Machine tool and control method

Abstract

The invention provides a machine tool and a control method. The machine tool includes: a machining unit; a flow path for supplying the lubricating oil to the processing part; a pump for pressure-feeding the lubricating oil to the flow path; a sensor that detects the pressure of the lubricating oil flowing through the flow path; and a control unit that controls the pump on the basis of the prescribed pressure of the lubricating oil required by the processing unit and the detection result of the sensor.

Description

Technical Field

[0001] The invention relates to a machine tool and a control method. Background Art

[0002] As a machine tool of background technology, there is a hot stamping device in the following patent document 1. The hot stamping device drives the hydraulic cylinder by a hydraulic pump, repeating a series of action cycles of rising, pressurizing, holding pressure and then lowering the hot plate. Thus, the hot stamping device produces a molded product by stamping.

[0003] In the hot stamping device, there are 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 stamping device has a motor and a pump. The motor generates power through commercial power supply voltage. The pump uses the power generated by the motor to pressurize the lubricating oil to the flow path. The lubricating oil is supplied to the hot stamping device through the flow path.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2005-152902

[0005] In a hot stamping device, the motor is always rotated at a constant speed by the commercial power frequency, so that excessive pressure or flow rate may be generated in the flow path due to the lubricating oil. Summary of the invention

[0006] An object of the present invention is to provide a machine tool and a control method capable of suppressing generation of an unnecessary pressure or flow rate in a flow path.

[0007] An exemplary machine tool of the present invention comprises: a processing part; a flow path for lubricating oil supplied to the processing part; a pump for pressurizing the lubricating oil to the flow path; a sensor for detecting the pressure of the lubricating oil flowing in the flow path; and a control part for controlling the pump based on a specified pressure of the lubricating oil required by the processing part and a detection result of the sensor.

[0008] Another exemplary machine tool of the present invention comprises: a processing part; a flow path for lubricating oil supplied to the processing part; a pump for pressurizing the lubricating oil to the flow path; a sensor for detecting the flow rate of the lubricating oil flowing in the flow path; and a control part for controlling the pump based on a specified flow rate of the lubricating oil required by the processing part and the detection result of the sensor.

[0009] An exemplary control method of the present invention utilizes a pump to pressurize lubricating oil to a flow path connected to a processing part of a machine tool, detects the pressure or flow rate of the lubricating oil flowing in the flow path, and controls the pump based on a specified pressure of the lubricating oil required by the processing part and the pressure detected by a sensor, or controls the pump based on a specified flow rate of the lubricating oil required by the processing part and the flow rate detected by the sensor.

[0010] According to the exemplary present invention, it is possible to provide a machine tool capable of suppressing generation of an unnecessary pressure or flow rate in a flow path.

[0011] The above and other features, elements, steps, characteristics and advantages of the present invention will be more clearly understood from the following detailed description of preferred embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a figure which shows the machine tool which concerns on one embodiment.

[0013] Figure 2 This is a graph showing the results of measuring the pressure of the lubricating oil with respect to the rotation speed [RPM] of the second motor according to the number of machining operations. DETAILED DESCRIPTION

[0014] The exemplary embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated.

[0015] Figure 1 FIG. 1 is a diagram showing a machine tool 100 according to one embodiment. Figure 1 As shown, the machine tool 100 is a punching machine. The punching machine places a workpiece (e.g., a thin metal plate) as a processing object between a fixed die 11 and a movable die 12 of the punching machine. Then, the punching machine moves the movable die 12 up and down. By repeating a series of actions including the placement of the workpiece and the up and down movement of the movable die 12, the machine tool 100 repeatedly punches and forms the workpiece into a shape determined by the fixed die 11 and the movable die 12.

[0016] In addition, the machine tool 100 is not limited to a press machine, and may be a machine that forms a workpiece into a desired shape by at least one of cutting and grinding.

[0017] Specifically, the machine tool 100 includes, in addition to the fixed mold 11 and the movable mold 12 , a housing 13 , a mold holding portion 14 , a first motor 15 , and a power transmission mechanism 16 as an example of the “processing portion” of the present invention.

[0018] The housing 13 includes at least a frame. The housing 13 may further include an outer casing. The housing 13 is provided with the fixed mold 11 , the movable mold 12 , the mold holding portion 14 , the first motor 15 , the power transmission mechanism 16 , the control portion 17 , and the inverter 28 .

