JP2007077804A - Hydraulic pump diagnostic device and hydraulic pump diagnostic method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic pump diagnostic device and a hydraulic pump diagnostic method specifying a failure portion in a hydraulic pump with a simple construction. <P>SOLUTION: The hydraulic pump comprises a rotary member, sliding members, which are fittingly inserted in hydraulic chambers recessed in the rotary member to be rotatively driven together with the rotary member and are provided slidably in the fittingly-inserted direction in the hydraulic chambers, a housing member receiving the rotary member and the sliding members, and a valve member provided adjacent to the rotary member for opening and closing a flow path of hydraulic oil discharged from the hydraulic chambers in accordance with slide of the sliding members. The hydraulic pump diagnostic device comprises an internal pressure grasp means 2 for grasping internal pressure of the housing member, a discharge pressure detection means 1 for detecting discharge pressure of the hydraulic oil discharged from the hydraulic chambers, and a diagnostic means 3 for diagnosing an abrasion condition at a contact surface of the valve member with the rotary member based on the internal pressure and the discharge pressure. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a diagnostic apparatus and a diagnostic method suitable for use in a hydraulic pump mounted on a work machine.

2. Description of the Related Art Conventionally, in work machines equipped with hydraulically driven work devices, hydraulic devices such as hydraulic pumps and diagnostic devices for diagnosing failures in their control devices have been developed.
For example, in Patent Document 1, interference between a front device and a machine main body (cab) is prevented based on angle information obtained from angle sensors provided in front devices such as a boom, an arm, and a stick of a work machine. In the control device, a configuration including a determination unit that determines a failure of each sensor is described. In this technique, it is determined whether or not each sensor has failed depending on whether or not the input angle information is within a predetermined range set in advance. That is, when there is no failure, the failure can be easily determined by utilizing the fact that the information detected by the sensor is within a predetermined operating range set in advance.

  By the way, when diagnosing a failure of a hydraulic pump, a method of detecting whether or not the detected information is within a predetermined range by detecting the flow rate and discharge pressure of hydraulic oil discharged from the hydraulic pump can be considered. . In this method, for example, when the discharge pressure of the hydraulic oil is not within a predetermined range, it is determined that the component for adjusting the discharge pressure is defective, and when the flow rate of the hydraulic oil is not within the predetermined range. Then, it is determined that the component for adjusting the flow rate has failed.

Further, in Patent Document 2, in a variable displacement hydraulic pump, a target pump that is calculated based on data stored in advance during actual operation by detecting the discharge flow rate and discharge pressure of hydraulic oil discharged from the hydraulic pump. A configuration is described in which a hydraulic pump failure is determined by calculating how much the actual discharge flow rate is deviated from the theoretical discharge flow rate value. That is, by learning the threshold value of a predetermined range of sensor information at the time of steady state from detection data obtained from a plurality of sensors, and comparing the learned threshold value at the time of steady state with the detection data, the operation of the unsteady hydraulic pump The status can be grasped.
Japanese Patent No. 3539815 (paragraphs 0043 and 0044, FIG. 11) JP 2002-242849 A (paragraphs 0071 to 0073)

However, in the case of a hydraulic pump, the failure determination of each component may be caused by the failure of another component.
For example, in the case of a piston-type hydraulic pump that presses and discharges hydraulic oil in a cylinder with a piston or plunger, if the valve plate for controlling the flow rate of hydraulic oil flowing in and out of the cylinder is worn, it is discharged from the hydraulic pump The hydraulic oil flow changes. On the other hand, variable displacement hydraulic pumps are provided with a regulator that keeps the pump output constant by increasing or decreasing the flow rate in response to fluctuations in the discharge pressure. It is also conceivable that the oil flow rate changes. Therefore, when an unsteady hydraulic fluid flow rate is detected, it is difficult to determine whether the cause is due to wear of the valve plate or a malfunction of the regulator. It is not possible to identify whether a component is faulty.

In addition, if the fluctuation of the hydraulic oil flow due to wear of the valve plate is within the controllable range of the regulator, the hydraulic oil flow may be adjusted by the regulator. It may not be detected. In other words, the determination method as described above may not be able to identify the true fault site.
A method of providing a sensor for each component and performing diagnosis for each component is also conceivable. For example, a sensor dedicated to diagnosis of a regulator or a sensor dedicated to diagnosis of a valve plate is provided, and each component is diagnosed individually based on each sensor information. However, as the number of sensors increases, the manufacturing cost increases. Therefore, it is desirable to make an accurate diagnosis without increasing the number and types of sensors mounted on an actual machine as much as possible.

