Hydraulic Device

Abstract

A hydraulic device (10) includes a gear pump (14) or a gear motor, a first temperature sensor (18) provided to the gear pump (14) or gear motor, and a control device (22) that controls the drive of the gear pump (14) or gear motor according to the temperature measured by the first temperature sensor (18). The first temperature sensor (18) is attached to a casing (64). The first temperature sensor (18) is attached near a driven shaft (58) in the casing (64) and near a bearing (62) of the driven shaft (58). The first temperature sensor (18) measures the temperature of the casing (64).

Description

[Technical Field]

[0001] The present invention relates to a hydraulic device. [Background technology]

[0002] Hydraulic systems have traditionally been used in loading and unloading equipment and mounted vehicles. Hydraulic systems include a gear pump, a hydraulic cylinder (hydraulic cylinder), a valve, piping for the hydraulic fluid (hydraulic oil), and a tank for storing the hydraulic fluid. The gear pump discharges the hydraulic fluid stored in the tank. The flow of the hydraulic fluid is controlled by a valve, which drives the hydraulic cylinder. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] WO2014 / 192172 Summary of the Invention [Problem to be solved by the invention]

[0004] If the bearings of a gear pump seize, it may lead to damage to the gear pump, hydraulic cylinder, and valve. In Patent Document 1, a thermometer is installed in the tank to measure the temperature of the working fluid. When the temperature exceeds a certain value, a cooling device is activated to cool the working fluid. However, simply measuring the temperature of the working fluid with a thermometer in the tank as in Patent Document 1 may not be enough to prevent the bearings of the gear pump from seizing.

[0005] SUMMARY OF THE INVENTION An object of the present invention is to provide a hydraulic device that prevents seizure of bearings in a gear pump or gear motor. [Means for solving the problem]

[0006] In order to solve the above problems, a hydraulic device according to the present invention has the following configuration.

[0007] The hydraulic device of the present invention includes a gear pump or a gear motor, a first temperature sensor provided in the gear pump or the gear motor, and a control device that controls the operation of the gear pump or the gear motor in accordance with the temperature measured by the first temperature sensor. [Effects of the Invention]

[0008] According to the present invention, by measuring the temperature of the gear pump or gear motor with the first temperature sensor, the temperature of the bearings of the gear pump or gear motor can be determined, and seizure can be prevented. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram showing a configuration of a hydraulic device according to the present invention; [Figure 2] FIG. 2 is a diagram showing the configuration of a gear pump. [Figure 3] 4 is a flowchart showing a control method of the control device. [Figure 4] FIG. 10 is a diagram showing the configuration of a gear pump equipped with a plurality of first temperature sensors. [Figure 5] FIG. 10 is a diagram showing the configuration of a hydraulic device in which the second temperature sensor is omitted. [Figure 6] FIG. 1 is a diagram illustrating a configuration of a hydraulic device equipped with a communication device. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the accompanying drawings. In the following description of the preferred embodiments, the same components are designated by the same reference numerals and the description thereof will be omitted.

[0011] [Embodiment 1] 1 is a device for driving a hydraulic cylinder (hydraulic cylinder) 12. The hydraulic device 10 includes a hydraulic circuit 16 including a gear pump 14, a first temperature sensor 18, a second temperature sensor 20, and a control device 22.

[0012] The gear pump 14 discharges hydraulic fluid (hydraulic oil). The hydraulic fluid drives the hydraulic cylinder 12. Figure 1 shows an example of a hydraulic circuit 16 for driving the hydraulic cylinder 12. The hydraulic circuit 16 includes the gear pump 14, a tank 24, piping 26, a valve 28, and a cooler 30. Hydraulic fluid is stored in the tank 24, and the gear pump 14 discharges the stored hydraulic fluid and flows through the piping 26. The valve 28 controls the flow of hydraulic fluid. Hydraulic fluid is supplied to either the piston rod side 34 or the opposite side 36 of the piston rod of the cylinder tube 32 of the hydraulic cylinder 12. Depending on which side 34 or 36 of the cylinder tube 32 the valve 28 supplies hydraulic fluid to, the piston rod 38 moves out of or into the cylinder tube 32. A cooler 30 is provided in the piping 26, and the heated hydraulic fluid is cooled by the cooler 30.

