Injection molding machine

Abstract

The present invention provides an injection molding machine (10), which has a belt transmission mechanism (a mold opening and closing mechanism (55), an ejection mechanism (72), a screw drive mechanism (104), and an injection mechanism (105)) for transmitting power from a driving shaft (a driving pulley (58, 76, 108, 116)) to a driven shaft (a driven pulley (62, 80, 112, 120)) through a belt (60), and has a cover (142) that covers a part or the whole of the above-mentioned belt (60), and a sensor (148) installed on the above-mentioned cover (142) and detecting abnormalities of the above-mentioned belt (60).

Description

Technical Field

[0001] The invention relates to an injection molding machine having a belt transmission mechanism for transmitting power from a driving shaft to a driven shaft through a belt. Background Art

[0002] Japanese Patent Application Laid-Open No. 2012-161995 discloses an injection molding machine having a belt transmission mechanism for transmitting power from a driving shaft to a driven shaft through a belt. The injection molding machine has a driving pulley as a driving shaft side, a driven pulley as a driven shaft side, a belt for transmitting power from the driving pulley to the driven pulley, and a soundproof cover, wherein the soundproof cover covers the driving pulley, the driven pulley, and the belt. Summary of the invention

[0003] In an injection molding machine with a belt transmission mechanism, when the belt is damaged such as cracks, the belt tension will decrease, causing deviations in the operation of the injection molding machine. In addition, when the belt breaks, the injection molding machine needs to be stopped. In order to prevent deviations in the operation of the injection molding machine or the injection molding machine from stopping, it is necessary to be able to detect belt abnormalities at an early stage.

[0004] Therefore, an object of the present invention is to provide an injection molding machine capable of detecting belt abnormality at an early stage.

[0005] The solution of the present invention is an injection molding machine having a belt transmission mechanism for transmitting power from a driving shaft to a driven shaft through a belt, and having a cover covering a part or the whole of the above-mentioned belt, and a sensor installed on the above-mentioned cover and detecting abnormality of the above-mentioned belt.

[0006] According to the present invention, an abnormality of the belt can be detected at an early stage, the cover can be used as a part of a detection device for detecting an abnormality of the belt, and an increase in size of the injection molding machine can be prevented.

[0007] The above-mentioned objects, features and advantages can be easily understood from the following embodiments described with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a schematic diagram showing the structure of the injection molding machine viewed from the side.

[0009] Figure 2 It is a schematic diagram showing the structure of a belt transmission mechanism without a cover.

[0010] Figure 3 This is a schematic diagram showing the structure of a belt transmission mechanism in which a cover is provided on the drive shaft side.

[0011] Figure 4This is a schematic diagram showing the structure of a belt transmission mechanism in which a cover is provided on the driven shaft side.

[0012] Figure 5 This is a schematic diagram showing the structure of a belt transmission mechanism in which a cover is provided on the entire body.

[0013] Figure 6 Yes means Figure 3 Schematic diagram of the position of the sensors in the belt drive and the structure of the reporting device.

[0014] Figure 7 Yes means Figure 4 Schematic diagram of the position of the sensors in the belt drive and the structure of the reporting device.

[0015] Figure 8 Yes means Figure 5 Schematic diagram of the position of the sensors in the belt drive and the structure of the reporting device.

[0016] Fig. 9 This is a schematic diagram showing the arrangement of the rotary encoder with respect to the driven shaft. DETAILED DESCRIPTION

[0017] Hereinafter, preferred embodiments of the injection molding machine of the present invention will be described in detail with reference to the accompanying drawings.

[0018] [1. Structure of injection molding machine 10]

[0019] Figure 1 1 is a schematic diagram showing the structure of the injection molding machine 10. The injection molding machine 10 includes a base 12, a mold closing device 14 provided on the base 12, and an injection device 16.

[0020] [1.1. Structure of the mold closing device 14]

[0021] The mold closing device 14 has a fixed platen 18, a rear platen 20, and four tie rods 22. The four tie rods 22 connect the fixed platen 18 and the rear platen 20. The four tie rods 22 are arranged so that their axial directions are parallel to each other. A movable platen 24 is arranged between the fixed platen 18 and the rear platen 20. The movable platen 24 is arranged on the base 12 via a sliding portion 26. The sliding portion 26 can move along a guide rail 28 provided on the base 12. Thus, the movable platen 24 is arranged relative to the fixed platen 18 so as to be able to advance and retreat along the axial direction of the tie rods 22.