[0019] The housing 13 has a bed 131, a crown 132, and a pair of columns 133. The bed 131 is in contact with the setting surface S01 when the machine tool 100 is set to a state in which it can be used (hereinafter referred to as the "setting state"). The crown 132 is located above the bed 131 in the setting state. A crank shaft 164 and a connecting rod 165 are installed on the crown 132. The pair of columns 133 is interposed between the bed 131 and the crown 132, and is located on the left and right sides facing the front surface of the machine tool 100 in the setting state.

[0020] The mold holding part 14 includes a pad 141 and a slider 142. The pad 141 is a platform fixed to the bed 131. The slider 142 is located above the pad 141. The slider 142 can move in the up and down direction together with a pair of plungers 166. During stamping, the fixed mold 11 is installed on the pad 141, and the movable mold 12 is installed on the slider 142.

[0021] The first motor 15 generates power for moving the slider 142 up and down. Specifically, 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 mounted on the output shaft 151. Hereinafter, the direction in which the output shaft 151 extends is described as the "output shaft direction".

[0022] 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. As a result, the slider 142 reciprocates in the vertical direction.

[0023] 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 .

[0024] 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 substantially parallel to the output shaft direction. The diameter of the flywheel 162 is larger than that of the pulley 152.

[0025] 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. Thus, the flywheel 162 rotates around the rotation axis of the flywheel 162.

[0026] A pair of bearings 134 is provided on the crown portion 132 of the housing 13. Specifically, the pair of bearings 134 are opposed to each other in the output shaft direction.

[0027] The crankshaft 164 is mounted on the pair of bearings 134. The crankshaft 164 is supported by the pair of bearings 134 so as to be rotatable around a rotation axis along the output shaft direction.

[0028] The crankshaft 164 is a bent rod-shaped component, and is configured to extend in the output shaft direction. A friction plate 163 is installed at one end of the crankshaft 164 in the output shaft direction. The friction plate 163 and the flywheel 162 are part of the clutch mechanism. The friction plate 163 and the flywheel 162 are switched to a state of being disconnected from each other (hereinafter referred to as the "disconnected state") and a state of being connected to each other (hereinafter referred to as the "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.

[0029] The crankshaft 164 has a plurality of eccentric portions 1641. Each eccentric portion 1641 extends approximately parallel to the rotation axis at a position radially away from the rotation axis of the crankshaft 164. The upper end of each of a pair of connecting rods 165 is connected to the eccentric portion 1641 in a rotatable manner. In addition, the lower end of each of a pair of connecting rods 165 is connected to the upper end of a pair of plungers 166 in a rotatable manner. Each plunger 166 reciprocates in the up and down direction along a guide member not shown in the figure. In addition, the lower end of each of the pair of plungers 166 is connected to the slider 142.

[0030] When the crankshaft 164 rotates, a pair of connecting rods 165 connected to the crankshaft 164 swings in a lateral direction including a horizontal component. In addition, as the connecting rods 165 swing, a pair of plungers 166 reciprocate in the vertical direction. As a result, the slider 142 holding the movable mold 12 reciprocates in the vertical direction between the top dead center and the bottom dead center. When the slider 142 descends to the bottom dead center, the movable mold 12 approaches the fixed mold 11, and the workpiece sandwiched between the two molds is processed.

[0031] The control unit 17 includes a microcomputer, a memory, etc. In the control unit 17 , the microcomputer operates according to a program stored in the memory. Thus, the control unit 17 controls each unit constituting the machine tool 100 .

[0032] In the machine tool 100 , the processing part includes a friction part where mechanical elements rub against each other. In the embodiment, the friction part includes a pair of bearings 134 in the housing 13 , a crankshaft 164 in the power transmission mechanism 16 , each connecting rod 165 , and each plunger 166 .

[0033] In order to provide lubricating oil to the friction parts, such as Figure 1As shown, the machine tool 100 further includes a lubricating oil supply device 200. The lubricating oil supply device 200 includes a lubricating oil storage unit 21, a temperature control unit 22, a common flow path 231, independent flow paths 232 and 233, a pump 24, a second motor 25, a relief valve 26, a sensor 27, and an inverter 28.

[0034] The storage unit 21 is a tank and stores lubricating oil.

[0035] The temperature adjustment unit 22 is an oil heater cooler, and adjusts the temperature of the lubricating oil in the storage unit 21 to near a set temperature.

