Patent Description:
<NUM> Conventionally, an injection molding machine has been known that includes a screw rotation driving section to rotate a screw inserted to a heat sleeve and a screw forward/rear move driving section to forwardly or rearwardly move this screw at least by a hydraulic cylinder (in particular a pair of left and right hydraulic cylinders), including an injection molding machine including an injection apparatus disclosed in Patent Literature <NUM> and an injection molding machine disclosed in Patent Literature <NUM>.

<NUM> The injection molding machine (injection apparatus) disclosed in Patent Literature <NUM> includes an injection cylinder (heat sleeve) including therein an injection screw rotatably provided in a slidable manner in an axial direction; a hopper for supplying resin material into this heat sleeve; a hopper jacket attached to this hopper and integrated with this heat sleeve; and a pair of left and right injection hydraulic cylinders to allow the injection screw to slide relative to the heat sleeve. The hopper jacket is integrated with the pair of left and right injection hydraulic cylinders.

<NUM> The injection molding machine disclosed in Patent Literature <NUM> is configured to include an injection unit by which the injection screw in the injection cylinder (heat sleeve) is allowed to rearwardly move while rotating to plasticize the resin and a pair of hydraulic cylinders provided at left and right sides of the heat sleeve are used to immediately move the injection screw in a forward direction to inject the resin collected at a tip end of the injection screw through an injection nozzle at the tip end of the heat sleeve into the cavity of a metal mold.

Patent Literature <NUM> discloses a plasticizing and injecting unit for use in an injection molding machine, the plasticizing and injecting unit having a carrier and supply block including a pair of second bores that are symmetrical with respect to an injection axis, The second bores contain advance-retract cylinders operable to axially advance and retract the plasticizing and injecting unit, and the third bores contain injection cylinders operable to inject molten plastic material into an injection mold.

Patent Literature <NUM> discloses an injection molding apparatus comprising a rotor interconnected to a distal end of one or more elongated cables in an arrangement such that the one or more elongated cables are controllably rotatably drivable via controlled driven rotation of the rotor around the rotor axis, wherein the one or more elongated cables have a cable axis and are flexibly bendable along at least a portion of their axis into a curved or curvilinear configuration. The injection molding apparatus further comprises a rotary to linear motion converter interconnected to the rotor and an upstream end of the valve pin.

<NUM> However, the following disadvantage is caused in the case of the above-described conventional injection molding machine (injection apparatus).

<NUM> Firstly, a user using an injection molding machine produces molded pieces of various products and parts. However, one injection molding machine cannot always produce all of various molded pieces. Thus, in order to produce a large-size molded piece for example by an available injection molding machine, the actual situation is that the production is achieved by exchanging the parts (specifically, the parts are changed to a screw and a heat sleeve that can handle the large-size molded piece). In this case, the screw and the heat sleeve are a precision part or a large-sized part. Thus, a disadvantage is caused in which the part exchange inevitably requires a significantly-increased cost and the use of the large-sized part requires the exchange operation with a great amount of labor.

<NUM> Secondly, the high-accuracy production of precision molded pieces requires resin to enter minute parts of the metal mold cavity, thus requiring a high-pressure injection capacity. This case can be handled by the exchange of the screw and the heat sleeve to a certain level. However, a situation may be caused where appropriate molding conditions cannot be set to various molded pieces. In particular, a disadvantage is caused in which the need to change the screw and the heat sleeve responsible for the plasticization of the resin causes a change of the plasticize environment (plasticization performance), which may lead to a variation of the molding quality or the mixture of not-yet-plasticized resin.

<NUM> It is an objective of this invention to provide an injection molding machine for solving the disadvantage existing in the prior art as described above and the molding method thereof.

<NUM> In order to eliminate the above-described disadvantage, aspects of embodiments provide injection molding machines and molding methods of injection molding machines, as defined in the independent claims.

<NUM> Further aspects of embodiments are defined in the dependent claims.

<NUM> For the avoidance of doubt, the claims define the scope of the invention.

<NUM> The injection molding machine <NUM> and the molding method thereof according to this invention can provide remarkable effects as described below.

<NUM> Next, the following section will describe a preferred embodiment according to this invention in detail based on the drawings.

<NUM> First, the following section will specifically describe the configuration of the injection molding machine <NUM> according to this embodiment with reference to <FIG>.

<NUM> In the drawing, the reference numeral <NUM> denotes an injection molding machine in which a clamping apparatus is omitted (i.e., an injection apparatus 1i). The injection apparatus 1i includes a base frame <NUM> functioning as a pair of left and right guide rails 21r. This base frame <NUM> is provided on a molding machine bed (not shown) via a slide mechanism. Thus, the base frame <NUM> is supported on a molding machine bed to be slidably displaced in a front-and-rear direction Fs and is caused by a nozzle touch cylinder (not shown) to move in the front-and-rear direction Fs.

