JP2000274378A - Operating condition diagnostic device for hydraulic rotating machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect initial abnormalities based on change in internal pressure in a casting corresponding to the rotating condition of a rotating shaft, and simplify maintenance works and the like after abnormalities have been detected. SOLUTION: A pressure sensor 17 for detecting the internal pressure of a drain oil chamber 6, is provided for the casing 3 of a hydraulic pump 1, and a rotation sensor 20 for detecting the revolution of a rotating shaft 8 is also provided. It is determined by a controller based on detected signals from the pressure sensor 17 and the rotation sensor 20 whether or not the amount of leaking oil is in a normal range while corresponding to the rotating condition of a cylinder block 9. When the pressure pulsation level within the casing 3 is extraordinally high, it is determined that there occur abrasion, scaffing and the like between the cylinder 10 and the piston 11 of the hydraulic pump 1 so as to let the amount of leaking oil be rapidly increased in the drain oil chamber 6, so that the amount of leaking oil exceeds its normal range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for diagnosing the operating condition of a hydraulic rotary machine suitable for use as, for example, a hydraulic pump or a hydraulic motor for construction equipment.

[0002]

2. Description of the Related Art In general, a construction machine such as a hydraulic shovel is equipped with a hydraulic rotary machine such as a hydraulic pump used as a hydraulic source of hydraulic equipment and a hydraulic motor used as a driving source for traveling or turning. I have.

[0003] A hydraulic rotary machine of this type according to the prior art includes a casing, a rotating shaft rotatably provided on the casing, and a casing provided with a plurality of cylinders so as to rotate integrally with the rotating shaft. A plurality of pistons reciprocally inserted into respective cylinders of the rotor, and a pair of intermittently communicating with the respective cylinders provided on the casing so as to be in sliding contact with the rotor. And a valve member such as a valve plate in which a supply / discharge port is formed, and is known as, for example, a swash plate type, an oblique axis type, and a radial piston type hydraulic rotary machine.

[0004] In these hydraulic rotary machines,
For example, when used as a hydraulic pump, when the rotating shaft is driven by a motor such as an engine, the piston reciprocates in each cylinder of the rotor as the rotor rotates with the rotating shaft in the casing. become.

As a result, the piston repeats a suction stroke and a discharge stroke. In the suction stroke, hydraulic oil is sucked into the cylinder from one of the supply / discharge ports of the valve plate, and the cylinder is discharged in the discharge stroke. The working oil in the inside is pressurized by a piston, and is discharged as pressure oil from the other port side.

In such a hydraulic rotary machine, the piston is reciprocated at a high speed when the piston is slid and displaced in each cylinder of the rotor. Therefore, the sliding surface between the cylinder and the piston is worn or damaged. In such a case, galling and the like are likely to occur, and with this, the pressure oil in the cylinder leaks into the casing from the sliding surface side with the piston.

[0007] In the piston suction stroke, etc.,
A sliding force generated between the piston and the cylinder due to galling or the like may cause a separating force in a direction in which the rotor is separated from a valve member such as a valve plate. Pressure oil leaks into the casing from the side of the sliding contact surface.

[0008] Such leakage oil is drained as drain oil to the tank through a drain pipe or the like. However, if the amount of leaked oil increases rapidly, a large amount of oil flows into the drain pipe, etc., causing throttling resistance and increasing the pressure inside the casing, thereby increasing the pressure inside the casing. When it becomes abnormally high, the casing of the hydraulic rotating machine may be damaged or broken by the internal pressure.

Therefore, in the prior art, in order to prevent an abnormal pressure from being generated in the casing, a low pressure side port of a pair of supply / discharge ports provided on the valve plate is communicated with the drain chamber of the casing. An abnormality detection and breakage prevention device for a hydraulic rotary machine has been proposed in which a communication passage is additionally provided and the communication passage is opened and closed in accordance with the pressure in the casing (for example, Japanese Utility Model Application Laid-Open No. 63-163). -17421).

