Oil pump device

Abstract

To provide an oil pump device capable of avoiding foreign matters from being bitten into a position where an oil pump slides, and of preventing the oil pump from being locked to be non-rotatable.SOLUTION: An oil pump device includes: an oil pump 3 connected to a supply target device 1 via a hydraulic circuit 5 to discharge and supply oil through the hydraulic circuit 5 to the supply target device 1; a motor 4 for driving the oil pump 3; a trapping member 11 mounted in the hydraulic circuit 5 and trapping foreign matters mixed in the oil discharged from the oil pump 3; and a motor control part 12 for controlling the motor 4 to execute a normal control mode in which the oil pump 3 is driven in a normal control rotation region, and, at starting the operation of the oil pump 3, to execute a lock avoidance mode in which the oil pump 3 is driven at a preset lock avoidance rotation speed as a lower limit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an oil pump device. [Background technology]

[0002] As an example of this type of oil pump device, Patent Document 1 discloses an electric oil pump device for an automatic transmission mounted on a vehicle. The oil pump device is equipped with a trochoidal oil pump driven by a motor, and oil discharged from the oil pump is supplied to the automatic transmission via a hydraulic circuit. Due to various factors, foreign matter such as metal powder and dust may become mixed into the oil. These foreign matter may not only cause malfunctions or breakdowns in the automatic transmission, but may also interfere with the rotation of the oil pump.

[0003] For example, a trochoidal oil pump transports oil by utilizing the volume change that occurs when the inner rotor rotates relative to the outer rotor. Small foreign objects are swept downstream along with the oil through the clearance between the rotors, but larger objects become trapped in the sliding area. Engine-driven oil pumps can maintain rotation by crushing trapped foreign objects with sufficient drive torque. However, electric oil pumps lack sufficient motor drive torque, so foreign objects can interfere with the relative rotation of the rotors, causing the oil pump to become unable to rotate. In the following explanation, this phenomenon is referred to as oil pump lock. Furthermore, increasing the size of the motor to compensate for the drive torque can result in adverse effects such as increased costs and a larger oil pump device.

[0004] To prevent foreign matter from getting caught, Patent Document 1 discloses a countermeasure for when the oil pump is stopped in a high-temperature range. Specifically, if the oil pump is stopped with foreign matter caught in the sliding parts, the clearance between the sliding parts will decrease as the temperature drops. As a result, the amount of foreign matter caught in the oil pump gradually increases as the clearance decreases, and the lock cannot be released even by rotating the oil pump forward or backward, making it impossible to resume operation. As a countermeasure, Patent Document 1 discloses a technology that periodically removes foreign matter by repeatedly operating the oil pump for short periods at predetermined intervals when the oil pump is stopped in a high-temperature range. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-242599 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the technology described in Patent Document 1 is only a measure to be taken after foreign matter has become lodged in the oil pump. Therefore, even if the oil pump is driven, it may not be possible to remove the lodged foreign matter, which can cause a serious problem in that the oil pump remains locked and cannot resume operation.

[0007] The present invention has been made to solve these problems, and its purpose is to provide an oil pump device that can prevent foreign matter from getting caught in the sliding parts of the oil pump, thereby preventing the oil pump from locking and becoming unable to rotate. [Means for solving the problem]

[0008] In order to achieve the above object, the oil pump device of the present invention is characterized by comprising: an oil pump connected to a supply target device via a hydraulic circuit, which discharges oil and supplies it to the supply target device via the hydraulic circuit; a motor that drives the oil pump; a capturing member that is interposed in the hydraulic circuit and captures foreign matter that gets mixed into the oil discharged from the oil pump; and a motor control unit that controls the motor to execute a normal control mode in which the oil pump is driven in a normal control rotation range, and, when the oil pump starts operating, executes a lock avoidance mode in which the oil pump is driven with a preset lock avoidance rotation speed as the lower limit.

[0009] As another aspect, when the motor control unit starts operating the oil pump for the first time after the operation of the oil pump device has been started, the motor control unit may execute the lock avoidance mode, assuming that this is the start of operation of the oil pump.

[0010] In another aspect, the motor control unit may repeatedly operate and stop the oil pump while the oil pump device is in operation, and each time the operation of the stopped oil pump is resumed, it may consider this to be the start of operation of the oil pump and execute the lock avoidance mode.

[0011] In another aspect, when the motor control unit starts operation of the oil pump for the first time after the oil pump device is manufactured, the lock avoidance mode may be executed, assuming that this is the start of operation of the oil pump.

[0012] In another aspect, when the motor control unit first operates after maintenance of the oil pump device to start operating the oil pump, it may execute the lock avoidance mode, assuming that this is the start of operation of the oil pump.

[0013] In another aspect, the oil pump device may further include a reset input unit that can be operated at will, and when the oil pump device starts operating with the reset input unit operated, the motor control unit may consider this to be the first operation after manufacture or the first operation after maintenance has been performed, and may execute a lock avoidance mode when starting operation of the oil pump.

[0014] In another aspect, when the oil pump device starts operating and the motor control unit begins operating the oil pump, if the reset input unit is not operated, the motor control unit may execute the lock avoidance mode for a predetermined first execution time, and if the reset input unit is operated and the motor control unit determines that this is the first operation of the oil pump device after manufacture or the first operation after maintenance has been performed, the motor control unit may execute the lock avoidance mode for a second execution time that is predetermined to be longer than the first execution time.

[0015] In another aspect, the motor control unit may execute the lock avoidance mode for a preset third execution time when the oil pump starts operating for the first time after the oil pump device has started operating, and may execute the lock avoidance mode for a fourth execution time that is preset to be shorter than the third execution time each time the operation of the oil pump that has been stopped while the oil pump device is operating is resumed.

[0016] In another aspect, the lockup avoidance rotational speed may be set to a higher rotational speed than the normal control rotational speed range, and the motor control unit may drive the oil pump at the lockup avoidance rotational speed in the lockup avoidance mode.

