Lubrication unit and extruder
A unified lubrication unit for multiple targets in an extruder simplifies the configuration and reduces components by supplying lubricating oil to multiple gears simultaneously, addressing the complexity of multiple oil supply units.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- THE JAPAN STEEL WORKS LTD
- Filing Date
- 2022-10-13
- Publication Date
- 2026-05-26
AI Technical Summary
Existing systems require multiple oil supply units for each lubrication target, leading to a complex configuration and increased number of components.
A single lubrication unit with a common oil passage, pumps, tanks, and control mechanisms that can simultaneously supply lubricating oil to multiple targets, including reduction gears in an extruder, reducing the need for separate units.
This solution allows for efficient and simplified lubrication of multiple targets using a single unit, minimizing components and ensuring consistent lubrication without over-supply or under-supply.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to an oil supply unit and an extruder.
Background Art
[0002] In order to smoothly operate the elements constituting the power transmission system and the elements to which power is transmitted through the power transmission system, it is necessary to supply lubricating oil to those elements. Patent Document 1 describes an extruder provided with a speed reducer that transmits the rotational driving force output from a motor to a screw. The speed reducer provided in the extruder described in Patent Document 1 is an example of the above-described elements (lubrication targets).
[0003] In order to continuously supply lubricating oil to the lubrication targets, an oil supply unit in which a pump, a tank, a valve, etc. are integrated may be configured. And when there are a plurality of lubrication targets, an oil supply unit may be prepared for each lubrication target.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0005] Reduction in the number of oil supply units with respect to the number of lubrication targets and simplification of the configuration of the oil supply unit are desired.
[0006] Other problems and novel features will become apparent from the description of this specification and the accompanying drawings.
Means for Solving the Problems
[0007] A lubrication unit according to one embodiment includes a first tank for storing lubricating oil, a common oil passage connected to the first tank, a first pump, an oil filter, and an oil cooler provided in the common oil passage, a first branch oil passage connecting the common oil passage to a first lubrication target, a second branch oil passage connecting the common oil passage to a second lubrication target, a first return oil passage for returning lubricating oil from the first lubrication target to the first tank, a second return oil passage for returning lubricating oil from the second lubrication target to the first tank, a second tank and a second pump provided in the second return oil passage, a replenishment oil passage connecting the second return oil passage to the second tank, a second valve provided in the replenishment oil passage, a monitoring unit for monitoring the oil level of lubricating oil stored in the second tank, and a control unit for controlling the second valve based on the monitoring results of the monitoring unit. When the oil level of the lubricating oil in the second tank is within a specified range, the second valve is closed, and when the oil level of the lubricating oil in the second tank falls below the specified range, the second valve is opened. [Effects of the Invention]
[0008] According to one embodiment, a single lubrication unit capable of simultaneously supplying lubricating oil to multiple lubrication targets is realized. [Brief explanation of the drawing]
[0009] [Figure 1] This is a schematic diagram illustrating a granulation apparatus. [Figure 2] This is a schematic diagram illustrating the lubrication unit of an extruder. [Figure 3] This is an explanatory diagram showing the flow of lubricating oil when the valve is closed. [Figure 4] This is an explanatory diagram showing the flow of lubricating oil when the valve is open. [Figure 5] This is a flowchart illustrating an example of the control process for a fueling unit. [Figure 6] This is a schematic diagram illustrating other extruders. [Modes for carrying out the invention]
[0010] The following describes one embodiment in detail with reference to the drawings. In all drawings used to describe the embodiment, elements and components having the same or substantially the same function are denoted by the same reference numerals. Furthermore, elements and components that have already been described will not be described again in principle.
[0011] <Overall Structure> Figure 1 is a schematic diagram illustrating a granulation apparatus 1A according to one embodiment. The granulation apparatus 1A shown in Figure 1 includes an extruder 10 and a granulator 30.