  The present invention has been made in view of the above problems, and provides a hydraulic pump diagnostic device and a hydraulic pump diagnostic method capable of specifying a failure site in a hydraulic pump with a simple configuration. With the goal.

  In order to achieve the above object, a diagnostic apparatus for a hydraulic pump according to the present invention (Claim 1) is fitted into a rotating member (for example, a barrel) rotated by a drive shaft and an oil chamber recessed in the rotating member. A sliding member (for example, a piston) that is inserted and driven to rotate integrally with the rotating member and that is slidable in the fitting direction in the oil chamber, and the rotating member and the sliding member are accommodated. An accommodating member (for example, a case) and a valve member (for example, a valve plate) that is provided adjacent to the rotating member and opens or closes a flow path of hydraulic oil discharged from the oil chamber by sliding of the sliding member ), An internal pressure grasping means for grasping the internal pressure of the housing member, a discharge pressure detecting means for detecting the discharge pressure of the hydraulic oil discharged from the oil chamber, Based on the internal pressure and the discharge pressure, the valve portion It is characterized by a and a diagnostic means for diagnosing the state of wear at the contact surface between the rotary member.

In the case of a swash plate type piston pump, the hydraulic pump includes a swash plate (for example, a swash plate) disposed so as to be able to maintain a predetermined inclination angle with respect to a plane perpendicular to the drive shaft. The sliding member is preferably provided so that one end thereof is supported by the swash plate and is slidable in the direction of the drive shaft in the oil chamber.
Further, the hydraulic pump has a drain port for discharging hydraulic oil outside the oil chamber in the storage member to the outside of the storage member, and the internal pressure grasping means is hydraulic fluid discharged from the drain port. It is preferable to have a drain pressure detecting means for detecting the pressure as a drain pressure and to grasp the internal pressure based on the magnitude of the drain pressure.

In addition, the diagnostic means may include the valve when the discharge pressure is equal to or higher than a first predetermined pressure set in advance and the internal pressure is equal to or higher than a second predetermined pressure calculated according to the discharge pressure. It is preferable to diagnose that the amount of wear of the member is large (claim 3).
In addition, the diagnostic means may include the valve member when the ratio of the variation amount of the internal pressure to the variation amount of the discharge pressure (for example, the slope of the discharge pressure-case internal pressure graph) is not within a predetermined range. It is preferable to diagnose that the amount of wear is large.

  The hydraulic pump diagnosis method of the present invention (Claim 5) includes a rotating member that is rotationally driven by a drive shaft and an oil chamber that is recessed in the rotating member and rotates integrally with the rotating member. A sliding member that is driven and slidable in the oil insertion direction in accordance with the rotation, a housing member that houses the rotating member and the sliding member, and adjacent to the rotating member A hydraulic pump having a valve member that opens or closes a flow path of hydraulic oil discharged from the oil chamber by sliding of the sliding member, the internal pressure of the housing member being reduced Grasping and detecting the discharge pressure of the hydraulic oil discharged from the oil chamber, and diagnosing the wear state of the contact surface of the valve member with the rotating member based on the internal pressure and the discharge pressure It is characterized by.

According to the hydraulic pump diagnostic device and hydraulic pump diagnostic method of the present invention (claims 1 and 5), the wear state of the contact surface of the valve member with the rotating member is accurately determined by the diagnosis based on the internal pressure and the discharge pressure. Can be diagnosed. Thereby, wear of a valve member can be discovered at an early stage.
Also, for example, when a failure of the hydraulic pump is diagnosed from the detected value of the flow rate of hydraulic oil discharged from the hydraulic pump or the discharge pressure, the failure part of the hydraulic pump is a valve member or otherwise according to the above diagnosis. It can be specified.

Further, according to the hydraulic pump diagnostic apparatus of the present invention (Claim 2), the internal pressure of the housing member can be easily grasped using the drain port of the hydraulic pump.
Further, according to the diagnostic apparatus for a hydraulic pump of the present invention (Claim 3), based on the magnitude of the internal pressure in a region where the internal pressure is observed to increase remarkably with respect to acceleration of wear of the valve member. Thus, the wear state of the valve member can be diagnosed. Thereby, the reliability of a diagnostic result can be improved.