[0017] In another aspect, the lock-avoidance rotational speed may be set within the normal control rotation range, and when the target rotational speed of the oil pump set in the normal control mode is less than the lock-avoidance rotational speed, the motor control unit may drive the oil pump at the lock-avoidance rotational speed in the lock-avoidance mode, and when the target rotational speed set in the normal control mode is equal to or greater than the lock-avoidance rotational speed, the motor control unit may drive the oil pump at the target rotational speed in the lock-avoidance mode. [Effects of the Invention]

[0018] According to the oil pump device of the present invention, foreign matter can be prevented from getting caught in the sliding parts of the oil pump, thereby preventing the oil pump from locking up and becoming unable to rotate. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is an overall configuration diagram showing an oil pump device according to an embodiment; [Figure 2] 4 is a flowchart showing an oil control routine executed by an oil control controller. [Figure 3] 10 is a flowchart showing an oil control routine executed by an oil control controller according to another example. [Figure 4] 10 is a flowchart showing a lock avoidance rotation speed N setting routine executed by an oil control controller according to another example. DETAILED DESCRIPTION OF THE INVENTION

[0020] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in which the present invention is embodied in an oil pump device intended for a drive system for an electric vehicle. In the following description, the electric vehicle will be simply referred to as a vehicle. FIG. 1 is a diagram showing the overall configuration of an oil pump device according to this embodiment. Although not shown in Fig. 1, the traveling drive device 1 of this embodiment is composed of a traveling motor as a power source, a generator for generating electricity, a transmission for changing the rotation speed of the traveling motor, a reducer for reducing the rotation speed of the traveling motor, etc. In this embodiment, this traveling drive device 1 corresponds to the "supplied equipment" of the present invention. For example, the traveling motor is configured as a brushless DC motor, and its output shaft is connected to the front wheels of the vehicle via the generator, transmission, and reducer.

[0021] The traveling drive device 1 is controlled by a traveling control controller (not shown), but the details of the control are not directly related to the gist of the present invention and will therefore only be briefly described. For example, when the accelerator of the vehicle is operated and the traveling motor is driven by power supplied from a battery (not shown), the resulting drive torque is transmitted to the front wheels of the vehicle via a generator, transmission, and speed reducer, causing the vehicle to travel. Furthermore, when the vehicle decelerates, the rotation of the front wheels is transmitted to the generator via a speed reducer and transmission, and the generated power is charged into the battery. Note that the configuration of the traveling drive device 1 is not limited to the above and can be modified as desired.

[0022] Each component of the traveling drive device 1 requires lubrication and cooling. For example, the bearings of the traveling motor and generator, or the gear trains of the transmission and reducer, require lubrication to ensure smooth sliding. Furthermore, the traveling motor and generator generate heat due to losses in the coils, cores, etc. during operation, and therefore require cooling to prevent overheating.

[0023] For the purpose of such lubrication and cooling, the traveling drive device 1 is provided with an oil pump device 2, the details of which will be described below. The oil pump 3 of the oil pump device 2 is configured as a trochoidal oil pump driven by a motor 4, and is connected to the traveling drive device 1 via a circulation path 5. In this embodiment, this circulation path 5 corresponds to the "hydraulic circuit" of the present invention. The motor 4 is capable of driving the oil pump 3 at any rotational speed, and the amount of oil discharged from the oil pump 3 is adjusted according to the rotational speed.

[0024] The circulation path 5 is made up of a supply circulation path 5a that connects the discharge port 3a of the oil pump 3 to the inlet side of the traveling drive device 1, and a discharge circulation path 5b that connects the outlet side of the traveling drive device 1 to the suction port 3b of the oil pump 3. Oil discharged from the discharge port 3a of the oil pump 3 is supplied to the traveling drive device 1 via the supply circulation path 5a, and after performing its lubricating and cooling functions, the oil is discharged from the traveling drive device 1 and is sucked into the suction port 3b of the oil pump 3 via the discharge circulation path 5b.

[0025] In the supply circulation path 5a, a switching valve 6, an oil cooler 7, and an oil temperature sensor 8 are installed in this order from the oil pump 3 side. The switching valve 6 is connected to a point on the supply circulation path 5a downstream of the oil cooler 7 via a bypass path 9. Oil from the oil pump 3 is guided to either the supply circulation path 5a side toward the oil cooler 7 or the bypass path 9 side, depending on the switching of the switching valve 6. As a result, oil that has been cooled by circulating through the oil cooler 7 or oil that has bypassed the oil cooler 7 is supplied to the traveling drive device 1. The temperature of the oil supplied to the traveling drive device 1 in this way is detected by the oil temperature sensor 8.

[0026] Meanwhile, an oil tank 10 and a filter 11 are installed in the discharge circulation path 5b in this order from the traveling drive device 1 side. The oil discharged from the traveling drive device 1 passes through the discharge circulation path 5b and is temporarily returned to the oil tank 10 where it is stored, and then passes from the oil tank 10 through the discharge circulation path 5b and the filter 11 and is sucked back into the oil pump 3.

[0027] Metal powder, dust, and the like can become mixed into oil due to various factors, and in the following explanation, these will sometimes be collectively referred to as foreign matter. For example, after manufacturing the oil pump device 2 and the traveling drive device 1, fine metal powder and the like generated during the cutting process may adhere to the interior. Furthermore, for a while after manufacturing, wear progresses due to initial break-in of the sliding parts of the oil pump device 2 and the traveling drive device 1, generating fine metal powder and contaminating the oil. Even after the initial break-in, metal powder due to wear decreases but continues to be generated. Examples of sliding parts include the rotors of the oil pump 3, or the gear trains of the transmission and reducer. The rotors of the oil pump 3, which are one of the sliding parts, are also places where foreign matter can become caught, so in the following explanation, they will be specifically referred to as the pump sliding parts.