[0012] The extruder 10 comprises an extruder body 10a that heats and kneads the supplied resin raw material to produce molten resin, a gear pump 20 that transports the molten resin to a granulator 30, and a lubrication unit 40 that simultaneously supplies lubricating oil to multiple lubrication targets.
[0013] The granulator 30 includes a die head 31 that forms the molten resin extruded from the extruder 10 into strands (strings, ropes), and a cutter 32 that cuts the molten resin formed into strands.
[0014] The lubrication target supplied by the lubrication unit 40 in this embodiment is the two reduction gears of the extruder 10. More specifically, one of the lubrication targets is the reduction gear of the extruder body 10a, and the other is the reduction gear of the gear pump 20. However, the lubrication targets to which the lubrication unit 40 simultaneously supplies lubrication oil are not limited to the two reduction gears mentioned above.
[0015] <Extruder body> The extruder body 10a includes a main motor 11, a reduction gear 12, and a kneading unit 13. The main motor 11 is the drive source for the kneading unit 13. The rotational driving force output from the main motor 11 is input to the reduction gear 12. The reduction gear 12 reduces the rotational speed of the input rotational driving force, increases the rotational force, and outputs it to the kneading unit 13. The kneading unit 13 is equipped with two screws 14a and 14b that are driven by the input rotational driving force.
[0016] The screws 14a and 14b provided in the kneading processing unit 13 convey the molten resin while kneading it. The screws 14a and 14b are provided inside a cylinder (barrel) 15 to which a resin raw material is supplied and are rotatably supported. The resin raw material is supplied into the cylinder 15 through a raw material hopper 16 provided at one end in the longitudinal direction of the cylinder 15.
[0017] As described above, the two screws 14a and 14b are rotationally driven by the main motor 11. The screws 14a and 14b are arranged parallel to each other and are rotationally driven simultaneously. That is, the extruder 10 includes two screws 14a and 14b that are parallel to each other and are simultaneously driven, and is generally called a "twin-screw extruder". However, the extruder 10 is not limited to a twin-screw type and may be a single-screw type.
[0018] In the following description, the two screws 14a and 14b may be collectively referred to as "screw 14".
[0019] <Gear pump> The gear pump 20 transfers (pressure-feeds) the molten resin sent out from the extruder body 10a (the cylinder 15 of the kneading processing unit 13) to the granulator 30. The gear pump 20 has a motor 21, a speed reducer 22, and a pair of gears 23. The gears 23 are provided in a housing 24 arranged on a conveyance path extending at a right angle to the cylinder 15 and are rotatably supported.
[0020] There is also an embodiment in which the housing 24 is arranged on a conveyance path parallel to the cylinder 15. Viewed from another perspective, there is also an embodiment in which the conveyance path on which the housing 24 is arranged extends linearly from the cylinder 15.
[0021] The rotational driving force output from the motor 21 is input to the reduction gear 22. The reduction gear 22 reduces the rotational speed of the input rotational driving force, increases the rotational force, and outputs it to the gear 23. The gear 23 rotates within the housing 24 due to the input rotational driving force, pushing the molten resin that has been fed into the housing 24 toward the granulator 30.
[0022] <Pelletizer> The die head 31 of the granulator 30 includes a die holder, die plate, die plate cover, etc., and is equipped with multiple nozzles from which molten resin is extruded. The molten resin, which is fed into the granulator 30 by the gear pump 20, is extruded from each nozzle of the die head 31 and formed into strands (strings, ropes).
[0023] The cutter 32 of the granulator 30 continuously cuts the strand-shaped molten resin extruded from the die head 31. The cutter 32 is located on the flow path of pellet transport water circulating within the manufacturing system, including the granulator 1A, and is equipped with a cutter head driven by a cutter motor 33. The molten resin is extruded from the die head 31 into the pellet transport water and cut to a predetermined length by the cutter head. As a result, resin pellets of a predetermined size (length and thickness) are produced.
