Machine tool and method

Abstract

To provide a machine tool and a method which can inhibit occurrence of excess pressure or flow in a passage.SOLUTION: A machine tool of the disclosure includes: a processing part; a passage of a lubrication oil supplied to the processing part; a pump configured to pump the lubrication oil to the passage; a sensor configured to detect a pressure of the lubrication oil flowing in the passage; and a control unit which controls the pump based on a predetermined pressure of the lubrication oil needed in the processing part and a detection result of the sensor.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to machine tools and methods. [Background technology]

[0002] As a machine tool according to the background art, the following Patent Document 1 discloses a hot press machine. The hot press machine uses a hydraulic pump to drive a hydraulic cylinder, and repeats a series of operation cycles from raising the hot platen, applying pressure, maintaining pressure, and lowering it. In this way, the hot press machine produces a molded product by pressing.

[0003] The hot press device has friction parts where metals rub against each other, such as bearings, gears, hydraulics, and sliding surfaces. In order to supply lubricating oil to the friction parts, the hot press device is equipped with a motor and a pump. The motor generates power using commercial power voltage. The pump uses the power generated by the motor to pressure-feed the lubricating oil to a flow path. The lubricating oil is supplied to the hot press device through the flow path. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-152902 A Summary of the Invention [Problem to be solved by the invention]

[0005] In a heat press device, the motor always rotates at a constant speed due to the commercial power frequency, so that excess pressure or flow rate may be generated by the lubricating oil in the flow passage.

[0006] The present disclosure aims to provide a machine tool and method capable of suppressing the generation of excess pressure or flow rate in a flow path. [Means for solving the problem]

[0007] An exemplary machine tool of the present disclosure includes a machining unit, a flow path for lubricating oil supplied to the machining unit, a pump for pressurizing the lubricating oil into the flow path, a sensor for detecting the pressure of the lubricating oil flowing through the flow path, and a control unit for controlling the pump based on a predetermined pressure of the lubricating oil required by the machining unit and the detection result of the sensor.

[0008] Another exemplary machine tool of the present disclosure includes a machining unit, a flow path for lubricating oil supplied to the machining unit, a pump for pressurizing the lubricating oil into the flow path, a sensor for detecting the flow rate of the lubricating oil flowing through the flow path, and a control unit for controlling the pump based on a predetermined flow rate of the lubricating oil required by the machining unit and the detection result of the sensor.

[0009] An exemplary method of the present invention includes using a pump to pump lubricating oil into a flow path leading to a machining section of a machine tool, detecting the pressure or flow rate of the lubricating oil flowing through the flow path, and controlling the pump based on a predetermined pressure of the lubricating oil required at the machining section and the pressure detected by the sensor, or based on a predetermined flow rate of the lubricating oil required at the machining section and the flow rate detected by the sensor. Effect of the Invention

[0010] According to an exemplary embodiment of the present disclosure, it is possible to provide a machine tool capable of suppressing the generation of excess pressure or flow rate in a flow path. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram showing a machine tool according to an embodiment. [Diagram 2] FIG. 2 is a graph showing the results of measuring the pressure of the lubricating oil versus the rotation speed [RPM] of the second motor for each number of machining operations. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Exemplary embodiments of the present disclosure will now be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and description thereof will not be repeated.

[0013] FIG. 1 is a diagram showing a machine tool 100 according to one embodiment. As shown in FIG. 1, the machine tool 100 is a press machine. The press machine places a workpiece (e.g., a thin metal plate) that is an object to be processed between a fixed die 11 and a movable die 12 provided in the press machine. The press machine then moves the movable die 12 up and down. By repeating a series of operations including the placement of the workpiece and the up and down movement of the movable die 12, the machine tool 100 repeatedly press-forms the workpiece into a shape determined by the fixed die 11 and the movable die 12.

[0014] It should be noted that machine tool 100 is not limited to a press machine, and may be a machine that processes a workpiece into a desired shape by at least one of cutting and grinding.