  According to the hydraulic pump diagnostic apparatus of the present invention (claim 4), the wear state of the valve member is diagnosed using the fluctuation characteristics of the discharge pressure of the hydraulic pump and the fluctuation characteristics of the internal pressure of the housing member. Can do. Thereby, diagnosis can be performed easily.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 7 show a diagnostic apparatus for a hydraulic pump as one embodiment of the present invention. FIG. 1 is a block diagram showing the configuration of the diagnostic apparatus. FIG. 2 is a hydraulic pressure to which the diagnostic apparatus is applied. FIG. 3 is a cross-sectional view taken along an arrow A in FIG. 2, FIG. 4 is a cross-sectional view taken along the line BB in FIG. 2, FIG. 5 is a component diagram of a valve plate in the hydraulic pump in FIG. Is a flowchart showing the control contents of the diagnostic apparatus, and FIG. 7 is a graph showing the relationship between the discharge pressure and the drain pressure in the hydraulic pump of FIG.

[Mechanical structure]
This diagnostic apparatus is applied to the hydraulic pump 10 shown in FIGS. The hydraulic pump 10 includes a first main pump 30, a second main pump 40, and a regulator 20. The first main pump 30 and the second main pump 40 are piston type pumps that are driven by an engine (not shown) and discharge high-pressure hydraulic oil. 2, a cross-sectional view of the first main pump 30 is shown in the left half of the drawing, and a side view of the second main pump 40 is shown in the right half of the drawing.

The first main pump 30 is directly connected to the drive shaft 12 of the engine. On the other hand, the second main pump 40 is juxtaposed with the first main pump 30 and is driven by the engine via the gear 23. The first main pump 30 and the second main pump 40 are supplied with hydraulic oil from a hydraulic oil tank (not shown), pressurize and discharge the hydraulic oil, and circulate it into the hydraulic circuit. It has the same internal structure.
One regulator 20 is provided for each of the first main pump 30 and the second main pump 40, and controls the flow rate of hydraulic oil discharged from the pumps 30 and 40.

  Hereinafter, the internal structure of the first main pump 30 will be described with reference to FIG. The first main pump 30 includes a barrel (rotary member) 11, a piston (sliding member) 14, a valve plate (valve member) 16, a swash plate (swash plate) 18, and a case (accommodating member) 15. .

The case 15 accommodates other components inside. The engine drive shaft 12 is inserted into the case 15 through a bearing 26.
The barrel 11 is fitted to the outer peripheral surface of the drive shaft 12 of the engine via a spline. Thereby, the barrel 11 is rotationally driven by the drive shaft 12. The barrel 11 is formed with a plurality of recessed cylinder chambers (oil chambers) 13. The cylinder chamber 13 is a cylindrical space formed along the axial direction of the drive shaft 12, and is arranged at equal intervals in the circumferential direction around the drive shaft 12. As shown in FIG. 2, the upper end side of the cylinder chamber 13 is opened so that the piston 14 can be inserted from above. Further, a flow path for sucking or discharging hydraulic oil into the cylinder chamber 13 is formed at the lower end side of the cylinder chamber 13.

  The valve plate 16 is a valve member that is fixed to the case 15 so as to be adjacent to the lower surface of the barrel 11 and opens or closes the flow path of the hydraulic oil discharged from the cylinder chamber 12. As shown in FIG. 5, the valve plate 16 has a disk shape, and a central hole 16 c through which the drive shaft 12 is inserted is formed at the center. Further, when the valve plate 16 is divided in the vertical direction along a line passing through the center of the central hole 16c, the upper half side in FIG. 5 extends in the circumferential direction so as to draw an arc around the central hole 16c. A hole 16a is formed. On the other hand, a plurality of circular small holes 16b drilled at equal intervals in the circumferential direction are formed on the lower half side.

The piston 14 is slidably fitted inside each cylinder chamber 13 of the barrel 11 and is provided so as to be able to protrude and retract with respect to the barrel 11. Further, the head 14 a of each piston 14 is formed in a substantially spherical shape and is held by a retainer 17.
The swash plate 18 is a disk-shaped member disposed so as to be able to maintain a predetermined inclination angle θ with respect to a plane perpendicular to the drive shaft 12. The inclination angle θ of the swash plate 18 is controlled by a regulator 20 described later. The swash plate 18 is formed with a sliding surface that supports the retainer 17 slidably in the circumferential direction of the drive shaft 12. When the barrel 11 is rotationally driven together with the drive shaft 12, the retainer 17 slides on the sliding surface of the swash plate 18 while holding the head portion 14 a of the piston 14.

