JP4533341B2 - Drive mechanism of injection molding machine - Google Patents

Description

  The present invention relates to a drive mechanism for an injection molding machine having a built-in load cell that detects axial pressure between an injection block and a screw coupling.

  Conventionally, an injection block to which axial movement is transmitted from an advancing / retreating drive unit and a screw coupling to which rotational motion is transmitted via a timing belt of the rotation drive unit are provided, and a bearing portion is provided by an inner peripheral portion of the injection block. As a drive mechanism of an injection molding machine that incorporates a load cell that detects the axial pressure between the injection block and the screw coupling while rotatably supporting the screw coupling, a special feature previously proposed by the present applicant has been proposed. A drive mechanism for an injection molding machine disclosed in Japanese Patent Publication No. 5-50973 is known.

FIG. 9 shows an outline of a drive mechanism 60 having the same basic structure as the drive mechanism disclosed in the publication. The drive mechanism 60 rotatably supports a screw coupling 62 to which rotational motion is transmitted by an injection block (guide joint) 61 to which linear motion is transmitted, and between the injection block 61 and the screw coupling 62, The load cell 63 includes a washer-shaped load cell 63 that has an inner ring portion 63i, an outer ring portion 63o, and an intermediate strain portion 63m, and detects axial pressure applied to the screw coupling 62. Inner ring portion 63i and a pair of bearing portions disposed on both sides of the inner ring portion 63i, that is, a thrust bearing 64 disposed on the front end surface side of the inner ring portion 63i and an angular surface disposed on the rear end surface side of the inner ring portion 63i. The ball bearing 65 is fixed on the outer periphery of the screw coupling 62 by a bearing nut 66, and the outer ring portion 63o of the load cell 63 is injected into the injection block. Those fixed to the click 61. In this case, linear movement is transmitted to the injection block 61 from an unillustrated screw advance / retreat drive motor (servo motor) and an advance / retreat drive unit 67 having a ball screw mechanism, and to the screw coupling 62, screw rotation. Rotation drive having a drive motor (servo motor) 69, a drive pulley 70 attached to the drive motor 69, a driven pulley 71 attached to the screw coupling 62, and a timing belt 72 bridged between the drive pulley 70 and the driven pulley 71 A rotational motion is transmitted from the portion 68. As a result, the pressure detection is not affected by both the preload due to the tightening of the bearing nut 66 and the injection block 61, so that the detection accuracy and reliability can be improved, and the high accuracy management for the preload and the injection block 61, injection can be performed. Since high-precision processing and assembly of the base, injection drive base, guide shaft, and the like are not required, parts manufacture and mechanism assembly are facilitated.
JP 5-50973

  However, the conventional drive mechanism of the injection molding machine described above has the following problems to be solved.

  First, when the timing belt 72 is used for the rotation drive unit 68, the screw coupling 62 supported by the injection block 61 that moves straight is pulled in one radial direction by the rotation drive unit 68. The screw itself attached to is also subjected to a tensile load in the radial direction. Therefore, so-called galling occurs on the heating cylinder due to misalignment of the screw due to long-term use, which not only hinders smooth operation but also reduces durability due to wear.

  Second, when the screw coupling 62 is pulled in one radial direction by the rotation driving unit 68, the angular ball bearing 65 also receives a tensile load in the radial direction. In addition, the angular ball bearing 65 repeatedly receives a pressure force applied backward from the screw coupling 62 in this state, and usually an inevitable clearance on the mechanism exists between the injection block 61 and the screw coupling 62. Therefore, the angular ball bearing 65 also causes galling or increases the frictional resistance against the injection block 61 in the axial direction, leading to a decrease in detection accuracy of the load cell 63 that directly contacts the angular ball bearing 65. Although the influence of the tensile load in the radial direction (tilting of the angular ball bearing 56) can be reduced by tightening the bearing nut 66 more strongly, the strong tightening adversely affects the detection characteristics of the load cell 63, and the bearing nut 66 It cannot be handled by tightening.