<NUM> The base frame <NUM> has thereon the cylinder attachment mechanism <NUM>. This cylinder attachment mechanism <NUM> includes a pair of front and rear units (i.e., a fixed block section <NUM> as a front unit and a support block section <NUM> as a rear unit).

<NUM> The fixed block section <NUM> is fixed by being positioned at an intermediate position of the base frame <NUM>. In an embodiment, as shown in <FIG>, an example is shown in which the fixed block section <NUM> and the base frame <NUM> are fixed via a plurality of attachment plates <NUM>. <FIG> show the fixed block section <NUM> configured in an integrated manner as a part. This fixed block section <NUM> has a heat sleeve fixation section <NUM> at a center position in a left-and-right direction Fh. This heat sleeve fixation section <NUM> has a front face 12f to which the rear end 2r of the heat sleeve <NUM> having an injection nozzle 2n in a front end is attached and fixed. Thus, the front-and-rear direction Fs of the heat sleeve fixation section <NUM> is inserted with a screw insertion hole <NUM> having a circular cross section to which a unique screw <NUM> (which will be described later) is inserted. A front face 12u of the heat sleeve fixation section <NUM> has a front-side position provided at a hopper attachment face 12uc. A material dropping hole <NUM> is formed from this hopper attachment face 12uc to the screw insertion hole <NUM>. This hopper attachment face 12uc is attached with a hopper <NUM> shown in <FIG> by the virtual line.

<NUM> At both of the left and right sides of the heat sleeve fixation section <NUM>, a pair of left and right front detachable sections 13p and 13q are provided in an integrated manner that constitute the front side (one side) of a cylinder detachable section <NUM>. A front detachable section 13p at the right side is configured by an upper-front detachable section 13pu provided at the upper side and a lower-the front detachable section 13qd provided at the lower side so that the former and the latter are parallelly protruded to the right side in the horizontal direction, respectively. The front detachable section 13q at the left side is configured by an upper-front detachable section 13qu provided at the upper side and a lower-the front detachable section 13qd provided at the lower side that are parallelly protruded to the left side in the horizontal direction, respectively.

<NUM> In this manner, the four front detachable sections 13pu, 13pd, 13qu, and 13qd are provided at the left and right sides in the upper and lower directions, respectively. The respective front detachable sections 13pu, 13pd, 13qu, and 13qd, which have faces orthogonal to the front-and-rear direction Fs, have front end faces each of which includes a plurality of (or exemplarily four) screw holes <NUM>. In this case, one front detachable section 13p and the other front detachable section 13q are formed to have the same configuration except for being symmetric in the left-and-right direction and have sufficient strength and rigidity.

<NUM> Thus, the respective hydraulic cylinders 6a. (which will be described later) can be attached and fixed to the front end faces of the respective front detachable sections 13pu, 13pd, 13qu, and 13qd by a plurality of bolts <NUM>. (see <FIG>). Specifically, the front sides of the respective hydraulic cylinders 6a. are detachable to the fixed block section <NUM> by tightening or detaching the bolts <NUM>. The reference numeral <NUM> denotes a concave section that is provided at the rear side of the front face 12u of the heat sleeve fixation section <NUM> and that has an opening in the front face.

<NUM> As described above, one side (front side) of the cylinder attachment mechanism <NUM> is configured by the fixed block section <NUM> having a fixed position that has the heat sleeve fixation section <NUM> supporting the rear end 2r of the heat sleeve <NUM> and a pair of the front detachable sections 13p and 13q constituting the cylinder detachable section <NUM> that is provided at both sides of this heat sleeve fixation section <NUM> and that provides the detachability of the hydraulic cylinders 6a. , respectively. Thus, the respective hydraulic cylinders 6a, 6b, and 6c may be attached to the front detachable sections 13p and 13q functioning as the attachment base of the cylinder body. Thus, the simplified attachment structure can advantageously provide an easier attachment and can contribute to a smaller size and a lower cost.

<NUM> On the other hand, the support block section <NUM> is supported on the rear part of the base frame <NUM> functioning as a guide rail 21r to be displaced in a slidable manner in the direction shown by the arrow Fs (front-and-rear direction). <FIG> shows the support block section <NUM> configured in an integrated manner as a part. This support block section <NUM> has a motor attachment section <NUM> provided at the center position in the left-and-right direction Fh. As shown in <FIG> and <FIG>, this motor attachment section <NUM> is attached with a measurement motor <NUM> to configure a screw rotation driving section <NUM> that causes the screw to rotate. Thus, a rear shaft section 3sr of the unique screw <NUM> inserted to the heat sleeve <NUM> is allowed to rearwardly protrude from the rear end of the fixed block section <NUM> through the screw insertion hole <NUM> of the fixed block section <NUM> to couple the rear end of the rear shaft section 3sr to a rotation output shaft <NUM> of the measurement motor <NUM>.

