JP2007077832A - 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, a swash plate, 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 a drive axis direction in the hydraulic chambers with one ends supported on the swash plate, and a tilting angle adjusting member for adjusting a tilting angle of the swash plate in accordance with pressure of hydraulic oil discharged from the hydraulic chambers by the sliding members and with the magnitude of an output demanded for the hydraulic pump. The hydraulic pump diagnostic device comprises a discharge pressure detection means 1 for detecting discharge pressure of the hydraulic oil, an output detection means 6 for detecting the magnitude of an output demanded for the hydraulic pump, a hydraulic oil amount detection means 5 for detecting a hydraulic oil amount discharged from the hydraulic oil, and a diagnosing means 3 for diagnosing a condition of the tilting angle adjusting member based on the discharge pressure, the magnitude of the output and the hydraulic oil amount. <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) includes a rotating member (for example, a barrel) rotated by a drive shaft and a predetermined inclination with respect to a plane perpendicular to the drive shaft. A swash plate (for example, a swash plate) disposed so as to be able to hold a turning angle, and is fitted into an oil chamber recessed in the rotating member and is rotationally driven together with the rotating member, and one end thereof is A sliding member (for example, a piston) supported by a swash plate so as to be slidable in the direction of the drive shaft in the oil chamber, the pressure of the hydraulic oil discharged from the oil chamber by the sliding member, and the hydraulic pressure An apparatus for diagnosing a hydraulic pump, comprising a tilt angle adjusting member (for example, a regulator) that adjusts the tilt angle of the swash plate in accordance with the magnitude of output required for the pump, the hydraulic pump The discharge pressure of hydraulic fluid discharged from Output pressure detection means (for example, discharge pressure sensor), output detection means (for example, PS pressure sensor) for detecting the magnitude of output required for the hydraulic pump, and amount of hydraulic oil discharged from the hydraulic pump Hydraulic oil amount detection means (for example, a control spool stroke sensor) and diagnostic means for diagnosing the state of the tilt angle adjusting member based on the discharge pressure, the output magnitude, and the hydraulic oil amount It is characterized by having prepared.

The hydraulic oil discharge pressure detected by the discharge pressure detecting means is the pressure of the hydraulic oil actually discharged from the hydraulic pump, and the hydraulic oil amount detected by the hydraulic oil amount detecting means. Is the flow rate of the hydraulic oil actually discharged from the hydraulic pump.
In addition, the hydraulic pump has a pilot pressure supply device that supplies a pilot pressure (for example, PS pressure) corresponding to the magnitude of output required for the hydraulic pump, and the tilt angle adjusting member includes A swash plate drive member (for example, a control spool of a power piston) that drives the swash plate and adjusts the tilt angle according to the operating hydraulic pressure and the pilot pressure introduced from the pilot pressure supply device; The output detection means detects the magnitude of the pilot pressure, and the diagnosis means calculates a theoretical flow rate of the hydraulic oil that the hydraulic pump normally discharges from the magnitude of the pilot pressure and the discharge pressure, It is preferable to diagnose that the swash plate driving member is fixed when the difference between the theoretical flow rate and the hydraulic oil amount is a predetermined value or more.

In addition, the diagnosis means may fix the swash plate driving member when the ratio of the fluctuation amount of the hydraulic oil amount to the fluctuation of the output level required for the hydraulic pump is less than a first predetermined value. It is preferable to diagnose that it is (Claim 3).
Further, the diagnosis means diagnoses that the swash plate driving member is fixed when no discontinuous point at which the fluctuation gradient of the hydraulic oil amount changes substantially discontinuously with respect to the discharge pressure is found. (Claim 4).

In this case, the diagnostic means draws the fluctuation of the hydraulic oil amount with respect to the fluctuation of the discharge pressure as a graph, and when the gradient of the graph does not have a break point, the swash plate driving member It is preferable to diagnose that it has adhered (Claim 5).
Further, the hydraulic oil amount detection means has a swash plate sensor for detecting the tilt angle of the swash plate, and calculates the hydraulic oil amount actually discharged from the hydraulic pump based on the tilt angle. (Claim 6).

And a hydraulic pump diagnostic device for a work machine equipped with the hydraulic pump and a working cylinder driven by hydraulic oil discharged from the hydraulic pump, wherein the hydraulic oil amount detecting means It is preferable to calculate the flow rate of hydraulic oil supplied to the cylinder.
In this case, the working cylinder is a hydraulic cylinder that drives a working device (for example, a boom, a stick, a bucket, or the like) of the working machine, and includes an inclination sensor that detects an inclination angle of the working device with respect to a horizontal plane. Preferably, the hydraulic oil amount detection means calculates the hydraulic oil flow rate supplied to the hydraulic cylinder based on the time differential value of the inclination angle detected by the inclination sensor.

  In addition, the hydraulic pump is disposed adjacent to the rotating member and the sliding member for housing the rotating member and the rotating member, and is discharged from the oil chamber by sliding of the sliding member. A valve member (for example, a valve plate) that opens or closes the flow path of the hydraulic oil, and based on the internal pressure and the discharge pressure, internal pressure grasping means for grasping the internal pressure of the storage member, It is preferable that diagnostic means for diagnosing the wear state of the contact surface of the valve member with the rotating member is provided.

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 of 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 11).

Further, it is preferable that 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 ( Claim 12).
Further, the diagnostic method for a hydraulic pump according to the present invention (Claim 13) is arranged so as to be able to hold a predetermined tilt angle with respect to a rotating member driven to rotate by a drive shaft and a plane perpendicular to the drive shaft. And a swash plate inserted into an oil chamber recessed in the rotating member and driven to rotate together with the rotating member, and supported at one end by the swash plate and sliding in the oil chamber in the direction of the drive shaft. The sliding member provided movably, and the tilt angle of the swash plate according to the pressure of hydraulic oil discharged from the oil chamber by the sliding member and the magnitude of the output required for the hydraulic pump And a tilt angle adjusting member for adjusting the pressure of the hydraulic pump, and detecting a discharge pressure of the hydraulic oil discharged from the hydraulic pump, and a magnitude of an output required for the hydraulic pump Detecting the amount of hydraulic oil discharged from the hydraulic pump, It is characterized by diagnosing the state of the inclined rotation angle adjusting member on the basis of the size and the hydraulic oil amount of output.

  Further, the diagnosis method for a hydraulic pump according to the present invention (Claim 14) is arranged so that a rotation member driven to rotate by a drive shaft and a predetermined tilt angle with respect to a plane perpendicular to the drive shaft can be maintained. And a swash plate inserted into an oil chamber recessed in the rotating member and driven to rotate together with the rotating member, and supported at one end by the swash plate and sliding in the oil chamber in the direction of the drive shaft. The sliding member provided movably, and the tilt angle of the swash plate according to the pressure of hydraulic oil discharged from the oil chamber by the sliding member and the magnitude of the output required for the hydraulic pump A tilt angle adjusting member for adjusting the rotation angle, an accommodating member for accommodating the rotating member and the sliding member, and an operation provided adjacent to the rotating member and 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 an oil flow path. The discharge pressure of the hydraulic oil discharged from the hydraulic pump is detected, the amount of output required for the hydraulic pump is detected, the amount of hydraulic oil discharged from the hydraulic pump is detected, and the storage The internal pressure of the member is grasped, and then the wear state of the contact surface of the valve member with the rotating member is diagnosed based on the internal pressure and the discharge pressure, and then the discharge pressure and the magnitude of the output are measured. The state of the tilt angle adjusting member is diagnosed based on the height and the amount of hydraulic oil.