[0024] The above method of cutting molten resin in the pellet transport water (underwater) is sometimes called "underwater cutting." Depending on the properties of the resin raw material (especially the melting point), resin pellets may be manufactured without circulating the pellet transport water. In this case, the molten resin extruded from the die head 31 is extruded into the air and cut. This method of cutting molten resin in the air is sometimes called "hot cutting."
[0025] <Fueling Unit Configuration> Figure 2 is a schematic diagram illustrating the lubrication unit 40 provided in the extruder 10 according to this embodiment. The lubrication unit 40 simultaneously supplies lubricating oil to the reduction gear 12 provided in the extruder body 10a and the reduction gear 22 provided in the gear pump 20.
[0026] The refueling unit 40 has two tanks 51 and 63, and oil passages and pumps for circulating lubricating oil between these tanks 51 and 63 and the reduction gears 12 and 22.
[0027] More specifically, the refueling unit 40 has a common oil passage 52 connected to the tank 51. A pump 53a, an oil cooler 54, an oil filter 56, and an oil filter 62 are provided on the common oil passage 52. The common oil passage 52 is divided into a branch oil passage 55 connected to the reduction gear 12 and a branch oil passage 61 connected to the reduction gear 22, downstream of the oil filters 56 and 62.
[0028] A valve 57 is provided in the branch oil passage 55 connected to the reduction gear 12. Valve 57 is a manual valve. The opening of valve 57 is set so that a predetermined amount of lubricating oil is supplied to the reduction gear 12 and the reduction gear 22, and can be adjusted as needed.
[0029] The lubrication unit 40 further includes a return oil passage 58 that returns the lubricating oil supplied to the reduction gear 12 through the common oil passage 52 and the branch oil passage 55 back to the tank 51, and a return oil passage 65 that returns the lubricating oil supplied to the reduction gear 22 through the common oil passage 52 and the branch oil passage 61 back to the tank 51.
[0030] Tank 63 is located on the return oil passage 65, and pump 64a is located on the return oil passage 65 downstream of tank 63. However, the lubricating oil supplied to the reduction gear 22 flows into tank 63 by gravity (its own weight). Therefore, the section of the return oil passage 65 upstream of tank 63 is sometimes called the "connecting passage 65a" to distinguish it from other sections. Also, unless otherwise specified, in the following explanation, "return oil passage 65" refers to the section downstream of tank 63 (the section other than the connecting passage 65a).
[0031] The refueling unit 40 further includes a replenishment oil passage 70 connecting the return oil passage 65 and the tank 63. In addition, the refueling unit 40 includes a valve 71 provided in the replenishment oil passage 70, a control unit 72 that controls the valve 71, and a monitoring unit 73 that monitors the oil level of the lubricating oil stored in the tank 63. In the following description, the control unit 72 may be referred to as the "valve control unit 72".
[0032] Valve 71 is an electromagnetic valve. The control unit 72 controls valve 71 based on the monitoring results of the monitoring unit 73. The monitoring unit 73 is a level transmitter that measures the oil level without contacting the lubricating oil in tank 63. More specifically, the monitoring unit 73 measures the oil level based on the time it takes for ultrasonic waves or electromagnetic waves to be emitted towards the oil surface and then return.
[0033] However, the monitoring unit 73 is not limited to non-contact types such as level transmitters, but can be replaced with contact types such as float type or pressure type.
[0034] The refueling unit 40 further includes a reserve oil passage 59 connecting the tank 51 and the common oil passage 52, and a discharge oil passage 66 connecting the tank 63 and the return oil passage 65. A pump 53b is provided in the reserve oil passage 59, and a pump 64b is provided in the discharge oil passage 66.
[0035] One end of the backup oil passage 59 merges with the common oil passage 52 between pump 53a and oil cooler 54. Therefore, regardless of whether pump 53a or pump 53b is operated, the lubricating oil in tank 51 is sent to the common oil passage 52, passes through oil cooler 54, and flows downstream. Pump 53b is operated in place of pump 53a if pump 53a fails to operate for any reason. In other words, pump 53b is a backup pump.