<NUM> As shown in <FIG>, both of the left and right sides of the motor attachment section <NUM> of the support block section <NUM> have a pair of left and right rear detachable sections 15p and 15q constituting the rear side (the other side) of the cylinder detachable section <NUM> provided in an integrated manner. Specifically, the right side part of the support block section <NUM> has a rod bolt insertion hole 32p penetrating in the front-and-rear direction to constitute the right-side rear detachable section 15p. The left side part of the support block section <NUM> has a rod bolt insertion hole 32q penetrating in the front-and-rear direction to constitute the left-side the rear detachable section 15q.

<NUM> In this case, one rear detachable section 15p and the other the rear detachable section 15q have the same configuration except for being symmetric in the left-and-right direction. Thus, the respective rod bolt insertion holes 32p and 32q are inserted with the rod bolt sections 6arn. , and 6crn. formed at the tip end side of the piston rods 6ar. protruded from the respective hydraulic cylinders 6a. (which will be described later) and can be attached and fixed by nuts <NUM>. Specifically, the respective piston rods 6ar. (the rear sides of the respective hydraulic cylinders 6a. ) are detachable to the support block section <NUM> by tightening or detaching the respective nuts <NUM>. The reference numeral <NUM> denotes a slider base that is supported by the guide rail 21r to be displaced in a slidable manner in the front-and-rear direction Fs and that is integrated with the rear detachable sections 15p and 15q and the lower part of the motor attachment section <NUM>.

<NUM> As described above, the other side (rear side) of the cylinder attachment mechanism <NUM> is configured by the support block section <NUM> that has the screw rotation driving section <NUM> provided at the rear side of the fixed block section <NUM> to rotate the rear end of the unique screw <NUM> inserted with the heat sleeve <NUM> and a pair of rear detachable sections 15p and 15q. The rear detachable sections 15p and 15q are provided at both sides of this screw rotation driving section <NUM> and provide the detachability of the tip ends of the piston rods 6ar. protruding from the respective hydraulic cylinders 6a. , respectively. Thus, the piston rods 6ar. of the respective hydraulic cylinders 6a, 6b, and 6c may be attached to the rear detachable sections 15p and 15q. Thus, the simplified attachment structure can provide an easier attachment and can contribute to a smaller size and a lower cost.

<NUM> The configuration as described above provides the detachability of a pair of selected left and right hydraulic cylinders 6a. between the fixed block section <NUM> and the support block section <NUM>. As a result, the attachment of the hydraulic cylinders 6a. allows at least selected hydraulic cylinders 6a. to provide the screw forward/rear move driving section <NUM> that forwardly or rearwardly moves the unique screw <NUM>. It is noted that the injection apparatus base 1im is configured when the injection apparatus 1i shown in <FIG> is not attached with the hydraulic cylinders 6a. in the injection apparatus 1i.

<NUM> The injection molding machine <NUM> according to this invention having the configuration as described above has two important components shown below. The following section will describe the respective components with reference to <FIG> and <FIG>.

<NUM> First, the unique screw <NUM> is used for which the L/D ratio between the screw length L and the screw diameter D is set as the specific value Ns to the injection apparatus 1i. Thus, this unique screw <NUM> is a screw unique to the injection molding machine <NUM> and is prevented from being changed together with the heat sleeve <NUM>. The use of this the unique screw <NUM> is the first component important in this invention.

<NUM> In this case, the L/D ratio shows a value representing the characteristic of the shape of the screw. As shown in <FIG>, the screw length L represents the length of a part of the screw body <NUM> including a flight section 41f in the axial direction (the front-and-rear direction Fs). The screw diameter D represents the outer diameter of the flight section 41f. The specific value Ns is desirably selected from a range of <NUM>-<NUM>. The selection under these conditions generally allows the L/D ratio value to include desirable values of <NUM>-<NUM>. In addition, in this invention in particular, it is assumed that the unique screw <NUM> providing a fixed resin volume is used. Thus, a desirable value also can be easily selected from the viewpoint of covering the molding of various molding conditions (molded pieces) assumed in advance.

<NUM> Thus, the size of the unique screw <NUM> can be selected in consideration of the resin volume (resin cubic volume) Qm by which the assumed maximum large-sized molded piece can be measured. For example, when it is assumed that the resin volume Qm is <NUM> liters, then the injection molding machine can be set with the maximum large-sized molded piece of <NUM> liters as a grade. When assuming that the resin volume Qm is <NUM> liters, then the injection molding machine can be set with the maximum large-sized molded piece of <NUM> liters as a grade.