According to this prior art, a shut-off valve for keeping the communication passage closed at all times is provided, and when the pressure in the casing becomes abnormally high due to an increase in leakage oil, the shut-off valve is provided. By opening the valve against the spring, the abnormal pressure in the casing is released to the low-pressure port side.

[0011]

However, in the above-described abnormality detecting apparatus for a hydraulic rotary machine according to the prior art, the absolute amount of oil leaking from each cylinder of the rotor into the casing is increased, so that the inside of the casing is increased. When the pressure becomes abnormal, the shut-off valve is opened against the spring, so that the following problems occur.

In other words, the amount of pressure oil leaking from each cylinder of the rotor (leakage oil amount) is affected by external load pressure even during normal operation, as shown by a characteristic line 18 illustrated in FIG. It increases so as to draw a quadratic curve as the load pressure increases. When the load pressure acting on the hydraulic rotary machine is high, the amount of leaked oil increases even during normal operation, and the pressure in the casing becomes high.

For this reason, if the valve opening pressure of the shut-off valve is set to a low pressure value, it is determined that there is an abnormality even if the amount of leaked oil is in a normal range when the load pressure is high, and the shut-off valve May open, making it difficult to determine whether the amount of leaked oil is abnormally increased based on the opening and closing operations of the shut-off valve.

On the other hand, in order to open the shut-off valve against the spring only when a galling or the like occurs due to wear between the cylinder and the piston, the opening pressure of the shut-off valve is set to a high pressure value. In this case, it is possible to determine whether or not the amount of leaked oil is abnormally increased even when the load pressure acting on the hydraulic rotating machine is high.

However, in this case, when the shut-off valve is opened and an abnormality is detected, it is highly probable that the wear between the cylinder and the piston has progressed excessively, and the inside of the casing or the cylinder is likely to be worn. In this method, a large amount of abrasion powder is generated, and other components are damaged by the abrasion powder, so that the number of components to be replaced increases, and the subsequent maintenance work is troublesome.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is not based on the absolute amount of leaked oil generated inside, but on the basis of a change in the internal pressure of a casing corresponding to the rotational state of a rotor. Provided is an operating state diagnostic device for a hydraulic rotating machine that can detect an initial abnormality, simplify maintenance work after the abnormality is detected, and reliably extend the durability and life of each component. It is in.

[0017]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a casing, a rotating shaft rotatably provided on the casing, and a plurality of cylinders perforated to be integrated with the rotating shaft. A rotor provided in the casing so as to rotate, a plurality of pistons reciprocally inserted into respective cylinders of the rotor, and the respective cylinders provided in the casing so as to be in sliding contact with the rotor. And a valve member formed with a pair of supply / discharge ports intermittently communicating with the hydraulic rotary machine.

The first aspect of the present invention is characterized in that an internal pressure detecting means for detecting a pressure change in the casing due to oil leaking from each of the cylinders, and a rotation of the rotary shaft or the rotor. Leak detecting means for diagnosing whether or not the amount of the leaked oil is within a normal range according to a pressure detection signal output from the internal pressure detecting means and a rotation detection signal output from the rotation detecting means. And that it had.

With this configuration, the rotation number of the rotating shaft can be detected by the rotation detecting means while the pressure change in the casing is detected by the internal pressure detecting means. It is possible to determine at an early stage whether or not the amount of leaked oil exceeds the normal range according to the rotation detection signal.

The invention according to claim 2 is configured such that a notifying means for notifying the diagnosis result of the leak diagnosis means to the outside is provided on the output side of the leak diagnosis means.

With this configuration, the leak detecting means can determine at an early stage whether or not the amount of leaked oil exceeds the normal range according to the pressure detection signal and the rotation detection signal. When the oil amount is abnormally increased, the notification unit is operated to notify the abnormality at an early stage, and the operation of the hydraulic rotary machine is stopped to suppress the occurrence of wear, galling, and the like.