[0028] Maintenance of the oil pump device 2 and the traveling drive device 1 can also be an opportunity for foreign matter to become mixed into the oil. Maintenance involves, for example, replacing parts such as the oil pump 3 or piping, or replacing each device that makes up the traveling drive device 1, and foreign matter such as metal powder adhering to the replaced parts or the inside of the device may become mixed into the oil. Furthermore, if an oil change is performed as part of maintenance, there is a possibility that foreign matter has already become mixed into the oil itself.

[0029] Due to these factors, foreign matter of various sizes can become mixed into the oil, and foreign matter of a certain size can become lodged in the sliding parts of the pump, causing locking or significant damage to the sliding parts. As a countermeasure, a filter 11 is provided in the circulation path 5, and the mesh size of the filter 11 is set to capture even the smallest particles that could become lodged in or cause damage to the sliding parts of the pump. Therefore, the oil that has passed through the filter 11 can be considered to be free of foreign matter that could become lodged in the sliding parts of the pump. In this embodiment, the filter 11 corresponds to the "capturing member" of the present invention.

[0030] The configuration of the oil pump device 2 is not limited to the above and can be changed as desired. For example, the oil cooler 7 and the bypass path 9 may be omitted, an oil reservoir may be provided below the oil pump 3 instead of the oil tank 10, or the position of the filter 11 on the circulation path 5 may be changed.

[0031] The oil pump device 2 is provided with an oil control controller 12 that controls the state of oil supply to the traveling drive device 1. The input side of the oil control controller 12 is connected to each device that constitutes the traveling drive device 1, the oil temperature sensor 8, and a reset input unit 13, and is configured to input operation information for each device of the traveling drive device 1, detection information from the oil temperature sensor 8, and the operating state of the reset input unit 13. As will be described in detail later, the reset input unit 13 is a device that causes the oil control controller 12 to recognize the first operation after the oil pump device 2 is manufactured and the first operation after maintenance is performed.

[0032] The oil control controller 12 controls the rotation speed of the oil pump 3 and the switching state of the switching valve 6 to keep each device of the traveling drive device 1 in a good lubricated state and to suppress heat generation from the traveling motor and the like to maintain an appropriate temperature range. For this purpose, the motor 4 of the oil pump 3 and the switching valve 6 are connected to the output side of the oil control controller 12. In this embodiment, the oil control controller 12 corresponds to the "motor control unit" of the present invention. The basic control content of the oil control controller 12 is similar to that of a general oil pump device 2, so only a brief explanation will be given, and the control at this time will be referred to as the normal control mode in the following explanation.

[0033] When the vehicle's power switch is turned ON, the oil control controller 12 starts up together with the travel control controller and starts operating the oil pump device 2. For example, even if the travel motor is operated in response to accelerator operation, if the oil temperature is low, the oil control controller 12 may set the target rotation speed Ntgt of the oil pump 3 to 0 rpm and keep the oil pump 3 stopped. Then, as the travel motor continues to operate and the oil temperature gradually increases, the switching valve 6 is switched to the bypass path 9 side to stop oil cooling by the oil cooler 7, the target rotation speed Ntgt is increased from 0 rpm, and the oil pump 3 is driven at a low rotation speed by the motor 4. If the oil temperature subsequently increases, the switching valve 6 is switched to the supply circulation path 5a side to cool the oil by the oil cooler 7, and the target rotation speed Ntgt is reset to the increased side to increase the rotation speed of the oil pump 3.

[0034] The above is the control of the oil pump device 2 based on the oil temperature, but the oil pump device 2 is also controlled based on the operating state of each device in the traveling drive device 1. As a result, in normal control mode the oil pump 3 is controlled between 0 rpm, which corresponds to a stop, and a predetermined rotation speed, more specifically, up to the highest rotation speed required for lubricating and cooling the traveling drive device 1; hereinafter, this rotation range is referred to as the normal control rotation range.

[0035] However, if foreign matter mixed in the oil gets caught in the sliding parts of the pump, the oil pump 3 will fall into a locked state where it cannot rotate. The technology described in Patent Document 1 is a measure to be taken after foreign matter has become caught, so it does not lead to a solution to the above problem.

[0036] In view of these problems, the inventors of the present invention focused on the relationship between foreign matter getting caught in the pump sliding parts and the rotational speed of the oil pump 3. That is, while foreign matter of a certain size gets caught in the pump sliding parts, when the rotational speed of the oil pump 3 is increased, foreign matter of the same size passes through without getting caught in the pump sliding parts. This phenomenon is presumably caused by the increase in the amount of oil flowing through the pump sliding parts as the rotational speed increases, and foreign matter is transported with the flow of a large amount of oil, preventing it from getting caught in the pump sliding parts.

[0037] Therefore, even if foreign matter gets caught in the pump sliding parts when the oil pump 3 is operated in the normal control rotation range, it can be seen that this can be avoided by increasing the rotation speed of the oil pump 3. Furthermore, foreign matter that passes through the pump sliding parts with the flow of oil is captured by the filter 11 interposed in the circulation path 5, so there is no need to increase the rotation speed of the oil pump 3 thereafter, and it becomes possible to operate in the normal control rotation range, in other words, to switch to the original normal control mode.

[0038] Based on the above findings, the oil pump device 2 of this embodiment executes a lock avoidance mode in which the rotational speed of the oil pump 3 is increased instead of the normal control mode when the oil pump 3 starts operating. For this reason, a rotational speed higher than the normal control rotational speed range, for example, in this embodiment, the maximum rotational speed of the oil pump 3 that can be driven by the motor 4, is set in advance as the lock avoidance rotational speed N.

[0039] The start of operation of the oil pump 3 when the lock avoidance mode should be executed is roughly divided into three types: start of normal operation, start of operation after manufacture, and start of operation after maintenance.