<NUM> The screw forward/rear move driving section <NUM> is configured by at least two (or exemplarily three) different types of hydraulic cylinders 6a, 6b, and 6c that can be adapted to a molded piece moldable by the unique screw <NUM>. The use of different types of selectable hydraulic cylinders 6a, 6b, and 6c is the second important component.

<NUM> In the embodiment, as shown in <FIG>, the three different types of hydraulic cylinders 6a, 6b, and 6c were exemplarily used. In this invention, it is assumed that the unique screw <NUM> is used. Thus, the respective hydraulic cylinders 6a, 6b, and 6c desirably have the same length in the axial direction (the front-and-rear direction Fs) but do not always have to have the same length. In the case of the illustrated configuration, the hydraulic cylinders 6a, 6b, and 6c have the same length in the front-and-rear direction Fs and have different cylinder diameters, respectively. Specifically, the hydraulic cylinder 6a has the smallest cylinder diameter Da while the hydraulic cylinder 6c has the largest cylinder diameter Dc. The hydraulic cylinder 6b has a medium-sized cylinder diameter Db between the cylinder diameters Da and Dc.

<NUM> By the above configuration, when the hydraulic cylinder 6a is used as shown in <FIG>, the maximum pressure Pma can be set to the smallest value. When the hydraulic cylinder 6c is used, the maximum pressure Pmc can be set to the largest value. When the hydraulic cylinder 6b is used, the maximum pressure Pmb can be set to a value between the maximum pressures Pma and Pmc. Furthermore, since the use of the unique screw <NUM> is assumed, any of the respective hydraulic cylinders 6a, 6b, and 6c can provide the same resin volume Qm. Thus, the respective hydraulic cylinders 6a, 6b, and 6c can be selected based on the magnitude of the maximum pressure (the maximum injection pressure) Pm without requiring the consideration of the resin volume Qm. The case was shown in which the selection was made based on the maximum pressures Pma, Pmb, and Pmc. However, the selection also may be made based on the maximum speed or based on both of the maximum pressures Pma, Pmb, and Pmc and the maximum speed.

<NUM> As described above, when the different hydraulic cylinders 6a, 6b, and 6c are used, the hydraulic cylinders 6a, 6b, and 6c are allowed to output different maximum pressures. This eliminates the need to change the unique screw <NUM> and the heat sleeve <NUM> and allows the resin volume Qm to be fixed. Thus, the respective hydraulic cylinders 6a, 6b, and 6c can be selected by merely selecting the maximum pressure, thus advantageously providing an easy selection of the respective hydraulic cylinders 6a, 6b, and 6c.

<NUM> The illustrated respective hydraulic cylinders 6a, 6b, and 6c are double rod-type hydraulic cylinders. Thus, one hydraulic cylinder (e.g., the hydraulic cylinder 6b) includes a cylinder body 51b as shown in <FIG> and <FIG>. The cylinder body 51b has both end faces from which piston rods 6br and 6bf are protruded, respectively. In this case, a piston rod 6br protrudes from the rear end face of the cylinder body 51b and has the tip end side having a rod bolt section 6brn (<FIG>) formed to have a predetermined length. A piston rod 6bf is protruded from the front end face of the cylinder body 51b and thus is covered by a tube-shaped safety cover 52b. The cylinder body 51b has an outer periphery face at the axial direction intermediate position that is integrated with an attachment flange 53b. This the attachment flange 53b is configured so that a screw insertion hole <NUM>. is formed at the position corresponding to the screw hole <NUM>. provided in the front end face of the above-described respective front detachable sections 13pu, 13pd, 13qu, and 13qd (see <FIG>).

<NUM> Although one the hydraulic cylinder 6b has been described, other hydraulic cylinders 6a and 6c have the same basic configuration as that of the hydraulic cylinder 6b. In the hydraulic cylinder 6a, the reference numeral 51a denotes a cylinder body, the reference numeral 53a denotes an attachment flange, the reference numeral 6ar denotes a piston rod, and the reference numeral 6arn denotes a rod bolt section, respectively. In the hydraulic cylinder 6c, the reference numeral 51c denotes a cylinder body, the reference numeral 53c denotes an attachment flange, the reference numeral 6cr denotes a piston rod, and the reference numeral 6crn denotes a rod bolt section, respectively. Each of the hydraulic cylinders 6a, 6b, and 6c has two identical hydraulic cylinders 6a. Even when the respective hydraulic cylinders 6a. are changed, no change is required for a hydraulic circuit <NUM> including a hydraulic pump <NUM> shown in <FIG> that controls the driving of the respective hydraulic cylinders 6a.

<NUM> Next, the following section will describe the use method and function of the injection molding machine <NUM> including the molding method according to this embodiment with reference to <FIG> and based on the flowchart shown in <FIG>.