Further, according to a third aspect of the present invention, the leakage diagnosis means specifies the rotation frequency of the rotor based on the rotation detection signal output from the rotation detection means, and performs frequency analysis on the pressure detection signal output from the internal pressure detection means. A signal processing circuit for calculating the pressure pulsation level in the casing at the specific frequency, and comparing the pressure pulsation level calculated by the signal processing circuit with a predetermined determination value to thereby determine the oil amount of the leaked oil. Is in the normal range.

Thus, the signal processing circuit can specify the rotation frequency of the rotor in accordance with the rotation detection signal from the rotation detection means. In this state, the frequency analysis of the pressure detection signal from the internal pressure detection means enables the signal inside the casing to be analyzed. It is possible to calculate how much pressure pulsation level (pressure fluctuation width) of the pressure pulsation at the specified frequency. Then, by comparing the pressure pulsation level with a determination value, the determination circuit can determine at an early stage whether or not the amount of leaked oil in the casing exceeds a normal range, for example, on a sliding surface between a cylinder and a piston. It is possible to prevent the occurrence of further abrasion, galling and the like.

[0024]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a hydraulic rotary machine according to an embodiment of the present invention, which is applied to a variable displacement swash plate type hydraulic pump. This will be described in detail according to 6.

In FIG. 1, reference numeral 1 denotes a variable displacement type swash plate type hydraulic pump which constitutes a hydraulic source together with a tank 2. This hydraulic pump 1 is provided in a building cover of a construction machine such as a hydraulic shovel or the like, and has a motor ( (Not shown), the hydraulic oil (oil liquid) in the tank 2 is discharged to the outside from the supply / discharge passage 16B described later as high-pressure oil.

Reference numeral 3 denotes a casing of the hydraulic pump 1. The casing 3 is a casing body 4 formed in a bottomed tubular shape from a bottom 4A and a tubular portion 4B, and a lid covering the open end side of the tubular portion 4B. The lid 5 forms a drain oil chamber 6 between itself and the casing body 4. A drain port 4C is formed in the cylindrical portion 4B of the casing body 4, and the drain port 4C is formed.
C is connected to the tank 2 via a drain pipe 7.

Reference numeral 8 denotes a rotating shaft rotatably provided on the casing 3, 9 denotes a cylinder block as a rotor that is driven to rotate by the rotating shaft 8, and the cylinder block 9 is spline-coupled to the outer peripheral side of the rotating shaft 8. It rotates integrally with the rotating shaft 8 in the cylindrical portion 4B of the main body 4. The cylinder block 9 has an end face on one end side which is a swash plate 1 described later.
3 and the other end surface is in sliding contact with a surface of a valve plate 15 described later.

Reference numerals 10, 10,... Denote a plurality of cylinders formed in the cylinder block 9.
Are spaced apart from each other at a constant interval in the circumferential direction of the cylinder block 9 and extend in the axial direction of the cylinder block 9. Here, the front end side of each cylinder 10 is opened at one end side end surface of the cylinder block 9, and the base end side is connected to cylinder ports 10A, 15A, 15B, which communicate with supply / discharge ports 15A, 15B described later.
10A,... Are formed.

Numerals 11, 11,... Indicate a plurality of pistons slidably inserted into the respective cylinders 10, and these pistons 11 slide within the cylinders 10 as the cylinder block 9 rotates. At this time, the cylinder 1 is moved from the supply / discharge passage 16A through the cylinder port 10A.
While sucking the oil liquid into the chamber, the sucked oil liquid is discharged to the supply / discharge passage 16B side as high-pressure oil.

Are mounted on the protruding ends of the pistons 11 projecting from the cylinders 10 so as to be swingable.
3 is slid in a circular orbit.

Here, a minute gap (not shown) is formed between the cylinder 10 and the piston 11 in order to enhance the sliding characteristics of the piston 11, and a part of the pressure oil in the cylinder 10 The drain oil chamber 6 of the casing 3 through the gap
It leaks into the inside. Then, the drain oil chamber 6 in the casing 3 is substantially filled with the oil liquid by the leaked oil, and the oil liquid overflowing from the drain oil chamber 6 is returned to the tank 2 through the drain pipe 7. is there.