  An object of the present invention is to provide a drive mechanism of an injection molding machine that solves the problems existing in the background art.

  In order to solve the above-described problems, the present invention is a screw cup in which a rotational motion is transmitted via an injection block 3 to which a linear motion in the axial direction Fa is transmitted from the forward / backward drive unit 2 and a timing belt 5 of the rotational drive unit 4. A ring 6 is provided, and the screw coupling 6 is rotatably supported by the inner peripheral portion of the injection block 3 via the bearing portion 7 and the pressure in the axial direction Fa between the injection block 3 and the screw coupling 6 is detected. When configuring the drive mechanism 1 of the injection molding machine M incorporating the washer-shaped load cell 8 having the inner ring portion 8i, the outer ring portion 8o, and the intermediate strain portion 8m, the bearing portion 7 An angular ball bearing 9 arranged on the rear end face 8r side and a second bearing 10 arranged side by side on the angular ball bearing 9 are arranged. A gap Gs having a predetermined interval Ls is provided between the locks 3, and a thrust bearing 11, an inner ring portion 8 i, an angular ball bearing 9 and a second bearing 10 are arranged between the screw coupling 6 and the front end face 8 f of the load cell 8. The bearing nut 12 is fixed on the outer periphery of the screw coupling 6, and the outer ring portion 8 o is fixed to the injection block 3.

  In this case, according to a preferred aspect of the invention, the inner ring side spacer 13 is interposed between the inner ring 9 i of the angular ball bearing 9 and the inner ring 10 i of the second bearing 10, and the outer ring 9 o of the angular ball bearing 9 and the outer ring of the second bearing 10. The outer ring side spacer 14 can be interposed between 10 o and the thickness Lo of the outer ring side spacer 14 can be formed thinner than the thickness Li of the inner ring side spacer 13. The second bearing 10 can be a deep groove ball bearing 10y or a cylindrical roller bearing 10x. On the other hand, there is provided a pressure adjusting means P that is disposed on the injection block 3 and presses the screw coupling 6 in the opposite direction to the tensile load Fp by the timing belt 5 and has a position adjusting portion Pm that can adjust the pressing position Xp. Can be provided. This pressing adjusting means P has a tap hole 15n and is screwed into the base hole 15 attached to the injection block 3 and the tap hole 15n, and the tip presses the screw coupling 6 directly or indirectly. A possible adjustment pressing bolt 16 can be used. On the other hand, a deep groove ball bearing 17y or a cylindrical roller bearing 17x can be interposed between the injection block 3 and the screw coupling 6 on the front end face 8f side of the load cell 8.

  According to the drive mechanism 1 of the injection molding machine M according to the present invention having such a configuration, the following remarkable effects can be obtained.

  (1) Even if a radial tensile load Fp is applied to the screw coupling 6, the tensile load Fp can be received by the second bearing 10, so that the angular ball bearing 9 that directly contacts the load cell 8 is used. Generation of galling and increase in frictional resistance against the injection block 3 in the axial direction Fa can be avoided. In addition, since the gap Gs is positively provided between the angular ball bearing 9 and the injection block 3, the angular ball bearing 9 can more effectively prevent galling and reduce the frictional resistance. Can be increased.

  (2) A thrust bearing 11, an inner ring portion 8i, an angular ball bearing 9 and a second bearing 10 disposed between the screw coupling 6 and the front end face 8f of the load cell 8 are placed on the outer periphery of the screw coupling 6 by a bearing nut 12. Since the outer ring portion 8o is fixed to the injection block 3, the preload due to the tightening of the bearing nut 12 and the influence of both the injection block 3 are eliminated, and the detection accuracy and reliability are improved. Therefore, it is possible to contribute to facilitating parts manufacture and mechanism assembly by not requiring high-precision management and high-precision processing and assembly for the injection block 3 and the like.