[0040] The start of operation after manufacture refers to the timing when, after the oil pump device 2 and the traveling drive device 1 are manufactured and installed in the vehicle, the oil pump device 2 first starts operating and starts operating the oil pump 3. Since foreign matter such as metal powder may adhere to the inside of the oil pump device 2 and the traveling drive device 1 after manufacture, the lock avoidance mode is executed at this timing as a measure to prevent such foreign matter from becoming caught.

[0041] The start of operation after maintenance refers to the timing when the oil pump device 2 first starts operating and starts the oil pump 3 after maintenance is performed on the oil pump device 2 or the traveling drive device 1. There may be foreign matter such as metal powder adhering to the inside of parts or equipment replaced during maintenance, and there is also a possibility that foreign matter has already become mixed into the oil itself. Therefore, the lock avoidance mode is activated at this timing as a measure to prevent such matter from getting caught.

[0042] The start of normal operation refers to any timing at which the oil pump 3 starts operating, excluding the start of operation after manufacture and the start of operation after maintenance. When the oil pump device 2 and the traveling drive device 1 are operating, metal powder and the like are generated at the sliding points due to wear, and the lock avoidance mode is activated at this timing as a measure to prevent the powder from getting caught. In this embodiment, the oil pump 3 is not operated continuously while the oil pump device 2 is operating, but is instead operated and stopped repeatedly as appropriate based on the oil temperature, the operating state of the traveling drive device 1, and the like. For this reason, the lock avoidance mode is activated not only when the oil pump 3 is first started after the oil pump device 2 is started, but also each time the oil pump 3 is subsequently stopped and then restarted, as these are considered to be the start of normal operation.

[0043] As described above, the purpose of the lock avoidance mode is to prevent foreign matter mixed in the oil from getting caught by allowing it to pass through the pump sliding points until it is captured by the filter 11. Therefore, it is necessary to continue executing the lock avoidance mode until the foreign matter in the oil is captured by the filter 11, but the appropriate execution time t differs when normal operation starts, when operation starts after manufacture, and when operation starts after maintenance. Furthermore, even when normal operation starts, the appropriate execution time t of the lock avoidance mode differs between the first start of normal operation of the oil pump 3 after the oil pump device 2 starts operating and the second or subsequent start of normal operation.

[0044] At the start of normal operation, foreign matter such as metal powder is generated at the sliding parts of the pump due to wear caused by the operation of the oil pump device 2 and the travel drive device 1 immediately beforehand, but the amount generated is small and the foreign matter is mixed into the oil immediately after it is generated. Therefore, foreign matter that passes through the sliding parts of the oil pump 3 along with the oil passes through the circulation path 5 and is quickly captured by the filter 11, preventing it from being sucked back into the oil pump 3. Because the foreign matter is captured by the filter 11 in this short time, the execution time t of the lock avoidance mode that is applied at the start of normal operation is preset to be relatively shorter than that at the start of operation after manufacture and after maintenance.

[0045] Specifically, when normal operation is first started after the oil pump device 2 starts operating, the execution time t of the lockup avoidance mode is set to, for example, about 60 seconds. In this embodiment, the execution time t when set to 60 seconds corresponds to the "first execution time" or "third execution time" of the present invention. The lockup avoidance mode at the start of normal operation for the first time allows most of the foreign matter mixed in the oil to be captured by the filter 11. When the operation of the stopped oil pump 3 is subsequently restarted, that is, at the start of normal operation for the second or subsequent times, a shorter execution time t of the lockup avoidance mode is set to, for example, about 15 seconds, in order to allow only a very small amount of foreign matter newly generated due to wear to be captured by the filter 11. In this embodiment, the execution time t when set to 15 seconds corresponds to the "first execution time" or "fourth execution time" of the present invention.

[0046] In contrast, when operation starts after manufacturing, foreign matter such as metal powder generated during cutting work adheres to the interior of the oil pump device 2 and the traveling drive device 1, and when operation starts after maintenance, foreign matter such as metal powder adheres to the interior of parts and equipment replaced during maintenance. The amount of foreign matter such as metal powder adhering is often greater than the amount of metal powder and other foreign matter associated with wear at the start of normal operation. Furthermore, even if oil flows into the circulation path 5, it is not guaranteed that all of the adhering foreign matter will immediately peel off and pass through the sliding parts of the oil pump 3 along with the oil. Therefore, assuming that there will be foreign matter that takes time to peel off, a relatively long execution time t of, for example, 180 seconds is preset when operation starts after manufacturing and when operation starts after maintenance. In this embodiment, the execution time t set to 180 seconds corresponds to the "second execution time" of the present invention.

[0047] Because the oil control controller 12 controls the motor 4 that drives the oil pump 3, it can recognize the start of operation of the oil pump 3 based on its own control. However, it cannot determine whether the start of operation corresponds to the start of normal operation, or the start of operation after manufacture or after maintenance. Therefore, for example, at a vehicle manufacturing plant, when the oil pump device 2 and the traveling drive device 1 are manufactured and installed on the vehicle, a manufacturing technician operates the reset input unit 13 and then test-runs the oil pump device 2. Also, at a vehicle repair plant, when maintenance is performed on the oil pump device 2 or the traveling drive device 1, a repair technician operates the reset input unit 13 and then test-runs the oil pump device 2.

[0048] Based on operation of the reset input unit 13, the oil control controller 12 recognizes that the oil pump device 2 has started operating for the first time since manufacture or maintenance. Then, when operation of the oil pump 3 starts based on the oil temperature, the operating state of the traveling drive device 1, etc., it is considered to be the start of operation after manufacture or maintenance. Furthermore, if operation of the oil pump 3 starts without operating the reset input unit 13, the oil control controller 12 considers it to be the start of normal operation.

[0049] In this way, the reset input unit 13 is a device that should be operated arbitrarily by a person in charge at a vehicle manufacturing plant or repair plant, and is therefore provided in a location where the vehicle user will not operate it by mistake, such as a hidden location inside the vehicle.