[0013] The gear pump 14 is driven by a motor 40. The motor 40 is controlled by a drive circuit 42. The drive circuit 42 includes a power supply 44 and a switch 46. The control device 22 turns the switch 46 on and off by allowing or not allowing current to flow through a coil 48. When the switch 46 is turned on, power can be supplied to the motor 40. A diode 50 is arranged in parallel with the coil 48 and controls the flow of current when the motor 40 stops. The circuit configuration of the switch 46 is an example, and any other circuit may be used as long as it allows the control device 22 to control the motor 40.

[0014] 2 includes gears 52, 54, shafts 56, 58 of the gears 52, 54, and bearings 60, 62 that rotatably support the shafts 56, 58. The gears 52, 54, shafts 56, 58, and bearings 60, 62 are housed in a casing 64.

[0015] The gears are a pair of drive gear 52 and driven gear 54. Each gear 52, 54 has multiple teeth arranged at an equal angle. The drive gear 52 and driven gear 54 mesh with each other, and when the drive gear 52 rotates, the driven gear 54 also rotates. Side plates 66 with improved sliding properties are placed on the sides of each gear 52, 54.

[0016] A drive shaft 56 is formed integrally with the drive gear 52. A driven shaft 58 is formed integrally with the driven gear 54. Each shaft 56, 58 is disposed perpendicular to the side surface of the gears 52, 54 from the center of the side surface of the gears 52, 54. The drive shaft 56 is rotated by the motor 40, which rotates the drive gear 52, which in turn rotates the driven gear 54 and the driven shaft 58.

[0017] The casing 64 includes a casing body 68, a front cover 70, and a rear cover 72. The casing body 68, the front cover 70, and the rear cover 72 are fixed together with fasteners such as bolts. The casing 64 is manufactured by casting, cutting, or stamping a material such as cast iron or an aluminum alloy. The casing body 68 and the rear cover 72 may be integrated.

[0018] A gear storage chamber 74 for gears 52, 54 is formed inside casing 64, and storage spaces 76, 78 for bearings (bushes) 60, 62 are formed so as to connect to gear storage chamber 74. Gears 52, 54 are stored in gear storage chamber 74, and bearings 60, 62 are stored in storage spaces 76, 78 for bearings 60, 62. Bearings 60, 62 are cylindrical, and shafts 56, 58 are arranged inside bearings 60, 62.

[0019] A first temperature sensor 18 is attached to the casing 64. The first temperature sensor 18 is attached to the casing 64 near the driven shaft 58 and the bearing 62 of the driven shaft 58. The first temperature sensor 18 measures the temperature of the casing 64. The rotation of the drive gear 52 causes the driven gear 54 to rotate. At that time, the driven shaft 58 may be pressed against the bearing 62 and rotate, which makes it easy for the temperatures of the driven shaft 58 and the bearing 62 that supports the driven shaft 58 to rise. Therefore, by attaching the first temperature sensor 18 near the driven shaft 58 and the bearing 62 that supports the driven shaft 58, the first temperature sensor 18 can more easily detect a rise in temperature of the driven shaft 58 and the bearing 62.

[0020] The second temperature sensor 20 is attached to the tank 24. The second temperature sensor 20 measures the temperature of the hydraulic fluid.

[0021] The control device 22 controls the motor 40 by controlling the drive circuit 42 of the motor 40, and controls the gear pump 14 by controlling the motor 40. The control device 22 is a device equipped with an arithmetic circuit such as a CPU (Central Processing Unit) or a PLC (Programmable Logic Controller). The temperatures measured by the first temperature sensor 18 and the second temperature sensor 20 are input to the control device 22. The temperatures may be input to the control device 22 constantly or periodically. The control device 22 calculates the temperature change per unit time from the input temperatures. The control device 22 controls the switch 46 in accordance with the input temperatures and the change in temperature over time.

[0022] In addition to controlling the motor 40, the controller 22 may also control the valve 28. By controlling the valve 28, the flow of hydraulic fluid is controlled, thereby controlling the hydraulic cylinder 12.