  As a result, the head 14 a of the piston 14 moves in the axial direction of the drive shaft 12 according to the inclination angle θ of the swash plate 18, and the piston 14 reciprocates in the cylinder chamber 13. Yes. The larger the inclination angle θ (where 0 <θ <π / 2), the larger the reciprocating sliding distance (that is, the reciprocating stroke) of the piston 14, and the smaller the inclination angle θ, the smaller the reciprocating sliding distance. Become.

  On the other hand, as the drive shaft 12 rotates, the lower surface of the barrel 11 and the valve plate 16 slide in contact with each other. As a result, the valve plate 16 opens and closes the flow path for sucking or discharging the hydraulic oil into the cylinder chamber 13. For example, in a state where the lower end of the cylinder chamber 13 overlaps the long hole 16a or the small hole 16b of the valve plate 16, the cylinder chamber 13 and the flow path are communicated, and the lower end of the cylinder chamber 13 is connected to the long hole 16a and the small hole 16b. In a state where they do not overlap, the cylinder chamber 13 is closed with respect to the flow path.

  In the present embodiment, of the reciprocating sliding of the piston 14, when the piston 14 moves in the extending direction with respect to the cylinder chamber 13, the lower end of the cylinder chamber 13 is overlapped with the long hole 16 a, and the operation is performed. Oil is sucked into the cylinder chamber 13. Further, when the piston 14 moves in the shrinking direction with respect to the cylinder chamber 13, the lower end of the cylinder chamber 13 is intermittently overlapped with the small hole 16 b, and hydraulic oil is discharged from the cylinder chamber 13. Yes.

As shown in FIG. 4, an inflow line 24 and a discharge line 25 are formed below the valve plate 16 inside the case 15 as hydraulic oil passages. The hydraulic oil sucked into each cylinder chamber 13 is supplied from the inflow line 24, and the hydraulic oil discharged from the cylinder chamber 13 is discharged from the discharge port 22 to the outside of the hydraulic pump 10 through the discharge line 25. . Incidentally, as shown in FIG. 2, on the downstream side of the pipeline path than the ejection port 22, the discharge pressure sensor (discharge pressure detection means) for detecting the hydraulic pressure P _a to be discharged from the hydraulic pump 10 1 is mounted ing.

Further, a drain port 21 for discharging hydraulic oil outside the cylinder chamber 13 in the case 15 to the outside of the hydraulic pump 10 is provided on the side surface of the hydraulic pump 10. The drain port 21 discharges hydraulic oil leaked to the outside of the cylinder chamber 13 while lubricating the sliding surface between the piston 14 and the cylinder chamber 13 in the case 15 and returns it to the hydraulic oil tank. Port. A case internal pressure sensor (internal pressure grasping means, drain pressure detecting means) 2 for detecting the pressure (drain pressure) P _b of the hydraulic oil discharged from the drain port 21 is provided on the piping path on the downstream side of the drain port 21. Is provided. The case pressure sensor 2 detects the drain pressure of the hydraulic oil discharged from the drain port as the internal pressure of the case 15, and the drain pressure is regarded as the case internal pressure here.

  As shown in FIG. 2, a power piston 19 is provided inside the regulator 20. When the power piston 19 moves downward in FIG. 2, one end portion of the swash plate 18 moves in a direction approaching the barrel 11 to increase the inclination angle θ, while the power piston 19 moves upward in FIG. Then, one end of the swash plate 18 moves in a direction away from the barrel 11 and the inclination angle θ decreases. Control of the inclination angle θ of the swash plate 18 by the regulator 20 is referred to as inclination angle control.

  The hydraulic pump 10 according to the present embodiment is a variable displacement hydraulic pump that changes the discharge flow rate of hydraulic oil by controlling the inclination angle of the regulator 20. That is, increasing the tilt angle θ to increase the reciprocating stroke of the piston 14 increases the flow rate of hydraulic oil discharged from the hydraulic pump 10, while decreasing the tilt angle to decrease the reciprocating stroke of the piston 14. As a result, the flow rate of hydraulic fluid discharged from the hydraulic pump 10 is reduced. Note that the regulator 20 of the present embodiment performs PQ control that increases or decreases the hydraulic oil flow rate according to the magnitude of the hydraulic pressure discharged from the hydraulic pump 10 and keeps the pump output constant.