  (3) According to a preferred embodiment, an inner ring side spacer 13 is interposed between the inner ring 9i of the angular ball bearing 9 and the inner ring 10i of the second bearing 10, and between the outer ring 9o of the angular ball bearing 9 and the outer ring 10o of the second bearing 10 If the outer ring side spacer 14 is interposed in the outer ring side spacer 14 and the thickness Lo of the outer ring side spacer 14 is made thinner than the thickness Li of the inner ring side spacer 13, a predetermined greasing space can be secured. Can be done.

  (4) According to a preferred embodiment, a position adjusting portion Pm that is disposed on the injection block 3 and presses the screw coupling 6 in the opposite direction to the tensile load Fp by the timing belt 5 and can adjust the pressing position Xp. If the pressure adjusting means P is provided, even if it is a configuration in which a radial tensile load Fp is applied to the screw coupling 6, it is possible to effectively prevent screw misalignment. Therefore, it is possible to avoid the occurrence of screw galling with respect to the heating cylinder, and it is possible to improve durability by ensuring smooth operation and reducing wear.

  (5) According to a preferred embodiment, the pressing adjusting means P is screwed into the tap hole 15n and the base part 15 having the tap hole 15n and attached to the injection block 3, and the tip part directly connects the screw coupling 6 If the adjustment pressing bolt 16 that can be pressed manually or indirectly is used, it can be implemented easily and at low cost with a small number of parts. In addition, it can be easily carried out by retrofitting or simple improvement to an existing injection molding machine.

  (6) If a deep groove ball bearing 17y or a cylindrical roller bearing 17x is interposed between the injection block 3 and the screw coupling 6 on the front end face 8f side of the load cell 8 according to a preferred aspect, the load is applied to the screw coupling 6. An adverse effect (such as screw core misalignment) caused by a radial tensile load can be prevented more reliably.

  Next, the best embodiment according to the present invention will be given and described in detail with reference to the drawings.

  First, the structure of the injection molding machine M provided with the drive mechanism 1 according to the present embodiment will be described with reference to FIGS. 1 and 2.

  In FIG. 2, M is an injection molding machine, and particularly shows an injection device Mi. The injection device Mi includes an injection table 21 and an injection driving table 22 disposed behind the injection table 21, and a plurality (two in the illustrated example) of guide shafts 23 are installed between the injection table 21 and the injection driving table 22. Further, the injection block 3 is slidably loaded on the guide shafts 23 through the guide bush portions 24. On the other hand, the injection drive base 22 supports the transmission shaft 25 so as to be rotatable. A driven pulley 26 is attached to the rear end of the transmission shaft 25, and rotation is transmitted to the driven pulley 26 from a screw advance / retreat drive motor (servo motor) (not shown). The rear end of the ball screw 27 s of the ball screw mechanism 27 is coupled to the front end of the transmission shaft 25, and the ball nut 27 n that is screwed into the ball screw 27 s is coupled to the rear end of the injection block 3. Therefore, the screw advance / retreat drive motor (not shown) and the ball screw mechanism 27 constitute the advance / retreat drive unit 2. As a result, a linear movement for injection is transmitted from the advance / retreat drive unit 2 to the injection block 3.

  On the other hand, a rear end of the heating cylinder 28 is attached to the injection table 21, and a screw 29 is inserted through the heating cylinder 28. Further, the screw coupling 6 is rotatably supported by the inner peripheral portion of the support hole 3 s provided in the injection block 3 via the bearing portion 7, and the rear end of the screw 29 is placed at the center position of the front end of the screw coupling 6. Support it together. Further, a screw rotation drive motor (servo motor) 31 is supported by a support 30 attached to the outer surface of the injection block 3, and the drive motor 31 and the screw coupling 6 are connected via a rotation transmission mechanism 32. The rotation transmission mechanism 32 spans between a drive pulley 33 attached to the drive shaft of the drive motor 31, a driven pulley 34 attached with the shaft center aligned with the front end of the screw coupling 6, and between the drive pulley 33 and the driven pulley 34. A timing belt 5 is provided. The drive motor 31 and the rotation transmission mechanism 32 constitute the rotation drive unit 4. As a result, the rotational movement for measurement is transmitted to the screw coupling 6 from the rotational drive unit 4.