According to the hydraulic pump diagnostic apparatus and hydraulic pump diagnostic method of the present invention (Claims 1 and 13), the state of the tilt angle adjusting member is determined by the diagnosis based on the hydraulic pressure, the pump output magnitude, and the hydraulic oil amount. It can be diagnosed accurately.
Moreover, such a diagnosis can specify whether the failure site of the hydraulic pump is the tilt angle adjusting member or the other.

  According to the hydraulic pump diagnosis apparatus of the present invention (claim 2), the magnitude of the output required for the hydraulic pump can be accurately grasped by detecting the pilot pressure. Further, such a diagnosis makes it possible to diagnose the fixed state of the swash plate driving member. Moreover, since such a diagnosis is performed by comparing the calculated theoretical flow rate with the actual hydraulic oil amount, it is not necessary to perform learning for diagnosis.

According to the hydraulic pump diagnostic device of the present invention (Claim 3), it is possible to diagnose the fixed state of the swash plate driving member in a state where there is no fluctuation in the hydraulic pressure. Further, the amount of change in the hydraulic oil amount can be easily observed by changing the magnitude of the output required for the hydraulic pump.
According to the hydraulic pump diagnostic apparatus of the present invention (Claim 4), it is possible to diagnose the fixed state of the swash plate driving member in a state where there is no fluctuation in the output of the hydraulic pump.

According to the hydraulic pump diagnostic apparatus of the present invention (Claim 5), the fixed state of the swash plate driving member is easily diagnosed using the characteristics of the hydraulic pressure and hydraulic oil discharged from the hydraulic pump. be able to.
Further, according to the diagnostic apparatus for a hydraulic pump of the present invention (Claim 6), the amount of hydraulic oil actually discharged from the hydraulic pump can be easily grasped by using the swash plate sensor.

According to the hydraulic pump diagnostic apparatus of the present invention (Claim 7), it is possible to grasp the amount of hydraulic oil discharged from the hydraulic pump in the drive state of the working cylinder. In other words, diagnosis can be performed even during work.
Further, according to the diagnostic apparatus for hydraulic pumps of the present invention (Claim 8), the amount of hydraulic oil supplied to the working cylinder can be accurately grasped using the inclination sensor.

Further, according to the diagnosis device for a hydraulic pump of the present invention (Claim 9), the wear state of the contact surface of the valve member with the rotating member can be accurately diagnosed by the diagnosis based on the internal pressure and the discharge pressure. . 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.

Moreover, according to the diagnostic apparatus for a hydraulic pump of the present invention (claim 10), 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 11), 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 12), the wear state of the valve member is diagnosed by utilizing 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.
According to the method for diagnosing a hydraulic pump of the present invention (Claim 14), when the failure site is a swash plate driving member or a valve member in the diagnosis process of the hydraulic pump, it can be specified. In addition, since the diagnosis based on the internal pressure and the discharge pressure is performed first, wear of the valve member and adhesion of the swash plate driving device can be accurately diagnosed.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
1 to 12 show a diagnostic apparatus for a hydraulic pump as a first embodiment of the present invention. FIG. 1 is a block diagram showing the configuration of the diagnostic apparatus, and FIG. 2 is an application of the diagnostic apparatus. FIG. 3 is a sectional view taken along the arrow A in FIG. 2, FIG. 4 is a sectional view taken along the line BB in FIG. 2, and FIG. 5 is a valve in the hydraulic pump in FIG. 6 is a cross-sectional view taken along the line CC of FIG. 2 showing the configuration of the regulator, FIGS. 7 to 9 are flowcharts showing the control contents of the diagnostic device, and FIG. 10 is a block diagram relating to diagnostic control of the control spool. FIG. 11 is a graph showing the relationship between the discharge pressure and the case internal pressure in the hydraulic pump of FIG. 2, and 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 (tilt angle adjusting member) 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.

Then, the internal structure of the 1st main pump 30 is demonstrated using 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 hold a predetermined tilt angle θ (also referred to as a tilt angle) with respect to a plane perpendicular to the drive shaft 12. The tilt 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 tilt angle θ of the swash plate 18, and the piston 14 reciprocates in the cylinder chamber 13. ing. The larger the tilt angle θ (where 0 <θ <π / 2), the greater the reciprocating sliding distance (that is, the reciprocating stroke) of the piston 14, and the smaller the tilt angle θ, the reciprocating sliding distance. Becomes smaller.

  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 a flow path for hydraulic oil. 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, the piping system path downstream from the discharge port 22, discharge pressure sensor (discharge pressure detection means) for detecting a delivery pressure P _a of the hydraulic oil discharged from the hydraulic pump 10 1 Is attached. Here, it detected the discharge pressure P _a is input to the controller 3 which will be described later.

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 here the drain pressure is regarded as the case internal pressure (internal pressure of the case 15). . The case pressure P _b detected here, it is inputted to the controller 3 which will be described later.

One regulator 20 is provided in each of the first main pump 30 and the second main pump 40. The regulator 20 is a device for controlling the flow rate of hydraulic oil discharged from the pumps 30 and 40.
As shown in FIG. 6, the regulator 20 includes a power piston 19, a control spool 27, and a stroke sensor 5 inside. As shown in FIG. 2, the power piston 19 is connected to the swash plate 18 via a tilt pin 19 a and is provided to be slidable in the vertical direction in FIGS. 2 and 6 in conjunction with the operation of the control spool 27. . The control spool 27 is housed in the passage 29 with upper and lower ends supported by springs 28.

The control spool 27 receives the discharge pressure P _a of the hydraulic oil discharged from the pilot pressure (PS pressure) P _c and the pump 30, 40 is introduced from the PS port 31 to the regulator 20 shown in FIG. 2 passages It slides in 29, and the position according to the magnitude | size of each pressure is hold | maintained. Discharge pressure P _a is the control spool 27 acts to push the 6 upward direction, whereas, PS pressure P _c acts to push down the control spool to the middle and lower direction FIG.

The PS pressure _Pc introduced into the regulator 20 corresponds to the output required for the hydraulic pump 10, and the operation position of the engine dial switch for setting the target engine speed. Further, the magnitude of the output required for the hydraulic pump 10 is set according to the operation amount of the operation lever for setting the operation amount of various hydraulic actuators.
First, when the discharge pressure P _a to be introduced into the regulator 20 is decreased, the control spool 27 slides in the middle and lower direction 6, in conjunction with this the power piston 19 moves FIG medium downward, Swash One end of the plate 18 moves in the direction approaching the barrel 11 to increase the tilt angle θ, and the amount of hydraulic oil Q discharged from the hydraulic pump 10 increases. Also, when the discharge pressure P _a to be introduced into the regulator 20 is increased, the power piston 19 is moved to the Figure 2 upward direction with the control spool 27 slides to 6 upward direction, the one end portion of the swash plate 18 Moves in a direction away from the barrel 11, the tilt angle θ decreases, and the hydraulic oil amount Q decreases.

On the other hand, when the PS pressure _Pc introduced into the regulator 20 is high, the control spool 27 is easily pushed downward in FIG. 6 (it is easy to stroke downward), and the tilt angle θ of the swash plate 18 is increased. Tends to increase, that is, the hydraulic oil amount Q tends to increase. On the other hand, when the PS pressure P _c is low, the control spool 27 is likely to be pushed upward in FIG. 6 (it is easy to stroke upward), and the tilt angle θ of the swash plate 18 is likely to be small. The hydraulic oil amount Q is likely to decrease.