[0015] In detail, in addition to a fixed mold 11 and a movable mold 12, the machine tool 100 includes a housing 13, a mold holding section 14, a first motor 15, and a power transmission mechanism 16, which are examples of a "processing section" of the present disclosure.

[0016] The housing 13 includes at least a frame. The housing 13 may further include an exterior body. The housing 13 is provided with the fixed mold 11, the movable mold 12, the mold holding unit 14, the first motor 15, the power transmission mechanism 16, the control unit 17, and the inverter 28.

[0017] The housing 13 has a bed 131, a crown 132, and a pair of columns 133. The bed 131 contacts the installation surface S01 when the machine tool 100 is installed and ready for use (hereinafter referred to as the "installed state"). The crown 132 is located above the bed 131 in the installed state. A crankshaft 164 and a connecting rod 165 are attached to the crown 132. The pair of columns 133 are interposed between the bed 131 and the crown 132, and are located on both the left and right sides when facing the front of the machine tool 100 in the installed state.

[0018] The die holding unit 14 includes a bolster 141 and a slide 142. The bolster 141 is a surface plate and is fixed to the bed 131. The slide 142 is located above the bolster 141. The slide 142 is movable in the up and down direction together with a pair of plungers 166. During press molding, the fixed die 11 is attached to the bolster 141, and the movable die 12 is attached to the slide 142.

[0019] The first motor 15 generates power for moving the slide 142 up and down. In detail, the first motor 15 rotates an output shaft 151 protruding from the first motor 15 under the control of the control unit 17. A pulley 152 is attached to the output shaft 151. Hereinafter, the direction in which the output shaft 151 extends will be referred to as the "output shaft direction."

[0020] The power transmission mechanism 16 converts the power generated by the first motor 15 into a linear motion that reciprocates in the vertical direction. As a result, the power transmission mechanism 16 generates a force in the vertical direction. This causes the slide 142 to reciprocate in the vertical direction.

[0021] The power transmission mechanism 16 includes an endless belt 161 , a flywheel 162 , a friction plate 163 , a crankshaft 164 , a pair of connecting rods 165 , and a pair of plungers 166 .

[0022] The flywheel 162 is located below the pulley 152, and is supported by the column 133 so as to be rotatable about a rotation axis that is approximately parallel to the output shaft direction.

[0023] The endless belt 161 is wound around the pulley 152 and the flywheel 162. Therefore, when the first motor 15 is driven, the output shaft 151 and the pulley 152 rotate. The rotation of the pulley 152 is transmitted to the flywheel 162 via the endless belt 161. As a result, the flywheel 162 rotates around the rotation axis of the flywheel 162.

[0024] A pair of bearings 134 are provided on the crown 132 of the housing 13. In detail, the pair of bearings 134 face each other in the output axial direction.

[0025] The crankshaft 164 is suspended between the pair of bearings 134. The crankshaft 164 is supported by the pair of bearings 134 so as to be rotatable about a rotation axis along the output shaft direction.

[0026] The crankshaft 164 is a bent rod-shaped member and is disposed so as to extend in the output shaft direction. A friction plate 163 is attached to one end of the crankshaft 164 in the output shaft direction. The friction plate 163 and the flywheel 162 are part of a clutch mechanism. The friction plate 163 and the flywheel 162 are switched between a state in which they are disconnected from each other (hereinafter referred to as a "disconnected state") and a state in which they are connected to each other (hereinafter referred to as a "connected state"). In the connected state, the power of the first motor 15 is transmitted to the crankshaft 164 via the flywheel 162 and the friction plate 163. As a result, the crankshaft 164 rotates together with the flywheel 162. In the disconnected state, the power of the first motor 15 is not transmitted to the flywheel 162 and the crankshaft 164.

[0027] The crankshaft 164 has a plurality of eccentric parts 1641. Each eccentric part 1641 extends approximately parallel to the rotation shaft of the crankshaft 164 at a position radially away from the rotation shaft of the crankshaft 164. An upper end of each of the pair of connecting rods 165 is rotatably connected to the eccentric part 1641. A lower end of each of the pair of connecting rods 165 is rotatably connected to an upper end of a pair of plungers 166. Each of the plungers 166 reciprocates vertically along a guide (not shown). A lower end of each of the pair of plungers 166 is connected to the slide 142.

