Platen, mold clamping device, and injection molding machine

Abstract

This platen comprises: a platen base that includes a mold attachment surface to which a mold is attached; a plurality tie bar support sections that are connected to the platen base and respectively support a plurality of tie bars; and a rib structure that protrudes from the platen base in a direction that intersects the mold attachment surface. The rib structure comprises: an outer peripheral rib that is formed so as to follow the outer peripheral edge of the platen base; and an auxiliary rib that is formed so as to follow the outer peripheral rib and mutually connects the tie bar support sections.

Description

Platen, Mold Clamping Device, and Injection Molding Machine

[0001] The present disclosure relates to a platen, a mold clamping device, and an injection molding machine.

[0002] An injection molding machine is an industrial machine that produces molded products using molds. Japanese Patent Application Laid-Open No. 2005-205819 discloses a mold plate (platen) that supports a mold.

[0003] Better platens, mold clamping devices, and injection molding machines are eagerly awaited.

[0004] A first aspect of the present disclosure includes a platen base having a mold mounting surface to which a mold is attached, a plurality of tie bar support portions connected to the platen base and each supporting a plurality of tie bars, and a rib structure protruding from the platen base in a direction intersecting the mold mounting surface. The rib structure includes an outer peripheral rib formed along the outer peripheral edge of the platen base, and auxiliary ribs formed along the outer peripheral rib and connecting the tie bar support portions to each other.

[0005] A second aspect of the present disclosure is a mold clamping device including the platen according to the first aspect of the present disclosure.

[0006] A third aspect of the present disclosure is an injection molding machine including the mold clamping device according to the second aspect of the present disclosure.

[0007] FIG. 1 is a side view of an injection molding machine according to an embodiment. FIG. 2 is a perspective view of a fixed platen provided in the mold clamping device of the injection molding machine; FIG. 3 is a front view of the fixed platen; FIG. 4 is a cross-sectional view of the fixed platen; FIG. 5 is a perspective view of a fixed platen according to a comparative example; FIG. 6 is a perspective view of a fixed platen according to Modification 1; FIG. 7 is a perspective view of a fixed platen according to Modification 2; FIG. 8 is a perspective view of a fixed platen according to Modification 3; FIG. 9 is a perspective view of a fixed platen according to Modification 4; FIG. 10 is a perspective view of a fixed platen according to Modification 5; FIG. 11 is a front view of the fixed platen shown in FIG. 10.

[0008] The prior art, including Japanese Patent Publication No. 2005-205819, has the following problems, for example. Specifically, the platen is subjected to a couple of forces in response to the opening and closing operation of the mold by the clamping device, the clamping operation on the mold, etc. It is undesirable for the platen to deform due to this couple of forces. Furthermore, it is conceivable to increase the thickness (wall thickness) of the platen in order to suppress the deformation of the platen. However, increasing the wall thickness may hinder the reduction of the platen's weight.

[0009] Based on the above preliminary explanation, one embodiment will be described below.

[0010] (One Embodiment) Figure 1 is a side view of an injection molding machine 10 according to one embodiment.

[0011] The injection molding machine 10 comprises an injection device 12 and a mold clamping device 14. The injection molding machine 10 may further comprise a machine base 16. The machine base 16 supports the mold clamping device 14. The machine base 16 may further support the injection device 12. Although not shown in the figures, the injection molding machine 10 may further comprise a control device. The control device controls the injection device 12 and the mold clamping device 14. Such a control device may include, for example, an electronic device such as a numerical control device.

[0012] The injection device 12 comprises an injection cylinder 18 and an injection nozzle 20. The injection nozzle 20 is located at the tip of the injection cylinder 18. A molding material such as solid resin (pellets) is supplied to the inside of the injection cylinder 18.

[0013] The injection device 12 may further include a heater (not shown) that plasticizes the molding material supplied to the injection cylinder 18 by heating and melting. The injection device 12 may also include a first slider 221. The first slider 221 is a slider 22 that is movable along the direction from the injection device 12 toward the clamping device 14. In this case, the first slider 221 may be moved by being guided by a first guide rail 22g1. The first guide rail 22g1 is a guide rail 22g that extends along the direction from the injection device 12 toward the clamping device 14. The first guide rail 22g1 may be provided on the machine base 16. The direction from the injection device 12 toward the clamping device 14 may coincide with the first direction D1 shown in Figure 1.