[0022] A metal mold 30 is provided between the fixed platen 18 and the movable platen 24. The metal mold 30 is composed of a fixed metal mold 32 and a movable metal mold 34. The fixed metal mold 32 is attached to the movable platen 24 side of the fixed platen 18, and the movable metal mold 34 is attached to the fixed platen 18 side of the movable platen 24.

[0023] A toggle rod 36 is provided between the rear platen 20 and the movable platen 24. Four toggle rods 36 are provided, two at the top and two at the bottom. The toggle rod 36 includes a first link 38, a second link 40, a first toggle pin 42, a second toggle pin 44, and a third toggle pin 46. One end of the first link 38 is rotatably connected to the movable platen 24 via the first toggle pin 42. One end of the second link 40 is rotatably connected to the rear platen 20 via the second toggle pin 44. The other end of the first link 38 and the other end of the second link 40 are rotatably connected to each other via the third toggle pin 46.

[0024] The second link 40 is connected to the crosshead 50 via the transverse link 48. The crosshead 50 has arms 52 (upper arm 52a, lower arm 52b) extending upward and downward, and the transverse link 48 is connected to the front end of the arm 52. A guide rod (not shown) is provided on the rear plate 20. The guide rod (not shown) is set so that its axial direction is parallel to the axial direction of the tie rod 22. The crosshead 50 is set to be able to be guided by the guide rod (not shown) and move forward and backward in a direction parallel to the axial direction of the tie rod 22.

[0025] The mold closing device 14 has a mold opening and closing mechanism 55 for opening and closing the metal mold 30. The mold opening and closing mechanism 55 includes a servo motor 56, a driving pulley 58, a belt 60, a driven pulley 62, a ball screw 64, and a ball screw nut 66. The ball screw 64 is provided so that its axial direction is parallel to the axial direction of the tie rod 22.

[0026] The driving pulley 58 is provided so as to be able to be coupled to the rotating shaft 132 ( Figure 2 The driven pulley 62 is configured to rotate integrally with the ball screw 64. The belt 60 is suspended from the driving pulley 58 and the driven pulley 62, and transmits the rotational force of the driving pulley 58 to the driven pulley 62. The ball screw nut 66 is screwed with the ball screw 64, and moves along the ball screw 64 by the rotation of the ball screw 64. The ball screw nut 66 is fixed to the crosshead 50.

[0027] The rotation of the servo motor 56 transmits a rotational force to the ball screw 64 via the driving pulley 58, the belt 60, and the driven pulley 62, thereby rotating the ball screw 64. The crosshead 50 moves along the guide rod (not shown) together with the ball screw nut 66 by the rotation of the ball screw 64. The movable platen 24 moves along the axial direction of the tie rod 22 via the transverse link 48 and the toggle rod 36 by the movement of the crosshead 50. In addition, the ball screw 64 and the ball screw nut 66 constitute an advance and retreat mechanism 70 for advancing and retreating the crosshead 50.

[0028] When the movable platen 24 moves toward the fixed platen 18, the movable mold 34 abuts against the fixed mold 32, and the mold 30 is closed. In addition, when the movable platen 24 moves toward the rear platen 20, the movable mold 34 separates from the fixed mold 32, and the mold 30 is opened.

[0029] The mold closing device 14 has an ejector mechanism 72 for removing the molded product from the movable metal mold 34. The ejector mechanism 72 includes a servo motor 74, a drive pulley 76, a belt 78, a driven pulley 80, a ball screw 82, a ball screw nut 84, an ejector plate 86, an ejector pin 88, and a guide rod 90. The ball screw 82 and the guide rod 90 are arranged so that their axial directions are parallel to the axial direction of the tie rod 22.

[0030] The driving pulley 76 is provided so as to be rotatable integrally with the rotating shaft of the servo motor 74, and the driven pulley 80 is provided so as to be rotatable integrally with the ball screw 82. The belt 78 is suspended from the driving pulley 76 and the driven pulley 80, and transmits the rotational force of the driving pulley 76 to the driven pulley 80. The ball screw nut 84 is screwed with the ball screw 82, and moves along the ball screw 82 by the rotation of the ball screw 82. The ball screw nut 84 is fixed to an ejector plate 86 provided with an ejector pin 88.

