable and without rattling in the axial direction, the ball nut 9 moves along the ball screw shaft 8 by rotating, and the heating cylinder housing 2 Will move back and forth.

The drive mechanism 7 is for driving the ball screw 6, and includes an electric motor (motor with reduction gear) 25,
Drive gear 26, sleeve flange 1 having outer teeth
8 and idler gear 27. Electric motor 2
5 is integrally attached to the heating cylinder housing 2 in the vicinity of one nut attachment hole 10, and a control device (not shown)
Is controlled to operate before and after injection. The drive gear 26 is attached to the drive shaft 28 of the electric motor and is provided so as to mesh with the outer peripheral teeth formed on the flange portion 18 of the one sleeve. The idler gear 27 is an annular gear having outer peripheral teeth as shown in FIG. 2, and three upper and lower portions of the inner periphery are guided and supported by deep groove ball bearings 29 so as to mesh with the flange portion 18 of each sleeve.
As described above, the drive mechanism 7 operates the electric motor 25 to drive the drive gear 26 and the flange portion 1 of one sleeve.
8 is rotated, and this rotation is transmitted to the flange portion 18 of the other sleeve via the idler gear 27, and each sleeve 17
Will be rotated in the same direction at the same speed. As a result, each ball nut 9 rotates integrally with each sleeve 17 and moves at the same speed along each ball screw shaft 8 to move the heating cylinder housing 2 forward and backward.

Reference numeral 30 is an encoder which is a nozzle touch position detector, and is attached to a drive shaft 28 of the electric motor via a coupling 31 and a connecting shaft 32 so as to be positioned laterally of the nut mounting hole 10. This encoder 30
Measures the number of rotations of the drive shaft 28 of the electric motor. When the nozzle 4 comes into contact with a fixed mold (not shown), the electric motor 25 idles, and the output from the encoder 30 is stopped. The electric motor 25 is stopped when the period exceeds a predetermined time.

The nozzle touch mechanism shown in FIGS. 1 to 3 is constructed as described above, and its operation will be described below in relation to the operation of the injection molding machine. Before the injection, the heating cylinder housing 2 is advanced to bring the nozzle 4 into pressure contact with a fixed mold (not shown). That is, the electric motor 25 is operated by a mold clamping completion signal from the mold clamping device, the flange portion 18 of one sleeve is rotated via the drive gear 26, and the flange portion 18 of the other sleeve is rotated via the idler gear 27. To do. The rotation of the flange portion 18 of each sleeve causes each ball nut 9 to rotate in the same direction and advance along each ball screw shaft 8 to move the heating cylinder housing 2 in a direction approaching the fixed platen 1. During this time, the drive shaft 28 of the electric motor
The number of revolutions is measured by the encoder 30, and the electric motor 25 stops when the output of the encoder 30 does not change for a predetermined time. As a result, the heating cylinder housing 2 is stopped and the nozzle 4 is brought into pressure contact with a fixed mold (not shown). After the injection, the heating cylinder housing 2 is retracted, the nozzle 4 is separated from the fixed mold (not shown), and the nozzle is backed. That is, the electric motor 25 is reversely rotated by the plasticization end signal and the cooling completion signal, and the flange portion 18 and the ball nut 9 of the sleeve are reversely rotated, and the encoder 3 is rotated.
The electric motor 25 stops when the measured value of 0 reaches the set value. During this time, the ball nut 9 is retracted along the ball screw shaft 8 to move the heating cylinder housing 2 in a direction away from the fixed platen 1 to cause nozzle backing, and the nozzle 4 is separated from a fixed mold (not shown).

By the way, the heating cylinder housing 2 is advanced by pushing the front wall of the large diameter portion 13 of the nut mounting hole through the sleeve 17 and the second and third bearings 21 and 22 when the ball nut 9 is advanced. During the backward movement, the bearing pressing member 2 is inserted through the sleeve and the second and third bearings 21 and 22.
It can be retracted by pressing 4. At that time, the ball nut 9 and the sleeve 17, the sleeve 17 and the second and third bearings 21 and 22, the second and third bearings 21 and 22, and the bearing pressing member 24 are free from axial rattling, Since the ball nut 9 and the heating cylinder housing 2 have no rattling in the axial direction, the heating cylinder housing 2 moves back and forth integrally with the ball nut 9, and the contact and separation of the nozzle 4 can be repeated with high accuracy. Further, since the idler gear 27 is guided and supported by rolling contact with the deep groove ball bearing 29, and it is not necessary to supply a lubricant such as grease to the guide surface of the deep groove ball bearing 29, environmental pollution due to scattering of the lubricant and lubricant Maintenance-free operation is possible without problems such as management.