<NUM> Now, a case is assumed where the production is performed by a standard system (Step S1). The standard system uses the hydraulic cylinder 6b shown in <FIG> (intermediate diameter cylinder). Thus, when the standard system is configured, an injection apparatus base 1im shown in <FIG> is attached to a hydraulic cylinder 6b shown in <FIG>. Specifically, as shown in <FIG> and <FIG>, a pair of prepared hydraulic cylinders 6b and 6b is attached at the right side and the left side of the cylinder attachment mechanism <NUM> of the injection apparatus base 1im, respectively, to thereby constitute the injection molding machine <NUM>.

<NUM> In this case, the hydraulic cylinder 6b. can be attached to and detached from the cylinder attachment mechanism <NUM> in the manner as described below.

<NUM> First, as shown in <FIG>, the cylinder body 51b of the hydraulic cylinder 6b at one side (left side) is stored at the front detachable section 13q at the left side of the fixed block section <NUM> provided at the front side (i.e., between the upper-front detachable section 13qu and the lower-the front detachable section 13qd). As shown in <FIG> and <FIG>, the rod bolt section 6brn of the piston rod 6br protruded from the cylinder body 51b is inserted to a rod bolt insertion hole 32q of the rear detachable section 15q at the left side of the support block section <NUM> provided at the rear side. The rod bolt section 6brn is screwed with one the nut <NUM> in advance.

<NUM> As shown in <FIG>, separately-prepared eight bolts <NUM>. are inserted to the total of eight screw insertion holes <NUM>. provided in an attachment flange 53b of the cylinder body 51b. Thereafter, the tip ends of the respective bolts <NUM>. are screwed and tightened with the total of eight screw holes <NUM>. (see <FIG>) provided in the front end faces of the upper-front detachable section 13qu and the lower-the front detachable section 13qd to thereby fix the cylinder body 51b to the left side position of the fixed block section <NUM>.

<NUM> Next, a nut <NUM> screwed with the rod bolt section 6brn inserted to the rod bolt insertion hole 32q of a rear detachable section 15q is rotated and operated. As shown in <FIG> and <FIG>, the nut <NUM> is abutted to the front end face of the rear detachable section 15q. Thereafter, the tip end side of the rod bolt section 6brn is attached with a split ring 33r and is further screwed and tightened with the nut <NUM> to thereby fix the piston rod 6br to the left side position of the support block section <NUM>.

<NUM> As a result, the attachment to the left position of the cylinder attachment mechanism <NUM> of the hydraulic cylinder 6b at one side (left side) is completed. Furthermore, the attachment to the cylinder attachment mechanism <NUM> of the hydraulic cylinder 6b of the other side (right side) also can be performed by performing the above-described attachment procedure and operation to attach one hydraulic cylinder 6b. During this, the fixed block section <NUM> and the support block section <NUM> are both have a fixed position. However, the front detachable section 13p at the fixed block section <NUM> provided at the right side of the cylinder attachment mechanism <NUM> (i.e., between the upper-front detachable section 13pu and the lower-front detachable section 13pd) is configured to have a laterally-opened state. Thus, the rod bolt section 6brn of the hydraulic cylinder 6b can be inserted to the rod bolt insertion hole 32p at the right side the rear detachable section 15p of the support block section <NUM> and the cylinder body 51b of the hydraulic cylinder 6b can be stored in the front detachable section 13p of the fixed block section <NUM> (i.e., between the upper-front detachable section 13pu and the lower-front detachable section 13pd).

<NUM> Therefore, this standard system supplies molding material (pellet) from the hopper <NUM> into the heat sleeve <NUM> to use the measurement motor <NUM> of the screw rotation driving section <NUM> to rotate the unique screw <NUM>, thereby plasticizing and melting the molding material. The molten resin is measured and accumulated in the heat sleeve <NUM> at the front side of the unique screw <NUM>. Then, a pair of the hydraulic cylinders 6b and 6b constituting the screw forward/rear move driving section <NUM> is driven-controlled by the hydraulic circuit <NUM> including the hydraulic pump <NUM> to forwardly move the unique screw <NUM>. This allows the measured resin to be injected through the injection nozzle 2n, thereby performing a series of molding steps to fill a metal mold cavity (not shown) with the resin.

<NUM> A case is assumed where the injection molding machine <NUM> of this standard system requires a system change because a change of the metal mold causes such a molded piece that cannot be molded by this standard system or that causes a compromised molding operation (Step S2). In this case, the hydraulic cylinders 6b and 6b are firstly removed from the injection apparatus base 1im (Step S3). The hydraulic cylinders 6b and 6b can be easily removed by performing the above-described procedure and operation of the hydraulic cylinders 6b and 6b in a reverse order.

<NUM> If a new molded piece after the system change is a relatively large-sized molded piece that does not require s significantly-high molding accuracy (e.g., everyday goods), a high injection pressure is not required. Thus, molding conditions having a higher injection speed can be used and a high-speed system can be used in this case (Step S4).