[0031] The rotation of the servo motor 74 transmits the rotational force to the ball screw 82 via the driving pulley 76, the belt 78 and the driven pulley 80, thereby rotating the ball screw 82. The rotation of the ball screw 82 causes the ejector plate 86 and the ejector pin 88 to move along the guide rod 90 together with the ball screw nut 84. When the ejector pin 88 moves toward the movable platen 24, the molded product can be pushed out from the movable metal mold 34 and removed.

[0032] [1.2. Structure of injection device 16]

[0033] The injection device 16 includes a nozzle 92, a cylinder 94, a screw 96, a hopper 98, and a heater 100. The nozzle 92, the cylinder 94, and the screw 96 are referred to as an injection unit 97. The nozzle 92 is provided at the front end of the cylinder 94. The cylinder 94 is a hollow member, and the screw 96 is inserted into the cylinder 94. The cylinder 94 and the screw 96 extend in the opening and closing direction of the metal mold 30. The cylinder 94 is provided with a hopper 98. The hopper 98 is used to put a resin material into the cylinder 94. When the resin material put from the hopper 98 is in the form of pellets, the pelletized resin material is melted by the heater 100.

[0034] The injection device 16 is installed on the base 12 via the extruder base 102. The extruder base 102 is used to move the injection device 16 in the opening and closing direction of the metal mold 30. The injection device 16 has a screw drive mechanism 104 for rotating the screw 96 and an injection mechanism 105 for injecting the resin material from the nozzle 92.

[0035] The screw drive mechanism 104 includes a servo motor 106 , a drive pulley 108 , a belt 110 , and a driven pulley 112 .

[0036] The driving pulley 108 is rotatable integrally with the rotating shaft of the servo motor 106, and the driven pulley 112 is rotatable integrally with the screw 96. The belt 110 is suspended between the driving pulley 108 and the driven pulley 112, and transmits the rotational force of the driving pulley 108 to the driven pulley 112.

[0037] The rotation of the servo motor 106 transmits a rotational force to the screw 96 via the drive pulley 108, the belt 110, and the driven pulley 112, thereby rotating the screw 96. The rotation of the screw 96 conveys the resin material toward the nozzle 92 side.

[0038] The injection mechanism 105 includes a servo motor 114, a driving pulley 116, a belt 118, a driven pulley 120, a ball screw 122, a ball screw nut 124, and a push plate 126. The ball screw 122 is provided so that its axial direction is parallel to the axial direction of the screw 96.

[0039] The driving pulley 116 is configured to be rotatable integrally with the rotating shaft of the servo motor 114, and the driven pulley 120 is configured to be rotatable integrally with the ball screw 122. The belt 118 is suspended from the driving pulley 116 and the driven pulley 120, and transmits the rotational force of the driving pulley 116 to the driven pulley 120. The ball screw nut 124 is screwed with the ball screw 122, and moves along the ball screw 122 by the rotation of the ball screw 122. The ball screw nut 124 is fixed to the push plate 126.

[0040] The rotation of the servo motor 114 transmits a rotational force to the ball screw 122 via the driving pulley 116, the belt 118, and the driven pulley 120, so that the ball screw 122 rotates. The push plate 126 moves along the axial direction of the ball screw 122 together with the ball screw nut 124 due to the rotation of the ball screw 122. The movement of the push plate 126 causes the screw 96 to move along the axial direction of the ball screw 122 in the cylinder 94. The screw 96 moves toward the nozzle 92 side, so that the resin material stored at the front end side of the screw 96 in the cylinder 94 is injected from the nozzle 92.

[0041] [2. Structure of belt drive mechanism]

[0042] Figure 1 The mold opening and closing mechanism 55, ejection mechanism 72, screw drive mechanism 104 and injection mechanism 105 shown are belt drive mechanisms that transmit power from the driving shaft to the driven shaft through belts 60, 78, 110, 118. Figure 2 The belt transmission mechanism will be further described. The mold opening and closing mechanism 55 will be described as an example of the belt transmission mechanism.

[0043] The servo motor 56 on the drive shaft side is fixed to the motor bracket 130. The drive pulley 58 (drive shaft) is fixed to the end of the rotating shaft 132 of the servo motor 56. On the other hand, the ball screw 64 on the driven shaft side is supported by the retaining plate 134 so as to rotate freely. The driven pulley 62 (driven shaft) is fixed to the end of the ball screw 64. Although not shown in the figure, for example, the motor bracket 130 is connected to the retaining plate 134, and the retaining plate 134 is set on the base 12 ( Figure 1 ).