[0023] The present application includes an alarm device 80. The alarm device 80 is a device that issues an alarm when it is determined that an abnormality has occurred or is likely to occur in the gear pump 14. The abnormality in the gear pump 14 is seizure of the driven shaft 58, the bearing 62, or both. The alarm device 80 includes a speaker, a light, or both. The alarm device 80 issues an alarm sound from the speaker or turns on a light.

[0024] Next, a method for controlling the gear pump 14 in the hydraulic device 10 will be described with reference to Fig. 3. It is assumed that the switch 46 is turned on by the control device 22, and when the motor 40 is driven, the gear pump 14 is driven.

[0025] (1) The first temperature sensor 18 measures the temperature of the casing 64, and the second temperature sensor 20 measures the temperature of the working fluid (S1). The temperature of the first temperature sensor 18 is defined as t, and the temperature of the second temperature sensor 20 is defined as T. The measured temperatures t and T are input to the control device 22. The control device 22 calculates the rate of rise of each temperature t and T per unit time (S2), and defines the rate of rise of the temperature t per unit time as t' and the rate of rise of the temperature T per unit time as T'.

[0026] (2) If the temperature t is equal to or higher than the first predetermined temperature X (S3), the control device 22 activates the alarm device 80, stops the gear pump 14, or does both (S7). S3 in FIG. 3 is a control to prevent the bearing 62 from seizing when the temperature of the gear pump 14 becomes equal to or higher than the first predetermined temperature X. The first predetermined temperature X is set to a temperature lower than the temperature at which the bearing 62 of the gear pump 14 seizes, so that the gear pump 14 can be stopped before the bearing 62 seizes. The first predetermined temperature X is determined appropriately depending on the material, structure, type of working fluid, etc. that make up the gear pump 14. If the temperature t is lower than the first predetermined temperature X, the gear pump 14 continues to operate.

[0027] (3) Temperature t is compared with temperature T (S4). If temperature T is less than temperature t, the difference between the rate of increase t' of temperature t and the rate of increase T' of temperature T is calculated. If this difference is equal to or greater than the first temperature increase rate difference Y (S5), the control device 22 activates the alarm device 80, stops the gear pump 14, or does both (S7). This is because the rate of increase t' of the temperature t of the gear pump 14 is large, which could cause the bearing 62 to seize. If the calculated difference is less than the first temperature increase rate difference Y, the control device 22 continues to drive the gear pump 14.

[0028] (4) If the temperature T is equal to or higher than the temperature t, the difference between the rate of rise t' of the temperature t and the rate of rise T' of the temperature T is calculated. If the difference is equal to or higher than the second rate of rise difference Z (S6), the control device 22 activates the alarm device 80, stops the gear pump 14, or does both (S7). This is because the rate of rise t' of the temperature t of the gear pump 14 is large and there is a risk of the bearing 62 burning out. If the calculated difference is less than the second rate of rise difference Z, the control device 22 continues to drive the gear pump 14.

[0029] The first rise rate difference Y and the second rise rate difference Z are determined appropriately depending on the material, structure, and type of working fluid constituting the gear pump 14. For example, in S5 of Fig. 3, the temperature t is higher than the temperature T, and the temperature of the gear pump 14 is higher than the temperature of the working fluid, so the first rise rate difference Y may be set small. Also, in S6 of Fig. 3, the temperature T is higher than the temperature t, and the temperature of the gear pump 14 is lower than the temperature of the working fluid, so the temperature of the gear pump 14 is low, and the second rise rate difference Z may be set large.

[0030] As described above, the present invention is provided with the first temperature sensor 18 and the second temperature sensor 20, which measure the temperature of the gear pump 14 and the temperature of the working fluid, and calculate the temperature change. It is possible to detect an increase in the temperature of the gear pump 14 or a large increase in the temperature of the gear pump 14, and to prevent the bearings 62 of the gear pump 14 from seizing.

[0031] [Embodiment 2] The number of the first temperature sensors 18 is not limited to one. A plurality of first temperature sensors 18 may be provided for one gear pump 14. The drive shaft 56 is provided on both side surfaces of the drive gear 52, and the driven shaft 58 is provided on both side surfaces of the driven gear 54. As in the gear pump 82 shown in FIG. 4, one first temperature sensor 18 is provided for each of the drive shaft 56 and the driven shaft 58. That is, one gear pump 82 is provided with four first temperature sensors 18. When a plurality of first temperature sensors 18 are provided, at least one temperature sensor is arranged near the driven shaft 58 and the bearing 62 of the driven shaft 58. As described in Embodiment 1, the temperature near the driven shaft 58 where the temperature easily rises and the bearing 58 is always measured.