  Next, the structure of the principal part of the drive mechanism 1 according to the present embodiment will be described with reference to FIGS.

  The drive mechanism 1 includes the injection block 3 to which the linear movement in the axial direction Fa is transmitted from the advance / retreat drive unit 2 and the screw coupling 6 to which the rotational motion is transmitted via the timing belt 5 of the rotation drive unit 4. The screw coupling 6 is configured to be rotatably supported on the inner peripheral portion of the injection block 3 via the bearing portion 7. The drive mechanism 1 incorporates a load cell 8 that detects the pressure in the axial direction Fa between the injection block 3 and the screw coupling 6.

  FIG. 4 shows a cross-sectional side view of the load cell (pressure detector) 8. The load cell 8 is integrally formed in a washer shape by a relatively thick inner ring portion 8i and an outer ring portion 8o, and a relatively thin intermediate strain portion 8m. The intermediate strain portion 8m includes a plurality of strain gauges 8s. ... with. As a result, when the pressure in the arrow Ff direction (forward direction) acts on the outer ring portion 8o and the pressure in the arrow Fr direction (rearward direction) acts on the inner ring portion 8i, the inner ring portion 8i. Is offset by about 0.1 to 0.2 [mm] in the axial direction with respect to the outer ring portion 8o, and the strain gauge 8s... The load cell 8 is disposed between the screw coupling 6 and the injection block 3 as shown in FIG. Reference numeral 44 denotes a protrusion formed in a ring shape in the circumferential direction by raising a part on the rear end surface 8r of the inner ring portion 8i.

  When the load cell 8 is assembled, a flange-like stopper 41 protruding radially outward is provided at the front end position of the outer periphery of the screw coupling 6, and the thrust bearing 11 and the load cell 8 are provided behind the stopper 41. The inner ring portion 8i, the angular ball bearing 9, and the deep groove ball bearing 10y (second bearing 10) are sequentially loaded. At this time, the inner ring side spacer 13 is interposed between the inner ring 9i of the angular ball bearing 9 and the inner ring 10i of the deep groove ball bearing 10y, and the outer ring side spacer 14 is interposed between the outer ring 9o of the angular ball bearing 9 and the outer ring 10o of the deep groove ball bearing 10y. In addition, as shown in FIG. 3, the thickness Lo of the outer ring side spacer 14 is made thinner than the thickness Li of the inner ring side spacer 13. Thereby, since predetermined | prescribed greasing space can be ensured, greasing can fully and effectively be performed. Since the outer ring side spacer 14 does not substantially have a spacer function, the outer ring side spacer 14 is formed by making the thickness Lo of the outer ring side spacer 14 thinner than the thickness Li of the inner ring side spacer 13. This includes cases where it is not used.

  Further, as shown in FIG. 1 (FIG. 3), a gap Gs having a predetermined distance Ls is provided between the angular ball bearing 9 and the injection block 3. As the predetermined interval Ls, for example, about 1 [mm] in the diameter direction (0.5 [mm] interval along the circumferential direction) can be set. Thereby, generation | occurrence | production prevention and reduction of frictional resistance by the angular ball bearing 9 are realizable more effectively. Accordingly, the screw coupling 6 on the rear end face side of the load cell 8 is supported by the injection block 3 substantially only through the deep groove ball bearing 10y. Further, since the rear end surface 8r of the inner ring portion 8i has a protruding ridge portion 44 that is partly raised and integrally formed, the outer ring 9o of the angular ball bearing 9 is brought into contact with the protruding ridge portion 44, on the other hand, The thrust bearing 11 is brought into contact with the front end face 8f of the inner ring portion 8i.