[0036] The common flow path 231 connects the storage portion 21 and the upstream ends of the independent flow paths 232 and 233 in a manner that allows lubricating oil to flow. That is, the common flow path 231 extends from the storage portion 21 to the upstream ends of the independent flow paths 232 and 233. The independent flow path 232 connects the downstream end of the common flow path 231 to the crankshaft 164, the connecting rods 165, and the plungers 166 in a manner that allows lubricating oil to flow. That is, the independent flow path 232 extends from the downstream end of the common flow path 231 to the connecting rod 165. The independent flow path 233 connects the downstream end of the common flow path 231 to the bearings 134 in a manner that allows lubricating oil to flow. That is, the independent flow path 233 extends from the downstream end of the common flow path 231 to the bearings 134. The common flow path 231 and the independent flow paths 232 and 233 are examples of the "flow path" of the present invention.

[0037] The pump 24 is arranged on the common flow path 231. The pump 24 pressurizes the lubricating oil to the common flow path 231. In detail, the pump 24 has a pump rotor. The pump rotor is rotated by the power generated by the second motor 25. As a result, the pump 24 sucks the lubricating oil from the position upstream of the pump 24 in the common flow path 231, and discharges the sucked lubricating oil to the downstream part. Thus, the lubricating oil is provided to the friction part via the common flow path 231 and the independent flow paths 232 and 233.

[0038] The lubricating oil supplied to each friction part falls to the reservoir 1311 in the bed 131 through the flow path 1331 in the housing 13. Thus, the lubricating oil is recovered to the reservoir 1311. The lubricating oil in the reservoir 1311 is supplied to the reservoir 21 again through the return flow path 1312.

[0039] The second motor 25 is a three-phase motor, and is rotated by the AC voltage applied from the inverter 28. As a result, the second motor 25 generates power for operating the pump 24. Under the control of the control unit 17, the inverter 28 converts the DC voltage supplied to the inverter 28 into a pulse width modulated AC voltage. As a result, the inverter 28 supplies the obtained AC voltage to the second motor 25. Thus, the rotation speed of the pump 24, more specifically, the pump rotor can be changed by inverter control.

[0040] The relief valve 26 is located downstream of the pump 24 in the common flow passage 231. The relief valve 26 is a valve that releases excess pressure or flow rate when excess pressure or flow rate is generated in the common flow passage 231.

[0041] In the embodiment, the sensor 27 detects the pressure of the lubricating oil flowing in the common flow path 231. The sensor 27 sends a signal related to the detected pressure to the control unit 17. In a modified example of the embodiment, the sensor 27 detects the flow rate of the lubricating oil flowing in the common flow path 231. The sensor 27 sends a signal related to the detected flow rate to the control unit 17.

[0042] However, in the machine tool 100, a first operation can be performed. The first operation is a manual operation of an operator, etc., and is an operation for specifying the number of processing times of the processing portion per unit time. For example, any one of a plurality of predetermined processing times can be specified. In the case of a punching machine, the number of processing times is expressed in units of SPM (Shots Per Minute), which is a value indicating how many times the workpiece can be punched per unit time by driving the first motor 15. In the embodiment, the operator can specify any one of X1 to X5 [SPM] for the machine tool 100.

[0043] The pressure (hereinafter referred to as "predetermined pressure") Pn of the lubricating oil required for the machining portion of the machine tool 100 is substantially constant regardless of the number of machining operations. However, the predetermined pressure Pn varies depending on the temperature of the lubricating oil.

[0044] The control unit 17 starts the operation of the pump 24 in response to the operator performing the first operation on the machine tool 100 and the second operation for starting the press working.

[0045] Specifically, the control unit 17 controls the pump 24 based on the predetermined pressure Pn and the detection result of the sensor 27. As a result, the generation of unnecessary pressure in the common flow path 231 and the independent flow paths 232 and 233 is suppressed. As a result, it is possible to achieve power saving of the machine tool 100. In addition, the amount of lubricating oil returned to the reservoir 21 via the relief valve 26 is reduced, so that the power supply voltage can be used effectively.

[0046] In more detail, the control unit 17 periodically obtains the detection result indicating the current pressure of the lubricating oil from the sensor 27 during the control of the pump 24. Each time the control unit 17 obtains the detection result, it determines the duty cycle used to compensate for the deviation by feedback control based on the deviation (pressure difference) between the pressure indicated by the obtained detection result and the specified pressure Pn pre-recorded in the program. Feedback control is typically proportional integral differential control. The inverter 28 switches power transistors such as IGBTs at the duty cycle determined by the control unit 17, and generates a pulse signal whose pulse width is modulated by the duty cycle. The inverter 28 outputs the generated pulse signal to the second motor 25. The second motor 25 rotates according to the input pulse signal to generate power for the pump 24. As a result, the pump 24 presses the lubricating oil with the specified pressure Pn as the target value.