[0050] Next, we will explain the control of the oil pump device 2, particularly the control related to the lock avoidance mode, executed by the oil control controller 12. When the vehicle power switch is turned on, the oil control controller 12 executes the oil control routine shown in Figure 2 at predetermined control intervals, and the oil pump device 2 starts operating.

[0051] First, we will describe the execution status of the lock avoidance mode at the start of normal operation when the reset input unit 13 is not operated. In step S1, it is determined whether operation of the oil pump 3 has started, and if the result is No (negative), the process proceeds to step S2, where the normal control mode is executed, and then the routine is temporarily terminated. As described above, in the normal control mode, the operating state of the oil pump 3 is controlled based on the oil temperature, the operating state of the travel drive unit 1, and the like. While the oil pump 3 is kept stopped in the normal control mode, even if the routine is started again, the determination in step S1 is No, and the normal control mode in step S2 continues.

[0052] Then, when it is determined that operation of the oil pump 3 should be started in the normal control mode, a Yes (affirmative) determination is made when the process subsequently proceeds to step S1, and the process proceeds to step S3. In step S3, it is determined whether the reset input unit 13 has been operated, and in this case, since it has not been operated, it is considered that normal operation has started and a No determination is made. Thereafter, the process proceeds to step S4, where it is determined whether operation of the oil pump 3 has started for the first time since operation of the oil pump device 2 began. Since this is the first operation of the oil pump 3 since operation began, in this case it is considered that this is the first time normal operation has started, and the process proceeds to step S5.

[0053] In step S5, the execution time t of the lockup mode is set to 60 seconds, and in the following step S6, the lockup mode is executed based on the set execution time t. Accordingly, in this case, the motor 4 is controlled to drive the oil pump 3 at the lockup rotational speed N for 60 seconds. The target rotational speed Ntgt is set to any value within the normal control rotational speed range. The rotational speed of the oil pump 3 is increased from the target rotational speed Ntgt to the lockup rotational speed N, which corresponds to the maximum rotational speed, and foreign matter is transported by the large flow of oil. Therefore, even if a foreign matter is large enough to become caught in the oil sliding parts when the oil pump 3 is operated in the normal control rotational speed range, it passes through the pump sliding parts without becoming caught in the pump sliding parts in the lockup mode. The foreign matter then passes through the circulation path 5 and is quickly captured by the filter 11, thereby preventing the foreign matter from being sucked into the oil pump 3 again and thereby preventing it from becoming caught in the pump sliding parts.

[0054] Since the oil pump 3 is driven at the lock-avoidance rotational speed N, which is higher than the normal control rotational speed range, a larger amount of oil is supplied to the traveling drive device 1 while the lock-avoidance mode is being executed. However, unlike when the amount of oil supplied is insufficient, even if there is a slight excess, no problems arise with regard to lubrication and cooling.

[0055] When the lockup avoidance mode is terminated in step S6, the process proceeds to step S2, where the normal control mode is executed again. For example, if oil supply should be continued based on the oil temperature at that time, the operating state of the traveling drive unit 1, and the like, a predetermined target rotation speed Ntgt is set within the normal control rotation range, and operation of the oil pump 3 is continued. Alternatively, if oil supply is not required, the target rotation speed Ntgt is set to 0 rpm, and the oil pump 3 is stopped. Then, in the normal control mode, if a determination is made to resume operation of the oil pump 3 that was once stopped, a "Yes" determination is made in step S1, and then, after passing through step S3, a "No" determination is made in step S4 because this is the second or subsequent start of normal operation, and the process proceeds to step S7. In step S7, the execution time t of the lockup avoidance mode is set to 15 seconds, and the lockup avoidance mode is executed in the following step S6, where the oil pump 3 is driven at the lockup avoidance rotation speed N for 15 seconds.

[0056] Because most of the foreign matter is trapped in the filter 11 when normal operation is first started, the execution time t of the lock-up avoidance mode is shortened from the second time onward. However, even if a small amount of foreign matter occurs thereafter, it is successfully trapped in the filter 11 while the lock-up avoidance mode is being executed. From then on, as long as the oil pump device 2 continues to operate, the lock-up avoidance mode is executed for 15 seconds each time the operation of the oil pump 3 is stopped and restarted, thereby trapping the foreign matter in the filter 11 and removing it from the oil. As a result, there are no foreign matter in the oil that is large enough to become trapped in the oil sliding parts. Therefore, not only during the execution of the lock-up avoidance mode, but also when the rotational speed of the oil pump 3 decreases due to the subsequent transition to the normal control mode, it is possible to prevent foreign matter from getting trapped and, consequently, locking of the oil pump 3.

[0057] Next, we will explain the execution status of the lock avoidance mode when starting operation after manufacturing and when starting operation after maintenance. The lock avoidance mode executed at the start of both operations has the same content, and is also started based on the operation of the reset input unit 13. Therefore, we will explain the execution status of the lock avoidance mode when starting operation after manufacturing as a representative example.

[0058] Now, it is assumed that after the oil pump device 2 and the traveling drive device 1 are manufactured, the reset input unit 13 is operated by a manufacturing person, and the power switch of the vehicle is turned on to test run the oil pump device 2.

[0059] When the routine is first started, a No determination is made in step S1 and the routine proceeds to step S2, but if a determination is made that operation of the oil pump 3 should be started in the normal control mode, a Yes determination is made in step S1 and the routine proceeds to step S3. Because the reset input unit 13 has been operated in step S3, a Yes determination is made and the routine proceeds to step S8. In step S8, it is determined whether or not this is the first Yes determination in step S1 after the reset input unit 13 has been operated, in other words, whether or not this is the situation in which the oil pump device 2 has been operated for the first time since manufacture and operation of the oil pump 3 has started. If the determination is Yes, it is considered that this is the start of operation after manufacture, and the routine proceeds to step S9, where 180 seconds is set as the execution time t of the lockup avoidance mode, and the lockup avoidance mode is executed in the subsequent step S6, and the oil pump 3 is driven at the lockup avoidance rotation speed N for 180 seconds.