<NUM> Thus, the high-speed system can use the hydraulic cylinder 6a (small diameter cylinder) shown in <FIG>. In order to constitute the high-speed system, the hydraulic cylinder 6a shown in <FIG> is attached to the injection apparatus base 1im. Specifically, as shown in <FIG> and <FIG>, a pair of prepared hydraulic cylinders 6a and 6a are provided at the right side and the left side of the cylinder attachment mechanism <NUM> of the injection apparatus base 1im, respectively, to thereby constitute the injection molding machine <NUM> (Step S5). The hydraulic cylinders 6a and 6a also can be attached by the attachment procedure and operation similar to the above-described attachment of the hydraulic cylinder 6b. Thus, the injection molding machine <NUM> can be changed from the standard system to the high-speed system and a series of molding steps can be performed by the injection molding machine <NUM> using a pair of the hydraulic cylinders 6a and 6a (small diameter cylinder) providing a higher injection speed (Step S6).

<NUM> On the other hand, if a new molded piece after the system change requires a high molding accuracy (e.g., CD), a high injection pressure is required. In this case, the injection pressure can be changed to a high pressure system having a higher pressure (Step S7). Thus, the high pressure system can use the hydraulic cylinder 6c (large diameter cylinder) shown in <FIG>. In order to constitute the high pressure system, the hydraulic cylinder 6c shown in <FIG> is attached to the injection apparatus base 1im. Specifically, as shown in <FIG> and <FIG>, a pair of prepared hydraulic cylinders 6c and 6c is attached at the right side and the left side of the cylinder attachment mechanism <NUM> of the injection apparatus base 1im, respectively, to thereby constitute the injection molding machine <NUM> (Step S8). The hydraulic cylinders 6c and 6c also can be attached by the attachment procedure and operation similar to the above-described attachment of the hydraulic cylinder 6b. As a result, the injection molding machine <NUM> can be changed from a standard system to a high pressure system to perform a series of molding steps using the injection molding machine <NUM> using a pair of hydraulic cylinders 6c and 6c (large diameter cylinder) providing a higher injection pressure (Step S9).

<NUM> A case will be assumed in which the production by the high-speed system or high pressure system is completed and another system change is required (Step S10). In this case, the hydraulic cylinders 6a and 6a or the hydraulic cylinders 6c and 6c are firstly removed from the cylinder attachment mechanism <NUM> of the injection apparatus base 1im (Step S11). Then, when the current system is returned to the standard system, the hydraulic cylinders 6b and 6b are attached to the cylinder attachment mechanism <NUM> (Steps S12 and S13). This allows the current system to be returned to the injection molding machine <NUM> of the standard system (Step S1). When the current system is changed from a high-speed system to a high pressure system on the other hand, the hydraulic cylinders 6c and 6c are attached to the cylinder attachment mechanism <NUM> (Steps S12, S4, S7, and S8). This consequently can provide a change to the injection molding machine <NUM> functioning as a high pressure system (Step S9). A system change from a high pressure system to a high-speed system is performed by attaching the hydraulic cylinders 6a and 6a to the cylinder attachment mechanism <NUM> (Steps S12, S4, and S5). This can provide a change to the injection molding machine <NUM> functioning as a high-speed system (Step S6).

<NUM> Thus, according to the injection molding machine <NUM> according to this embodiment or the molding method thereof, the unique screw <NUM> having the L/D ratio of the screw length L and the screw diameter D as the specific value Ns to the injection apparatus 1i is basically used. The injection apparatus 1i includes the cylinder attachment mechanism <NUM> having the cylinder detachable section <NUM> that provides the detachability of at least two different types of hydraulic cylinders 6a, 6b, and 6c that can be adapted by the unique screw <NUM> to a moldable molded piece. In order to perform a molding operation, a hydraulic cylinder 6a (or 6b, 6c) is selected from among the respective hydraulic cylinders 6a, 6b, and 6c in advance that is adaptable to the to-be-molded piece and the unique screw <NUM>. This selected hydraulic cylinder 6a (or 6b, 6c) is attached to the cylinder attachment mechanism <NUM> and a molding operation is performed. Thus, even when various products or molded pieces such as parts are produced, no change is required for the unique screw section <NUM> and the heat sleeve <NUM> and the selected hydraulic cylinder 6a (or 6b, 6c) can be merely exchanged. In particular, the exchange of the general-purpose commercially-available hydraulic cylinder 6a (or 6b, 6c) is only required, thus achieving the significantly-reduced cost for the part exchange. Furthermore, only parts having a relatively-smaller size than those of the screw and the heat sleeve can be exchanged, thus realizing an exchange operation in a relatively easy and simple manner.