[0028] When the crankshaft 164 rotates, a pair of connecting rods 165 connected to the crankshaft 164 swing laterally, including a horizontal component. In addition, a pair of plungers 166 reciprocate vertically in response to the swinging of the connecting rods 165. This causes the slide 142 holding the movable die 12 to reciprocate vertically between the top dead center and the bottom dead center. When the slide 142 descends to the bottom dead center, the movable die 12 approaches the fixed die 11, and the workpiece sandwiched between the two dies is machined.

[0029] Control unit 17 has a microcomputer, a memory, etc. In control unit 17, the microcomputer operates according to a program stored in the memory. In this way, control unit 17 controls each part constituting machine tool 100.

[0030] In the machine tool 100, the machining portion includes friction parts where machine elements rub against each other. In the embodiment, examples of the friction parts include a pair of bearings 134 in the housing 13, and a crankshaft 164, each connecting rod 165, and each plunger 166 in the power transmission mechanism 16.

[0031] 1, in order to supply lubricant to the friction parts, the machine tool 100 further includes a lubricant supplying device 200. The lubricant supplying device 200 includes a lubricant storage section 21, a temperature adjusting section 22, a common flow path 231, individual flow paths 232, 233, a pump 24, a second motor 25, a relief valve 26, a sensor 27, and an inverter 28.

[0032] The reservoir 21 is a tank and stores the lubricating oil.

[0033] Temperature adjustment unit 22 is an oil heater cooler, and adjusts the temperature of the lubricating oil in reservoir 21 to approximately a set temperature.

[0034] The common flow passage 231 connects the storage section 21 and the upstream ends of the individual flow passages 232 and 233 so that the lubricating oil can flow through them. That is, the common flow passage 231 reaches from the storage section 21 to the upstream ends of the individual flow passages 232 and 233. The individual flow passage 232 connects the downstream end of the common flow passage 231 to the crankshaft 164, each connecting rod 165, and each plunger 166 so that the lubricating oil can flow through them. That is, the individual flow passage 232 reaches from the downstream end of the common flow passage 231 to the connecting rod 165. The individual flow passage 233 connects the downstream end of the common flow passage 231 to each bearing 134 so that the lubricating oil can flow through them. That is, the individual flow passage 233 reaches from the downstream end of the common flow passage 231 to each bearing 134. The common flow passage 231 and the individual flow passages 232 and 233 are examples of the "flow passage" of the present disclosure.

[0035] The pump 24 is disposed on the common flow path 231. The pump 24 pumps the lubricating oil to the common flow path 231. In detail, the pump 24 has a pump rotor. The pump rotor rotates by power generated by the second motor 25. As a result, the pump 24 sucks the lubricating oil from a portion upstream of the pump 24 in the common flow path 231, and discharges the sucked lubricating oil to a downstream portion. Thus, the lubricating oil is supplied to the friction portion through the common flow path 231 and the individual flow paths 232 and 233.

[0036] The lubricating oil supplied to each friction portion passes through a flow path 1331 in the housing 13 and falls into a reservoir 1311 in the bed 131. As a result, the lubricating oil is collected in the reservoir 1311. The lubricating oil in the reservoir 1311 passes through a return flow path 1312 and is re-supplied to the reservoir 21.

[0037] The second motor 25 is a three-phase motor, and rotates by the AC voltage applied from the inverter 28. As a result, the second motor 25 generates power for operating the pump 24. The inverter 28 converts the DC voltage supplied to the inverter 28 into a pulse-width modulated AC voltage under the control of the control unit 17. The inverter 28 supplies the resulting AC voltage to the second motor 25. As a result, the rotation speed of the pump 24, more specifically, the pump rotor, is made variable by inverter control.