[0060] As a result, the lockup avoidance mode continues for a longer period of time than when normal operation is first started based on the settings in step S5. While this lockup avoidance mode is in operation, foreign matter such as metal powder adhering to the interior of the oil pump device 2 and the travel drive device 1 peels off, passes through the pump sliding areas, and is captured by the filter 11. While some foreign matter may not peel off, foreign matter that has been adhering for 180 seconds is likely to remain attached thereafter. As a result, it can be assumed that there are no more foreign matter in the oil that is large enough to become trapped in the oil sliding areas. Therefore, just as in normal operation, foreign matter getting trapped in the pump sliding areas and, ultimately, the resulting lockup of the oil pump 3 can be prevented.

[0061] The process then transitions to normal control mode in step S2, and when it is determined that operation of the oil pump 3, which was temporarily stopped, should be restarted, the process transitions to step S8 via steps S1 and S3. Because the Yes determination in step S1 is not the first since the reset input unit 13 was operated, the process transitions to No in step S8 and the process transitions to step S4. Then, because the lockup avoidance mode has already been executed based on the execution time t set in step S9, the process transitions to No in this case in step S4, and the process transitions to step S7, assuming that this is the second or subsequent start of normal operation. Therefore, the subsequent processing is the same as that at the start of normal operation described above, and the lockup avoidance mode is executed in step S6 based on the 15 seconds set in step S7.

[0062] As described above, according to this embodiment, the lockup avoidance mode is executed when the oil pump 3 is started during operation of the oil pump device 2, and the oil pump 3 is driven at the lockup avoidance rotation speed N that is set on the higher rotation side than the normal control rotation range applied in normal control mode. Therefore, foreign matter is transported with the large amount of oil flow, passes through without getting caught in the sliding parts of the pump, and is captured in the filter 11. Therefore, not only while the lockup avoidance mode is being executed, but also after the lockup avoidance mode is ended and the control mode is switched to the normal control mode, foreign matter is prevented from being sucked into the oil pump 3 again and from getting caught in the sliding parts of the pump, and a lockup of the oil pump 3 due to this can be avoided in advance.

[0063] In addition, foreign matter getting caught in the pump sliding parts can not only lock the oil pump 3, but can also cause damage to the pump sliding parts. If the clearance of the pump sliding parts increases due to repeated damage, the pump efficiency will decrease, but the lock avoidance mode also greatly contributes to preventing such problems.

[0064] Furthermore, avoiding locking of the oil pump 3 leads to the advantage of being able to accurately perform a fail determination of the oil pump device 2. In normal control mode, the oil pump 3 is driven at a desired rotation speed within the normal control rotation range. If the rotation speed of the oil pump 3 decreases due to an increase in load or the like, the current supplied to the motor 4 is increased accordingly to maintain the desired rotation speed. If an overload occurs for some reason, a sudden increase in the supply current is deemed to be an overload, a fail determination is made, and driving of the oil pump 3 by the motor 4 is stopped. If the oil pump 3 locks due to the jamming of a foreign object, the supply current also increases suddenly, making it impossible to determine whether this condition is due to an overload, which is the original purpose of the fail determination, or due to the jamming of a foreign object. In this embodiment, locking due to the jamming of a foreign object is prevented in advance, so if the supply current to the motor 4 suddenly increases, it can be determined that an overload has occurred, and as a result, a fail determination can be performed accurately.

[0065] On the other hand, the lock avoidance mode, which increases the rotational speed of the oil pump 3, does not cause any problems in terms of lubrication or cooling of the traveling drive device 1, but it can increase, for example, the power consumption and operating noise of the motor 4. For this reason, it is desirable to terminate the lock avoidance mode and transition to the normal control mode as soon as possible after preventing the entry of foreign matter. From this perspective, in this embodiment, the execution time t of the lock avoidance mode is made different at the start of normal operation, the start of operation after manufacturing, and the start of operation after maintenance. Furthermore, even within the start of normal operation, the execution time t of the lock avoidance mode is made different between the first start of normal operation and the second or subsequent start of normal operation.

[0066] Specifically, when starting operation after manufacture and when starting operation after maintenance, the longest execution time t of the lock avoidance mode (e.g., 180 seconds) is set in consideration of the fact that all foreign matter, such as metal powder adhering to the interior of the oil pump device 2 and the traveling drive device 1, does not immediately peel off. Also, when starting normal operation for the first time, although foreign matter, such as metal powder due to wear, is mixed into the oil, it flows through the circulation path 5 together with the oil and is captured by the filter 11. Also, when starting normal operation for the second time or thereafter, the shortest execution time t of the lock avoidance mode (e.g., 15 seconds) is set in consideration of the fact that most foreign matter is captured by the filter 11 at the start of normal operation for the first time.

[0067] By setting the execution time t in this way, it is possible to reliably prevent foreign matter from getting caught in the sliding parts of the pump, and also to prevent unnecessary continuation of the lock avoidance mode, thereby reducing the power consumption and operating noise of the motor 4.

[0068] In the above embodiment, the maximum rotational speed of the oil pump 3 is set as the lock avoidance rotational speed N, but this is not limited to this. In consideration of the power consumption and operating noise of the motor 4, it is desirable to set the lock avoidance rotational speed N as low as possible while preventing jamming in the sliding parts of the pump. On the other hand, if the rotational speed of the oil pump 3 falls below the target rotational speed Ntgt set in the normal control mode, the amount of oil discharged may be insufficient, which may cause problems with lubrication and cooling of the traveling drive device 1. For this reason, it is necessary to drive the oil pump 3 at a rotational speed equal to or higher than the target rotational speed Ntgt set at that time, not only in the normal control mode but also in the immediately preceding lock avoidance mode.