[Diagnostic configuration]
As shown in FIG. 1, the diagnostic device for the hydraulic pump 10 includes a discharge pressure sensor 1, a case pressure sensor 2, a controller (diagnostic means) 3, and a monitor panel 4. As described above, the discharge pressure sensor 1 and the casing pressure sensor 2, respectively, for detecting a delivery pressure P _a and vent pressures P _b of hydraulic oil drainage from the drain port 21 of the hydraulic oil discharged from the hydraulic port 22 It is a sensor. Each sensor 1,2 is detected discharge pressure P _a, and inputs the casing internal pressure P _b to the controller 3.

Note that the monitor panel 4 is a device for displaying a diagnosis result in the present diagnosis device, and is provided in a cab of a work machine on which the hydraulic pump 10 is mounted.
The controller 3 includes a diagnosis unit 3a and a diagnosis result display unit 3b as control blocks. First, the diagnosis unit 3a stores a first predetermined pressure _Pa0 and a function f. The first predetermined pressure P _a0, the discharge pressure P _a is a threshold for determining whether the diagnosable area wear of the valve plate 16. The function f defines a second predetermined pressure _Pb0 as a threshold for determining whether or not the case internal pressure _Pb is a value corresponding to the wear state of the valve plate 16, and the discharge pressure P _{This is a} function [P _b0 = f (P _a )] for a.

Here, the setting of the first predetermined pressure _{Pa 0} and the function f will be described using the test results shown in FIG.
If there is no wear of the valve plate 16, indicating the relationship between the discharge pressure P _a and the case pressure P _b discharged from the hydraulic pump 10 graphically becomes as shown by a thick solid line in FIG. That is, although the case internal pressure P _b substantially in proportion to the increase in the discharge pressure P _a is increased, the increase ratio is moderate. On the other hand, when a state results in which the surface of the valve plate 16 is worn, as shown in FIG. 7 broken line by a one-dot chain line and two-dot chain line, the rate of increase in case the internal pressure P _b increases against increase of the discharge pressure P _a.

Moreover, focusing on the state of wear of the valve plate 16, towards the graph shown by a chain line than the graph shown by a broken line in FIG. 7 is increased gradient of the case internal pressure P _b, it becomes the graph shown by a two-dot chain line, further The gradient is large. That is, as the wear progresses, it can be seen that the rate of increase in case the internal pressure P _b increases. This is because when the hydraulic pump 10 is operated, the valve plate 16 and the barrel 11 are always slid, so that the surface wear of the valve plate 16 causes the hydraulic oil to leak in a direction along the sliding surface. It is considered that the case internal pressure _Pb is likely to increase. Thus, correspondence between the discharge pressure P _a and the case pressure P _b is found to be one that varies in accordance with the degree of progression of the wear of the valve plate 16.

In FIG. 7, the discharge pressure P _a low pressure state, the broken line than the graph shown by a thick solid line, towards the graph shown by a chain line and two-dot chain line is the case the internal pressure P _b is low. The cause of this phenomenon has not been elucidated, but as one reason, it is considered that the liquid tightness of the case 15 itself decreases due to wear of the valve plate 16 and the case internal pressure _Pb is difficult to increase.
In addition, the thin solid lines drawn above and below the thick solid line in FIG. 7 indicate the fluctuation range of the thick solid line graph in consideration of the detection error of the sensor.

Based on the test results as described above, the first predetermined pressure _{Pa 0} and the function f are regions in which it is possible to diagnose that the valve plate 16 is worn regardless of the wear state (the progress degree of wear) of the valve plate 16. The threshold is set as shown in FIG. That is, the larger one of the fluctuation ranges of the discharge pressure and the case internal pressure when there is no wear of the valve plate 16 indicated by a thin solid line is set as the function f, and a graph of the function f (here, the upper side) thin solid line) than wear has progressed (here, the degree of progress of wear small) discharge pressure in the valve plate 16 - the discharge pressure P _a point which the case the internal pressure graph is increased is set to a first predetermined pressure P _a0 The

Further, the diagnostic unit 3a compares the second predetermined pressure P _b0 defined by the discharge pressure P _a and vent pressures P _b and the first predetermined pressure P _a0 and the function f is input from the sensors 1 and 2, Diagnose the hydraulic pump 10. That is, the diagnosis unit 3a determines whether or not the detected data is above the graph of P _b0 = f (P _a ) in the range of P _a ≧ P _a0 .
First, the discharge pressure P _a is in the case of less than the first predetermined pressure P _a0, there is no detected data in a range where diagnosis is performed, not performed in the diagnosis of the valve plate 16. On the other hand, the discharge pressure P _a is in the case of the above first predetermined pressure P _a0 starts diagnosing state of wear of the valve plate 16, and compares the second predetermined pressure P _b0 case pressure P _b.