[0038] The relief valve 26 is located downstream of the pump 24 in the common flow path 231. The relief valve 26 is a valve that releases excess pressure or flow rate when excess pressure or flow rate occurs in the common flow path 231.

[0039] In the embodiment, the sensor 27 detects the pressure of the lubricant flowing through the common flow path 231. The sensor 27 transmits a signal correlating to the detected pressure to the control unit 17. In the modified embodiment, the sensor 27 detects the flow rate of the lubricant flowing through the common flow path 231. The sensor 27 transmits a signal correlating to the detected flow rate to the control unit 17.

[0040] Meanwhile, a first operation is possible with machine tool 100. The first operation is a manual operation by an operator, or the like, and is an operation for specifying the number of times the processing part is to be processed per unit time. For example, any one of a plurality of predetermined processing times can be specified. In the case of a press machine, the number of processing times is indicated in units of SPM (Shots Per Minute), and is a value indicating how many times the workpiece can be punched per unit time by driving first motor 15. In the embodiment, it is assumed that the operator can specify any one of X1 to X5 [SPM] for machine tool 100.

[0041] Furthermore, the lubricant pressure (hereinafter referred to as the "predetermined pressure") Pn required in the machining portion of machine tool 100 is generally equal to or greater than a certain value regardless of the number of machining operations. However, the predetermined pressure Pn varies depending on the temperature of the lubricant.

[0042] The control unit 17 starts the operation of the pump 24 in response to the first operation and the second operation for starting the press working being performed by the operator on the machine tool 100.

[0043] In detail, control unit 17 controls pump 24 based on predetermined pressure Pn and the detection result by sensor 27. This prevents excess pressure from being generated in common flow path 231 and individual flow paths 232, 233. As a result, it is possible to reduce power consumption of machine tool 100. In addition, the amount of lubricating oil returning to reservoir 21 through relief valve 26 is reduced, so that the power supply voltage is used efficiently.

[0044] More specifically, in controlling the pump 24, the control unit 17 periodically acquires a detection result indicating the current pressure of the lubricant from the sensor 27. Each time the control unit 17 acquires a detection result, the control unit 17 determines a duty ratio for compensating for the deviation by feedback control based on the deviation (pressure difference) between the pressure indicated by the acquired detection result and a predetermined pressure Pn previously described in the program. The feedback control is typically proportional integral differential control. The inverter 28 switches a power transistor such as an IGBT at the duty ratio determined by the control unit 17 to generate a pulse signal whose pulse width is modulated at the duty ratio. The inverter 28 outputs the generated pulse signal to the second motor 25. The second motor 25 rotates according to the input pulse signal and generates power for the pump 24. As a result, the pump 24 pumps the lubricant with the predetermined pressure Pn as a target value.

[0045] The predetermined pressure Pn is preferably the minimum pressure among the lubricant pressures required in the machining section of the machine tool 100. This further suppresses the generation of excess pressure in the common flow path 231 and the individual flow paths 232, 233, compared to a case in which the predetermined pressure Pn is set to a value higher than the minimum pressure. As a result, further power saving of the machine tool 100 is possible.

[0046] In addition, the control unit 17 preferably controls the pump 24 so that the detection result of the sensor 27 falls within a range Rn determined based on the predetermined pressure Pn. This further suppresses the generation of excess pressure in the common flow path 231 and the individual flow paths 232, 233, and suppresses excessive pressure drops in the flow paths. Note that the range Rn has an upper limit Pn1 that is, for example, a pressure that exceeds the predetermined pressure Pn. The range Rn has a lower limit Pn2 that is, for example, a pressure that is less than the predetermined pressure Pn.

[0047] Next, a first modification of this embodiment will be described.

[0048] The inventors of the present invention measured the pressure of the lubricating oil relative to the rotation speed [RPM] of the second motor 25 for each of the machining cycles X1 to X5 [SPM]. X1, X2, X3, X4, and X5 are different from one another. FIG. 2 is a graph showing the measurement results. As shown in FIG. 2, as the rotation speed of the second motor 25 increases, the pressure of the lubricating oil tends to increase. However, the lubricating oil pressure relative to the rotation speed of the second motor 25 differs depending on the machining cycle. Also, the amount of change in the lubricating oil pressure relative to an increment in the rotation speed of the second motor 25 varies depending on the machining cycle.