[0014] The injection cylinder 18 is equipped with an injection member (not shown). The injection member is, for example, a screw or a plunger. The injection member moves along the longitudinal direction of the injection cylinder 18 by a drive source (not shown), such as a motor. Such an injection member can push the plasticized molding material out of the injection cylinder 18 through the injection nozzle 20.

[0015] The injection device 12 may also plasticize the molding material while rotating the screw. The plunger may be equipped with a mixing device that kneads the molding material supplied to the injection cylinder 18.

[0016] The mold clamping device 14 comprises a plurality of platens 24, a toggle mechanism 32, and a plurality of tie bars 34. The plurality of platens 24 include a rear platen 26, a movable platen 28, and a fixed platen 30.

[0017] The movable platen 28 is positioned in a first direction D1 relative to the fixed platen 30. In other words, the first direction D1 shown in Figure 1 is the direction from the fixed platen 30 toward the movable platen 28. The first direction D1 is perpendicular to the vertical direction DV, but is not limited to this. The rear platen 26 is positioned in a first direction D1 relative to the movable platen 28.

[0018] The toggle mechanism 32 comprises a crosshead 32a and a plurality of toggle links 32b. The crosshead 32a is supported by the rear platen 26 via a ball screw mechanism 36. For example, the ball screw mechanism 36 comprises a nut 36a and a screw shaft member 36b. The nut 36a is attached to the crosshead 32a. The nut 36a is screwed onto the screw shaft member 36b. The screw shaft member 36b is attached to the rear platen 26. The plurality of toggle links 32b connect the crosshead 32a and the movable platen 28. The ball screw mechanism 36 is driven by a drive source such as a motor MOT. In response to the driving of the ball screw mechanism 36, the crosshead 32a is movable along a first direction D1. For example, the motor MOT rotates the screw shaft member 36b. As the screw shaft member 36b rotates, the nut 36a, together with the crosshead 32a, is displaced along the axial direction of the screw shaft member 36b. The axial direction of the screw shaft member 36b coincides with the first direction D1. Therefore, as the motor MOT rotates the screw shaft member 36b, the crosshead 32a moves along the first direction D1.

[0019] Each of the tie bars 34 extends along the first direction D1. The tie bars 34 connect the rear platen 26 and the fixed platen 30. The tie bars 34 are also inserted into the movable platen 28. As the crosshead 32a moves along the first direction D1, the movable platen 28 moves along the tie bars 34.

[0020] The movable platen 28 may include a second slider 222, which is a slider 22 that is movable along the first direction D1. In this case, the movable platen 28 (second slider 222) may be moved by being guided by a second guide rail 22g2. The second guide rail 22g2 is a guide rail 22g that extends along the first direction D1. The second guide rail 22g2 may be provided on the machine base 16.

[0021] A mold 38 is attached to the movable platen 28. More specifically, the mold 38 comprises a movable mold 38a and a fixed mold 38b. The movable mold 38a is attached to the movable platen 28.

[0022] A mold 38 is also attached to the fixed platen 30. More specifically, a fixed mold 38b is attached to the fixed platen 30. The fixed mold 38b attached to the fixed platen 30 faces the movable mold 38a attached to the movable platen 28.

[0023] As the movable platen 28 moves in the first direction D1, the distance between the movable mold 38a and the fixed mold 38b increases. When the movable mold 38a and the fixed mold 38b are separated, the mold 38 is in an open state. When the movable mold 38a and the fixed mold 38b are separated, as the movable platen 28 moves in the second direction D2, the distance between the movable mold 38a and the fixed mold 38b decreases. The second direction D2 is the opposite direction to the first direction D1. When the movable mold 38a and the fixed mold 38b are in contact, the mold 38 is in a closed state. The closed mold 38 forms a cavity 38c. The molding material described above is injected (filled) into this cavity 38c. The cavity 38c imparts the shape of the molded product to the filled molding material.