[0036] Of the components of the refueling unit 40, at least the tank 51, common oil passage 52, pump 53a, pump 53b, oil cooler 54, oil filter 56, valve 57, reserve oil passage 59, oil filter 62, tank 63, pump 64a, pump 64b, discharge oil passage 66, replenishment oil passage 70, valve 71, valve control unit 72, and monitoring unit 73 are mounted on a common base member (for example, a skid plate). In addition, the branch oil passage 55, return oil passage 58, branch oil passage 61, and part of the return oil passage 65 that span the refueling unit 40 and the reduction gears 12 and 22 are also mounted on the above base member.
[0037] In other words, the lubrication unit 40 is a single lubrication unit capable of simultaneously supplying lubricating oil to two or more lubrication targets (speed reducers 12, 22). From another perspective, in an extruder 10 equipped with the lubrication unit 40, lubricating oil can be supplied to speed reducers 12 and 22 simultaneously without the need to provide separate lubrication units for speed reducer 12 and speed reducer 22.
[0038] All or part of the above-mentioned oil passages are formed by piping materials such as metal pipes, resin pipes, and resin hoses. However, it is not necessary for all oil passages to be formed by the same piping materials. In other words, the above-mentioned oil passages can be formed by multiple piping materials of different types.
[0039] The above-mentioned pump is an electric pump and is controlled by the control unit 80. In the following description, the control unit 80 may be referred to as the "pump control unit 80". The pump control unit 80 controls the operation of at least the pump 64b based on the monitoring results of the monitoring unit 73.
[0040] In some embodiments, an integrated control unit is provided that comprehensively controls the entire lubrication unit 40, including the valve control unit 72 and the pump control unit 80, or an integrated control unit is provided that comprehensively controls the entire extruder 10, including the lubrication unit 40. In such embodiments, the valve control unit 72 controls the valve 71 under the control of the integrated control unit, and the pump control unit 80 controls the pump 64b and other pumps under the control of the integrated control unit.
[0041] <Flow of lubricating oil> In the refueling unit 40, the flow of lubricating oil differs depending on whether the valve 71 on the replenishment oil passage 70 is closed or open. As previously mentioned, the valve 57 on the branch oil passage 55 is always open at a preset opening.
[0042] Figure 3 is an explanatory diagram showing the flow of lubricating oil when valve 71 is closed. Figure 4 is an explanatory diagram showing the flow of lubricating oil when valve 71 is open.
[0043] Refer to Figure 3. When valve 57 is open and valve 71 is closed, pumps 53a and 64a are operated, and lubricating oil is supplied from tank 51 to reduction gear 12 through common oil passage 52 and branch oil passage 55. At the same time, lubricating oil is supplied from tank 51 to reduction gear 22 through common oil passage 52 and branch oil passage 61.
[0044] The lubricating oil supplied to the reduction gear 12 lubricates the bearings, gears, etc. inside the reduction gear 12, and then returns to the tank 51 through the return oil passage 58.
[0045] Meanwhile, the lubricating oil supplied to the reduction gear 22 lubricates the bearings, gears, etc., inside the reduction gear 22, and then returns to the tank 51 through the return oil passage 65. More specifically, the lubricating oil that has passed through the reduction gear 22 flows into the tank 63 through the return oil passage 65 (connecting passage 65a) and is temporarily stored there. After that, the lubricating oil is pumped out of the tank 63 by the pump 64a and sent to the return oil passage 65. In other words, the lubricating oil supplied to the reduction gear 22 returns to the tank 51 via the tank 63 and the pump 64a.
[0046] Refer to Figure 4. When valves 57 and 71 are open and pumps 53a and 64a are operating, the lubricating oil supplied to the reduction gear 12 returns to tank 51 via the same path as described above.