Thus, the regulator 20, in response to the discharge pressure P _a and PS pressure P _c by adjusting the tilting angle θ of the swash plate 18 increases or decreases the hydraulic oil amount Q discharged from the hydraulic pump 10, the pump PQ control is performed so that the output is maintained at a predetermined value corresponding to the PS pressure _Pc . Incidentally, the discharge pressure P _a of the normal time in the hydraulic pump 10, the corresponding graph of the hydraulic oil amount Q and PS pressure P _c shown in FIG. 12. This graph is generally called a PQ diagram.

Further, a stroke sensor (hydraulic oil amount detecting means) 5 for detecting the sliding stroke L of the control spool 27 is provided in the regulator 20, and is introduced into the regulator 20 on the upstream side of the PS port 31. A PS pressure sensor (output detection means) 6 for detecting the magnitude of the PS pressure P _c is provided. A sliding stroke L, represents the biasing force of the spring 28, the actual position of the control spool 27 that slides in the passage 29 in response to the discharge pressure P _a and PS pressure P _c, the tilting angle of the swash plate 18 theta Is a parameter corresponding to. The sliding stroke L of the control spool 27 detected by the stroke sensor 5 and the PS pressure P _c detected by the PS pressure sensor 6 are input to the controller 3.

[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 stroke sensor 5, a PS pressure sensor 6, a controller (diagnostic means) 3, and a monitor panel 4. The 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. The stroke sensor 5 is a sensor that detects the sliding stroke L of the control spool 27 of the regulator 20, and the PS pressure sensor 6 is a sensor that detects the PS pressure _Pc .

The monitor panel 4 is a device for displaying a diagnosis result in the present diagnostic device, and is provided in the cab of the work machine on which the hydraulic pump 10 is mounted.
The controller 3 includes a diagnosis unit 3a, a diagnosis result display unit 3b, and a storage unit 3c as control blocks. First, the storage unit 3c 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 P _a0 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. 11. 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. 11 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. 11 increases the slope 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 hydraulic oil flows in the direction along the sliding surface due to surface wear of the valve plate 16. It is considered that the hydraulic oil flows out to the outside of the cylinder chamber 13 and the case internal pressure _Pb is likely to rise. 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. 11, 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 one possible cause is a decrease in the liquid tightness of the case 15 itself due to wear of the valve plate 16. That is, the discharge pressure P _a is a low pressure state, the case the internal pressure P _b is assumed to be difficult to rise.

In addition, the thin solid line drawn above and below the thick solid line in FIG. 11 indicates 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, a PQ diagram as shown in FIG. 12 is stored in the storage unit 3c. FIG. 12 shows a PQ diagram corresponding to three types of PS pressures P _c , but actually, a plurality of PQ lines corresponding to the magnitudes of more PS pressures P _c are shown. The figure is stored. Further, the range of the PS pressure P _c corresponding to each PQ diagram stored here is the same as the entire possible range of the PS pressure P _c corresponding to the magnitude of the output that can be requested to the hydraulic pump 10. Or it is a wider range.
Diagnostic unit 3a, the discharge pressure P _a which is input from the sensors 1, 2, 5, 6, casing pressure P _b, in response to the sliding stroke L and PS pressure P _c, the diagnosis of the hydraulic pump 10.

[1] Diagnosis of valve plate 16 First, the diagnosis section 3a, second predetermined pressure which is determined 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 The valve plate 16 is diagnosed by comparing with P _b0 .

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).

That is, here, when the discharge pressure P _a and the port internal pressure P _b of the hydraulic pump 10 are above the graph of P _a ≧ P _a0 and P _b0 = f (P _a ) on the graph of FIG. The valve plate 16 is determined to be worn, and if it is below the graph of P _a ≧ P _a0 and P _b0 = f (P _a ), it is determined that the valve plate 16 is not worn. .
Incidentally, the discharge pressure P _a is the case without a diagnosis of the valve plate 16 be less than the first predetermined pressure P _a0 the diagnosis result display portion 3b monitor panel 4 navel of effect (for example, please refer to the "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.

[2] Diagnosis Next, diagnostic section 3a of the control spool 27, to calculate the theoretical flow rate Q _c of the discharge pressure P _a and PS pressure P _c, to calculate the actual flow rate Q _a of the sliding stroke L, the theoretical flow rate And the actual flow rate are compared, and the control spool 27 is diagnosed.
As shown in FIG. 10, the diagnosis unit 3a reads out the PQ diagram corresponding to the input PS pressure _{Pc from} the PQ diagram stored in the storage unit 3c, and inputs the discharge calculating the amount of hydraulic oil corresponding to the pressure P _a theoretical flow rate Q _c. That Here, in the hydraulic pump 10 in the normal, theoretical value of the hydraulic oil flow rate estimated from the discharge pressure P _a and PS pressure P _c is calculated.

On the other hand, the diagnosis unit 3a calculates the tilt angle θ of the swash plate 18 corresponding to the input sliding stroke L of the control spool 27, and based on the tilt angle θ and the rotational speed of the barrel 11, it actually The actual flow rate Q _a of the hydraulic oil discharged from the hydraulic pump 10 is calculated. That is, here, the hydraulic oil amount Q _a discharged from the hydraulic pump is calculated based on the tilt angle θ of the swash plate 18. In the present exemplary embodiment it is not shown, to the diagnostic device is input barrel 11 the same rotational speed of the engine rotational speed and is adapted to be referenced in the calculation of the actual flow rate Q _a.

Then, the diagnosis unit 3a determines that the control spool 27 is fixed in the passage 29 when the difference | Q _a −Q _c | between the theoretical flow rate Q _c and the actual flow rate Q _a is equal to or greater than a predetermined value Q _b. On the other hand, when the difference | Q _a −Q _c | is less than the predetermined value Q _b, it is determined that the control spool 27 is not fixed (that is, in a normal operating state).
In other words, here, when the actual flow rate Q _a is within the range that allows the error of the predetermined value Q _b with respect to the theoretical flow rate Q _c shown by the broken line in FIG. 12, it is determined that the control spool 27 is not fixed. If it is out of this range, it is determined that the control spool 27 is fixed.
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.

[flowchart]
The control contents of the diagnostic apparatus will be described with reference to FIGS. First, the flowchart shown in FIG. 7 is a main flow, and is repeatedly executed in the controller 3 at a predetermined cycle. 8 and 9 are appropriately called and executed as a subroutine of the flowchart shown in FIG. The flow in FIG. 8 is referred to as a valve plate diagnostic flow, and the flow in FIG. 9 is referred to as a control spool diagnostic flow.

[1] Main Flow As shown in FIG. 7, in step A10, the diagnostic flow of the valve plate is performed in the diagnosis unit 3a. In the subsequent step A20, it is determined whether or not the value of the flag F _A is F _A = 1. Determined.
The flag F _A is a flag indicating the worn state of the valve plate 16 and is set in a later-described valve plate diagnosis flow. Incidentally, possible values and their meaning of the flag F _A is as follows.

F _A = 0: a state in which the wear state is not diagnosed F _A = 1: a state in which wear is not performed (the progress of wear is very slight) F _A = 2: a state in which wear is performed (the progress of wear is small) In this step A20, if F _A ≠ 1, the process proceeds to step A30, and if F _A = 1, the process proceeds to step A60.

In step A30, it is determined whether or not the value of the flag F _A is F _A = 2. Here, if F _A ≠ 2, F _A = 0, and the process proceeds to step A50. On the other hand, if F _A = 2, the process proceeds to step A40.
In step A40, a display indicating that the valve plate 16 is worn is made on the diagnosis result display section 3c. Further, in step A50, the diagnosis of the wear state of the valve plate 16 is not performed, and “please relieve” is displayed on the monitor panel 4 in the diagnosis result display section 3b, and the process proceeds to step A60.