[0024] Figure 2 is a perspective view of a fixed platen 30 provided in the clamping device 14 of an injection molding machine 10. Figure 3 is a front view of the fixed platen 30. Figure 4 is a cross-sectional view of the fixed platen 30. The cross-section along line IV-IV in Figure 3 is shown in Figure 4.

[0025] The fixed platen 30 comprises a platen base (base, base portion) 40, a plurality of tie bar support portions 42, and a rib structure 44.

[0026] The platen base 40 is formed, for example, by casting. The platen base 40 has a mold mounting surface 46. The mold mounting surface 46 is the surface to which the mold 38 (fixed mold 38b) described above is attached. In other words, the mold mounting surface 46 is the surface on the movable platen 28 side. The in-plane direction of the mold mounting surface 46 intersects with the first direction D1. In that case, the in-plane direction of the mold mounting surface 46 may be perpendicular to the first direction D1.

[0027] The multiple tie bar support portions 42 are portions that support the multiple tie bars 34 described above. Each of the multiple tie bar support portions 42 may have an insertion hole 42h through which the tie bar 34 is inserted. The insertion hole 42h is a hole formed along the first direction D1. The insertion hole 42h may penetrate the tie bar support portion 42 along the first direction D1. The tie bar 34 inserted through the insertion hole 42h is fixed to the tie bar support portion 42 by a fixing member (not shown), such as a tie bar nut.

[0028] Multiple tie bar support portions 42 are connected to the platen base 40. The multiple tie bar support portions 42 may be formed integrally with the platen base 40. The multiple tie bar support portions 42 may be arranged at each of the multiple corner portions 48 (48a to 48d) of the platen base 40. For example, in a front view of the platen base 40 along the first direction D1 (hereinafter, front view), the platen base 40 may have a rectangular shape. In that case, the multiple tie bar support portions 42 may be arranged at each of the four corners (corner portions 48a, 48b, 48c, 48d) of the platen base 40 in a front view.

[0029] The rib structure 44 is a structure that protrudes from the platen base 40 in a second direction D2. In other words, the rib structure 44 is a structure that protrudes from the platen base 40 in a direction intersecting the mold mounting surface 46 (in the in-plane direction of the mold mounting surface 46).

[0030] The rib structure 44 comprises an outer circumferential rib 50 and auxiliary ribs 52. The rib structure 44 may have multiple auxiliary ribs 52.

[0031] The outer peripheral rib 50 is a rib (first rib) formed along the outer peripheral edge of the platen base 40 in a front view. The outer peripheral rib 50 connects a plurality of tie bar support portions 42 along the outer peripheral edge.

[0032] The auxiliary rib 52 is a rib (second rib) formed inside the outer peripheral rib 50. In a front view, the auxiliary rib 52 is located inside the outer peripheral rib 50. The auxiliary rib 52 is formed to follow the outer peripheral rib 50 (outer edge). The auxiliary rib 52 connects multiple tie bar support portions 42 to each other along the outer peripheral rib 50. The auxiliary rib 52 can connect two adjacent tie bar support portions 42 along the outer peripheral rib 50 (in the direction of extension of the outer peripheral rib 50).

[0033] Figure 3 shows an extension line EXL extending from the auxiliary rib 52. This extension line EXL is a hypothetical line that extends along the longitudinal direction of the auxiliary rib 52 in a front view. It is preferable that the center of the tie bar support portion 42 connected to the auxiliary rib 52 lies on the extension line EXL extending from the auxiliary rib 52. More specifically, it is preferable that the center C42h of the insertion hole 42h formed in the tie bar support portion 42 connected to the auxiliary rib 52 lies on the extension line EXL. In that case, the axis of the tie bar 34 inserted through the insertion hole 42h may be located on the extension line EXL in a front view.

[0034] The rib structure 44 may further include an annular rib 54. The annular rib 54 is a rib (third rib) formed inside the outer peripheral rib 50. In a front view, the annular rib 54 is located inside the outer peripheral rib 50. The annular rib 54 is, for example, positioned in the center of the platen base 40 in a front view. In a front view, the annular rib 54 has an annular shape. The auxiliary rib 52 described above is located between the outer peripheral rib 50 and the annular rib 54.