[0069] Therefore, in order to satisfy all of the above requirements, it is conceivable to set the lockup avoidance rotational speed N within the normal control rotational speed range, and then increase or decrease the lockup avoidance rotational speed N as appropriate based on the target rotational speed Ntgt. The details of this method will be described below as another example.

[0070] [Another example of embodiment] The difference from the embodiment lies in the processing of the oil control controller 12, and for example, the configuration shown in Fig. 1 is common to the embodiment. Therefore, the explanation will focus on the differences, and redundant explanations of the common configuration and control contents will be omitted.

[0071] In this alternative example, the lock-avoidance rotational speed N is set within the normal control rotational speed range. Specifically, considering the purpose of the lock-avoidance mode, which is to prevent foreign matter from getting caught in the sliding parts of the pump, if the lock-avoidance rotational speed N is set near the lower limit of the normal control rotational speed range, for example, the amount of oil flowing through the sliding parts of the pump will be insufficient, and the intended purpose will not be achieved. The lower limit of the rotational speed at which foreign matter can be prevented from getting caught varies depending on the specifications of the oil pump, but in this embodiment, the lock-avoidance rotational speed N is set to the median value within the normal control rotational speed range, based on the recognition that jamming can be prevented if the rotational speed is equal to or higher than the median value within the normal control rotational speed range. Note that the median value is just an example, and any rotational speed within the normal control rotational speed can be set as long as jamming can be prevented.

[0072] FIG. 3 is a flowchart showing an oil control routine executed by the oil controller 12 of another example, and FIG. 4 is a flowchart showing a lock avoidance rotation speed N setting routine executed by the oil controller 12 of the same example.

[0073] 3, the normal control mode is executed, and when a determination is made to start operation of the oil pump 3, the process proceeds to step S1 via step S11. In step S11, a process for setting the lockup avoidance rotation speed N is executed, specifically, a process for resetting the lockup avoidance rotation speed N, which is set to the median value within the normal control rotation range, to an increased value as necessary. Thereafter, the same process as in the embodiment is executed, and the execution time t of the lockup avoidance mode is set according to the start of normal operation for the first time, the start of normal operation for the second time or later, or the start of operation after manufacture and the start of operation after maintenance (S5, S7, S9). After the lockup avoidance mode is executed based on the execution time t (S6), the process proceeds to the normal control mode (S2).

[0074] When the process proceeds to step S11, the routine of Fig. 4 is started. First, in step S21, the target rotation speed Ntgt is calculated based on the oil temperature, the operating state of the traveling drive device 1, etc. The calculated target rotation speed Ntgt becomes the same value as the target rotation speed Ntgt set in the subsequent normal control mode. In the following step S22, it is determined whether the target rotation speed Ntgt is equal to or greater than the lock avoidance rotation speed N, and if the determination is No, the process proceeds to step S23, where the lock avoidance rotation speed N is determined as the median value. Also, if the determination is Yes in step S2, the process proceeds to step S24, where the target rotation speed Ntgt is set as the lock avoidance rotation speed N, and the lock avoidance rotation speed N is determined in the following step S23.

[0075] As a result of the above control, when a target rotation speed Ntgt lower than the lockup avoidance rotation speed N is set in the normal control mode, the oil pump 3 is driven at the lockup avoidance rotation speed N set to the median value within the normal control rotation range in the immediately preceding lockup avoidance mode. That is, the target rotation speed Ntgt at this time may be set, for example, near the lower limit of the normal control rotation range, but the rotation speed of the oil pump 3 is increased from this target rotation speed Ntgt to the lockup avoidance rotation speed N.

[0076] Furthermore, when a target rotation speed Ntgt equal to or higher than the lockup avoidance rotation speed N is set in the normal control mode, the oil pump 3 is driven at the target rotation speed Ntgt set as the lockup avoidance rotation speed N in the immediately preceding lockup avoidance mode. That is, the oil pump 3 is controlled at a target rotation speed Ntgt that is higher than the lockup avoidance rotation speed N. As a result, regardless of the setting of the target rotation speed Ntgt in the normal control mode, the oil pump 3 is driven in either case with the lockup avoidance rotation speed N as its lower limit, thereby making it possible to prevent the lockup from occurring.

[0077] Furthermore, when the target rotation speed Ntgt is set to be equal to or higher than the lock avoidance rotation speed N in normal control mode, this can be regarded as a situation in which a large amount of oil is required to lubricate and cool the traveling drive unit 1. In this case, the oil pump 3 is driven at the target rotation speed Ntgt not only in normal control mode but also in the immediately preceding lock avoidance mode, so that the traveling drive unit 1 can be well lubricated and cooled without a shortage of oil discharge amount.

[0078] The aspects of the present invention are not limited to this embodiment. For example, in the above embodiment, the oil pump device 2 is embodied in order to lubricate and cool the vehicle driving drive device 1, and is equipped with a trochoid oil pump 3. However, the use of the oil pump device 2 and the type of the oil pump 3 are not limited to this.

[0079] For example, the present invention may be embodied in an oil pump device for driving a hydraulic motor, a hydraulic cylinder, etc. In this case, the oil discharged from the oil pump is switched by a control valve and supplied as hydraulic oil to the hydraulic motor, hydraulic cylinder, etc. to drive them in a desired direction and at a desired speed. While the oil pump is operating, the oil pump continues to operate, but if the lock avoidance mode is executed when the oil pump starts operating, the same effects as those of the above embodiment can be achieved.

[0080] Furthermore, a vane-type or plunger-type oil pump may be used as the oil pump 3. In a vane-type oil pump, the pump slides between the tip of the vane and the inner peripheral surface of the housing, while in a plunger-type oil pump, the pump slides between the outer peripheral surface of the plunger and the inner peripheral surface of the sleeve. By applying the present invention, it is possible to prevent foreign matter from getting caught in these sliding parts of the pump.