[0032] When a plurality of first temperature sensors 18 are provided, the number of temperatures t measured by the first temperature sensors 18 also becomes plural. The control device 22 may average the plurality of temperatures t and perform the control shown in the flowchart of FIG. 3. In addition, since the plurality of first temperature sensors 18 are near the respective shafts 56, 58 and the bearings 60, 62, the control shown in the flowchart of FIG. 3 may be performed for each first temperature sensor 18 to detect seizure for the respective shafts 56, 58 and the bearings 60, 62.

[0033] [Embodiment 3] A plurality of temperatures X in FIG. 3 may be provided. For example, the temperature X is changed to temperatures X1 and X2 (X1 < X2). When the temperature t becomes equal to or higher than the temperature X1, the alarm device 80 is activated, and when the temperature t becomes equal to or higher than the temperature X2, the gear pump 14 is stopped. Also, the rate-of-rise difference Y in FIG. 3 may be changed to rate-of-rise differences Y1 and Y2 (Y1 < Y2). When the difference between the rate-of-rise t' and T' becomes equal to or greater than Y1, the alarm device 80 is activated, and when the difference between the rate-of-rise t' and T' becomes equal to or greater than Y2, the gear pump is stopped. Further, the rate-of-rise difference Z in FIG. 3 may be changed to rate-of-rise differences Z1 and Z2 (Z1 < Z2). When the difference between the rate-of-rise t' and T' becomes equal to or greater than Z1, the alarm device 80 is activated, and when the difference between the rate-of-rise t' and T' becomes equal to or greater than Z2, the gear pump is stopped.

[0034] [Embodiment 4] The control device 22 may convert the temperature measured by the first temperature sensor 18 into the temperature of the bearing 62. The first temperature sensor 18 directly measures the temperature of the casing 64. The correlation between the temperature of the bearing 62 and the temperature of the casing 64 is determined in advance by experiment. The control device 22 uses this correlation to convert the temperature of the casing 64 into the temperature of the bearing 62.

[0035] [Embodiment 5] The second temperature sensor 20 may measure the temperature of the hydraulic fluid at a location other than the tank 24. For example, the second temperature sensor 20 may measure the temperature of the hydraulic fluid flowing through the pipe 26.

[0036] The number of second temperature sensors 20 is not limited to one, and may be multiple. The second temperature sensors 20 are arranged in multiple locations, such as the tank 24 and the pipes 26, to measure the temperatures T of the working fluid at the multiple locations. The control device 22 may average the multiple temperatures T and perform the control shown in the flowchart of FIG. 3.

[0037] [Embodiment 6] If the temperature t exceeds the temperature T by a predetermined value or more, the alarm device 80 may be activated, the gear pump 14 may be stopped, or both may be performed. This is because if the temperature of the gear pump 14 becomes too high compared to the temperature of the hydraulic fluid in the tank 24 and the piping 26, the bearings 62 may seize.

[0038] [Embodiment 7] As in the hydraulic device 84 of Fig. 5, the second temperature sensor 20 may be omitted compared to the hydraulic device 10 of Fig. 1. The control device 22 utilizes the temperature t measured by the first temperature sensor 18. If the temperature t is equal to or greater than a first predetermined temperature X, the control device 22 activates the alarm device 80, stops the gear pump 14, or both. If the temperature t is less than the temperature X, the control device 22 continues to drive the gear pump 14.

[0039] The control device 22 may also calculate the rate of increase t' of the temperature t per unit time, and if the rate of increase t' exceeds a predetermined value, activate the alarm device 80, stop the gear pump 14, or do both. This is because there is a risk that the temperature of the gear pump 14 may exceed the temperature X.

[0040] [Embodiment 8] 6, the hydraulic device 86 may be provided with a communication device 88. The communication device 88 is a device for transmitting data to a server 92 via a network 90. ​​The communication device 88 includes a device for performing wireless communication such as LTE (Long Term Evolution) or WiFi. The network 90 includes the Internet and an LZN (Local Area Network). The temperature input to the control device 22 is stored in a storage device of the server 92. The gear pump 14 can be monitored for seizure remotely.