[0035] In a front view, a nozzle insertion hole 56 may be formed in the portion of the platen base 40 located inside the annular rib 54. The nozzle insertion hole 56 is a hole into which the injection nozzle 20 described above is inserted. The injection nozzle 20 is connected to the fixed mold 38b by being inserted into the nozzle insertion hole 56. More specifically, the injection nozzle 20 communicates with the cavity 38c described above by being inserted into the nozzle insertion hole 56.

[0036] The auxiliary rib 52 may be curved such that the distance between the auxiliary rib 52 and the outer circumferential rib 50 is equal to the distance between the auxiliary rib 52 and the annular rib 54. With respect to the curved shape of such an auxiliary rib 52, a virtual line segment VLS as shown in Figures 3 and 4 is specified. The virtual line segment VLS is a virtual line segment that passes through the auxiliary rib 52 and connects the outer circumferential rib 50 and the annular rib 54 in the shortest possible way, along the direction from the auxiliary rib 52 to the annular rib 54. In a front view, the midpoint CP of the virtual line segment VLS may overlap the auxiliary rib 52. In this case, the shortest distance between the auxiliary rib 52 and the outer circumferential rib 50 and the shortest distance between the auxiliary rib 52 and the annular rib 54 are specified along the virtual line segment VLS. The shortest distance between the auxiliary rib 52 and the outer circumferential rib 50 and the shortest distance between the auxiliary rib 52 and the annular rib 54, as specified in this way, are equal. The midpoint CP shown in Figure 3 overlaps the middle portion of the auxiliary rib 52 in the longitudinal direction. The auxiliary rib 52 may be curved symmetrically with respect to the imaginary line segment VLS passing through it.

[0037] If the rib structure 44 includes multiple auxiliary ribs 52, multiple virtual line segments VLS are identified corresponding to each of the multiple auxiliary ribs 52. For example, referring to Figures 3 and 4, virtual line segment VLS1 among the multiple virtual line segments VLS corresponds to auxiliary rib 521 among the multiple auxiliary ribs 52. Virtual line segment VLS2 among the multiple virtual line segments VLS corresponds to auxiliary rib 522. Virtual line segment VLS3 among the multiple virtual line segments VLS corresponds to auxiliary rib 523. Virtual line segment VLS4 among the multiple virtual line segments VLS corresponds to auxiliary rib 524.

[0038] The rib structure 44 may further include connecting ribs 58. The rib structure 44 may include multiple connecting ribs 58. The connecting ribs 58 are ribs (fourth ribs) that connect the tie bar support portion 42 and the annular rib 54. Multiple connecting ribs 58 connect multiple tie bar support portions 42 and annular ribs 54.

[0039] The connecting rib 58 may extend outward from the annular rib 54 along the radial direction of the annular rib 54 (also refer to FIG. 4). When each of the plurality of tie bar support portions 42 is disposed at the four corners (corners 48a to 48d) of the platen base 40, each of the plurality of connecting ribs 58 may extend along the diagonal line DL connecting the diagonals of the platen base 40.

[0040] The fixed platen 30 may further include a platen fixing portion (connecting portion, platen support portion) 60 for fixing the fixed platen 30 to the machine base 16. The fixed platen 30 may be provided with a plurality of platen fixing portions 60.

[0041] Such a fixed platen 30 is preferable from the viewpoint of achieving both suppression of deformation of the fixed platen and suppression of weight increase. This will be described below while comparing one embodiment with the following comparative example.

[0042] FIG. 5 is a perspective view of a fixed platen 300 according to a comparative example.

[0043] The fixed platen 300 includes a platen base 40, a plurality of tie bar support portions 42, and a rib structure `440`. The rib structure 440 includes an outer peripheral rib 50, an annular rib 54, and a connecting rib 58. The rib structure 440 does not include the auxiliary rib 52 described above. At least in this respect, the rib structure 440 of the comparative example is different from the rib structure 44 of one embodiment.

[0044] The fixed platen 300 transmits the clamping force generated by the clamping device 14 to the annular rib 54 via the tie bar 34, the tie bar support portion 42, and the connecting rib 58. The annular rib 54 applies a clamping force to the mold 38 (fixed mold 38b). In order to obtain a good clamping force regardless of the size and shape of the mold 38, it is conceivable to increase the thickness of the annular rib 54, but increasing the thickness of the annular rib 54 increases the weight of the fixed platen 30.