  Then, a screw portion is formed at the rear end position of the outer periphery of the screw coupling 6, and the bearing nut 12 is screwed onto the screw portion, whereby the outer periphery of the screw coupling 6 between the bearing nut 12 and the stopper portion 41. The thrust bearing 11, the load cell 8, the angular ball bearing 9 and the deep groove ball bearing 10y loaded on the top are fixed. At this time, the bearing nut 12 is brought into contact with the inner ring 10i of the deep groove ball bearing 10y. Further, an inner ring side spacer 42 is interposed between the inner ring 10i of the deep groove ball bearing 10y and the bearing nut 12, and an outer ring side spacer 43 is interposed between the outer ring 10o of the deep groove ball bearing 10y and the ball nut 27n. Is made thinner than the inner ring side spacer 42.

  On the other hand, a stopper surface 47 is formed by providing a step in the inner peripheral portion of the support hole 3s of the injection block 3, and this stopper surface 47 is brought into contact with the rear end surface of the outer ring portion 8o in the load cell 8 and is separately provided. The fixed block 48 is inserted into the inside of the front end opening of the injection block 3 and brought into contact with the front end surface of the outer ring portion 8o. Thereby, the fixed block 48 covers the outer side of the thrust bearing 11, and the outer ring portion 8 o is sandwiched and fixed between the fixed block 48 and the injection block 3.

  By assembling the load cell 8, the thrust bearing 11, the angular ball bearing 9 and the deep groove ball bearing 10y in this way, the optimum configuration of the drive mechanism 1 can be realized. In particular, the basic effect of the drive mechanism 1, that is, the bearing The detection accuracy and reliability are improved by eliminating the influence of both the preload and the injection block 3 due to the tightening of the nut 12, and furthermore, high-precision management for preload and high-precision processing and assembly for the injection block 3 and the like. It can contribute to facilitating parts manufacturing and mechanism assembly by not being required.

  A deep groove ball bearing 17y is interposed between the injection block 3 and the screw coupling 6 on the front end face 8f side of the load cell 8, that is, between the front end of the inner peripheral portion of the fixed block 48 and the stopper portion 41 of the screw coupling 6. Let Thereby, the bad influence (screw misalignment of a screw etc.) by the tensile load of the radial direction provided to the screw coupling 6 can be prevented more reliably.

  Further, as shown in FIGS. 1 and 5, the injection block 3 is provided with a pressure adjusting means P that presses the screw coupling 6 in the opposite direction to the tensile load Fp by the timing belt 5. The pressure adjusting means P includes a base portion 15 provided with a tap hole 15n and an adjustment pressing bolt 16 screwed into the tap hole 15n. The base portion 15 is attached to the front surface portion 3 f of the injection block 3 by two mounting bolts 51 and 52. Then, the adjustment pressing bolt 16 is screwed into the tap hole 15 n provided in the base portion 15, and the peripheral surface exposed to the outside of the fixed block 48 can be contacted (pressed) by the tip end portion of the adjustment pressing bolt 16. The rear end face of the adjustment pressing bolt 16 is formed with a locking portion that can be operated by turning the adjustment pressing bolt 16 by locking a bit (jig) such as a driver.

  Therefore, the tip of the adjustment pressing bolt 16 can indirectly press the screw coupling 6, and the shaft center of the adjustment pressing bolt 16 is the center of the drive pulley 33 and the center of the driven pulley 34 as shown in FIG. And the tip of the adjustment pressing bolt 16 is arranged with the center direction of the driven pulley 34 directed. This direction (orientation) is opposite to the tensile load Fp due to the timing belt 5. The base portion 15 and the adjustment pressing bolt 16 also serve as a position adjusting portion Pm that can adjust the pressing position Xp that presses the screw coupling 6. In addition, in the figure, 53 indicates a lock nut screwed to the adjustment pressing bolt 16, and 49... Indicate fixing bolts provided at a plurality of positions for fixing the fixing block 48 to the injection block 3.