[0041] 6 may store the control status of the control device 22 in the server 92 in addition to storing the temperature data. A command may be sent to the control device 22 via the network 90 to instruct the control device 22 on how to control the gear pump 14.

[0042] [Embodiment 9] In the above embodiment, the first temperature sensor 18 measures the temperature of the outer surface of the casing 64, but a hole may be formed in the casing 64 to directly measure the temperature of the bearing 62. The first temperature sensor 18 is attached to the casing 64, and the sensing portion is placed inside the hole.

[0043] [Embodiment 10] The first temperature sensor 18 may be a non-contact temperature sensor. In this case, the first temperature sensor 18 does not need to be directly attached to the gear pump 14, but may be located anywhere.

[0044] [Embodiment 11] In the above embodiment, the prevention of seizure of the driven shaft 58 and the bearing 62 was described, but the first temperature sensor 18 may be used to measure the temperatures of the drive shaft 56 and the bearing 60 to prevent seizure of the drive shaft 56 and the bearing 60.

[0045] [Embodiment 12] A third temperature sensor may be provided to measure the temperature around the gear pump 14. The temperature measured by the third temperature sensor is input to the control device 22. The control device 22 controls the gear pump 14 using the temperatures measured by the first temperature sensor 18, the second temperature sensor 20, and the third temperature sensor. By using the temperature around the gear pump 14, the temperature rise or cooling efficiency of the bearings 62 can be taken into consideration.

[0046] [Embodiment 13] The hydraulic circuit 16 in Fig. 1 is an example and may be modified as appropriate depending on the type of hydraulic cylinder 12, the driving method, etc. The number of hydraulic cylinders 12 is not limited and may be multiple, and the hydraulic circuit 16 is modified as appropriate depending on the number of hydraulic cylinders 12. The valve 28 may be equipped with a flow control valve, a pressure control valve, a backflow prevention valve, etc. in addition to a directional control valve. The hydraulic circuit 16 may be equipped with a filter to remove foreign matter from the hydraulic fluid as needed.

[0047] [Embodiment 14] Although the gear pump 14 in the above embodiment is an external gear pump, it may be an internal gear pump. A first temperature sensor 18 is attached to the casing of the internal gear pump.

[0048] [Embodiment 15] Although the above embodiment has been described with respect to the gear pump 14, a gear motor may be used instead of the gear pump.

[0049] (Item 1) The hydraulic device includes a gear pump or a gear motor, a first temperature sensor provided in the gear pump or gear motor, and a control device that controls the operation of the gear pump or gear motor in accordance with the temperature measured by the first temperature sensor.

[0050] According to the hydraulic device described in paragraph 1, by measuring the temperature of the gear pump or gear motor with the first temperature sensor, it is possible to prevent the bearings of the gear pump or gear motor from seizing up.

[0051] (Item 2) When the temperature measured by the first temperature sensor reaches or exceeds a predetermined temperature, the control device activates an alarm device, stops the gear pump or the gear motor, or both.

[0052] According to the hydraulic device described in paragraph 2, if the temperature measured by the first temperature sensor exceeds a predetermined temperature, it means that the temperature of the gear pump or gear motor has risen too high, and by stopping the gear pump or gear motor, etc., it is possible to prevent the bearings of the gear pump or gear motor from burning out.

[0053] (Item 3) The control device controls the driving of the gear pump or gear motor in accordance with the rate of rise of the temperature measured by the first temperature sensor per unit time.

[0054] According to the hydraulic device described in paragraph 3, if the rate of increase of the temperature measured by the first temperature sensor increases, there is a high possibility that the temperature of the gear pump or gear motor will increase. By controlling the drive of the gear pump or gear motor, it is possible to prevent the bearings of the gear pump or gear motor from seizing.

[0055] (Item 4) A second temperature sensor is provided to measure the temperature of the working fluid, and the control device controls the drive of the gear pump or gear motor according to the temperature measured by the first temperature sensor and the temperature measured by the second temperature sensor.