<NUM> Furthermore, the use of the unique screw <NUM> having the L/D ratio set as the specific value Ns to the injection apparatus 1i can provide the selection of the unique screw <NUM> in advance that can widely cover the molding of various molded pieces. Thus, such a hydraulic cylinder 6a (or 6b, 6c) can be selected optimal to a large-sized molded piece or a precision molded piece for example to thereby provide appropriate molding conditions to various molded pieces. Furthermore, no need to change the unique screw <NUM> and the heat sleeve <NUM> can provide a fixed plasticization environment (plasticization performance). Thus, a wasteful plasticization variation having an influence on the molded piece quality (e.g., insufficient plasticization) can be avoided, thus contributing to the improvement of the qualities of various molded pieces.

<NUM> Next, the following section will describe the modification example of the hydraulic cylinder 6a. used in the injection molding machine <NUM> according to this embodiment with reference to <FIG>.

<NUM> <FIG> illustrates a modification example of the rod type of the hydraulic cylinder 6a. The hydraulic cylinder 6a. shown in <FIG>(<FIG>) is a double rod-type hydraulic cylinder configured so that the piston rods 6br and 6bf are protruded from both end faces of a piston included in the cylinder body 51b, respectively.

<NUM> On the other hand, the hydraulic cylinder 6a. shown in <FIG> according to a modification example uses a single rod-type hydraulic cylinder. Thus, the end face of the other side (front side) of the cylinder body 51b is configured as a closed end face <NUM>. The piston included in the cylinder body 51b is configured so that the piston rod 6br is protruded from only one end face.

<NUM> As described above, the hydraulic cylinders 6a, 6b, and 6c used is not limited to any hydraulic cylinder type and may be a double rod-type hydraulic cylinder or a single rod-type hydraulic cylinder for example. Thus, the hydraulic cylinders 6a, 6b, and 6c can be selected with an increased freedom degree. The hydraulic control system also can be designed with an increased freedom degree. Thus, an appropriate hydraulic control system can be structured in consideration of the advantages of the double rod-type one and the single rod-type one, respectively.

<NUM> <FIG> illustrates a modification example in the case where the hydraulic cylinder 6a. has a different form (or a different appearance or shape for example). The embodiment shown in <FIG> (<FIG>) illustrates a configuration example in which the cylinder attachment mechanism <NUM> matching a commercially-available hydraulic cylinder 6a. for example is configured or the hydraulic cylinder 6a. matching an optimized cylinder attachment mechanism <NUM> is used as a so-called custom-made article. Thus, the matching is required in advance between the cylinder attachment mechanism <NUM> and each hydraulic cylinder 6a.

<NUM> On the other hand, in the case of the hydraulic cylinder 6a. shown in <FIG> according to modification example, no matching is obtained between the commercially-available and general-purpose hydraulic cylinder 6a. and the optimized cylinder attachment mechanism <NUM>. In this case, another attachment (attachment adapter) <NUM> can be introduced between the hydraulic cylinder 6a. and the cylinder attachment mechanism <NUM>.

<NUM> The attachment <NUM> shown in <FIG> as an example uses one doughnut-shaped plate. A plurality of screw insertion holes 65sf. provided in a plane closed to the center of the attachment <NUM> are inserted with a plurality of fixation bolts <NUM>. , respectively and can be subsequently fixed by being screwed and tightened with a plurality of screw holes 6asn. provided in the end face 6as of the hydraulic cylinder 6a, respectively. As a result, this hydraulic cylinder 6a can be added with a subsequently-installed flange section. A plurality of screw insertion holes 65ss. provided in a plane close to the periphery of the attachment <NUM> may be inserted with a plurality of fixation bolts <NUM>. , respectively, and may be subsequently fixed by being screwed and tightened with a plurality of screw holes <NUM>. provided in the respective front end faces of the upper-front detachable section 13qu and the lower-the front detachable section 13qd of the front detachable section 13q of the fixed block section <NUM>, respectively. Thus, even the hydraulic cylinders 6a. having various shapes can be easily attached to the cylinder attachment mechanism <NUM> by preparing the corresponding attachments (attachment adapters) <NUM>. <FIG> assumes a case where the attachment <NUM> is directly fixed to the end face 6as of the hydraulic cylinder 6a. However, many commercially-available hydraulic cylinders are configured as a flange-attached hydraulic cylinder in which a flange is integrated with the outer face of the cylinder. Thus, various fixation methods can be used such as a method to fix the attachment <NUM> to this flange.

<NUM> In <FIG>, the same parts as those shown in <FIG> are denoted with the same reference numerals to clarify the configurations thereof and will not be further described.

<NUM> A preferred embodiment including a modification example has been described in detail. However, this invention is not limited to such an embodiment. Thus, an arbitrary change, addition, or deletion can be made in the configuration, shape, material, number, or numerical value for example in detail within a scope as defined in the appended claims.