[0044] The belt 60 suspended from the driving pulley 58 and the driven pulley 62 is a meshing transmission belt. The belt teeth 140 formed on the belt 60 mesh with the driving pulley teeth 136 formed on the driving pulley 58 and the driven pulley teeth 138 formed on the driven pulley 62.

[0045] like Figure 3 to Figure 5 As shown, a part or the whole of the belt 60 of the belt transmission mechanism is covered by a cover 142 to prevent the operator from contacting the belt 60 or for sound insulation. Figure 3 As shown, the cover 142 will be suspended from the drive pulley 58 ( Figure 2 ) and the belt 60 of the driving pulley 58. In addition, it can also be as follows Figure 4 As shown, the cover 142 will be suspended from the driven pulley 62 ( Figure 2 ) and the belt 60 of the driven pulley 62. In addition, it can also be as follows Figure 5 As shown, the cover 142 covers the driving pulley 58, the driven pulley 62 and the belt 60. The cover 142 is fixed to one or both of the motor bracket 130 and the retaining plate 134, but may be fixed to other components. The cover 142 may be formed of metal, or may be formed of casting or resin.

[0046] [3. Structure for detecting abnormality of belt 60]

[0047] [3.1.Sensor 148]

[0048] like Figure 6 to Figure 8As shown in FIG. 1 , a sensor 148 is installed on the inner wall surface 144 or the outer wall surface 146 of the cover 142. The sensor 148 detects the state change caused by the abnormality of the belt 60, thereby detecting the abnormality of the belt 60 before it is damaged. For example, the sensor 148 can be a displacement meter, a thermometer, a microphone, a vibration meter, a rotary encoder 164 ( Fig. 9 ) and cameras, etc. The installation position of each sensor 148 is described below.

[0049] [3.1.1. Displacement meter]

[0050] The displacement meter is a non-contact type, for example, a laser displacement meter. The displacement meter can be installed on: the cover 142 ( Figure 6 ), the cover 142 ( Figure 7 ), and a cover 142 ( Figure 8 ). In addition, the displacement meter may be mounted on both the inner wall surface 144 and the outer wall surface 146 of the cover 142 .

[0051] [3.1.2. Thermometer]

[0052] The thermometer can be a contact type, such as a thermocouple or a thermistor, or a non-contact type, such as a radiation thermometer. The thermometer can be installed on: the cover 142 ( Figure 6 ), the cover 142 ( Figure 7 ), and a cover 142 ( Figure 8 ). In addition, the thermometer may be mounted on both the inner wall surface 144 and the outer wall surface 146 of the cover 142 .

[0053] [3.1.3. Microphone]

[0054] The microphone can be mounted on the cover 142 ( Figure 6 ), the cover 142 ( Figure 7 ), and a cover 142 ( Figure 8 ). In addition, the microphone may be mounted on both the inner wall surface 144 and the outer wall surface 146 of the cover 142.

[0055] [3.1.4. Vibration meter]

[0056] The vibrometer may be a mechanical, electromagnetic, piezoelectric, optical, or electromagnetic wave type. The vibrometer may be mounted on a cover 142 ( Figure 6 ), the cover 142 ( Figure 7 ), and a cover 142 ( Figure 8 ). In addition, the vibrator may be mounted on both the inner wall surface 144 and the outer wall surface 146 of the cover 142 .

[0057] [3.1.5. Rotary encoder 164]

[0058] The rotary encoder 164 can be mounted on the cover 142 ( Figure 7 ) and the cover 142 ( Figure 8 ) inner wall surface 144. In addition, the rotary encoder 164 is arranged on the inner wall surface 144 of the cover 142, at a position on the axis of the driven shaft, that is, the ball screw 64. In addition, as Fig. 9 As shown, the main shaft 166 (rotation shaft) of the rotary encoder 164 is arranged on the axis of the driven pulley 62 and connected to the ball screw 64. The main shaft 166 (rotation shaft) can be connected to the ball screw 64 via a coupling, a bolt, a nut, a washer, etc.

[0059] [3.1.6. Camera]

[0060] The camera is, for example, a network camera. The camera can be mounted on: the cover 142 ( Figure 6 ) inner wall surface 144, and a cover 142 ( Figure 7 ) and the cover 142 ( Figure 8 ) inner wall surface 144. It should be noted that the camera is configured to be able to capture the meshing portion of the belt 60 and the driving pulley 58, or the meshing portion of the belt 60 and the driven pulley 62.