[0056] According to the hydraulic device described in paragraph 4, the gear pump or gear motor can be controlled based on the temperatures measured by the first temperature sensor and the second temperature sensor, making it easier to prevent the bearings of the gear pump or gear motor from seizing.

[0057] (Item 5) The control device controls the driving of the gear pump or gear motor according to the difference between the temperature measured by the first temperature sensor and the temperature measured by the second temperature sensor.

[0058] According to the hydraulic device described in paragraph 5, if the difference between the temperatures measured by the first temperature sensor and the second temperature sensor becomes large, there is a high possibility that the temperature of the working fluid in the gear pump or gear motor has risen significantly, making it easier to prevent the bearings of the gear pump or gear motor from seizing.

[0059] (Item 6) The control device controls the driving of the gear pump or gear motor according to the difference between the rate of rise of the temperature measured by the first temperature sensor and the rate of rise of the temperature measured by the second temperature sensor.

[0060] According to the hydraulic device described in paragraph 6, the gear pump or gear motor can be controlled according to the difference in the rate of increase per unit time of the temperature measured by the first temperature sensor and the second temperature sensor, thereby preventing the gear pump or the gear pump bearings from seizing.

[0061] (Item 7) The first temperature sensor, the second temperature sensor, or both of them may be plural.

[0062] According to the hydraulic device described in item 7, by providing a plurality of first temperature sensors, a plurality of second temperature sensors, or both, it is possible to eliminate bias in the measured temperatures.

[0063] In addition, the present invention can be implemented in various forms with various improvements, modifications, and changes made based on the knowledge of those skilled in the art without departing from the spirit of the present invention. Although multiple embodiments have been described, the embodiments are not independent and may be implemented in appropriate combinations. [Explanation of symbols]

[0064] 10, 84, 86: Hydraulic equipment 12: Hydraulic cylinder 14, 82: Gear pump 16: Hydraulic circuit 18: First temperature sensor 20: Second temperature sensor 22: Control device 24: Tank 26: Piping 28: Valve 30: Air conditioner 40: Motor 42: Drive circuit 52: Drive gear 54: Driven gear 56: Drive shaft 58: Driven axis 60, 62: Bearings 64: Casing 68: Casing body 70: Front cover 72: Rear cover 80:Alarm device 88:Communication equipment 90: Network 92:Server

Claims

1. A gear pump, a first temperature sensor provided in the gear pump for detecting a temperature of a bearing of the gear pump; a second temperature sensor for measuring the temperature of the hydraulic fluid; a control device that controls driving of the gear pump in accordance with temperatures measured by the first temperature sensor and the second temperature sensor, The control device If the temperature measured by the first temperature sensor exceeds a predetermined temperature, an alarm is activated, the gear pump is stopped, or both are performed; If the temperature measured by the first temperature sensor is lower than a predetermined temperature, controlling the operation of the gear pump according to a difference between a rate of increase per unit time of the temperature measured by the first temperature sensor and a rate of increase per unit time of the temperature measured by the second temperature sensor; a hydraulic device that activates an alarm device, stops a gear pump, or both, when a value obtained by subtracting the rate of rise of the temperature per unit time measured by the second temperature sensor from the rate of rise of the temperature per unit time measured by the first temperature sensor is equal to or greater than a predetermined difference.

2. A gear pump, a first temperature sensor provided in the gear pump for detecting a temperature of a bearing of the gear pump; a second temperature sensor for measuring the temperature of the hydraulic fluid; a control device that controls the operation of the gear pump in accordance with the temperatures measured by the first temperature sensor and the second temperature sensor, The control device controlling the driving of the gear pump in accordance with a difference between a rate of increase per unit time of the temperature measured by the first temperature sensor and a rate of increase per unit time of the temperature measured by the second temperature sensor; a hydraulic device that activates an alarm device, stops a gear pump, or both, when a value obtained by subtracting the rate of rise of the temperature per unit time measured by the second temperature sensor from the rate of rise of the temperature per unit time measured by the first temperature sensor is equal to or greater than a predetermined difference.

3. the bearing is a bearing that receives a driven shaft of the gear pump, 3. The hydraulic device according to claim 1, wherein the first temperature sensor is a temperature sensor for detecting the temperature of a bearing that supports a driven shaft of the gear pump.

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