[0045] In that regard, according to one embodiment, the fixed platen 30 is provided with auxiliary ribs 52. Thereby, while maintaining the thickness of the annular rib 54 to be thin, the rigidity of the fixed platen 30 is enhanced. For this reason, according to one embodiment, the clamping force can be favorably applied to the mold 38 without increasing the thickness of the annular rib 54.

[0046] Also, according to one embodiment, the clamping force transmitted through the tie bar 34 is also transmitted to the auxiliary ribs 52. Thereby, it is suppressed that the clamping force concentrates on the connecting rib 58 to the annular rib 54. Since it is suppressed that the clamping force concentrates on the connecting rib 58 to the annular rib 54, there is room for reducing the size and weight of the connecting rib 58 to the annular rib 54. That is, according to the present embodiment, it is suppressed that the fixed platen 30 is deformed by the clamping force, and it is also suppressed that the fixed platen 30 becomes heavier.

[0047] The above-fixed platen 30 further exhibits the operational effects described below.

[0048] The center of the tie bar support portion 42 is located on the extension line EXL of the auxiliary rib 52. Thereby, the clamping force is favorably transmitted from the tie bar support portion 42 to the auxiliary rib 52. The center C42h of the insertion hole 42h formed in the tie bar support portion 42 may be located on the extension line EXL. In this case, the axial center of the tie bar 34 inserted into the insertion hole 42h is likely to be located on the extension line EXL. As a result, the clamping force can be favorably transmitted from the tie bar support portion 42 by the auxiliary rib 52.

[0049] The auxiliary rib 52 is curved. Thereby, the rigidity of the auxiliary rib is improved.

[0050] Also, in a front view, the midpoint CP of the virtual line segment VLS is located within the auxiliary rib 52. Thereby, the clamping force is favorably applied to the entire mold 38.

[0051] The auxiliary rib 52 may be curved such that the distance between the auxiliary rib 52 and the outer circumferential rib 50 is equal to the distance between the auxiliary rib 52 and the annular rib 54. More specifically, the auxiliary rib 52 may be curved such that the distance between the intermediate portion of the auxiliary rib 52 in the longitudinal direction (midpoint CP in Figure 3) and the outer circumferential rib 50 (shortest distance) is equal to the distance between the intermediate portion and the annular rib 54 (shortest distance). This ensures that the clamping force is evenly applied to the entire mold 38.

[0052] The connecting rib 58 transmits the clamping force from the tie bar support 42 to the annular rib 54. This allows the clamping force to be applied from the annular rib 54 to the fixed mold 38b. The annular rib 54 and the multiple tie bar support 42 are connected via the multiple connecting ribs 58, so that the clamping force is transmitted from the multiple tie bar support 42 to the annular rib 54. The annular rib 54 can aggregate the clamping force transmitted from the multiple tie bar support 42 and apply it to the fixed mold 38b.

[0053] Each of the multiple connecting ribs 58 extends along the radial DR of the annular rib 54. This allows the multiple connecting ribs 58 to effectively transmit the clamping force transmitted from the multiple tie bar support portions 42 to the annular rib 54.

[0054] One embodiment may be modified as follows. In the following modifications, explanations that overlap with the embodiment will be omitted as appropriate. Also, in the figures used in the following modifications, components identical to those described in the embodiment will be denoted by the same reference numerals.

[0055] (Modification 1) Figure 6 is a perspective view of the fixed platen 30 (fixed platen 301) according to Modification 1.

[0056] The connecting rib 58 may connect the outer circumferential rib 50 and the annular rib 54. In that case, the connecting rib 58 may intersect the auxiliary rib 52. The connecting rib 58 that connects the outer circumferential rib 50 and the annular rib 54 and intersects the auxiliary rib 52 will also be referred to as the intersecting rib 62 in the following description. The intersecting rib 62 is formed along the virtual line segment VLS described above (see also Figures 3 and 4), but is not limited to this.

[0057] As shown in Figure 6, the rib structure 44 may include a plurality of intersecting ribs 62.