Next, a method of mounting the ball nut 9 in the work of mounting the ball screw 6 will be described. The first bearing 20 is fitted on the outer circumference of the sleeve 17, the bearing pressing member 24 is fitted on the outer circumference of the first bearing 20, the second bearing 21 is adjacent to the first bearing 20, and the third bearing 22 is provided. The fourth bearing 23 is sequentially fitted, and the fastening nut 19 is engaged with the front end of the sleeve 17 for fastening. Since the second bearing 21 and the third bearing 22 are Angular ball bearings, they are fitted in opposite directions. As a result, the bearings 20, 21, 22, 23 are sandwiched in the axial direction by the tightening nut 19 and the flange portion 18, and the sleeve 17 and the bearings 20, 21, 22, 23 are assembled together. Thereafter, the ball nut 9 is fitted into the sleeve 17, and the flange portion 16 of the ball nut is bolted to the flange portion 18. As a result, the sleeve 17, the bearings 20, 21, 22, 23, and the ball nut 9 are assembled into an integrated nut unit.
This nut unit is inserted into the nut mounting hole 10 from the rear side, the fourth bearing 23 on the tightening nut 19 side is fitted into the small diameter portion 12 of the nut mounting hole, and the third bearing 22 is inserted into the large diameter portion 13 of the nut mounting hole. Fit so that it abuts the front wall. At that time, the first bearing 20 and the flange portion 18 on the flange portion 18 side of the sleeve protrude from the nut mounting hole 10, and in this state, the bearing pressing member 24 is bolted to the rear wall of the heating cylinder housing 2. As a result, in the nut unit, the large diameter second and third bearings 21 and 22 have the large diameter portion 1 of the nut mounting hole.
The ball nut 9 is attached to the heating cylinder housing 2 integrally so that the ball nut 9 is rotatable in the nut mounting hole 10 and does not rattle in the axial direction. In addition, the sleeve 17 and each bearing 20, 21, 2
The ball nut 9 may be attached to the sleeve 17 after attaching the two and 23 assembled together to the nut attaching hole 10. As described above, the sleeve 17 and the bearings 2 are previously prepared.
0, 21, 22, 23, or sleeve 17 and each bearing 2
0, 21, 22, 23 and the ball nut 9 are integrally assembled to form a nut unit, the nut unit is inserted into the nut mounting hole 10, and the bearing pressing member 24 is bolted to the heating cylinder housing 2 to make the ball nut 9
Can be mounted in the nut mounting hole 10, so that it can be mounted without requiring special skill.

On the other hand, the work of removing the ball screw 6 is performed as follows. The front end of the ball screw shaft 8 is removed from the stationary platen 1, the bolt connection between the bearing pressing member 24 and the heating cylinder housing 2 is released, and the ball nut 9 together with the nut unit is pulled out or pushed out from the nut mounting hole 10 and removed. . In addition, after the bolt nut between the ball nut 9 and the sleeve 17 is released and the ball nut 9 is separated from the sleeve 17, the bearing pressing member 2
Alternatively, the bolt connection between the heating cylinder housing 2 and the heating cylinder housing 2 may be released, and the sleeve 17 and the bearings 20, 21, 22, 23 may be integrally removed. As described above, the ball nut 9 is removed from the sleeve 17 and the bearing 2 when removing the ball screw 6.
It is a nut unit that is integrated with 0, 21, 22, 23, the bearing pressing member 24, etc., and does not need to be disassembled in the nut mounting hole 10 and can be pulled out or pushed out to the rear of the nut mounting hole 10. Since it can be removed, the ball nut 9 together with the ball screw shaft 8 is attached to the nut mounting hole 10
Easy and quick to remove from.

[0022]

According to the present invention, the following respective effects can be obtained. The nut mounting hole is cylindrical with the front part having a small diameter part and the rear part having a large diameter part, and the ball nut is designed to be mounted in the nut mounting hole through the sleeve and the bearing. Assembling or assembling the bearing, the sleeve and the ball nut together to form a nut unit, and mounting this nut unit in the nut mounting hole allows the ball nut to be integrally attached to the heating cylinder housing.
At that time, in the bearing, the inner race is axially clamped by the flange portion of the sleeve and the tightening nut and is integrally attached to the sleeve, and the outer race is formed by the front wall of the large diameter portion of the nut mounting hole and the bearing pressing member. Since it is sandwiched in the axial direction and is integrally attached to the heating cylinder housing, it is not necessary to finely adjust the tightening torque of the bearing as in the conventional case. Therefore, no special skill is required for mounting the ball nut, and anyone can mount the ball nut easily, quickly and accurately. In the operation of removing the ball screw, the ball nut can be removed from the nut mounting hole together with the sleeve, the bearing, the bearing pressing member, etc. by releasing the bolt connection of the bearing pressing member, which can be performed easily and quickly. Therefore, the ball screw replacement work can be performed more easily and quickly. Since the nut mounting hole is formed in a cylindrical shape having a front portion having a small diameter portion and a rear portion having a large diameter portion, a front wall having a circular hole through which the ball screw shaft is inserted can be provided. As a result, the lubricant such as grease supplied to the ball screw and each bearing can be prevented from scattering, so that a nozzle touch position detector such as an encoder can be provided on the side of the nut mounting hole, and the drive shaft of the electric motor can be prevented. Can be installed almost directly. as a result,
The measurement accuracy of the nozzle touch position detector can be improved, and the nozzle touch operation can be performed with higher accuracy. Attach a small diameter ball bearing to the nut side of the sleeve.
By fitting this ball bearing into the small diameter portion of the nut mounting hole, the ball nut can be mounted on the heating cylinder housing without rattling in the direction orthogonal to the ball screw shaft. As a result, the nozzle touch operation can be performed with higher accuracy. By forming outer peripheral teeth on the flange part at the rear end of the sleeve and integrating the driven gear of the drive mechanism with the sleeve,
The structure of the drive mechanism can be simplified, and the ball screw replacement work can be performed more easily and quickly. In the case of employing a plurality of ball screws, by guiding and supporting an idler gear composed of an annular gear with a deep groove ball bearing, it is possible to operate without causing wear and galling of the idler gear even without oiling. This eliminates the need for lubricant management of the drive mechanism and prevents environmental pollution and the like due to the lubricant.