  Next, the function (action) of the drive mechanism 1 according to the present embodiment will be described with reference to FIGS.

  First, in the drive mechanism 1, if the bearing nut 12 is tightened, preload is applied to the thrust bearing 11, the angular ball bearing 9, and the deep groove ball bearing 10 y, and the inner ring portion 8 i of the load cell 8 is the outer periphery of the screw coupling 6. Fixed on the part. In this case, the preload does not affect the intermediate strain generating portion 8m that detects the pressure. Further, the outer ring portion 8o of the load cell 8 is fixed only to the injection block 3, and the force for fixing the outer fitting portion 8o does not affect the intermediate strain portion 8m.

  Therefore, as shown in FIG. 6, the pressure in the direction of arrow Fr applied from the screw 29 is applied to the front end face 8 f of the inner ring portion 8 i of the load cell 8 via the screw coupling 6 (stopper portion 41) and the thrust bearing 11. To be added. On the other hand, since the position of the outer ring portion 8o of the load cell 8 is regulated by the injection block 3, the reaction pressure against the pressure applied from the screw 29 is applied from the direction of the arrow Ff and passes through the stopper surface 47 of the injection block 3. To the rear end surface 8r of the outer ring portion 8o. At this time, since the inner ring portion 8i to which the pressure in the direction of the arrow Fr is applied contacts only the outer ring 9o of the angular ball bearing 9, relative displacement (offset) relative to the rear of the inner ring portion 8i is allowed. Therefore, a strain (deflection) corresponding to the pressure is generated in the intermediate strain generating portion 8m, and this strain is detected as a pressure by the strain gauges 8s attached to the intermediate strain generating portion 8m. Since the output of the strain gauges 8s is not affected by the preload and the presence of the injection block 3, it is proportional to the pressure applied from the screw 29.

  Further, the drive mechanism 1 having such a configuration includes a screw cup via a bearing portion 7 using an angular ball bearing 9 and a deep groove ball bearing 10y arranged side by side on the angular ball bearing 9 by the inner peripheral portion of the injection block 3. Since the ring 6 is rotatably supported, even if the radial tension load Fp shown in FIG. 6 is applied to the screw coupling 6 by using the timing belt 5 for the rotation drive unit 4, Since the deep groove ball bearings 10y arranged side by side on the angular ball bearings 9 can receive the tensile load Fp, the angular ball bearings 9 that are in direct contact with the load cell 8 generate galling and increase the frictional resistance against the injection block 3 in the axial direction Fa. Can be avoided. In addition, since there is a positive gap Gs between the angular ball bearing 9 and the injection block 3, the angular ball bearing 9 can more effectively prevent galling and reduce frictional resistance. 8 detection accuracy can be increased.

  On the other hand, the pressing position Xp for pressing the screw coupling 6 can be adjusted by the position adjusting portion Pm in the pressing adjusting means P. In this case, all the fixing bolts 49 provided at a plurality of positions are loosened, and the lock nut 53 screwed into the adjustment pressing bolt 16 is loosened.

  Next, the adjustment pressing bolt 16 is turned by a jig. At this time, a turning operation can be performed by locking a bit (jig) such as a driver to a locking portion formed on the rear end surface of the adjustment pressing bolt 16. By operating the adjustment pressing bolt 16 to rotate, the adjustment pressing bolt 16 moves forward and backward, and the position of the tip of the adjustment pressing bolt 16 that contacts the peripheral surface of the fixed block 48, that is, the pressing position Xp can be adjusted. . Since the tension load Fp is applied to the screw coupling 6 by the timing belt 5, if the pressing position Xp changes, the position of the screw coupling 6 also changes. Therefore, the screw cup can be adjusted by adjusting the pressing position Xp. The centering of the ring 6, that is, the axis of the screw 29 and the axis of the heating cylinder 28 can be matched.

