JP2005271210A - Motor for driving resin molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize the simplification of the whole structure of the drive device of a resin molding machine, the reduction of noise, the reduction of a weight and the contraction of a dimension at a low cost. <P>SOLUTION: A DD motor 50 for driving the screw 64 of an extruder (resin molding machine) 52 is equipped with a motor shaft 56 having a recessed part 56A, in which the end part 64A of the screw 64 is directly inserted, provided to its end part on a load side, a thrust bearing 70 provided between the motor shaft 56 and a casing 54 to receive the axial load from the screw 64 through the motor shaft 56 and a (first) radial bearing 68 provided to the outer periphery of the recessed part 56A and supporting the motor shaft 56 and the screw 64 inserted in the recessed part 56A at the same time. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a motor used for driving a resin molding machine such as an extruder or an injection molding machine.

  Patent Document 1 discloses an example of a driving device for an extruder. FIG. 3 shows the main cross section. This drive device is composed of a motor unit M including a motor m as a power generation source, a deceleration unit R that decelerates the rotation of the motor m, and a screen unit S that receives the rotation decelerated from the deceleration unit R. .

  The motor shaft 10 of the motor m is connected to the input shaft 14 of the speed reduction unit R through a key joint 12. The power input from the motor m to the input shaft 14 is transmitted to the output shaft 26 via the first helical pinion 16, the first helical gear 18, the intermediate shaft 20, the second helical pinion 22, and the second helical gear 24.

  A screw 30 is connected to the output shaft 26 via a spline 28. The output shaft 26 is supported by the speed reduction unit casing 34 by a pair of tapered roller bearings 32 and 33. This is because a helical gear set is used to achieve low noise, and an axial load is generated on the output shaft 26 due to the meshing of the second helical pinion 22 and the second helical gear 24.

  A bearing case 38 is interposed between the speed reduction part casing 34 and the screw housing 36. A thrust bearing 40 for receiving an axial load from the screw 30 is incorporated in the bearing case 38. The axial load applied to the thrust bearing 40 is received by the wall portion 34 </ b> A of the speed reduction portion casing 34 through the bearing case 38.

  A pair of radial bearings 42 and 44 are incorporated on both axial sides of the thrust bearing 40. The radial bearings 42 and 44 support the screw 30 rotatably with respect to the bearing case 38 and the screw housing 36, respectively.

JP 2002-250407 A

  However, the drive device for this type of extruder has a structure for connecting the output shaft 26 of the reduction part R and the screw 30, a structure for receiving an axial load applied from the second helical gear 24 to the output shaft 26, and the screw 30. Therefore, there is a problem that a large number of bearings such as tapered roller bearings 32, 33, thrust bearings 40, radial bearings 42, 44 are required. there were. As a result, the structure is complicated and the cost is increased.

  In addition, the speed reduction unit R is used to obtain a predetermined low speed / high torque drive output. Therefore, due to the presence of the speed reduction unit R, noise and weight are increased, and the entire apparatus is The size of was inevitably increased.

  The present invention has been made to solve such a conventional problem, and realizes simplification of the structure of the entire driving device of the resin molding machine, reduction of noise, reduction of weight, and reduction of dimensions. An object of the present invention is to provide a motor for driving a resin molding machine that can be used.

  The present invention relates to a resin molding machine driving motor for driving a screw of a resin molding machine, a motor shaft having a recess into which an end portion of the screw is directly inserted at an end portion on a load side, and the motor shaft A thrust bearing provided between the casing and capable of receiving the axial load from the screw side via the motor shaft, and provided on the outer periphery of the recess, simultaneously supports the motor shaft and the screw inserted into the recess. By providing the first radial bearing possible, the above-mentioned problems are solved.

  The two-stage structure of the motor part and the speed reduction part, which has been considered essential in order to obtain a predetermined drive output, has been radically reviewed, and the motor part and the speed reduction part are integrated using a DD motor (direct drive motor). .

  So-called DD motors have already existed as general-purpose single-piece products (for example, products manufactured by Yaskawa Siemens Automation Drive Co., Ltd.). However, the DD motors currently available on the market are not in the area where low speed and high torque output characteristics can be obtained. That is, it is not intended to be applied to a resin molding machine in which there is a special situation in which a strong axial load is applied from the screw side. For this reason, if such a DD motor is to be diverted to an extruder, a structure for receiving an axial load is required separately, which requires a large number of bearings and the structure must be complicated as a result. .

  Furthermore, the general-purpose DD motors provided on the market have a hollow structure whose output shaft has a large inner diameter, and a structure in which the mating member is flange-coupled is adopted. There was also a structural problem that was difficult as it was.