In step A60, the diagnosis flow of the control spool is executed in the diagnosis unit 3a, and in the subsequent step A70, it is determined whether or not the value of the flag F _B is F _B = 1.
The flag F _B, a flag indicating stuck control spool 27, is set in the diagnostic flow control spool to be described later. Incidentally, possible values and their meaning of the flag F _B is as follows.

F _B = 0: status control spool 27 is stuck in passage 29 F _B = 1: control spool 27 is in a state step A70 that is not fixed in passage 29, the value of the flag F _B is F _B ≠ If 1, the process proceeds to step A80, and if F _B = 1, the process proceeds to step A90.
In step A80, a display indicating that the control spool 27 is fixed is made on the diagnosis result display section 3c. On the other hand, in step A90, it is determined whether or not to continue diagnosis of the hydraulic pump 10.

The conditions for continuing or ending the diagnosis of the hydraulic pump 10 are arbitrary. For example, it is conceivable to provide a switch for executing or ending the diagnosis in the cab of the work machine equipped with the hydraulic pump 10. . In this case, in step A90, it is determined whether to continue or end the diagnosis according to the signal from the switch.
When continuing diagnosis, it returns to step A10 and repeats the said control, and when stopping diagnosis, this flow is complete | finished.

  In this flowchart, only the control for diagnosing the worn state of the valve plate 16 and the fixed state of the control spool is shown, and this flow is finished here, but the hydraulic pump 10 is continued following this flow. A flow for diagnosing other components may be executed.

[2] As shown in the diagnostic flow chart 8 of the valve plate, in step B10, the diagnostic unit 3a from the discharge pressure sensor 1 and the casing pressure sensor 2, the discharge pressure P _a and vent pressures P _b is input. In step B20, whether the discharge pressure P _a is a first predetermined pressure P _a0 or stored in the storage unit 3c (P _a ≧ P _a0) is determined. If P _a ≧ P _a0 , the process proceeds to step B40, and if P _a <P _a0 , the process proceeds to step B30.

In step B30, since there is no detection data in a range where diagnosis is possible, diagnosis of the valve plate 16 is not performed in the diagnosis unit 3a, the flag F _A is set to F _A = 0, and this flow ends.
That is, the discharge pressure P _a is in the region of the P _a <P _a0, as shown in FIG. 11, 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 B40. That is, until the condition (P _a ≧ P _a0 ) is satisfied, the diagnosis standby state is entered.

On the other hand, in step B40, the diagnostic 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 B50, and if P _b <f (P _a ), the process proceeds to step B60.
In step B50, the diagnosis unit 3a diagnoses that the valve plate 16 is worn, sets the flag F _A to F _A = 2 and ends this flow. On the other hand, in step B60, the diagnostic unit 3a, the valve plate 16 is diagnosed as not worn, the flag F _A is set to F _A = 1 and this flow is finished.

[3] As shown in the diagnostic flow diagram 9 of a control spool, in step C10, the discharge pressure sensor 1, to the diagnostic portion 3a from the stroke sensor 5 and PS pressure sensor 6, the discharge pressure P _a, the sliding stroke L and PS pressure P _c is entered. In subsequent step C20, the PQ diagram corresponding to the input PS pressure _Pc is read from the PQ diagram stored in the storage unit 3c in the diagnosis unit 3a. In step C30, based on P-Q diagram, and inputted the discharge pressure P _a, the hydraulic oil amount of the hydraulic pump 10 at the normal time is calculated as the theoretical flow rate Q _c.

On the other hand, in the subsequent step C40, the diagnosis unit 3a calculates the tilt angle θ of the swash plate 18 corresponding to the input sliding stroke L, and is actually discharged from the hydraulic pump 10 based on the tilt angle θ. hydraulic oil amount is calculated as the actual flow rate Q _a.
In step C50, the diagnosis unit 3a, the difference between the theoretical flow rate Q _c and the actual flow rate Q _a | Q _a -Q _c | is equal to or more than a predetermined value Q _b is determined. Here, if | Q _a −Q _c | ≧ Q _b , the process proceeds to step C60, where it is diagnosed that the control spool 27 is stuck in the passage 29, and the flag F _B is set to F _B = 0. This flow is finished.

On the other hand, if | Q _a −Q _c | <Q _b in step C50, the process proceeds to step C70, where it is diagnosed that the control spool 27 is not fixed in the passage 29, and the flag F _B is F _B = 1. Is set to end this flow.

[effect]
Thus, according to the diagnostic device of the hydraulic pump 10 according to the first embodiment, 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, according to the diagnostic device, it is possible to discharge pressure P _a, the diagnosis based on the sliding stroke L and PS pressure P _c, diagnosing the fixing state of the control spool 27. Further, by calculating the difference between the theoretical flow rate Q _c and the actual flow rate Q _a, it is possible to make a diagnosis in consideration of the error range shown by the broken line in FIG. 12, and the control spool 27 can be diagnosed accurately. Further, since the theoretical flow rate Q _c and the actual flow rate Q _a are always compared based on the detection data, for example, a configuration for learning the actual flow rate Q _a is not necessary.

Further, according to the present diagnostic apparatus, since the diagnostic flow of the valve plate and the control spool is provided, whether the failure part of the hydraulic pump 10 is the valve plate 16 or the control spool 27 or other parts. It can be specified whether there is.
Further, since the diagnosis of the valve plate is performed prior to the diagnosis of the control spool, for example, the variation of the hydraulic oil amount Q _a due to wear of the valve plate 16 is within the controllable range of the regulator 20. Even if it is a case, a true failure part can be specified.

Further, in this diagnostic apparatus, the tilt angle θ of the corresponding swash plate 18 is obtained from the sliding stroke L of the control spool 27, and the actual flow rate Q _a discharged from the hydraulic pump 10 is calculated based on the tilt angle θ. Therefore, the calculation is accurate and the reliability of diagnosis can be improved.
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. 11 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.

[Second Embodiment]
A diagnostic apparatus for a hydraulic pump according to a second embodiment of the present invention will be described with reference to FIGS. Figure 13 is a flowchart showing a diagnosis flow of the control spool in the diagnostic apparatus, FIG. 14 is a graph showing a relationship between the discharge pressure P _a and hydraulic pressure Q of the hydraulic pump 10 when the control spool sticking. In addition, this embodiment is a diagnostic apparatus which differs only in the diagnostic method in the diagnostic part 3a of the controller 3 in 1st Embodiment, and structures other than the diagnostic method in the diagnostic part 3a are the same.

This diagnostic apparatus utilizes the characteristics of the hydraulic pump 10 shown in FIG. That is, when the control spool 27 is fixed in the passage 29 in the hydraulic pump 10, the amount of hydraulic oil Q discharged from the hydraulic pump 10 is maintained even if the magnitude of the PS pressure introduced into the regulator 20 is changed. Almost no change.
FIG. 14 shows respective PQ diagrams when the control spool 27 is fixed at three fixing positions. In any case, the control spool 27 is always set regardless of the value of the PS pressure. relationship between the discharge pressure P _a and the hydraulic oil amount Q becomes correspondence relationship shown here. The fixing position A is a position where the tilt angle θ of the swash plate 18 is relatively large in the sliding range of the control spool 27 (for example, a position on the lower side in FIG. 6). The position C is a position where the tilt angle θ is relatively small (for example, a position on the upper side in FIG. 6). Further, the fixing position B is an intermediate position between the fixing position A and the fixing position C.

Therefore, in the present embodiment, while maintaining the discharge pressure P _a conduct control to change the PS pressure, hydraulic oil amount Q by observing whether changes to diagnose stuck in the control spool 27 It is like that.
Controller 3 in this diagnostic process, to the size of the increasing PS pressure P _c is P _c0, adapted to implement the control to gradually increase the PS pressure P _c. The diagnosis unit 3a performs a diagnosis by observing _a change in the actual flow rate Qa before and after the increase of the PS pressure _Pc .