[0047] On the other hand, at least a portion of the lubricating oil supplied to the reduction gear 22 does not return to tank 51 but returns to tank 63. More specifically, when valve 71 on the replenishment oil passage 70 connecting the return oil passage 65 and tank 63 is open, the lubricating oil pumped out of tank 63 by pump 64a and sent to the return oil passage 65 returns to tank 63 through the replenishment oil passage 70.
[0048] <Fueling Unit Operation> Figure 5 is a flowchart showing an example of the control process of the refueling unit 40. When the control process starts, step S1 is performed. In step S1, the valve control unit 72 determines the height of the lubricating oil level in the tank 63. More specifically, the valve control unit 72 determines, based on the monitoring results of the monitoring unit 73, whether the height of the lubricating oil level in the tank 63 is between the lower limit and upper limit of a specified range.
[0049] If it is determined in step S1 that the oil level of the lubricating oil is below a specified range, the process proceeds to step S2. More specifically, if the valve control unit 72 determines that the oil level of the lubricating oil is below the lower limit of the specified range, the process proceeds to step S2. In step S2, the valve 71 is opened under the control of the valve control unit 72. Specifically, power is supplied to the solenoid coil of the valve 71, and the valve 71 is opened.
[0050] Next, the process moves to step S3. In step S3, the valve control unit 72 determines the oil level of the lubricating oil in the tank 63 again. More specifically, the valve control unit 72 determines, based on the monitoring results from the monitoring unit 73, whether the oil level of the lubricating oil in the tank 63 has returned to within the specified range. In other words, the valve control unit 72 determines whether the oil level of the lubricating oil in the tank 63 is between the lower and upper limits of the specified range.
[0051] When valve 71 is opened in step S2, the lubricating oil flow shown in Figure 4 occurs, causing the oil level in tank 63 to gradually rise. In other words, the amount of lubricating oil in tank 63 gradually increases.
[0052] If it is determined in step S3 that the oil level of the lubricating oil in tank 63 has returned to within the specified range, the process proceeds to step S4.
[0053] In step S4, the valve 71 is closed by the control of the valve control unit 72. Specifically, the power supply to the solenoid coil of the valve 71 is cut off, and the valve 71 is closed.
[0054] On the other hand, if it is determined in step S1 that the oil level of the lubricating oil exceeds the upper limit of the specified range, the process proceeds to step S5 instead of step S2. In step S5, the pump 64b is operated under the control of the pump control unit 80. Also, since step S2 is not performed, the valve 71 is not opened and remains closed.
[0055] When pump 64b is activated in step S5, in addition to the flow of lubricating oil shown in Figure 3, a flow of lubricating oil is generated from tank 63 through the discharge oil passage 66 to the return oil passage 65. In other words, lubricating oil is pumped out of tank 63 by the two pumps 64a and 64b. Also, since valve 71 is closed, no lubricating oil returns to tank 63. As a result, the oil level of the lubricating oil in tank 63 gradually decreases. In other words, the amount of lubricating oil in tank 63 gradually decreases.
[0056] Pump 64b is manually stopped after the oil level of the lubricating oil in tank 63 returns to within the specified range. However, in some embodiments, pump 64b is automatically stopped when the oil level of the lubricating oil in tank 63 returns to within the specified range. After pump 64b is stopped, the opening of valve 57 is adjusted as needed.
[0057] One of the reasons why the oil level of the lubricating oil is determined to be below the lower limit of the specified range in step S1 is clogging of the oil filter 62. When the oil filter 62 becomes clogged, the amount of lubricating oil supplied to the reduction gear 22 through the branch oil passage 61 decreases. As a result, the amount of lubricating oil that passes through the reduction gear 22 and flows into the tank 63 also decreases. Consequently, the amount of lubricating oil in the tank 63 gradually decreases. Another way to look at it is that the balance between the amount of oil stored in tank 51 and the amount of oil stored in tank 63 is disrupted.