  In the present invention, a recess into which the end of the screw is directly inserted is formed at the load side end of the motor shaft of the DD motor, and a thrust bearing capable of receiving the thrust load of the screw is incorporated in the motor shaft itself. . In addition, a radial bearing is incorporated in the outer periphery of the recess, and the radial bearing is provided with a function of simultaneously supporting the motor shaft and the screw.

  As a result, not only the speed reduction unit itself is eliminated, but also the connection between the motor shaft and the screw and the reception of the axial load from the screw side can be realized with a very simple structure, and the number of bearings can be reduced.

  Simplification of the structure of the entire driving device of the resin molding machine, reduction of noise, reduction of weight, and reduction of dimensions can be realized.

  Hereinafter, an example of an embodiment of the present invention will be described in detail based on the drawings.

  FIG. 1 is an enlarged exploded cross-sectional view showing a main part of a screw driving device of an extruder incorporating a resin molding machine driving motor (DD motor 50) according to the present invention.

  This DD motor 50 is designed exclusively for driving the extruder 52, and realizes a low speed by increasing the number of poles by three times or more than a normal motor (4 poles or 6 poles). A multi-pole SPM motor (surface permanent magnet motor) that achieves high torque by using a high-performance magnet (for example, a neodymium magnet) is employed.

  The DD motor 50 includes a motor shaft 56 at the center in the radial direction of the casing 54. The motor shaft 56 is integrated with a rotor 58 rotated by a coil 58 and a stator core 60.

  As shown in FIG. 2, the casing 54 of the DD motor 50 is mainly composed of a bearing case 54A, a center plate 54B, a main body case 54C serving as a motor frame, and an anti-load side cover 54D in order from the load side. Are connected by a bolt 55. The load side cover of the casing 54 is also used as the screw housing 53 of the extruder 52, and can be connected to the bearing case 54A by a bolt (not shown). In FIG. 2, reference numeral 80 indicates a hopper of the extruder 52.

  Returning to FIG. 1, the motor shaft 56 of the DD motor 50 has a concave portion 56 </ b> A into which the end portion 64 </ b> A of the screw 64 is directly inserted at the end portion on the load side. An end portion 64 </ b> A of the screen 64 is connected via a key 66. However, this connection structure may be either press-fit connection or spline connection, and is not particularly limited.

  A through hole 56 </ b> C is formed in the center of the motor shaft 56. The through hole 56C is provided to easily separate the concave portion 56A of the motor shaft 56 from the end portion 64A of the screen 64. A bolt of a jig (not shown) is inserted into the through-hole 56C from the non-load side and screwed while being brought into contact with the front end surface 64A1 of the end portion 64A of the screw 64, whereby the recess 56A of the motor shaft 56 and the screw 64 are inserted. It is possible to move away from the end 64A.

  The outer periphery of the concave portion 56A of the motor shaft 56 is formed to have an outer diameter d2 larger than the outer diameter d1 of the other portion (the portion near the rotor 62 where the concave portion 56A does not exist) as much as the end 64 of the screw 64 is inserted. ing. A first radial bearing (load-side radial bearing) 68 is disposed on the outer periphery of the recess 56A, and a second radial bearing 69 is disposed on the opposite end of the motor shaft. The motor shaft 56 is supported at both ends by the first radial bearing 68 and the second radial bearing 69 on the bearing case 54A and the anti-load side cover 54D.

  On the outer periphery of the recess 56A of the motor shaft 56, a flange portion 56B is integrally formed to project in the radial direction. The anti-load side surface 56 </ b> B <b> 1 of the flange portion 56 is in contact with the inner ring 70 </ b> A of the thrust bearing 70. The outer ring 70B of the thrust bearing 70 is in contact with the center plate 54B. The axial load transmitted from the screen 64 side can be received by the center plate 54B via the flange portion 56B and the thrust bearing 70. The load side surface 56B2 of the flange portion 56B is in contact with the first radial bearing 68, and defines the position of the first radial bearing 68 in the axial direction.

  On the other hand, a ring member 72 and an oil seal 74 that define the axial position of the first radial bearing 68 are disposed on the load side of the bearing case 54A. The center plate 54B is formed with a through hole 54B1 through which the motor shaft 56 penetrates in the center in the radial direction. A ring member 76 and an oil seal 78 are disposed between the through hole 54B1 and the outer periphery of the motor shaft 56. ing. As a result, a sealed space A can be formed inside the bearing case 54A, and a lubricant for lubricating the first radial bearing 68 and the thrust bearing 70 is enclosed in the space A. The second radial bearing 69 incorporated in the anti-load side cover 54D is a sealed bearing having a self-lubricating function. As a result, a sealed space B can also be formed inside the main body case 54C, and the internal mechanism of the DD motor 50 is protected from external dust and the like.