Here, the case internal pressure P _b is in the case of less than the second predetermined pressure P _b0 determines the valve plate 16 is not worn (the degree of progress of the wear is very minor). On the other hand, when the case internal pressure P _b is equal to or higher than the second predetermined pressure P _b0 , it is determined that the valve plate 16 is worn (here, the degree of progress of wear has progressed more than the small state).
The diagnosis result display unit 3b functions to receive each determination result as described above in the diagnosis unit 3a and display it on the monitor panel 4.

Incidentally, the diagnostic result display portion 3b, the discharge pressure P _a may not perform diagnostics on the monitor panel 4 navel effect of a by valve plate 16 smaller than the first predetermined pressure P _a0 (e.g., "Please relief" ) to display the, so that prompt the operator's operation so as to increase the discharge pressure P _a of the hydraulic pump 10.

[flowchart]
The control contents of the diagnostic apparatus will be described with reference to FIG. This flowchart is repeatedly executed in the controller 3 at a predetermined cycle.
First, in step A10, the discharge pressure P _a and vent pressures P _b detected by the discharge pressure sensor 1 and the casing pressure sensor 2 is input to the diagnostic unit 3a. In step A20, the discharge pressure P _a is whether a first predetermined pressure P _a0 or stored in the diagnosis section 2a (P _a ≧ P _a0) is determined. If P _a ≧ P _a0 , the process proceeds to step A40, and if P _a <P _a0 , the process proceeds to step A30.

In step A30, since there is no detection data in a range where diagnosis is possible, the diagnosis of the valve plate 16 is not performed in the diagnosis unit 3a. Then, in the diagnosis result display section 3b, “Please relieve” is displayed on the monitor panel 4, and this flow is finished.
That is, the discharge pressure P _a is in the region of the P _a <P _a0, as shown in FIG. 7, even though they progressed progress of wear of the valve plate 16, it is difficult to accurately determine, Diagnosis is not performed to avoid erroneous detection, and diagnosis is performed only when the condition (P _a ≧ P _a0 ) is satisfied.

Note that, by where the operator operation, the hydraulic oil in the hydraulic circuit operating such that the relief is made, so that the discharge pressure P _a of the hydraulic pump 10 is increased. In the process of repeatedly executing this flow, if the condition (P _a ≧ P _a0 ) is satisfied, the process proceeds to step A40. That is, until the condition (P _a ≧ P _a0 ) is satisfied, the diagnosis standby state is entered.

On the other hand, in step A40, the diagnosis unit 3a, whether vent pressures P _b is the second predetermined pressure P _b0 or more defined by the function f with respect to the discharge pressure P _a [P _b ≧ f (P _a)] is Determined. If P _b ≧ f (P _a ), the process proceeds to step A50, and if P _b <f (P _a ), the process proceeds to step A60.
In step A50, the diagnosis unit 3a diagnoses that the valve plate 16 is worn, and the diagnosis result display unit 3b displays on the monitor panel 4. On the other hand, in step A60, the diagnosis unit 3a diagnoses that the valve plate 16 is not worn, and the diagnosis result display unit 3b displays on the monitor panel 4.

In this flowchart, only the control for diagnosing the wear state of the valve plate 16 is shown, and this flow is completed. However, following this flow, other components of the hydraulic pump 10 are A flow for performing diagnosis may be executed. For example, _a diagnosis based on the discharge pressure Pa of the hydraulic oil discharged from the hydraulic pump 10 and the discharge flow rate is performed using a known hydraulic pump diagnosis technique.

[effect]
Thus, according to the diagnostic device of the present hydraulic pump, the diagnosis based on the discharge pressure P _a and the case pressure P _b, the state of wear of the valve plate 16 can be accurately diagnosed. Thereby, even if the progress of the wear of the valve plate 16 is not large, it can be diagnosed, and the wear of the valve plate 16 can be detected at an early stage.