Specifically, when the amount of fluctuation of the actual flow rate Q _a when the magnitude of the PS pressure P _c increases by P _c0 is less than a preset predetermined value Q _a0 , almost no change is seen. It is determined that the control spool 27 is in a fixed state. On the other hand, when the fluctuation amount of the actual flow rate Q _a is equal to or greater than Q _a0 , it is diagnosed that the control spool 27 is in a normal state that is not in a fixed state.
In other words, in the present embodiment, when the ratio of the fluctuation amount of the hydraulic oil amount to the fluctuation of the output level required for the hydraulic pump 10 is less than Q _a0 / P _c0 (first predetermined value), It is diagnosed that the plate driving member is fixed.

[flowchart]
FIG. 13 shows a control spool diagnostic flow in the diagnostic apparatus. The main flow and the valve plate diagnosis flow are the same as those in the first embodiment shown in FIGS.
As shown in FIG. 13, in step D10, the counter n is set to n = 1. The counter n is a variable for observing changes in the PS pressure P _c and the hydraulic oil amount Q, and the actual flow rate Q _a calculated at any time in the process of changing the PS pressure P _c is the calculation result of what cycle. It is a value indicating whether or not. Note that one cycle referred to here is a unit flow in which a series of steps having the same value of n are combined, and indicates a control in which steps D20 to D60 are performed once.

In subsequent step D20, the sliding stroke L and the PS pressure _Pc are input from the stroke sensor 5 and the PS pressure sensor 6 to the diagnosis unit 3a. In step D30, the diagnosis section 3a calculates the tilt angle θ of the swash plate 18 corresponding to the input sliding stroke L, and the operation is actually discharged from the hydraulic pump 10 based on the tilt angle θ. The oil amount is calculated as the actual flow rate Q _a (n). When n = 1, the actual flow rate is expressed as Q _a (1).

In step D40, the diagnosis unit 3a performs control to gradually increase the PS pressure P _c (n) while maintaining the discharge pressure. When n = 1, the PS pressure is expressed as P _c (1).
In the subsequent step D50, n + 1 is assigned to the counter n (1 is added to the counter n). In step D60, it is determined whether or not | P _c (n) −P _c (1) | is equal to or greater than a predetermined value P _c0 set in advance. If | P _c (n) −P _c (1) | ≧ P _c0 , the process proceeds to step D70. If | P _c (n) −P _c (1) | <P _c0 Returning to step D20, the above flow is repeated.

That is, by repeating the flow, the actual flow rate Q _a (n) is calculated as Q _a (1), Q _a (2), Q _a (3)... In each cycle in step D30. The PS pressure P _c (n) is calculated as P _c (1), P _c (2), P _c (3)... For each cycle. In step D60, the process proceeds to the next flow only when the difference between the PS pressure P _c (1) of the first cycle and the PS pressure P _c (n) of the current cycle becomes equal to or greater than a predetermined value P _c0. It will be. Therefore, the larger the predetermined value P _c0 set in advance, the larger the PS pressure to be increased.

In step D70, the diagnosis unit 3a determines whether or not | Q _a (n) −Q _a (1) | is less than a predetermined value Q _a0 set in advance. That is, in this step, how much the actual flow rate increases when the PS pressure is increased by the predetermined value P _c0 is calculated. Here, if the increase amount | Q _a (n) −Q _a (1) | of the actual flow rate is less than the predetermined value Q _a0 , the process proceeds to step D80 and the control spool 27 is in a fixed state in the passage 29. And the flag F _B is set to F _B = 0, and this flow ends.

On the other hand, if the increase amount | Q _a (n) −Q _a (1) | of the actual flow rate is greater than or equal to the predetermined value Q _a0 in step D70, the diagnosis is made that the control spool 27 is not in a fixed state in the passage 29. Then, the flag F _B is set to F _B = 1 and this flow ends.
Incidentally, if the control spool 27 is stuck, unless the discharge pressure P _a is changed is maintained, since the hydraulic oil amount Q does not change, a predetermined value Q _a0 according to the determination of step D70 is 0 or substantially 0 It may be a very small value.

[effect]
As described above, according to the diagnostic apparatus for the hydraulic pump 10 according to the second embodiment, the actual performance when the magnitude of the PS pressure P _c is changed using the characteristics of the hydraulic pump 10 as shown in FIG. when a change of the flow rate Q _a is hardly observed, the control spool 27 can be diagnosed with the stuck.

Further, the method for the diagnosis of the control spool 27 without discharge pressure P _a, which can be implemented with a simple configuration. Further, by controlling the PS pressure, that is, the pilot pressure input to the regulator 20, the fluctuation of the hydraulic oil amount Q can be easily observed.

[Third Embodiment]
A hydraulic pump diagnosis apparatus according to a third embodiment of the present invention will be described with reference to FIGS. FIG. 15 is a flowchart showing a control flow of the control spool in this diagnostic apparatus, and FIG. 16 is a graph showing a correspondence relationship between the discharge pressure of the hydraulic pump and the hydraulic pressure when the control spool is fixed compared with the normal time. In addition, this embodiment is a diagnostic apparatus which differs only in the diagnostic method in the diagnostic part 3a of the controller 3 in 1st Embodiment, and structures other than the diagnostic method in the diagnostic part 3a are the same.

This diagnostic apparatus utilizes the characteristics of the hydraulic pump 10 shown in FIG. That is, at a normal time when the control spool 27 is not fixed in the passage 29 in the hydraulic pump 10, there is a break point at which the fluctuation gradient of the hydraulic oil amount Q changes as shown by a thick solid line in FIG. Further, the discharge pressure P _a corresponding to the break point is changed depending on the size of the PS pressure P _c. But,
When the control spool 27 is fixed in the passage 29, as shown by a thin solid line in FIG. 16, there is no break point at which the fluctuation gradient of the hydraulic oil amount Q changes. Such a phenomenon is observed regardless of the fixing position of the control spool 27.

Therefore, in this embodiment, by performing control for changing the discharge pressure P _a of the hydraulic oil discharged from the hydraulic pump 10, to observe whether the hydraulic oil amount Q how to change, sticking of the control spool 27 The condition is to be diagnosed.
Note here, between the diagnosis in the diagnostic unit 3a, together with the amount of change is gradually increased discharge pressure P _a to a predetermined value P _a2 size or more, the variation gradient of the actual flow rate Q _a (i.e., the hydraulic oil in Fig. 16 Control is performed to calculate whether or not the fluctuation gradient changes gently.

Further, the diagnostic unit 3a calculates the actual flow rate Q _a of variation gradient K a (n) according to Equation 1 below.

  When there is a break point as shown in FIG. 16 in the fluctuation of the hydraulic oil amount Q, the value of the fluctuation gradient K (n) changes abruptly at the break point. Therefore, the diagnosis unit 3a determines whether or not there is a break point in the hydraulic oil amount Q by determining whether there is a portion where the value of the fluctuation gradient K (n) changes rapidly or always changes gently. To do. Then, when no discontinuous point where the fluctuation gradient K (n) changes substantially discontinuously is found, it is diagnosed that the control spool 27 is fixed.

[flowchart]
FIG. 15 shows a diagnostic flow of the control spool in this diagnostic apparatus. The main flow and the valve plate diagnosis flow are the same as those in the first embodiment shown in FIGS.
As shown in FIG. 15, in step E10, the counter n is set to n = 1, the following step E20, the discharge pressure sensor 1 and the stroke sensor 5 to the diagnostic unit 3a, the discharge pressure P _a and the sliding stroke L is Entered. In step E30, the diagnosis section 3a calculates the tilt angle θ of the swash plate 18 corresponding to the input sliding stroke L, and the actual discharge from the hydraulic pump 10 based on the tilt angle θ. The oil amount is calculated as the actual flow rate Q _a (n).