  When the alignment is completed, all the fixing bolts 49 that have been loosened temporarily are tightened to fix the fixing block 48 to the injection block 3, and the lock nut 53 is tightened to lock the adjustment pressing bolt 16 in the adjustment position.

  Therefore, by providing such a pressure adjusting means P, it is possible to more effectively prevent the misalignment of the screw 29 even when the radial coupling load Fp is applied to the screw coupling 6. Therefore, generation | occurrence | production of the galling of the screw 29 with respect to the heating cylinder 28 can be avoided, and durability improvement can be aimed at by ensuring smooth operation | movement and reducing abrasion. In addition, the pressing adjusting means P has a base portion 15 attached to the injection block 3 by having a tap hole 15n, and an adjusting pressing bolt 16 whose tip portion can press the screw coupling 6 by screwing into the tap hole 15n. Since it can be configured, it can be implemented easily and at low cost with a small number of parts, and there is an advantage that it can be easily implemented by retrofitting or simple improvement to an existing injection molding machine.

  By the way, in this kind of drive mechanism 1, there is usually a cylindrical roller bearing as a bearing in place of the deep groove ball bearings 10y, 17y, and the cylindrical roller bearing is from the viewpoint of preventing misalignment of the screw 29 and the angular ball bearing 9. Is more desirable. However, cylindrical roller bearings have aspects that are difficult to increase in size due to technical and cost aspects, and in the case of a large injection molding machine, there are many cases where cylindrical roller bearings cannot be used. FIG. 7 shows a drive mechanism mounted on a large injection molding machine provided with a forward / backward drive unit 2 in which a pair of ball screw mechanisms 101, 102 are arranged on the left and right, which are rotationally transmitted from a screw advance / retreat drive motor (servo motor) (not shown). 1 is shown.

  In such a large injection molding machine, a cylindrical roller bearing may not be used in many cases. However, if the gap Gs having the predetermined interval Ls described above and further the pressure adjusting means P are provided, the rotational drive unit 4 is timed. Even when the radial coupling force Fp is applied to the screw coupling 6 by using the belt 5, misalignment of the screw 29 and the angular ball bearing 9 can be effectively prevented.

  On the other hand, in a small or medium-sized injection molding machine, cylindrical roller bearings can be used instead of the deep groove ball bearings 10y, 17y. FIG. 8 shows a case where the drive mechanism 1 is applied to a small-sized or medium-sized injection molding machine. This figure relates to a modified embodiment in which a cylindrical roller bearing 10x is used instead of the deep groove ball bearing 10y (second bearing 10) shown in FIG. 1, and a cylindrical roller bearing 17x is used instead of the deep groove ball bearing 17y. The drive mechanism 1 is shown. In this case, since the advantages associated with the use of the cylindrical roller bearing can be enjoyed, it can be implemented in an optimum form that can more effectively prevent the misalignment of the screw 29 and the angular ball bearing 9. 7 and 8, the same parts as those in FIGS. 1 to 5 are denoted by the same reference numerals to clarify the configuration, and detailed description thereof is omitted.

  Although the best embodiment has been described in detail above, the present invention is not limited to such an embodiment, and departs from the gist of the present invention in the detailed configuration, shape, material, quantity, numerical value, and the like. It can be changed, added, or deleted as long as it is not.

  For example, the configuration of the pressing adjustment means P is not limited to the illustrated configuration, and has a function of pressing the screw coupling 6 in the opposite direction with respect to the tensile load Fp by the timing belt 5, and the pressing position Xp. If it has the position adjustment part Pm which can be adjusted, the structure will not be ask | required. In addition, although the case where it applied to the electric injection molding machine was illustrated, it can apply similarly also to the injection molding machine by other drive formats, such as a hydraulic injection molding machine.