[Brief description of drawings]

FIG. 1 is a conceptual explanatory view of an embodiment of the present invention, and is a plan view showing a state when a nozzle is touched by cutting a part thereof.

FIG. 2 is a view on arrow AA of FIG.

FIG. 3 is an enlarged view of a main part of FIG.

FIG. 4 is a conceptual explanatory view of a conventional technique, and is a plan view showing a state when a nozzle is touched by cutting a part thereof.

5 is a view taken along the line BB of FIG.

FIG. 6 is an enlarged view of a main part of FIG.

[Explanation of symbols]

1 Fixed Platen 2 Heating Cylinder Housing 3 Heating Cylinder 4 Nozzle 6 Ball Screw 7 Drive Mechanism 8 Ball Screw Shaft 9 Ball Nut 10 Nut Mounting Hole 12 Small Diameter Part of Nut Mounting Hole 13 Large Diameter Part of Nut Mounting Hole 14 Front Wall of Nut Mounting Hole 16 Ball Nut Flange 17 Sleeve 18 Sleeve Flange 19 Sleeve Tightening Nut 20 1st Bearing (Small Diameter Ball Bearing) 21 2nd Bearing (Large Angular Ball Bearing) 22 3rd Bearing (Large Angular Ball) Bearings) 23 Fourth bearing (small diameter ball bearing) 24 Bearing pressing member 25 Electric motor (motor with reduction gear) 26 Drive gear 27 Idler gear 28 Drive shaft 29 Deep groove ball bearing

Claims (4)

[Claims] 1. A ball screw for drivingly connecting a fixed platen having a fixed mold attached thereto and a heating cylinder housing having a heating cylinder having a nozzle at the tip thereof, and a drive mechanism for driving the ball screw. One end of the screw is fixed to the fixed platen, and the ball screw shaft is inserted into the nut mounting hole formed in the heating cylinder housing in parallel with the heating cylinder, and the screw is screwed into this ball screw shaft and the bearing is inserted into the nut mounting hole. It consists of a ball nut that is rotatably mounted, and the drive mechanism consists of a driven gear that is drivingly connected to the ball nut, and a drive source that rotationally drives this driven gear, and the ball nut is rotated via the driven gear by the operation of the drive source. The nozzle touch mechanism of the injection molding machine in which the heating cylinder housing is moved back and forth to bring the nozzle into contact with and separate from the fixed mold. The mounting hole is formed in a cylindrical shape with the front part having a small diameter part and the rear part having a large diameter part, and the bearing has a flange part on the rear end and engages the tightening nut on the front end side on the outer periphery of the sleeve. It is mounted by sandwiching it in the axial direction by the flange part and the tightening nut, and the front wall of the large diameter part of the nut mounting hole and the rear of the heating cylinder housing so that the sleeve is rotatable and the flange part of the sleeve projects rearward. A nozzle touch mechanism for an injection molding machine, characterized in that it is mounted by being sandwiched in the axial direction by a bearing pressing member mounted on a wall, and a ball nut is mounted integrally on a sleeve. 2. The bearing comprises a small-diameter bearing, a large-diameter bearing and a small-diameter bearing which are mounted in order from the flange side of the sleeve, and the small-diameter bearing on the tightening nut side is mounted on the small-diameter part of the nut mounting hole. The nozzle touch mechanism of an injection molding machine according to claim 1, wherein a large-diameter bearing is mounted in the large-diameter portion of the nut mounting hole, and a bearing pressing member is mounted on the outer periphery of the small-diameter bearing on the flange side. 3. The nozzle touch mechanism of an injection molding machine according to claim 1, wherein the flange portion of the sleeve is a driven gear / flange portion integrally formed with a driven gear of the drive mechanism. 4. A plurality of ball screws are provided in parallel to the heating cylinder, and a drive mechanism is provided with an idler gear provided so that the driven gears rotate in the same manner between the driven gears drivingly connected to the ball nuts of the ball screws. The nozzle touch mechanism of an injection molding machine according to claim 1, 2 or 3, wherein the idler gear is an annular gear having outer peripheral teeth, and two or more inner peripheral portions are guided and supported by deep groove ball bearings.