  Next, the operation of the DD motor 50 will be described.

  When the rotor 62 rotates, the motor shaft 56 integrated with the rotor 62 rotates. This rotation is low speed and high torque due to the characteristics of the multipole SPM motor. Therefore, since the screw 64 is directly key-coupled to the recess 56A of the motor shaft 56, the screw 64 can be directly driven without passing through the speed reducing portion or the like.

  Due to the function of the extruder 52, the axial load input from the screw 64 side is brought into contact with the load side end portion 56A1 of the motor shaft 56 and the stepped portion 64A1 formed at the end portion 64A of the screw 64. Further, it is finally received by the center plate 54B via the flange portion 56B formed on the outer periphery of the recess 56A of the motor shaft 56 and the thrust bearing 70.

  In this embodiment, the thrust bearing 70 is disposed between the first radial bearing 68 and the second radial bearing 69, and the motor shaft 56 is endmost by the first radial bearing 68 and the second radial bearing 69. The bearing case 54A and the main body case 54D are supported in a both-sided manner near the portion. Therefore, the motor shaft 56 can be supported in an extremely stable state.

  Further, since the first radial bearing 68 is disposed on the outer periphery of the concave portion 56A in which the end portion 64A of the screw 64 is inserted, the first radial bearing 68 is connected to the load side end portion (the concave portion 56A) of the motor shaft 56. ) And the end 64A of the screw 64 are also supported at the same time.

  As a result, the DD motor 50 is eventually supported by only one pair of radial bearings 68 and 69 and one thrust bearing 70 to support the end portion 64A of the screw 64, the both-end support of the motor shaft 56, and the screw 64. This means that the axial load input from the side is received.

  Since this DD motor 50 does not have any speed reduction part, there is basically no noise generated in the speed reduction part. Therefore, the noise is extremely low, and there is no room for problems such as installation of a helical gear set. Furthermore, since there is no portion that rotates at high speed, there is almost no vibration. Therefore, the screw 64 of the extruder 52 can be driven in a very stable state.

  Since the space A inside the bearing case 54A is completely sealed by the oil seals 74 and 78, the lubricating oil sealed in the space A is placed in the space B or around the screw 64 of the extruder 52. It can prevent leaking. Furthermore, since the space B inside the main body case 54C is also sealed by the oil seal 78 and the radial bearing 69 having a sealing function, the inside of the space B can be kept from being shut off from the outside, and the DD motor can be kept for a long time. A stable operation can be achieved.

  Although the lubricating oil is not sealed in the space B, since a sealed bearing having a self-lubricating function is adopted for the second radial bearing 69, there is no problem in durability.

  The present invention is applicable to the field of drive devices used to drive resin molding machines such as extruders or injection molding machines.

The principal part expansion disassembled sectional view which shows the drive device of the screw of the extruder with which the motor for resin molding machine drive which concerns on embodiment of this invention was integrated Sectional drawing which shows the state with which the motor of FIG. 1 was assembled | attached to the screw housing. Schematic sectional view showing an example of a driving device for driving a screw of a conventional resin molding machine

Explanation of symbols

DESCRIPTION OF SYMBOLS 50 ... DD motor 52 ... Extruder 53 ... Screw housing 54 ... Casing 55 ... Bolt 56 ... Motor shaft 56A ... Recess 56B ... Flange part 58 ... Coil 60 ... Stator core 62 ... Rotor 64 ... Screw 64A ... End part 68 ... 1st Radial bearing 69 ... 2nd radial bearing 70 ... Thrust bearing 72, 76 ... Ring members 74, 78 ... Oil seal

Claims (4)

In the resin molding machine drive motor for driving the screw of the resin molding machine,
A motor shaft having a recess into which the end of the screw is directly inserted, at the end on the load side;
A thrust bearing provided between the motor shaft and the casing and capable of receiving an axial load from the screw side via the motor shaft;
A first radial bearing provided on an outer periphery of the recess and capable of simultaneously supporting a motor shaft and a screw inserted into the recess;
A motor for driving a resin molding machine. In claim 1,
The interior of the motor is separated into at least two spaces in the axial direction;
The resin molding machine driving motor, wherein the thrust bearing and the first radial bearing are accommodated in the same closed space. In claim 1 or 2,
The resin molding machine driving motor, wherein the thrust bearing is disposed between the first radial bearing and a second radial bearing provided on a non-load side of the motor shaft. In claim 3,
The motor shaft has a flange portion that is formed to project radially between the thrust bearing and the first radial bearing;
A resin molding machine driving motor, wherein an axial load related to the motor shaft is transmitted to the thrust bearing side through the flange portion.

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