[0049] Furthermore, from the measurement results, it was found that the rotation speed of the second motor 25 at which the predetermined pressure Pn is obtained varies depending on the number of times of machining. For example, when the number of times of machining is X1, X2, X3, X4, and X5, the rotation speeds are R1, R2, R3, R4, and R5. Note that only the rotation speeds R1 and R5 are shown in FIG. 2. R1, R2, R3, R4, and R5 are, for example, different from each other. However, this is not limited to the above, and at least two of R1, R2, R3, R4, and R5 may be the same.

[0050] Therefore, in controlling the pump 24, the control unit 17 first determines an initial value of the rotation speed of the second motor 25 based on the number of times the processed part is processed per unit time. Therefore, the rotation speed of the pump 24 is controlled so that the pressure of the lubricating oil quickly approaches the predetermined pressure Pn. When the rotation speed of the second motor 25 reaches the initial value, the control unit 17 executes the above-mentioned feedback control.

[0051] Specifically, when the number of machining times is X1, X2, X3, X4, and X5, the initial values ​​of the number of rotations are determined to be R1, R2, R3, R4, and R5. Control unit 17 controls the number of rotations of second motor 25 so that the detection result of a rotation sensor (not shown) mounted on second motor 25 reaches the initial value of the number of rotations. Note that, in order to realize this type of control, a table describing the initial values ​​of the number of rotations corresponding to each number of machining times may be stored in the memory of control unit 17 at the time of manufacturing machine tool 100. Alternatively, the initial values ​​of the number of rotations corresponding to each number of machining times may be described in a program recorded in the memory.

[0052] The above describes the embodiments of the present disclosure with reference to the drawings. However, the above embodiments are merely examples of the present disclosure, and the present disclosure is not limited to the above embodiments, and can be implemented in various aspects without departing from the gist of the present disclosure. The drawings are mainly schematic illustrations of each component for ease of understanding, and the thickness, length, number, etc. of each component shown in the drawings are different from the actual ones due to the convenience of drawing. In addition, the material, shape, dimensions, etc. of each component shown in the above embodiments are only examples and are not particularly limited, and various modifications are possible within a range that does not substantially deviate from the effects of the present disclosure. The configuration of the embodiment may be appropriately modified within a range that does not exceed the technical idea of ​​the present disclosure. In addition, the embodiments may be implemented in combination within a possible range.

[0053] In the embodiment, the sensor 27 detects the pressure of the lubricant, and the control unit 17 controls the pump 24 based on the predetermined pressure Pn of the lubricant required in the machining unit and the detection result of the sensor 27. However, there is a correlation between the pressure and flow rate of the lubricant in the flow path. Therefore, the term "pressure" in the embodiment may be read as "flow rate". For example, the sensor 27 may detect the flow rate of the lubricant, and the control unit 17 may control the pump 24 based on the predetermined flow rate of the lubricant required in the machining unit and the detection result of the sensor 27. This suppresses the generation of excess flow rate in the common flow path 231 and the individual flow paths 232, 233, and enables the power saving of the machine tool 100. In addition, the amount of lubricant returning to the storage unit 21 through the relief valve 26 is reduced, so that the power supply voltage is used efficiently.

[0054] The present disclosure may also adopt the following configuration.

[0055] (1) a processing section; A flow path for lubricating oil to be supplied to the processing section; A pump that pumps the lubricating oil into the flow path; a sensor for detecting a pressure of the lubricating oil flowing through the flow passage; a control unit that controls the pump based on a predetermined pressure of the lubricating oil required in the processing unit and a detection result of the sensor; A machine tool comprising:

[0056] (2) The machine tool according to claim 1, wherein the predetermined pressure is a minimum pressure of the lubricant required in the machining section.