[0061] [3.2. Reporting device 150]

[0062] like Figure 6 to Figure 8 As shown, the sensor 148 outputs the detection information to the reporting device 150 by wired communication or wireless communication. The reporting device 150 may be a controller provided in the injection molding machine 10, or may be a personal computer or a mobile device (tablet terminal, smart phone, etc.).

[0063] The reporting device 150 includes: an input unit (not shown), a computing unit 152, a storage unit 154, and a reporting unit 156. The input unit includes a device such as a touch panel or a keyboard for the operator to input information. The computing unit 152 includes a processor such as a CPU. The computing unit 152 functions as an abnormality determination unit 158 ​​by executing a program stored in the storage unit 154. The storage unit 154 includes various memories. The storage unit 154 stores various programs, and also stores, according to the type of the sensor 148: a predetermined range of detection values ​​detected by the sensor 148 when the belt 60 is normal (hereinafter referred to as a normal range). The reporting unit 156 includes either or both of a display device and a speaker device.

[0064] [3.3. Operation of the reporting device 150]

[0065] [3.3.1. Operation of the reporting device 150 using displacement timing]

[0066] Reference Figure 6 to Figure 8 The operation of the reporting device 150 using a displacement meter as the sensor 148 is described. When the belt 60 is abnormal such as worn, stretched, or cracked, the vibration of the belt 60 increases. As a result, the displacement of the belt 60 increases. In addition, the displacement of the cover 142 that receives the vibration of the belt 60 via the motor bracket 130 or the retaining plate 134 also increases. In the case where the displacement meter is mounted on the inner wall surface 144 of the cover 142, the displacement of the belt 60 relative to the cover 142 is detected by irradiating a laser beam to the belt 60. In the case where the displacement meter is mounted on the outer wall surface 146 of the cover 142, the displacement of the cover 142 relative to the reference portion 160 provided on the outside of the cover 142 is detected by irradiating a laser beam to the reference portion 160.

[0067] The storage unit 154 stores the range of the displacement of the belt 60 when there is no abnormality in the belt 60, or the range of the displacement of the cover 142 when there is no abnormality in the belt 60, as a normal range. The abnormality determination unit 158 ​​compares the displacement of the belt 60 detected by the displacement meter with the upper limit value of the displacement of the belt 60 stored in the storage unit 154. Alternatively, the abnormality determination unit 158 ​​compares the displacement of the cover 142 detected by the displacement meter with the upper limit value of the displacement of the cover 142 stored in the storage unit 154. When the displacement detected by the displacement meter exceeds the upper limit value, the abnormality determination unit 158 ​​determines that an abnormality has occurred in the belt 60, and outputs a report instruction to the reporting unit 156. The reporting unit 156 reports to the operator that an abnormality has occurred in the belt 60 according to the report instruction.

[0068] [3.3.2. Operation of the reporting device 150 using the thermometer]

[0069] Reference Figure 6 to Figure 8The operation of the reporting device 150 in which a thermometer is used as the sensor 148 is described. When the belt 60 is abnormal such as worn, stretched, or cracked, the vibration of the belt 60 increases. As a result, the vibration of each part connected to the belt 60 increases, and the heat generated by the vibration increases. Therefore, the temperature of the belt 60, the temperature of the cover 142, and the temperature of the ambient air inside the cover 142 increase. The non-contact thermometer mounted on the inner wall surface 144 of the cover 142 detects the temperature of the belt 60. The contact thermometer mounted on the inner wall surface 144 of the cover 142 detects the temperature of the inner wall surface 144 of the cover 142, or the temperature of the ambient air inside the cover 142. The contact thermometer mounted on the outer wall surface 146 of the cover 142 detects the temperature of the outer wall surface 146 of the cover 142.