Further, by using a diagnostic method that focuses on a corresponding relationship between such discharge pressure P _a and the case pressure P _b, failure area of the hydraulic pump 10 is a valve plate 16 (having a wear of the valve plate 16) Can be diagnosed. That is, according to this diagnostic apparatus, it is possible to specify whether the failure part of the hydraulic pump 10 is the valve plate 16 or other than the valve plate 16.

Further, the diagnostic method, the wear state of the valve member Upon, in a region where significantly vent pressures P _b is observed to increase to utilize the correspondence between the discharge pressure P _a and the case pressure P _b as shown in FIG. 7 Can be diagnosed accurately.
In the diagnostic apparatus, since the detecting hydraulic pressure discharged from the drain port 21 as a case internal pressure P _b, you are possible to easily grasp the internal pressure of the case 15.

[Others]
Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the present invention.
In the above embodiment, the diagnosis unit 3a of the controller 3 compares the discharge pressure P _a and vent pressures P _b and the first predetermined pressure P _a0 and the second predetermined pressure P _b0 is input from the sensors 1 and 2 Thus, the hydraulic pump 10 is diagnosed. This is synonymous with whether or not the input data exists in the area A shown in FIG. 8, but in addition to this configuration, for example, the input data is shown in FIG. It may be configured to determine whether or not it exists in the region B shown.

Region B, the discharge pressure P _a is 0 <P _a ≦ P _a1, and vent pressures P _b is a region of 0 <P _b ≦ P _b1. P _b1 is _a value determined according to the discharge pressure _Pa, and is defined as P _b1 = g (P _a ) by the function g. Here, the smaller one of the fluctuation range of the discharge pressure and the case internal pressure when there is no wear of the valve plate 16 indicated by a thin solid line is set as the function g.
Further, as shown in FIG. 8, wear progressed (here, the degree of progress of wear is greater) than the graph of the function g (here, the thin solid line on the lower side). graph discharge pressure P _a of the small point is set to the threshold P _a1. Note that the areas A and B may be set in advance as areas where the valve plate 16 can be discriminated from the worn state and the worn state. With this configuration, the discharge pressure P _a is also a low pressure state, it is possible to diagnose the state of wear of the valve plate 16.

In the aforementioned embodiment, by comparing the discharge pressure P _a and vent pressures P _b and the first predetermined pressure P _a0 and the second predetermined pressure P _b0, but to diagnose the state of wear of the valve plate 16, FIG. It is also conceivable to make a diagnosis using the difference in slope of each graph as shown in FIG.
For example, by using a correspondence between the plurality of sets of discharge pressure P _a and vent pressures P _b supplied from each of the sensors 1 and 2, to calculate the increase in percentage of cases pressure P _a for the increase in discharge pressure P _b, the increased It can be considered that the valve plate 16 is determined to be worn when the ratio becomes equal to or higher than a predetermined ratio. That is, the ratio of the variation amount of the case internal pressure P _b for the amount of fluctuation of the discharge pressure P _a - will diagnose (discharge pressure gradient of the casing internal pressure graph).

With this configuration, regardless of the size of the detected discharge pressure P _a data, the state of wear of the valve plate 16 can be easily diagnosed. Also in this case, as the data of the discharge pressure P _a and vent pressures P _b is input from the sensors 1 is large, can be calculated with less accurate rise rate of detection error.
Also, as in the embodiment described above, diagnosis is not performed if the condition (P _a ≧ P _a0) is not satisfied, notification that increases the discharge pressure P _a of the hydraulic pump 10 is made to the operator However, such notification is not essential. When the diagnostic control of the wear state of the valve plate 16 in the diagnostic apparatus is started by the operator's intention (for example, when a switch operation for starting the diagnosis is performed), the control configuration as described above may be used. When this diagnostic control is automatic control, that is, considering a diagnostic device that performs self-diagnosis independent of the operator's intention, if the condition (P _a ≧ P _a0 ) is not satisfied, diagnosis is simply performed. not performed, only it includes an arrangement to implement the diagnosis when a condition (P _a ≧ P _a0) is satisfied.

In the above-described embodiment, when the condition (P _a ≧ P _a0 ) is not satisfied, the message “Please relieve” is displayed on the monitor panel 4 to prompt the operator to operate. in addition to the do control configuration, if the lever operation amount by the operator for the relief is relatively small sufficiently discharge pressure P _a is not increased, and further "Please raise the discharge pressure P _a of the hydraulic pump 10 ' display may be more reliably prompt the operator's operation so as to increase the discharge pressure P _a of the hydraulic pump 10 configuration.