Sectional plan view showing the main part of the drive mechanism according to the best embodiment of the present invention, A partial cross-sectional plan view of an injection molding machine (injection device) provided with the drive mechanism, A cross-sectional plan view of a bearing portion in the drive mechanism, A cross-sectional side view of a load cell used for the drive mechanism, Front configuration diagram of the pressure adjusting means in the drive mechanism, Function (action) explanatory diagram of the drive mechanism, Front configuration diagram of the drive mechanism mounted on a large injection molding machine, Sectional top view which shows the principal part of the drive mechanism which concerns on the modified embodiment of this invention, The block diagram which shows the principal part of the drive mechanism concerning background art,

Explanation of symbols

  1: drive mechanism, 2: forward / backward drive unit, 3: injection block, 4: rotation drive unit, 5: timing belt, 6: screw coupling, 7: bearing unit, 8: load cell, 8i: inner ring unit, 8o: Outer ring portion, 8m: Intermediate strain portion, 8f: Front end surface of load cell, 8r: Rear end surface of load cell, 9: Angular ball bearing, 9i: Inner ring of angular ball bearing, 9o: Outer ring of angular ball bearing, 10: No. Two bearings, 10i: Inner ring of second bearing, 10o: Outer ring of second bearing, 10x: Cylindrical roller bearing, 10y: Deep groove ball bearing, 11: Thrust bearing, 12: Bearing nut, 13: Inner ring spacer, 14: Outer ring Side spacer, 15: base portion, 15n: tapped hole, 16: adjusting pressure bolt, 17x: cylindrical roller bearing, 17y: deep groove ball bearing, Fa: axial direction, Fp: tensile load, M: injection molding machine, Ls Predetermined spacing, Lo: outer ring thickness of the spacer, Li: the thickness of the inner ring spacer, Gs: Gap, Xp: pressing position, Pm: Position adjustment portion, P: pressure adjusting means

Claims (6)

  An injection block to which axial movement is transmitted from the advancing / retreating drive unit, and a screw coupling to which the rotation motion is transmitted via the timing belt of the rotation drive unit, and an inner peripheral portion of the injection block via the bearing unit And a washer type having an inner ring portion, an outer ring portion and an intermediate strain portion for detecting the axial pressure between the injection block and the screw coupling. In the drive mechanism of an injection molding machine incorporating the load cell, the bearing portion is constituted by an angular ball bearing disposed on the rear end face side of the load cell and a second bearing disposed side by side on the angular ball bearing, and the angular ball bearing. And a screw coupling provided between the injection block and the injection block. The thrust bearing, the inner ring portion, the angular ball bearing and the second bearing disposed between the front end surfaces of the load cell are fixed on the outer peripheral portion of the screw coupling by a bearing nut, and the outer ring portion is An injection molding machine drive mechanism characterized by being fixed to an injection block.   An inner ring side spacer is interposed between the inner ring of the angular ball bearing and the inner ring of the second bearing, and an outer ring side spacer is interposed between the outer ring of the angular ball bearing and the outer ring of the second bearing, and the outer ring side spacer 2. The drive mechanism for an injection molding machine according to claim 1, wherein the thickness of the inner ring side spacer is made thinner than the thickness of the inner ring side spacer.   The drive mechanism for an injection molding machine according to claim 1 or 2, wherein the second bearing is a deep groove ball bearing or a cylindrical roller bearing.   A pressure adjusting means is provided on the injection block for pressing the screw coupling in a direction opposite to the tensile load by the timing belt and having a position adjusting unit capable of adjusting the pressing position. The drive mechanism of the injection molding machine according to claim 1.   The pressure adjusting means has a tapped hole, a base portion attached to the injection block, and an adjustment that can be screwed into the tapped hole and the tip portion can directly or indirectly press the screw coupling. The drive mechanism for an injection molding machine according to claim 4, further comprising a pressing bolt.   The drive mechanism for an injection molding machine according to claim 1, wherein a deep groove ball bearing or a cylindrical roller bearing is interposed between the injection block and the screw coupling on the front end face side of the load cell.

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