[0047] The prescribed pressure Pn is preferably the lowest pressure among the pressures of the lubricating oil required for the processing part of the machine tool 100. Thus, compared with the case where the prescribed pressure Pn exceeds the lowest pressure, the generation of excess pressure in the common flow path 231 and the independent flow paths 232 and 233 is further suppressed. As a result, further power saving of the machine tool 100 can be achieved.

[0048] In addition, it is preferred that the control unit 17 controls the pump 24 so that the detection result of the sensor 27 falls within the range Rn determined according to the prescribed pressure Pn. Thus, the generation of excess pressure in the common flow path 231 and the independent flow paths 232 and 233 is further suppressed, and the excessive decrease in the pressure in the flow path is suppressed. In addition, in the range Rn, for example, the pressure exceeding the prescribed pressure Pn is set to the upper limit value Pn1. In the range Rn, for example, the pressure less than the prescribed pressure Pn is set to the lower limit value Pn2.

[0049] Next, a first modified example of the present embodiment will be described.

[0050] The inventors of the present application measured the pressure of the lubricating oil with respect to the rotation speed [RPM] of the second motor 25 at the number of machining times X1 to X5 [SPM]. X1, X2, X3, X4, and X5 are different from each other. Figure 2 is a graph showing the measurement results. Figure 2 As shown in FIG. 1 , when 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 varies according to the number of machining operations. In addition, the amount of change in the lubricating oil pressure relative to the increment of the rotation speed of the second motor 25 varies according to the number of machining operations.

[0051] Furthermore, according to the measurement results, the rotation speed of the second motor 25 for obtaining the predetermined pressure Pn varies depending on the number of machining operations. For example, when the number of machining operations is X1, X2, X3, X4, and X5, the rotation speed is R1, R2, R3, R4, and R5. Figure 2 Only the rotation speeds R1 and R5 are shown. R1, R2, R3, R4, and R5 are different from each other, for example. However, this is not limiting, and there may be a case where at least two of R1, R2, R3, R4, and R5 are the same.

[0052] Therefore, the control unit 17 first determines the initial value of the rotation speed of the second motor 25 according to the number of times the processing of the processing part per unit time in the control of the pump 24. Therefore, the rotation speed of the pump 24 is controlled so that the pressure of the lubricating oil quickly approaches the specified pressure Pn. When the rotation speed of the second motor 25 reaches the initial value, the control unit 17 performs the above-mentioned feedback control.

[0053] Specifically, when the number of processing times is X1, X2, X3, X4, and X5, the initial value of the rotation speed is determined to be R1, R2, R3, R4, and R5. The control unit 17 controls the rotation speed of the second motor 25 so that the detection result of the rotation sensor (not shown) mounted on the second motor 25 reaches the initial value of the rotation speed. In addition, in order to realize such control, in the memory of the control unit 17, it is sufficient to store a table recording the initial value of the rotation speed corresponding to each number of processing times when the machine tool 100 is manufactured. In addition, the initial value of the rotation speed corresponding to each number of processing times can also be recorded in the program recorded in the memory.

[0054] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the above embodiments are merely illustrations of the present invention, and the present invention is not limited to the above embodiments, and can be implemented in various ways within the scope of the main purpose thereof. In the accompanying drawings, for ease of understanding, each component is schematically shown as the main body, and the thickness, length, number, etc. of each component shown in the drawings are different from the actual ones for the convenience of making the drawings. In addition, the material, shape, size, etc. of each component shown in the above embodiments are an example, and are not particularly limited, and various changes can be made within the scope of the effect of the present invention. The structure of the embodiment can also be appropriately changed within the scope of not exceeding the technical idea of ​​the present invention. In addition, the embodiments can also be implemented in combination within the possible scope.

[0055] In the embodiment, the sensor 27 detects the pressure of the lubricating oil, and the control unit 17 controls the pump 24 according to the specified pressure Pn of the lubricating oil required for the processing part and the detection result of the sensor 27. However, there is a correlation between the pressure and flow rate of the lubricating oil in the flow path. Therefore, the term "pressure" in the embodiment may be replaced by "flow rate". For example, the sensor 27 may detect the flow rate of the lubricating oil, and the control unit 17 controls the pump 24 according to the specified flow rate of the lubricating oil required for the processing part and the detection result of the sensor 27. Thereby, it is possible to suppress the generation of excess flow in the common flow path 231 and the independent flow paths 232 and 233, thereby achieving power saving of the machine tool 100. In addition, the amount of lubricating oil returned to the storage part 21 via the overflow valve 26 is reduced, so that the power supply voltage can be effectively utilized.