In step E40, the change gradient K (n) of the actual flow rate is calculated according to Equation 1 in the diagnosis unit 3a.
That is, in this step, the change gradient K (n) is obtained by dividing the difference between the actual flow rate Q _a (n) in the current cycle and the actual flow rate Q _a (n-1) in the previous cycle by the change amount of the discharge pressure. Calculated.
In step E50, the control for increasing the discharge pressure P _a (n) is performed. In this step, PS pressure is not controlled. This is because if the control spool 27 is in a fixed state, the characteristics of the hydraulic pump 10 as shown in FIG. 16 do not change regardless of the increase or decrease of the PS pressure, and there is no influence on this control. That is, the PS pressure may not be changed, and conversely, the PS pressure may be changed (may be changed). In step E60, n + 1 is assigned to the counter n.

In step E70, it is determined whether or not | P _a (n) −P _a (1) | is equal to or greater than a predetermined value _{Pa 2} . Here, if | P _a (n) −P _a (1) | ≧ P _a2 , the process proceeds to step E80, while | P _a (n) −P _a (1) | <P _a2 . In that case, the flow returns to step E20 to repeat the above flow.
That is, by repeating the flow, the actual flow rate Q _a (n) is calculated as Q _a (1), Q _a (2), Q _a (3)... In each cycle in step E30. The fluctuation gradient K (n) is calculated as K (1), K (2), K (3). Then, in step E70, the first time when the difference between the discharge pressure of the first cycle P _a (1) and the discharge pressure of the current cycle P _a (n) becomes a predetermined value P _a2 or more, the process proceeds to the next flow It will be. Accordingly, the larger the predetermined value _Pa2 set in advance, the larger the magnitude of the discharge pressure to be increased.

In step E80, the diagnosis unit 3a determines whether or not there is a discontinuous point in the fluctuation gradient K (n). That is, here, it is determined whether or not a fluctuation gradient K (n) such that the fluctuation of the hydraulic oil amount Q becomes a broken line is detected.
If there is a discontinuous point, a break point will be seen in the fluctuation graph of the hydraulic oil amount Q, the process proceeds to step E90, and it is diagnosed that the control spool 27 is not in the fixed state, and the flag F _B is F _B = 0. Is set to end this flow. On the other hand, when there is no discontinuous point, that is, the fluctuation gradient K (n) is gently changing, and no breakpoint is seen in the fluctuation graph of the hydraulic oil amount Q, the process proceeds to step E100. It is diagnosed that the control spool 27 is in the fixed state, the flag F _B is set to F _B = 1, and this flow is finished.

[effect]
Thus, according to the diagnostic apparatus for the hydraulic pump 10 according to the third embodiment, the fluctuation of the actual flow rate Q _a when the discharge pressure is changed using the characteristics of the hydraulic pump 10 as shown in FIG. When there is no discontinuous point in the gradient K (n), it can be diagnosed that the control spool 27 is in a fixed state.

In addition, since this method does not use the PS pressure P _c , it can be realized with a simpler configuration than the first and second embodiments. Further, by varying the discharge pressure P _a, it is possible to observe the variation of readily hydraulic oil amount Q.

[Fourth Embodiment]
A hydraulic pump diagnosis apparatus according to a fourth embodiment of the present invention will be described with reference to FIGS. FIG. 17 is a flowchart showing a diagnostic flow of a control spool in the diagnostic apparatus, and FIG. 18 is a partial side view showing a configuration of a work machine equipped with the hydraulic pump 10 to which the diagnostic apparatus is applied. In addition, this embodiment is a diagnostic apparatus which differs only in the diagnostic method in the diagnostic part 3a of the controller 3 in 1st Embodiment.

The hydraulic pump 10 according to this diagnostic apparatus is applied to the work machine shown in FIG. The work machine includes a boom 41 and a stick 43 as work devices, and includes a boom hydraulic cylinder 42 for driving the boom 41 and a stick hydraulic cylinder 44 for driving the stick 43. The boom hydraulic cylinder 42 and the stick hydraulic cylinder 44 are operated by hydraulic oil discharged from the hydraulic pump 10. In addition, the boom 41, the boom 41 itself is the boom inclination sensor (inclination sensor, the hydraulic oil amount detection means) for detecting whether the forms how much tilt angle theta _B is 5a provided with respect to the horizontal plane. Note that the tilt angle θ _B detected by the boom tilt sensor 5 a is input to the diagnosis unit 3 a of the controller 3.

The controller 3 in this diagnostic apparatus is configured to calculate the hydraulic oil amount Q discharged from the hydraulic pump 10 based on the inclination angle θ _B detected by the boom inclination sensor 5a. That is, in the state where only the boom 41 is operated, the amount of hydraulic oil flowing into the boom cylinder 42 and the amount of hydraulic oil discharged from the hydraulic pump 10 are equal. Therefore, if the change in the inclination angle θ _B is grasped and the amount of hydraulic fluid flowing into the boom cylinder 42 is calculated, the actual flow rate Q _a discharged from the hydraulic pump 10 is calculated.

In FIG. 18, the connection point between the boom 41 and the upper end of the boom cylinder 42 is P ₁ , the connection point between the boom cylinder 42 and the work machine is P ₂ , and the connection point between the boom 41 and the work machine is P _3. The distance between the points P ₂ to P ₃ is L ₁ , and the distance between the points P ₁ to P ₃ is L _2, and two straight lines are formed from the point P ₃ to the points P ₁ and P ₂ . When the angle is θ _C , the distance between the points P ₁ and P ₂ (that is, the cylinder length) S is expressed as a function of θ _C as shown in Equation 2 below.

That is, if performing the correspondence between the angle theta _C in inclination angle theta _B and 18 in advance the boom 41, it is possible to grasp the cylinder length of the boom cylinder 42 based on the inclination angle theta _B of the boom 41. Further, the change (elongation or contraction) of the cylinder length per unit time can be calculated from the change amount per unit time of the inclination angle θ _{B, and} the amount of hydraulic oil flowing into the boom cylinder 42 can be calculated. As a result, the actual flow rate Q _a discharged from the hydraulic pump 10 can be calculated.

Similarly to the case of the first embodiment described above, the diagnosis unit 3a displays a PQ diagram corresponding to the input PS pressure _Pc among the PQ diagrams stored in the storage unit 3c. reads, calculates the amount of hydraulic oil corresponding to the discharge pressure P _a, which is input as a theoretical flow rate Q _a.
When the difference | Q _a −Q _c | between the theoretical flow rate Q _c and the actual flow rate Q _a is equal to or greater than a predetermined value Q _d, it is determined that the control spool 27 is fixed in the passage 29, When the difference | Q _a −Q _c | is less than the predetermined value Q _d, it is determined that the control spool 27 is not fixed (that is, in a normal operating state).

[flowchart]
A diagnostic flow of the control spool in this diagnostic apparatus will be described. In this diagnostic apparatus, the following control is performed in a state where the hydraulic oil supplied from the hydraulic pump 10 drives only the boom cylinder 42.
As shown in FIG. 17, in step F10, the counter n is set to n = 1, and in the subsequent step F20, the discharge pressure P _{a is} sent from the discharge pressure sensor 1, the boom tilt sensor 5a and the PS pressure sensor 6 to the diagnosis unit 3a. (n), inclination angle θ _B (n) and PS pressure P _c (n) are input. In step F30, a PQ diagram corresponding to the input PS pressure P _c (n) is read from the PQ diagram stored in the storage unit 3c. In step F 40, based previously loaded P-Q diagram, and an input discharge pressure P _a (n) in step, calculating the amount of hydraulic oil in the hydraulic pump 10 at the normal time and a theoretical flow rate Q _c (n) Is done.