[0070] The storage unit 154 stores the temperature range of the belt 60 when there is no abnormality in the belt 60, the temperature range of the cover 142 when there is no abnormality in the belt 60, or the temperature range of the atmosphere inside the cover 142 when there is no abnormality in the belt 60 as a normal range. The abnormality determination unit 158 ​​compares the temperature of the belt 60 detected by the thermometer with the upper limit value of the temperature of the belt 60 stored in the storage unit 154. Alternatively, the abnormality determination unit 158 ​​compares the temperature of the cover 142 detected by the thermometer with the upper limit value of the temperature of the cover 142 stored in the storage unit 154. Alternatively, the abnormality determination unit 158 ​​compares the temperature of the atmosphere inside the cover 142 detected by the thermometer with the upper limit value of the temperature of the atmosphere inside the cover 142 stored in the storage unit 154. When the temperature detected by the thermometer exceeds the upper limit value, the abnormality determination unit 158 ​​determines that an abnormality has occurred in the belt 60, and outputs a report instruction to the reporting unit 156. The reporting unit 156 reports to the operator that an abnormality has occurred in the belt 60 according to the report instruction.

[0071] [3.3.3. Operation of the reporting device 150 when using a microphone]

[0072] Reference Figure 6 to Figure 8 The operation of the reporting device 150 when a microphone is used as the sensor 148 is described. When the belt 60 is worn, stretched, cracked, or otherwise abnormal, the vibration of the belt 60 increases. As a result, the sound pressure level of the sound emitted from the belt 60, the driving pulley 58, and the driven pulley 62 increases. The microphone detects the sound pressure level of the sound emitted around the cover 142.

[0073] The storage unit 154 stores the range of the sound pressure level of the sound emitted around the cover 142 when there is no abnormality in the belt 60 as a normal range. The abnormality determination unit 158 ​​converts the information of the sound around the cover 142 output from the microphone into a sound pressure level, and compares it with the upper limit value of the normal range stored in the storage unit 154. When the converted sound pressure level exceeds the upper limit value, the abnormality determination unit 158 ​​determines that the belt 60 has an abnormality, and outputs a report instruction to the reporting unit 156. The reporting unit 156 reports to the operator that the belt 60 has an abnormality according to the report instruction.

[0074] [3.3.4. Operation of the reporting device 150 using vibration timing]

[0075] Reference Figure 6 to Figure 8 The operation of the reporting device 150 using a vibration meter as the sensor 148 is described. When the belt 60 is worn, stretched, cracked, or otherwise abnormal, the vibration of the belt 60 changes. As a result, the vibration of the cover 142 receiving the vibration of the belt 60 via the motor bracket 130 or the retaining plate 134 also changes. The vibration meter detects the vibration of the cover 142.

[0076] The storage unit 154 stores in advance the range of the vibration amount (e.g., frequency or amplitude) of the cover 142 when there is no abnormality in the belt 60 as a normal range. The abnormality determination unit 158 ​​compares the vibration amount detected by the vibration meter with the upper limit value of the normal range stored in the storage unit 154. When the vibration amount detected by the vibration meter exceeds the upper limit value, the abnormality determination unit 158 ​​determines that an abnormality has occurred in the belt 60, and outputs a report instruction to the reporting unit 156. The reporting unit 156 reports to the operator that an abnormality has occurred in the belt 60 according to the report instruction.

[0077] [3.3.5. Operation of the reporting device 150 when the rotary encoder 164 is used]

[0078] Reference Figure 7 to Figure 9 The operation of the reporting device 150 when the rotary encoder 164 is used as the sensor 148 is described. When the belt 60 is abnormal such as worn, stretched, cracked, etc., the tension of the belt 60 will decrease. As a result, the belt 60 will float on the drive shaft side and the driven shaft side, and the driving force transmitted from the drive pulley 58 to the driven pulley 62 may be interrupted momentarily. Therefore, the phase difference (speed difference) of the driven pulley 62 relative to the drive pulley 58 increases. The rotary encoder 164 detects the rotational position of the ball screw 64 and the driven pulley 62.

[0079] On the other hand, the servo motor 56 has a detector that detects the rotation position of the rotation shaft 132 of the servo motor 56 . This detector is referred to as a motor-side encoder 162 . The motor-side encoder 162 detects the rotation positions of the rotation shaft 132 of the servo motor 56 and the drive pulley 58 .

[0080] The storage unit 154 stores the range of the phase difference (speed difference) between the driven shaft and the driving shaft when there is no abnormality in the belt 60 as a normal range. The abnormality determination unit 158 ​​obtains the phase difference between the driven shaft and the driving shaft based on the information output from the motor-side encoder 162 and the information output from the rotary encoder 164 as the sensor 148, and compares it with the upper limit value of the normal range stored in the storage unit 154. When the obtained phase difference exceeds the upper limit value, the abnormality determination unit 158 ​​determines that an abnormality has occurred in the belt 60, and outputs a report instruction to the reporting unit 156. The reporting unit 156 reports to the operator that an abnormality has occurred in the belt 60 according to the report instruction.