  In the above-described embodiment, the drain pressure is regarded as the case internal pressure, and the case internal pressure sensor 2 that detects the drain pressure from the drain port 21 is used as means for grasping the internal pressure of the case 15. The means for grasping the internal pressure of 15 is not limited to this. For example, a pressure sensor may be provided inside the case 15.

It is a block diagram which shows the structure of the diagnostic apparatus of the hydraulic pump as one Embodiment of this invention. It is a side view and a sectional view showing composition of a hydraulic pump to which this diagnostic device was applied. FIG. 3 is a view as seen from an arrow A in FIG. 2. It is BB sectional drawing of FIG. FIG. 3 is a component diagram of a valve plate in the hydraulic pump of FIG. 2. It is a flowchart which shows the control content of this diagnostic apparatus. It is a graph which shows the relationship between the discharge pressure and case internal pressure in the hydraulic pump of FIG. It is a graph for demonstrating the control content in the modification of this diagnostic apparatus.

Explanation of symbols

1 Discharge pressure sensor (Discharge pressure detection means)
2 Case internal pressure sensor (Internal pressure grasping means, drain pressure detection means)
3 Controller (diagnostic means)
3a Diagnosis section 3b Diagnosis result display section 4 Monitor panel 10 Hydraulic pump 11 Barrel (rotating member)
12 Drive shaft 13 Cylinder chamber (oil chamber)
14 Piston (sliding member)
15 Case (housing member)
16 Barrel plate (valve member)
16a Long hole 16b Small hole 16c Center hole 17 Retainer 18 Swash plate (swash plate)
19 Power Piston 20 Regulator 21 Drain Port 22 Discharge Port 23 Gear 24 Inflow Line 25 Discharge Line 26 Bearing 30 First Main Pump 40 Second Main Pump

Claims (5)

A rotating member that is driven to rotate by a drive shaft, and is inserted into an oil chamber that is recessed in the rotating member, and is driven to rotate integrally with the rotating member, and can slide in the oil chamber in the inserting direction. A sliding member provided; a rotating member; a housing member that accommodates the sliding member; and a flow of hydraulic oil that is provided adjacent to the rotating member and is discharged from the oil chamber by sliding of the sliding member. A hydraulic pump diagnostic device having a valve member that opens or closes a path,
An internal pressure grasping means for grasping the internal pressure of the housing member;
A discharge pressure detecting means for detecting a discharge pressure of the hydraulic oil discharged from the oil chamber;
A diagnostic device for a hydraulic pump, comprising diagnostic means for diagnosing a wear state of a contact surface of the valve member with the rotating member based on the internal pressure and the discharge pressure. The hydraulic pump has a drain port for discharging hydraulic oil outside the oil chamber in the housing member to the outside of the housing member,
The internal pressure grasping means has drain pressure detecting means for detecting the pressure of the hydraulic oil discharged from the drain port as a drain pressure, and grasps the internal pressure based on the magnitude of the drain pressure. The diagnostic device for a hydraulic pump according to claim 1. When the discharge pressure is equal to or higher than a preset first predetermined pressure and the internal pressure is equal to or higher than a second predetermined pressure calculated according to the discharge pressure, the diagnostic means The diagnostic apparatus for a hydraulic pump according to claim 1, wherein the diagnosis is made that the amount of wear is large. The diagnostic means diagnoses that the amount of wear of the valve member is large when the ratio of the fluctuation amount of the internal pressure to the fluctuation amount of the discharge pressure is not within a predetermined range set in advance. The diagnostic device of the hydraulic pump according to any one of claims 1 to 3. A rotating member that is rotationally driven by a drive shaft, and is inserted into an oil chamber that is recessed in the rotating member and is driven to rotate integrally with the rotating member. A sliding member provided so as to be slidable, a rotating member, a housing member that houses the sliding member, and a sliding member that is provided adjacent to the rotating member and is discharged from the oil chamber by sliding of the sliding member. A method of diagnosing a hydraulic pump having a valve member that opens or closes a flow path of hydraulic oil,
While grasping the internal pressure of the housing member, detecting the discharge pressure of the hydraulic oil discharged from the oil chamber,
A diagnostic method for a hydraulic pump, characterized by diagnosing a wear state of a contact surface of the valve member with the rotating member based on the internal pressure and the discharge pressure.

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