On the other hand, in step F50, the cylinder length S (n) of the boom cylinder 42 is calculated according to the above equation 2 based on the inclination angle θ _B (n), and in the subsequent step F60, the cylinder length is calculated as in the following equation 3. The time differential value is calculated to calculate the cylinder speed V (n).

In step F70, the actual flow rate Q _a (n) of the hydraulic oil in the hydraulic pump 10 is calculated based on the cylinder speed V (n) calculated in the previous step.
In step F80, the diagnosis unit 3a, the difference between the theoretical flow rate Q _c and the actual flow rate Q _a | Q _a -Q _c | is equal to or greater than a predetermined value Q _d is determined. Here, if | Q _a −Q _c | ≧ Q _d , the process proceeds to step F 90, where it is diagnosed that the control spool 27 is stuck in the passage 29, and the flag F _B is set to F _B = 0. The

On the other hand, if | Q _a −Q _c | <Q _d at step F80, the routine proceeds to step F100, where it is diagnosed that the control spool 27 is not fixed in the passage 29, and the flag F _B is set to F _B = 1. Set to That is, here, it is determined whether or not the actual flow rate Q _a is within a range that allows for an error of the predetermined value Q _d with respect to the theoretical flow rate Q _c .
In step F110, the n + 1 is substituted into the counter n, in subsequent step F 120, whether the counter n is a predetermined value n ₀ or more is determined. If n <n ₀ , the process returns to step F20 to repeat the flow. On the other hand, if n ≧ n ₀ , the flow ends.

That is, here, control is performed such that the control in which the flow from step F20 to step F120 is one cycle is repeated n ₀ times. The larger the predetermined value n ₀ , the greater the number of repetitions.

[effect]
Thus, according to the diagnostic device of the hydraulic pump 10 according to the second embodiment, the discharge pressure P _a, the diagnosis based on the inclination angle theta _B and PS pressure P _c of the boom 41, diagnosis sticking state of the control spool 27 can do. Further, by calculating the difference between the theoretical flow rate Q _c and the actual flow rate Q _a, it is possible to make a diagnosis in consideration of the error range, and the control spool 27 can be diagnosed accurately.

  Further, for example, compared with the first embodiment described above, it is not necessary to provide the stroke sensor 5 for detecting the sliding stroke L of the control spool 27, and the hydraulic pump 10 has a simple configuration using the boom tilt sensor 5a. Can be diagnosed.

[Others]
The first to fourth embodiments of the present invention have been described above, but the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the present invention. .

For example, the stroke sensor 5 is provided in the first to third embodiments described above, and the tilt angle θ of the swash plate 18 is calculated based on the sliding stroke L of the control spool 27 detected here. The actual flow rate Q _a of the hydraulic oil actually discharged from the hydraulic pump 10 is calculated based on the rotation angle θ and the rotational speed of the barrel 11. However, instead of the stroke sensor 5, a sensor that detects the tilt angle θ of the swash plate 18 may be provided, or a flow meter that directly detects the actual flow rate Q _a of the hydraulic oil discharged from the hydraulic pump 10. It is good also as a structure which provided.

In the above-described embodiment, the magnitude of the PS pressure P _c is detected as the magnitude of the output required for the hydraulic pump 10. It is good also as a structure which detects a magnitude | size.
In the first embodiment, when the difference | Q _a −Q _c | between the theoretical flow rate Q _c and the actual flow rate Q _a is equal to or greater than a predetermined value Q _b , the control spool 27 is fixed in the passage 29. However, the determination condition in step C50 of the control spool diagnosis flow is not limited to this. For example, the determination may be made based on the ratio of the actual flow rate Q _{a to} the theoretical flow rate Q _c .

In the third embodiment, it is adapted to diagnose the presence or absence of break point based on the actual flow rate Q _a of variation gradient K (n), check method of broken point is not limited to such a method various Conceivable. For example, the graph the variation in virtually discharge pressure P _a and the actual flow rate Q _a in the controller 3 (i.e., P-Q diagram) drawn as, configured to confirm the presence of break points directly from the slope of the graph May be.

Moreover, in 4th Embodiment, although comprised so that the hydraulic oil quantity Q discharged from the hydraulic pump 10 may be calculated using the boom inclination sensor 5a which detects the inclination | tilt angle (theta) _B of the boom 41, in addition to this, Thus, the stick 43, the bucket, and other hydraulic actuators may be provided with a sensor for grasping the flow rate of the hydraulic oil supplied to each hydraulic actuator.
For example, when a stick tilt sensor that detects the tilt angle of the stick 43 is used, the hydraulic oil amount Q can be calculated even when the boom 41 and the stick 43 are interlocked.

In this control, it is only necessary to know the flow rate of the hydraulic oil supplied to each hydraulic actuator. For example, instead of the boom tilt sensor 5a, the boom cylinder 42 flows into the boom cylinder 42 using a sensor that directly detects the boom cylinder length S. It is also possible to employ a configuration that calculates the amount of hydraulic fluid that has been used.
Further, in the first to fourth embodiments described above, the diagnosis unit 3a of the controller 3, the discharge pressure P _a and vent pressures P _b and the first predetermined pressure P _a0 and second predetermined input from the sensors 1 and 2 The valve plate is diagnosed by comparing with the pressure _Pb0 . This is synonymous with whether or not the input data exists in the area A shown in FIG. 19, 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, the wear progressed more than the smaller graph (here, the thin solid line on the lower side) of the fluctuation range of the discharge pressure and the case internal pressure when the valve plate 16 is not worn. (here, the degree of progress of wear large) discharge pressure in the valve plate 16 - the discharge pressure P _a of the case pressure graph small point is set to the threshold P _a1, setting equalizer case internal pressure P _b is the threshold P _b1 Is done. 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.
Further, regarding the diagnosis of the valve plate 16 in the first to fourth embodiments described above, if the condition (P _a ≧ P _a0 ) is not satisfied, the diagnosis is not performed, and the discharge pressure P _{a of the} hydraulic pump 10 is directed to the operator. Such a notification is not indispensable. 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 diagnosis of the valve plate 16 in the first to fourth embodiments described above, in step A50, “please relieve” is displayed on the monitor panel 4 to prompt the operator to operate. in addition to the control configuration as, when the lever operation amount by the operator for the relief is relatively small sufficiently discharge pressure P _a is not increased, further "please raise the discharge pressure P _a of the hydraulic pump 10 ' and displays 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 1st Embodiment of this invention. It is the side view (right half part) and sectional view (left half part) which show the structure of the hydraulic pump to which this diagnostic apparatus was applied. FIG. 3 is a view as seen from an arrow A in FIG. 2. It is BB sectional drawing which shows the structure of the hydraulic pump of FIG. FIG. 3 is a component diagram of a valve plate in the hydraulic pump of FIG. 2. It is CC sectional drawing which shows the structure of the regulator of FIG. It is a flowchart which shows the control content of this diagnostic apparatus. It is a flowchart which shows the diagnostic content of the valve plate by this diagnostic apparatus. It is a flowchart which shows the diagnostic content of the control spool by this diagnostic apparatus. It is a block diagram concerning diagnostic control of a control spool. 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 which shows the correspondence of the discharge pressure and hydraulic pressure of a hydraulic pump at the normal time. It is a flowchart which shows the diagnostic content of a control spool in the diagnostic apparatus of the hydraulic pump as 2nd Embodiment of this invention. It is a graph which shows the correspondence of the discharge pressure and hydraulic pressure of a hydraulic pump at the time of control spool adhering. It is a flowchart which shows the diagnostic content of a control spool in the diagnostic apparatus of the hydraulic pump as 3rd Embodiment of this invention. It is a graph which shows the correspondence of the discharge pressure and hydraulic pressure of a hydraulic pump at the time of control spool adhering compared with the time of normal. It is a flowchart which shows the diagnostic content of a control spool in the diagnostic apparatus of the hydraulic pump as 4th Embodiment of this invention. It is a partial side view which shows the structure of the working machine carrying the hydraulic pump to which this diagnostic apparatus was applied. It is a graph for demonstrating the control content in the modification of this diagnostic apparatus.