[0058] In this embodiment, if the amount of oil stored in tank 63 falls below a specified range due to any reason, including the above-mentioned cause, lubricating oil is automatically replenished in tank 63. Therefore, the balance between the amount of oil stored in tank 51 and the amount of oil stored in tank 63 is not disrupted.
[0059] The present invention has been described in detail above based on embodiments and examples, but the present invention is not limited to the above embodiments or examples, and can be modified in various ways without departing from its spirit. For example, the multiple lubrication targets to which the lubrication unit simultaneously supplies lubricating oil are not limited to the reduction gear of the extruder body and the reduction gear of the gear pump.
[0060] Figure 6 is a schematic diagram illustrating an extruder 10 according to another embodiment. The extruder 10 shown in Figure 6 comprises two or more extruder bodies and an oil supply unit that simultaneously supplies lubricating oil to the extruder bodies. More specifically, it comprises two extruder bodies 10A and 10B and an oil supply unit 40 that simultaneously supplies lubricating oil to the extruder bodies 10A and 10B.
[0061] The extruder bodies 10A and 10B have the same or substantially the same configuration as the extruder 10a in the above embodiment. However, the extruder bodies 10A and 10B may be installed in parallel or in series. For example, the extruder body 10A may constitute the first stage extrusion mechanism, and the extruder body 10B may constitute the second stage extrusion mechanism.
[0062] The lubrication unit 40 supplies lubricating oil to the components to be lubricated in each of the extruder bodies 10A and 10B. For example, the lubrication unit 40 simultaneously supplies lubricating oil to the main motor reducers in each of the extruder bodies 10A and 10B. Alternatively, the lubrication unit 40 simultaneously supplies lubricating oil to other reducers in each of the extruder bodies 10A and 10B.
[0063] The granulator 30 in the above embodiment can be replaced with a film forming machine. In this case, the film forming apparatus is composed of the extruder 10 and the film forming machine.
[0064] The valve 71 in the above embodiment is not limited to an electromagnetic valve. Also, the valve 57 is not limited to a manual valve. The position of the oil cooler 54 can be changed as appropriate. However, in the above embodiment in which the oil cooler 54 is located on the common oil passage 52, the lubricating oil circulating within the unit is cooled by a single oil cooler 54. From another perspective, the number of oil coolers required is reduced. From yet another perspective, the number of parts requiring maintenance is reduced.
[0065] The casing to be lubricated may also be used as the tank for the lubrication unit. For example, the casing of the speed reducer 12 in the above embodiment may also serve as the tank 51, and the casing of the speed reducer 22 may also serve as the tank 63. [Explanation of symbols]
[0066] 1A...Granulator, 10...Extruder, 10a, 10A, 10B...Extruder body, 11...Main motor, 12...Reduction gear, 13...Kneading section, 14, 14a, 14b...Screw, 15...Cylinder (barrel), 16...Raw material hopper, 20...Gear pump, 21...Motor, 22...Reduction gear, 23...Gears, 24...Housing, 30...Granulator, 31...Die head, 32...Cutter, 33...Cutter motor, 40...Oil supply unit, 51...Tank, 5 2…Common oil passage, 53a, 53b…Pump, 54…Oil cooler, 55…Branch oil passage, 56…Oil filter, 57…Valve, 58…Return oil passage, 59…Spare oil passage, 61…Branch oil passage, 62…Oil filter, 63…Tank, 64a, 64b…Pump, 65…Return oil passage, 65a…Connecting passage, 66…Discharge oil passage, 70…Refill oil passage, 71…Valve, 72…Control unit (Valve control unit), 73…Monitoring unit, 80…Control unit (Pump control unit)
Claims
1. A lubrication unit that simultaneously supplies lubricating oil to multiple lubrication targets, A first tank for storing lubricating oil, A common oil passage connected to the first tank, The first pump, oil filter, and oil cooler are provided in the aforementioned common oil passage. A first branch oil passage connects the common oil passage and the first lubrication target, A second branch oil passage connects the aforementioned common oil passage to the second lubrication target, A first return oil passage for returning lubricating oil from the first lubrication target to the first tank, A second return oil passage for returning lubricating oil from the second lubrication target to the first tank, The second tank and the second pump provided in the second return oil passage, A replenishment oil passage connecting the second return oil passage and the second tank, A second valve provided in the aforementioned replenishment oil passage, A monitoring unit that monitors the oil level of the lubricating oil stored in the second tank, The system includes a control unit that controls the second valve based on the monitoring results of the monitoring unit, The second valve is closed when the oil level of the lubricating oil in the second tank is within a specified range, and the second valve is opened when the oil level of the lubricating oil in the second tank falls below the specified range. Fueling unit.