[0081] In the above embodiment, the lock-up avoidance mode is executed at the start of normal operation for the first time, at the start of normal operation for the second time onward, at the start of operation after manufacturing, and at the start of operation after maintenance. However, this is not limited to this. For example, since the lock-up avoidance mode is executed much less frequently at the start of operation after manufacturing and at the start of operation after maintenance than at the start of normal operation, one or both of these may be omitted. Furthermore, since most of the foreign matter is captured by the filter 11 at the start of normal operation for the first time as described above, the lock-up avoidance mode may be omitted at the start of normal operation for the second time onward.

[0082] Furthermore, the setting of the execution time t of the lock avoidance mode is not limited to the above embodiment. For example, the same execution time t may be set at the start of normal operation for the first time and at the start of normal operation for the second time or later. Also, different execution times t may be set at the start of operation after manufacture and the start of operation after maintenance. For example, at the start of operation after maintenance, when only replaced parts are new, it is assumed that the amount of metal powder and the like adhering to the parts is less than at the start of operation after manufacture, when all parts are new, so a shorter execution time t may be set.

[0083] Furthermore, instead of the execution time t of the lock avoidance mode, the lock avoidance rotational speed N may be varied. For example, a first lock rotational speed, a second lock rotational speed, and a third lock rotational speed may be preset as different values ​​in order from the high rotation side, and a common execution time t of the lock avoidance mode may be set to, for example, 60 seconds. The oil pump 3 is driven at the first lock rotational speed when starting operation after manufacture and when starting operation after maintenance, the oil pump 3 is driven at the second lock rotational speed when starting normal operation for the first time, and the oil pump 3 is driven at the third lock rotational speed when starting normal operation for the second time or later. Also, although not described in detail, both the execution time t and the lock avoidance rotational speed N may be varied.

[0084] In the above embodiment, the oil control controller 12 recognizes the start of operation after maintenance based on the operation of the reset input unit 13, but this is not limited to this. When a component constituting the traveling drive device 1 or the oil pump device 2 is replaced, the removal and installation of the component at that time may be detected electrically and input as removal and installation information to the oil control controller 12. For example, if the oil pump 3 is removed and replaced with a new one, the oil control controller 12 recognizes the replacement of the oil pump 3 based on the input removal and installation information and executes a lock avoidance mode corresponding to the start of operation after maintenance. This makes it possible to eliminate the need to operate the reset input unit 13 in advance. [Explanation of symbols]

[0085] 1. Traveling drive unit (supplied equipment) 2 Oil pump device 3 Oil pump 4 motors 5 Circulation path (hydraulic circuit) 11 Filter (capture member) 12 Oil control controller (motor control unit) 13 Reset input section

Claims

1. An oil pump device, an oil pump connected to a target device via a hydraulic circuit, discharging oil and supplying the oil to the target device via the hydraulic circuit; a motor that drives the oil pump; a capturing member interposed in the hydraulic circuit for capturing foreign matter mixed in the oil discharged from the oil pump; a motor control unit that controls the motor to execute a normal control mode in which the oil pump is driven in a predetermined normal control rotation range, and that executes a lock avoidance mode in which the oil pump is driven with a preset lock avoidance rotation speed as a lower limit when the oil pump starts to operate; Equipped with The oil pump device is characterized in that when the oil pump starts operating for the first time after the oil pump device has started operating, the motor control unit executes the lock avoidance mode, assuming that this is the start of operation of the oil pump.

2. The motor control unit repeatedly operates and stops the oil pump while the oil pump device is in operation, and executes the lock avoidance mode every time the operation of the stopped oil pump is restarted, regarding this as the start of operation of the oil pump.

2. The oil pump device according to claim 1.

3. When the oil pump device is first operated after manufacture and starts operation of the oil pump, the motor control unit executes the lock avoidance mode, assuming that the oil pump is starting operation.

2. The oil pump device according to claim 1.

4. When the oil pump device is first operated after maintenance is performed and the oil pump is started, the motor control unit executes the lock avoidance mode, assuming that the oil pump is starting to operate.

2. The oil pump device according to claim 1.

5. Further provided with a reset input unit that can be operated arbitrarily, When the operation of the oil pump device is started with the reset input unit operated, the motor control unit considers that this is the first operation of the oil pump device after manufacture or the first operation of the oil pump device after maintenance is performed, and executes the lock avoidance mode when starting operation of the oil pump.

2. The oil pump device according to claim 1.

6. When the oil pump device is started and the oil pump is started, if the reset input unit is not operated, the motor control unit executes the lock avoidance mode for a preset first execution time, and if the reset input unit is operated and it is determined that the oil pump device is being operated for the first time after manufacture or the first time after maintenance of the oil pump device is performed, the motor control unit executes the lock avoidance mode for a second execution time that is preset to be longer than the first execution time.

6. The oil pump device according to claim 5.

7. The motor control unit executes the lock-up avoidance mode for a preset third execution time when starting operation of the oil pump for the first time after operation of the oil pump device has been started, and executes the lock-up avoidance mode for a fourth execution time that is preset to be shorter than the third execution time each time operation of the oil pump that has been stopped during operation of the oil pump device is restarted.

3. The oil pump device according to claim 2.

8. The lock avoidance rotation speed is set to a higher rotation side than the normal control rotation speed range, The motor control unit drives the oil pump at the lock-avoidance rotational speed in the lock-avoidance mode.

8. The oil pump device according to claim 1, wherein the oil pump device comprises: a first oil passage;

9. the lock avoidance rotation speed is set within the normal control rotation range, When the target rotation speed of the oil pump set in the normal control mode is less than the lock avoidance rotation speed, the motor control unit drives the oil pump at the lock avoidance rotation speed in the lock avoidance mode, and when the target rotation speed set in the normal control mode is equal to or greater than the lock avoidance rotation speed, the motor control unit drives the oil pump at the target rotation speed in the lock avoidance mode.

8. The oil pump device according to claim 1, wherein the oil pump device comprises: a first oil passage;

Images