Explanation of symbols

1 Operating oil pressure sensor (Operating oil 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 5 Control spool stroke sensor (hydraulic oil amount detecting means)
5a Boom tilt sensor (tilt sensor)
6 PS pressure sensor (output detection means)
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 19a Tilt pin 20 Regulator (Tilt angle adjustment member)
21 Drain port 22 Discharge port 23 Gear 24 Inflow line 25 Discharge line 26 Bearing 27 Control spool (swash plate drive member)
28 Spring 29 Passage 30 First main pump 31 PS pressure port 40 Second main pump 41 Boom 42 Boom cylinder 43 Stick 44 Stick cylinder

Claims (14)

A rotating member that is rotationally driven by the drive shaft, a swash plate that is disposed so as to be able to maintain a predetermined tilt angle with respect to a plane perpendicular to the drive shaft, and an oil chamber that is recessed in the rotating member. A sliding member that is inserted and rotationally driven together with the rotating member and that is supported at one end by the swash plate and is slidable in the direction of the driving shaft in the oil chamber; And a tilt angle adjusting member that adjusts the tilt angle of the swash plate in accordance with the pressure of the hydraulic oil discharged from the chamber and the magnitude of the output required for the hydraulic pump. Because
A discharge pressure detecting means for detecting a discharge pressure of the hydraulic oil discharged from the hydraulic pump;
Output detection means for detecting the magnitude of output required for the hydraulic pump;
Hydraulic oil amount detecting means for detecting the hydraulic oil amount discharged from the hydraulic pump;
A diagnostic device for a hydraulic pump, comprising diagnostic means for diagnosing the state of the tilt angle adjusting member based on the discharge pressure, the magnitude of the output, and the amount of hydraulic oil. The hydraulic pump has a pilot pressure supply device that supplies a pilot pressure according to the magnitude of output required for the hydraulic pump,
The tilt angle adjusting member has a swash plate driving member that drives the swash plate according to the hydraulic pressure and the pilot pressure introduced from the pilot pressure supply device to adjust the tilt angle,
The output detection means detects the magnitude of the pilot pressure,
The diagnostic means calculates a theoretical flow rate of the hydraulic oil that the hydraulic pump normally discharges from the magnitude of the pilot pressure and the discharge pressure, and a difference between the theoretical flow rate and the hydraulic oil amount is a predetermined value or more. In this case, it is diagnosed that the swash plate driving member is fixed. The diagnostic means has the swash plate driving member fixed when the ratio of the variation amount of the hydraulic oil amount to the variation in the magnitude of the output required for the hydraulic pump is less than a first predetermined value. The diagnostic device for a hydraulic pump according to claim 1 or 2, wherein The diagnostic means diagnoses that the swash plate driving member is fixed when no discontinuous point at which the fluctuation gradient of the hydraulic oil amount changes substantially discontinuously with respect to the discharge pressure is found. The diagnostic device for a hydraulic pump according to any one of claims 1 to 3. The diagnostic means draws the fluctuation of the hydraulic oil amount with respect to the fluctuation of the discharge pressure as a graph, and the swash plate driving member is fixed when there is no break point where the gradient of the graph suddenly changes. The diagnostic device for a hydraulic pump according to claim 4, wherein the diagnostic device is diagnosed as having The hydraulic oil amount detecting means has a swash plate sensor for detecting the tilt angle of the swash plate, and calculates the hydraulic oil amount actually discharged from the hydraulic pump based on the tilt angle. The diagnostic device for a hydraulic pump according to any one of claims 1 to 5, wherein the diagnostic device is a hydraulic pump diagnostic device. A hydraulic pump diagnostic apparatus in a work machine equipped with the hydraulic pump and a working cylinder driven by hydraulic oil discharged from the hydraulic pump,
The hydraulic pump diagnosis apparatus according to any one of claims 1 to 6, wherein the hydraulic oil amount detection means calculates a hydraulic oil flow rate supplied to the working cylinder. The working cylinder is a hydraulic cylinder that drives a working device of the work machine,
An inclination sensor that detects an inclination angle of the working device with respect to a horizontal plane;
8. The hydraulic pressure according to claim 7, wherein the hydraulic oil amount detecting means calculates a hydraulic oil flow rate supplied to the hydraulic cylinder based on a time differential value of the inclination angle detected by the inclination sensor. Pump diagnostic device. The hydraulic pump includes a housing member that houses the rotating member and the sliding member, and a flow path 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 valve member that opens or closes,
An internal pressure grasping means for grasping the internal pressure of the housing member;
9. A diagnostic device 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. Hydraulic pump diagnostic device. 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 9. 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 9 or 10, 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 for a hydraulic pump according to any one of claims 9 to 11. A rotating member that is rotationally driven by the drive shaft, a swash plate that is disposed so as to be able to maintain a predetermined tilt angle with respect to a plane perpendicular to the drive shaft, and an oil chamber that is recessed in the rotating member. A sliding member that is inserted and rotationally driven together with the rotating member and that is supported at one end by the swash plate and is slidable in the direction of the driving shaft in the oil chamber; A hydraulic pump having a tilt angle adjusting member that adjusts the tilt angle of the swash plate according to the pressure of hydraulic oil discharged from the chamber and the magnitude of the output required for the hydraulic pump is diagnosed A method,
Detecting the discharge pressure of the hydraulic oil discharged from the hydraulic pump;
Detecting the magnitude of output required for the hydraulic pump;
Detecting the amount of hydraulic oil discharged from the hydraulic pump,
A diagnostic method for a hydraulic pump, wherein the state of the tilt angle adjusting member is diagnosed based on the discharge pressure, the magnitude of the output, and the amount of hydraulic oil. A rotating member that is rotationally driven by the drive shaft, a swash plate that is disposed so as to be able to maintain a predetermined tilt angle with respect to a plane perpendicular to the drive shaft, and an oil chamber that is recessed in the rotating member. A sliding member that is inserted and rotationally driven together with the rotating member and that is supported at one end by the swash plate and is slidable in the direction of the driving shaft in the oil chamber; A tilt angle adjusting member that adjusts the tilt angle of the swash plate in accordance with the pressure of the hydraulic oil discharged from the chamber and the output required for the hydraulic pump, the rotating member, and the sliding member A hydraulic pump comprising: a housing member that houses the member; and a valve member 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 A method for diagnosing
The discharge pressure of the hydraulic oil discharged from the hydraulic pump is detected, the amount of output required for the hydraulic pump is detected, the amount of hydraulic oil discharged from the hydraulic pump is detected, and the storage Know the internal pressure of the material,
Based on the internal pressure and the discharge pressure, diagnose the wear state on the contact surface of the valve member with the rotating member,
Thereafter, the state of the tilt angle adjusting member is diagnosed on the basis of the discharge pressure, the magnitude of the output, and the amount of hydraulic oil.

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