<NUM> For example, three or more types of hydraulic cylinders 6a, 6b, and 6c have been illustrated as two or more different types of hydraulic cylinders. However, two or more or four or more types of the hydraulic cylinders 6a, 6b, and 6c also may be provided. The specific value Ns is desirably selected from a range of <NUM>-<NUM> but also may be other values. A technical importance is placed on the use of a specific value. Furthermore, a case has been shown in which different maximum pressures are outputted from the respective hydraulic cylinders 6a, 6b, and 6c, respectively. However, other cases also may be considered where characteristic values other than the maximum pressure are different or another characteristic value (e.g., the maximum stroke) is used in addition to the maximum pressure. A case has been shown with the use of the fixed block section <NUM> having a fixed position that has the heat sleeve fixation section <NUM> supporting the rear end 2r of the heat sleeve <NUM> and a pair of the front detachable sections 13p and 13q constituting the cylinder detachable section <NUM> that is provided at both sides of this heat sleeve fixation section <NUM> and that provides the detachability of the hydraulic cylinders 6a. , respectively. However, another configuration having a similar function also may be used. A case has been shown with the use of the cylinder attachment mechanism <NUM> configured to include the screw rotation driving section <NUM> that is provided at the rear side of the fixed block section <NUM> and that provides the rotation of the rear end of the unique screw <NUM> inserted to the heat sleeve <NUM> and the support block section <NUM> having a pair of rear detachable sections 15p and 15q that are provided at both sides of this screw rotation driving section <NUM> and that constitute the cylinder detachable section <NUM> providing the detachability of the tip ends of the piston rods 6ar. protruding from the respective hydraulic cylinders 6a. , respectively.

<NUM> This invention can be applied to various injection molding machines including a screw forward/rear move driving section to forwardly or rearwardly move a screw at least by a hydraulic cylinder and can be applied to a molding method using the injection molding machine.

<NUM> <NUM>: Injection molding machine, 1i: Injection apparatus, <NUM>: Heat sleeve, 2r: Heat sleeve rear end, <NUM>: Unique screw, <NUM>: Screw rotation driving section, <NUM>: Screw forward/rear move driving section, <NUM>: Cylinder attachment mechanism, 6a: Hydraulic cylinder, 6b: Hydraulic cylinder, 6c: Hydraulic cylinder, 6ar: Piston rod, 6br: Piston rod, 6cr: Piston rod, <NUM>: Cylinder detachable section, <NUM>: Fixed block section, <NUM>: Heat sleeve fixation section, 13p: Front detachable section, 13q: Front detachable section, <NUM>: Support block section, 15p: Rear detachable section, 15q: Rear detachable section, L: Screw length, D: Screw diameter, Ns: Specific value.

Claim 1:
An injection molding machine (<NUM>), comprising: an injection apparatus (1i) having a screw rotation driving section (<NUM>) for rotating a screw (<NUM>) inserted to a heat sleeve (<NUM>) and a screw forward/rear move driving section (<NUM>) for forwardly or rearwardly moving the screw (<NUM>) at least by a hydraulic cylinder, wherein the screw (<NUM>) has an L/D ratio between a screw length L and a screw diameter D that is set as a specific value to the injection apparatus (1i),
wherein the injection apparatus (1i) includes a cylinder attachment mechanism (<NUM>) having a cylinder detachable section (<NUM>) that is configured to allow the detachability of two or more different types of hydraulic cylinders (6a-c), the two or more different types of hydraulic cylinders (6a-c) comprising hydraulic cylinders (6a-c) having different dimensions to one another, each of the hydraulic cylinders (6a-c) being adaptable to a molded piece that can be molded by the screw (<NUM>),
wherein the cylinder attachment mechanism (<NUM>) includes a fixed block section (<NUM>) having a fixed position that has a heat sleeve fixation section (<NUM>) to support a rear end (2r) of the heat sleeve (<NUM>) and two pairs of front detachable sections (13p, 13q), one of the pairs of front detachable sections (13p, 13q) being provided at each side of the heat sleeve fixation section (<NUM>) to provide the detachability of the hydraulic cylinders (6a-c), respectively, and
wherein the cylinder attachment mechanism (<NUM>) includes the screw rotation driving section (<NUM>) that is provided at the rear side of the fixed block section (<NUM>) and that provides the rotation of the rear end of the screw (<NUM>) inserted to the heat sleeve (<NUM>) and a support block section (<NUM>) having two pairs of rear detachable sections (15p, 15q), one of the pairs of rear detachable sections (15p, 15q) being provided at each side of this screw rotation driving section (<NUM>) and that constitute the cylinder detachable section (<NUM>) providing the detachability of the tip ends of the piston rods (6ar-cr) protruding from the respective hydraulic cylinders (6a-c), respectively.