[0057] (3) The machine tool according to claim 1 or 2, wherein the control unit controls the pump so that the detection result falls within a range determined based on the specified pressure.

[0058] (4) The processing unit processes a workpiece, The pump has a pump rotor that rotates to pump the lubricating oil to the flow path, 3. The machine tool according to claim 1, wherein an initial value of the rotational speed of the pump rotor is based on the number of times the machined portion is machined per unit time.

[0059] (5) a processing section; A flow path for lubricating oil to be supplied to the processing section; A pump that pumps the lubricating oil into the flow path; a sensor for detecting a flow rate of the lubricating oil flowing through the flow passage; a control unit that controls the pump based on a predetermined flow rate of the lubricating oil required in the processing unit and a detection result of the sensor; A machine tool comprising:

[0060] (6) The machine tool according to claim 5, wherein the predetermined flow rate is a minimum flow rate of the lubricant required in the machining section.

[0061] (7) The machine tool according to claim 5 or 6, wherein the control unit controls the pump so that the detection result falls within a range determined based on the predetermined flow rate.

[0062] (8) The processing unit processes a workpiece, The pump has a pump rotor that rotates to pump the lubricating oil to the flow path, 7. The machine tool according to claim 5, wherein an initial value of the rotational speed of the pump rotor is based on the number of times the machined portion is machined per unit time.

[0063] (9) A pump is used to pump lubricating oil into a flow passage leading to a machining part of the machine tool; Detecting a pressure or a flow rate of the lubricant flowing through the flow passage; The method includes controlling the pump based on a predetermined pressure or a predetermined flow rate of the lubricant required in the processing section and a detection result of the sensor. [Industrial Applicability]

[0064] The lubricant oil supplying device according to the present disclosure can be used in machine tools and the like, and has industrial applicability. [Explanation of symbols]

[0065] 100: Machine tools 15: First motor 16: Power transmission mechanism 17: Control section 200: Lubricating oil supply device 24: Pump 25: Second motor 26: Relief valve 27: Sensor 28: Inverter 231: Common flow path 232: Individual flow path 233: Individual flow path

Claims

1. A processing section; A flow path for lubricating oil to be supplied to the processing section; A pump that pumps the lubricating oil into the flow path; a sensor for detecting a pressure of the lubricating oil flowing through the flow passage; a control unit that controls the pump based on a predetermined pressure of the lubricating oil required in the processing unit and a detection result of the sensor; A machine tool comprising:

2. 2. The machine tool according to claim 1, wherein the predetermined pressure is a minimum pressure of the lubricant required in the machining portion.

3. 3. The machine tool according to claim 1, wherein the control unit controls the pump so that the detection result falls within a range determined based on the predetermined pressure.

4. 3. The machine tool according to claim 1, wherein an initial value of the rotational speed of the pump is based on the number of times the machining portion is machined per unit time.

5. A processing section; A flow path for lubricating oil to be supplied to the processing section; A pump that pumps the lubricating oil into the flow path; a sensor for detecting a flow rate of the lubricating oil flowing through the flow passage; a control unit that controls the pump based on a predetermined flow rate of the lubricating oil required in the processing unit and a detection result of the sensor; A machine tool comprising:

6. 6. The machine tool according to claim 5, wherein the predetermined flow rate is a minimum flow rate of the lubricating oil required in the machining portion.

7. 7. The machine tool according to claim 5, wherein the control unit controls the pump so that the detection result falls within a range determined based on the predetermined flow rate.

8. 7. The machine tool according to claim 5, wherein an initial value of the rotational speed of the pump is based on the number of times the machining portion is machined per unit time.

9. The lubricating oil is pumped into the flow passage leading to the machining part of the machine tool, Detecting a pressure or a flow rate of the lubricant flowing through the flow passage; A method for controlling the pump based on a predetermined pressure of the lubricant required in the processing section and the pressure detected by a sensor, or based on a predetermined flow rate of the lubricant required in the processing section and the flow rate detected by the sensor.

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