2. An extruder comprising an extruder body, a gear pump, and a lubrication unit, The extruder body is, First motor and A first reduction gear to which the rotational driving force output from the first motor is input, The system comprises a screw driven by a rotational driving force output from the first reduction gear, The gear pump described above is The second motor and A second reduction gear to which the rotational driving force output from the second motor is input, The system comprises a gear that is driven by the rotational driving force output from the second reduction gear to extrude molten resin, The aforementioned fuel supply unit is A first tank for storing lubricating oil, A common oil passage connected to the first tank, The first pump, oil filter, and oil cooler are provided in the aforementioned common oil passage. A first branch oil passage connecting the common oil passage and the first reduction gear, A second branch oil passage connecting the common oil passage and the second reduction gear, A first return oil passage for returning lubricating oil from the first reduction gear to the first tank, A second return oil passage for returning lubricating oil from the second reduction gear to the first tank, The second tank and the second pump provided in the second return oil passage, A replenishment oil passage connecting the second return oil passage and the second tank, A second valve provided in the aforementioned replenishment oil passage, A monitoring unit that monitors the oil level of the lubricating oil stored in the second tank, The system includes a control unit that controls the second valve based on the monitoring results of the monitoring unit, The second valve is closed when the oil level of the lubricating oil in the second tank is within a specified range, and the second valve is opened when the oil level of the lubricating oil in the second tank falls below the specified range. Extruder.
3. An extruder comprising two or more extruder bodies and an oil supply unit that simultaneously supplies lubricating oil to those extruder bodies, The aforementioned fuel supply unit is A first tank for storing lubricating oil, A common oil passage connected to the first tank, The first pump, oil filter, and oil cooler are provided in the aforementioned common oil passage. A first branch oil passage connects the common oil passage and the first extruder body, A second branch oil passage connects the aforementioned common oil passage to the second extruder body, A first return oil passage for returning lubricating oil from the first extruder body to the first tank, A second return oil passage for returning lubricating oil from the second extruder body to the first tank, The second tank and the second pump provided in the second return oil passage, A replenishment oil passage connecting the second return oil passage and the second tank, A second valve provided in the aforementioned replenishment oil passage, A monitoring unit that monitors the oil level of the lubricating oil stored in the second tank, The system includes a control unit that controls the second valve based on the monitoring results of the monitoring unit, The second valve is closed when the oil level of the lubricating oil in the second tank is within a specified range, and the second valve is opened when the oil level of the lubricating oil in the second tank falls below the specified range. Extruder.
4. In the extruder according to claim 2 or 3, The refueling unit includes a discharge oil passage connecting the second tank and the second return oil passage, and a third pump provided in the discharge oil passage. When the oil level of the lubricating oil in the second tank exceeds the specified range, the third pump is operated with the second valve closed. Extruder.
5. In the extruder according to claim 4, The refueling unit includes a reserve oil passage connecting the first tank and the common oil passage, and a fourth pump provided in the reserve oil passage. Extruder.
6. In the extruder according to claim 5, The monitoring unit is a level transmitter that measures the oil level without coming into contact with the lubricating oil stored in the second tank. Extruder.