[0058] The clamping force transmitted to the auxiliary rib 52, the annular rib 54, and the outer peripheral rib 50 is also distributed to the intersecting rib 62. As a result, the clamping force is evenly distributed throughout the mold 38.

[0059] (Modification 2) Figure 7 is a perspective view showing the fixed platen 30 (fixed platen 302) according to Modification 2.

[0060] The number of intersecting ribs 62 (see Modification 1) may be changed as appropriate. For example, as shown in Figure 7, the fixed platen 302 is provided with two intersecting ribs 62. Each of the two intersecting ribs 62 intersects with an auxiliary rib 52 (521, 523) that connects two adjacent tie bar support portions 42 along the vertical direction DV.

[0061] Auxiliary ribs 521 and 523, which connect two adjacent tie bar support sections 42 along the vertical direction DV, are more susceptible to load compared to the other auxiliary ribs 52 (522, 524). By intersecting auxiliary ribs 521 and 523 with intersecting ribs 62, deformation of auxiliary ribs 521 and 523 due to load can be suppressed.

[0062] (Modification 3) Figure 8 is a perspective view of the fixed platen 30 (fixed platen 303) according to Modification 3.

[0063] Multiple intersecting ribs 62 may intersect a single auxiliary rib 52. For example, as shown in Figure 8, two intersecting ribs 62 may intersect each of the auxiliary rib 521 and the auxiliary rib 523. This allows the intersecting ribs 62 to more effectively suppress the deformation of the auxiliary rib 52.

[0064] Furthermore, the number of auxiliary ribs 52 provided on the fixed platen 30 is not limited to four. For example, as shown in Figure 8, the auxiliary rib 52 connecting the tie bar support 42 located at corner 48a and the tie bar support 42 located at corner 48b may be omitted. Similarly, the auxiliary rib 52 connecting the tie bar support 42 located at corner 48c and the tie bar support 42 located at corner 48d may be omitted.

[0065] (Modification 4) Figure 9 is a perspective view of the fixed platen 30 (fixed platen 304) according to Modification 4.

[0066] The fixed platen 304 is provided with a guide connection portion 64. A guide member 66 is connected to the guide connection portion 64. The guide member 66 is a member that guides the injection device 12 (Figure 1) along the first direction D1 to the second direction D2. The guide member 66 may be a ball screw (screw shaft member) connected to the slider 22. In that case, the slider 22 is connected to the guide member 66 via a nut (not shown) that is screwed onto the ball screw guide member 66. As the ball screw guide member 66 rotates, the slider 22 can move along the axial direction of the guide member 66 (first direction D1, second direction D2).

[0067] The guide connection portion 64 may be connected to the rib structure 44. For example, as shown in Figure 9, the guide connection portion 64 is positioned below the annular rib 54 in a plan view and is connected to the connecting rib 58. By being connected to the connecting rib 58, the guide connection portion 64 prevents the connecting rib 58 from deforming. In this case, the crossing rib 62 does not need to be positioned below the annular rib 54.

[0068] (Modification 5) Figure 10 is a perspective view of the fixed platen 30 (fixed platen 305) according to Modification 5. Figure 11 is a front view of the fixed platen 305 shown in Figure 10.

[0069] As shown in Figures 10 and 11, the auxiliary rib 52 may be a straight rib.

[0070] (Modification 6) The rib structure 44 may be applied to the movable platen 28.

[0071] (Combinations of multiple variations) The above-mentioned variations may be combined as appropriate, within the bounds of consistency.

[0072] According to one embodiment and its modifications, the platen 24, the clamping device 14, and the injection molding machine 10 are preferable in terms of achieving both suppression of deformation and suppression of weight increase of the platen 24.

[0073] With respect to the above-described embodiment, the following additional information is disclosed.

[0074] (Note 1) The platen according to the present disclosure is a platen (24) comprising: a platen base (40) having a mold mounting surface (46) to which a mold (38) is attached; a plurality of tie bar support portions (42) connected to the platen base and each supporting a plurality of tie bars (34); and a rib structure (44) protruding from the platen base in a direction intersecting the mold mounting surface, wherein the rib structure comprises an outer peripheral rib (50) formed along the outer peripheral edge of the platen base and an auxiliary rib (52) formed along the outer peripheral rib and connecting the tie bar support portions to each other.