[0081] [3.3.6. Operation of the reporting device 150 when using a camera]

[0082] Reference Figure 6 to Figure 8 The operation of the reporting device 150 when a camera is used as the sensor 148 will be described. When the belt 60 is abnormal such as worn, stretched, or cracked, the tension of the belt 60 decreases. As a result, the belt 60 floats relative to the drive pulley 58 or the belt 60 floats relative to the driven pulley 62. The camera captures the floating state of the belt 60 at the meshing position between the drive pulley 58 and the belt 60 or the floating state of the belt 60 at the meshing position between the driven pulley 62 and the belt 60.

[0083] The information output from the camera can be displayed in real time on a display included in the reporting unit 156 .

[0084] [4. Other embodiments]

[0085] The mold opening and closing mechanism 55 as an example of a belt transmission mechanism has been described in [2] and [3] above. However, Figure 1 The ejection mechanism 72, the screw drive mechanism 104 and the injection mechanism 105 shown are also belt drive mechanisms. Therefore, the ejection mechanism 72, the screw drive mechanism 104 and the injection mechanism 105 can also be provided with: Figure 3 to Figure 8 The cover 142 shown, Figure 6 to Figure 8 Sensor 148 and reporting device 150 are shown.

[0086] The belt 60 may be a friction drive belt instead of a meshing drive belt.

[0087] [5. Inventions derived from embodiments]

[0088] The invention obtained from the above-mentioned embodiments will be described below.

[0089] The solution of the present invention is an injection molding machine 10, which has a belt transmission mechanism (mold opening and closing mechanism 55, ejection mechanism 72, screw drive mechanism 104, injection mechanism 105) for transmitting power from a driving shaft (driving pulley 58, 76, 108, 116) to a driven shaft (driven pulley 62, 80, 112, 120) through a belt 60, 78, 110, 118, and has: a cover 142 that covers a part or the whole of the above-mentioned belts 60, 78, 110, 118, and a sensor 148 installed on the above-mentioned cover 142 and detecting abnormalities of the above-mentioned belts 60, 78, 110, 118.

[0090] According to the above configuration, the sensor 148 is used to detect the state change caused by the abnormality of the belts 60, 78, 110, 118, so that the abnormality of the belts 60, 78, 110, 118 can be found at an early stage. In addition, according to the above configuration, the sensor 148 is attached to the cover 142 covering the belts 60, 78, 110, 118, so the cover 142 can be used as a part of the detection device for detecting the abnormality of the belts 60, 78, 110, 118. In addition, according to the above configuration, the injection molding machine 10 can be prevented from being enlarged.

[0091] In the scheme of the present invention, the sensor 148 may include one of a displacement meter, a thermometer, a microphone, and a vibration meter, wherein the displacement meter detects the displacement of the cover 142 or the displacement of the belts 60, 78, 110, 118, the thermometer detects the temperature, the microphone detects the sound pressure level, and the vibration meter detects the vibration of the cover 142.

[0092] In the scheme of the present invention, the sensor 148 may be a rotary encoder 164 for detecting the rotational position of the driven shaft (driven pulley 62, 80, 112, 120), and the rotation axis (main shaft 166) of the rotary encoder 164 is arranged on the same straight line as the axis of the driven shaft.

[0093] In an aspect of the present invention, the sensor 148 may be a camera that takes an image of the belts 60 , 78 , 110 , 118 .

[0094] In an aspect of the present invention, the injection molding machine 10 may include a reporting unit 156 for reporting the detection result of the sensor 148 .

[0095] According to the above configuration, the operator can recognize whether the belts 60 , 78 , 110 , 118 have abnormalities without directly monitoring the belts 60 , 78 , 110 , 118 .

[0096] In the scheme of the present invention, it may be provided with: an abnormality determination unit 158, which determines that an abnormality has occurred in the belts 60, 78, 110, 118 when the detection value of the sensor 148 is outside a predetermined range; and a reporting unit 156, which reports when an abnormality of the belts 60, 78, 110, 118 is detected by the abnormality determination unit 158.

[0097] According to the above configuration, the operator can recognize that an abnormality has occurred in the belts 60 , 78 , 110 , 118 .