[0056] In addition, the present invention can also adopt the following structures.

[0057] (1) A machine tool comprising: a processing portion; a flow path for lubricating oil supplied to the processing portion; a pump for pressurizing the lubricating oil into the flow path; a sensor for detecting the pressure of the lubricating oil flowing in the flow path; and a control portion for controlling the pump based on a specified pressure of the lubricating oil required by the processing portion and a detection result of the sensor.

[0058] (2) The machine tool according to (1), wherein the predetermined pressure is a minimum pressure of the lubricating oil required for the processing portion.

[0059] (3) In the machine tool according to (1) or (2), the control unit controls the pump so that the detection result falls within a range determined based on the prescribed pressure.

[0060] (4) A machine tool according to (1) or (2), wherein the processing portion processes a workpiece, the pump has a pump rotor that presses the lubricating oil to the flow path by rotating, and an initial value of the rotation speed of the pump rotor is based on the number of times the processing portion is processed per unit time.

[0061] (5) A machine tool comprising: a processing part; a flow path for lubricating oil supplied to the processing part; a pump for pressurizing the lubricating oil into the flow path; a sensor for detecting the flow rate of the lubricating oil flowing in the flow path; and a control part for controlling the pump based on a specified flow rate of the lubricating oil required by the processing part and the detection result of the sensor.

[0062] (6) The machine tool according to (5), wherein the predetermined flow rate is a minimum flow rate of the lubricating oil required for the machining portion.

[0063] (7) In the machine tool according to (5) or (6), the control unit controls the pump so that the detection result falls within a range determined based on the prescribed flow rate.

[0064] (8) A machine tool according to (5) or (6), wherein the processing portion processes a workpiece, the pump has a pump rotor that presses the lubricating oil into the flow path by rotating, and an initial value of the rotation speed of the pump rotor is based on the number of times the processing portion is processed per unit time.

[0065] (9) A control method, wherein the control method uses a pump to pressurize lubricating oil to a flow path connected to a processing part of a machine tool, detects the pressure or flow rate of the lubricating oil flowing in the flow path, and controls the pump based on a specified pressure or specified flow rate of the lubricating oil required by the processing part and the detection result of the sensor.

[0066] The lubricating oil supply device of the present invention can be used in, for example, machine tools and the like, and has industrial applicability.

Claims

1. A machine tool comprising: Processing department; a flow path for lubricating oil supplied to the processing portion; a pump configured to pressure-feed the lubricating oil to the flow path; and a sensor for detecting the pressure of the lubricating oil flowing in the flow path, It is characterized in that The machine tool includes a control unit configured to control the pump based on a predetermined pressure of the lubricating oil required for the machining portion and a detection result of the sensor.

2. The machine tool according to claim 1, characterized in that: The predetermined pressure is the lowest pressure of the lubricating oil required for the processing portion.

3. The machine tool according to claim 1 or 2, characterized in that: The control unit controls the pump so that the detection result falls within a range determined according to the prescribed pressure.

4. The machine tool according to claim 1 or 2, characterized in that: An initial value of the rotation speed of the pump is based on the number of times the processing of the processing portion is performed per unit time.

5. A machine tool comprising: Processing department; a flow path for lubricating oil supplied to the processing portion; a pump configured to pressure-feed the lubricating oil to the flow path; and a sensor for detecting a flow rate of the lubricating oil flowing in the flow path, It is characterized in that The machine tool includes a control unit configured to control the pump based on a predetermined flow rate of the lubricating oil required for the machining portion and a detection result of the sensor.

6. The machine tool according to claim 5, characterized in that: The predetermined flow rate is a minimum flow rate of the lubricating oil required for the processing portion.

7. The machine tool according to claim 5 or 6, characterized in that: The control unit controls the pump so that the detection result falls within a range determined according to the prescribed flow rate.

8. The machine tool according to claim 5 or 6, characterized in that: An initial value of the rotation speed of the pump is based on the number of times the processing of the processing portion is performed per unit time.

9. A control method, which uses a pump to pressurize lubricating oil to a flow path connected to a processing part of a machine tool, and detects the pressure or flow rate of the lubricating oil flowing in the flow path, characterized in that: The control method controls the pump based on a predetermined pressure of the lubricating oil required for the processing portion and the pressure detected by the sensor, or controls the pump based on a predetermined flow rate of the lubricating oil required for the processing portion and the flow rate detected by the sensor.

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