[0075] (Note 2) The platen described in Note 1 may be a platen in which the auxiliary rib connects two adjacent tie bar support portions along the outer peripheral rib.

[0076] (Note 3) A platen as described in Note 1 or 2, wherein the center of the tie bar support portion is located on the extension line (EXL) of the auxiliary rib.

[0077] (Note 4) A platen as described in any one of Notes 1 to 3, further comprising an annular rib (54) formed in an annular shape inside the outer peripheral rib, wherein the auxiliary rib is located between the outer peripheral rib and the annular rib.

[0078] (Note 5) The platen described in Note 4 may be a platen in which the auxiliary rib is curved.

[0079] (Note 6) A platen as described in Note 5, in which the auxiliary rib is curved such that the distance between the intermediate portion of the auxiliary rib and the outer peripheral rib in the longitudinal direction of the auxiliary rib is equal to the distance between the intermediate portion and the annular rib.

[0080] (Note 7) The platen described in any one of Notes 4 to 6 may further include a crossing rib (62) that connects the outer peripheral rib and the annular rib and intersects the auxiliary rib.

[0081] (Note 8) The platen described in any one of Notes 4 to 7 may further include a connecting rib (58) that connects the tie bar support portion and the annular rib.

[0082] (Note 9) The clamping device relating to this disclosure is a clamping device (14) equipped with a platen as described in any one of Notes 1 to 8.

[0083] (Note 10) The injection molding machine relating to this disclosure is an injection molding machine (10) equipped with the clamping device described in Note 9.

[0084] While this disclosure has been described in detail, it is not limited to the individual embodiments described above. These embodiments can be added, replaced, modified, partially deleted, etc., in any way that does not depart from the gist of this disclosure or from the intent of this disclosure derived from the claims and their equivalents. These embodiments can also be implemented in combination. For example, the order of operations and processes in the embodiments described above are given as examples only and are not limited thereto. The same applies when numerical values ​​or mathematical formulas are used in the description of the embodiments described above.

[0085] 10...Injection molding machine 14...Clamping device 24...Platen 34...Tie bar 38...Mold 40...Platen base 42...Tie bar support 44...Rib structure 46...Mold mounting surface 50...Outer periphery rib 52, 521-524...Auxiliary rib 54...Annular rib 58...Connecting rib 62...Intersecting rib CP...Midpoint EXL...Extension line VLS, VLS1-VLS4...Virtual line segment

Claims

1. A platen comprising: a platen base having a mold mounting surface to which a mold is attached; a plurality of tie bar support portions connected to the platen base and each supporting a plurality of tie bars; and a rib structure protruding from the platen base in a direction intersecting the mold mounting surface, wherein the rib structure comprises: an outer peripheral rib formed along the outer peripheral edge of the platen base; and auxiliary ribs formed along the outer peripheral rib and connecting the tie bar support portions to each other.

2. A platen according to claim 1, wherein the auxiliary rib connects two adjacent tie bar support portions along the outer peripheral rib.

3. A platen according to claim 1 or 2, wherein the center of the tie bar support portion is located on the extension line of the auxiliary rib.

4. A platen according to any one of claims 1 to 3, further comprising an annular rib formed in an annular shape inside the outer peripheral rib, wherein the auxiliary rib is located between the outer peripheral rib and the annular rib.

5. A platen according to claim 4, wherein the auxiliary rib is curved.

6. A platen according to claim 5, wherein the auxiliary rib is curved such that the distance between the intermediate portion of the auxiliary rib and the outer peripheral rib in the longitudinal direction of the auxiliary rib is equal to the distance between the intermediate portion and the annular rib.

7. A platen according to any one of claims 4 to 6, further comprising intersecting ribs that connect the outer peripheral ribs and the annular ribs and intersect the auxiliary ribs.

8. A platen according to any one of claims 4 to 7, further comprising a connecting rib for connecting the tie bar support portion and the annular rib.

9. A clamping device comprising a platen according to any one of claims 1 to 8.

10. An injection molding machine comprising the clamping device described in claim 9.

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