[0098] In the scheme of the present invention, it may be that it has: a servo motor 56, 74, 106, 114, which rotates the above-mentioned drive shaft (drive pulley 58, 76, 108, 116) and detects the rotation position of the above-mentioned drive shaft; an abnormality judgment unit 158, which calculates the phase difference between the above-mentioned drive shaft and the above-mentioned driven shaft based on the rotation position of the above-mentioned drive shaft detected by the above-mentioned servo motor 56, 74, 106, 114 and the rotation position of the above-mentioned driven shaft (driven pulley 62, 80, 112, 120) detected by the above-mentioned rotary encoder 164, and when the above-mentioned phase difference is outside the predetermined range, it is judged that the above-mentioned belt 60, 78, 110, 118 has an abnormality; and a reporting unit 156, which reports when the above-mentioned belt 60, 78, 110, 118 is detected to have an abnormality by the above-mentioned abnormality judgment unit 158.

[0099] According to the above configuration, the operator can recognize that an abnormality has occurred in the belts 60 , 78 , 110 , 118 .

[0100] In the aspect of the present invention, the belt transmission mechanism (mold opening and closing mechanism 55) may open and close the metal mold 30 by advancing and retracting the cross head 50 of the toggle lever 36 through the rotation of the driven shaft (driven pulley 62).

[0101] In the scheme of the present invention, the belt transmission mechanism (ejector mechanism 72 ) may advance and retract the ejector pin 88 by the rotation of the driven shaft (driven pulley 80 ), and the ejector pin 88 may push the molded product out of the movable metal mold 34 .

[0102] In the aspect of the present invention, the belt transmission mechanism (screw driving mechanism 104 ) may rotate the screw 96 of the injection unit 97 by the rotation of the driven shaft (driven pulley 112 ), thereby supplying the resin material to the cylinder 94 .

[0103] In the solution of the present invention, the belt transmission mechanism (injection mechanism 105 ) moves the screw 96 of the injection part 97 forward and backward by rotating the driven shaft (driven pulley 120 ), thereby injecting the resin material from the cylinder 94 into the metal mold 30 .

[0104] In the solution of the present invention, the belts 60, 78, 110, 118 may be meshing transmission belts.

[0105] In addition, the injection molding machine of the present invention is not limited to the above-mentioned embodiment, and various structures can be adopted without departing from the gist of the present invention.

Claims

1. An injection molding machine having a belt transmission mechanism for transmitting power from a driving shaft to a driven shaft through a belt, The above-mentioned injection molding machine is characterized in that it has: a cover covering a part or the whole of the belt; and A sensor is mounted on the inner wall of the cover to detect abnormalities of the belt. The sensor is a rotary encoder for detecting the rotational position of the driven shaft. The rotating shaft of the rotary encoder and the axis line of the driven shaft are arranged on the same straight line.

2. The injection molding machine according to claim 1, characterized in that A reporting unit is provided, and the reporting unit reports the detection result of the above-mentioned sensor.

3. The injection molding machine according to claim 1, characterized in that have: a servo motor that rotates the drive shaft and detects a rotational position of the drive shaft; an abnormality determination unit that determines a phase difference between the drive shaft and the driven shaft based on the rotational position of the drive shaft detected by the servo motor and the rotational position of the driven shaft detected by the rotary encoder, and determines that an abnormality has occurred in the belt when the phase difference is outside a predetermined range; and A reporting unit reports when an abnormality of the belt is detected by the abnormality determination unit.

4. The injection molding machine according to any one of claims 1 to 3, characterized in that The belt transmission mechanism utilizes the rotation of the driven shaft to move the cross head of the toggle lever forward and backward to open and close the metal mold.

5. The injection molding machine according to any one of claims 1 to 3, characterized in that The belt transmission mechanism uses the rotation of the driven shaft to advance and retreat the ejector pin, which pushes the molded product out of the movable metal mold.

6. The injection molding machine according to any one of claims 1 to 3, characterized in that The belt transmission mechanism rotates the screw of the injection unit by utilizing the rotation of the driven shaft, thereby supplying the resin material to the cylinder.

7. The injection molding machine according to any one of claims 1 to 3, characterized in that The belt transmission mechanism uses the rotation of the driven shaft to advance and retreat the screw of the injection part, thereby injecting the resin material from the cylinder into the metal mold.

8. The injection molding machine according to any one of claims 1 to 3, characterized in that The above-mentioned belt is a meshing transmission belt.

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