Reference numeral 13 denotes a swash plate provided in the casing 3 on the side of the lid 5. The swash plate 13 is tiltably supported by a swash plate support member 14 on the side of the lid 5. Shoe 12
Have a smooth surface in sliding contact. The shoe 12 slides on the smooth surface of the swash plate 13 in a circular orbit, and reciprocates the piston 11 along the sliding surface of the cylinder 10.

On the back side of the swash plate 13, a pair of legs 13A (only one is shown) formed of a convex curved surface are formed, and on the front side of the swash plate support member 14, corresponding to these legs 13A. A pair of concave curved portions 14A (only one is shown) are formed. The swash plate 13 is tilted and driven in the directions of arrows A and B in FIG. 1 by a tilt actuator (not shown) along the concave curved portion 14A of the swash plate support member 14.

Reference numeral 15 denotes a valve plate as a valve member fixedly provided on the bottom portion 4A side of the casing body 4 so as to be in sliding contact with the end surface on the other end side of the cylinder block 9. The valve plate 15 has a pair of eyebrows. Supply and discharge ports 15A and 15B are formed. And these supply / discharge ports 15A, 15B are
Each cylinder 10 in the cylinder block 9 is intermittently communicated via a cylinder port 10A, and the oil liquid in the tank 2 is sucked into the cylinder 10 from the supply / discharge passage 16A side.
High-pressure oil is discharged from the supply / discharge passage 16B toward an external hydraulic actuator.

Reference numerals 16A and 16B denote a pair of supply / discharge passages formed on the bottom 4A side of the casing main body 4. One of the supply / discharge passages 16A and 16B is connected to the tank 2 by piping (not shown). ), And the other supply / discharge passage 16B is connected to a hydraulic pipe (not shown) for supplying high-pressure oil to the hydraulic actuator.

Reference numeral 17 denotes a pressure sensor as an internal pressure detecting means for detecting the pressure in the casing 3. The pressure sensor 17 detects the pressure in the drain oil chamber 6 from outside the casing 3 as the internal pressure Px of the casing 3, and detects the pressure. The detection signal is output to a controller 21 described later.

Here, while the cylinder block 9 is driven to rotate in the casing 3 and the piston 11 is reciprocated in the cylinder 10, part of the pressure oil generated in the cylinder 10 is partially transferred to the cylinder 10 and the piston 11. And leaks into the drain oil chamber 6 of the casing 3 through the minute gap between them.

In the suction stroke of the piston 11, the cylinder block 9 is opened in a direction to separate the cylinder block 9 from the valve plate 15 due to sliding resistance generated between the piston 11 and the cylinder 10 due to galling or the like. Separation force is generated, and pressure oil leaks into the drain oil chamber 6 from the sliding contact surface side between the cylinder block 9 and the valve plate 15 due to the separation force.

Then, such leakage oil is supplied to the drain oil chamber 6.
Usually, it is discharged to the tank 2 side through the drain line 7 while being temporarily stored in the inside. However, when abrasion, galling, etc. occur between the cylinder 10 and the piston 11 and the amount of leaked oil increases rapidly due to this, a large amount of oil flows into the drain line 7. A throttle resistance is generated in the middle of the flow path, and the internal pressure Px of the casing 3 is increased.
Will rise sharply.

Further, even when the load pressure of the hydraulic actuator connected to the supply / discharge passage 16B via the hydraulic pipe increases, the amount of oil leaking from the drain oil chamber 6 as shown by the characteristic line 18 in FIG. The internal pressure Px of the casing 3 also fluctuates so as to draw a quadratic curve.

The internal pressure Px of the casing 3 fluctuates periodically as shown by a characteristic line 19 in FIG. 4 according to the rotation of the cylinder block 9. In the low load pressure state where the load pressure is low, the peak value of the internal pressure Px is obtained. Is relatively low, and the internal pressure Px becomes relatively high in the high load pressure state.

Reference numeral 20 denotes a rotation sensor as rotation detection means for detecting the rotation of the rotation shaft 8. The rotation sensor 20 is constituted by an electromagnetic pickup type or optical rotation detector, etc. The number of rotations N such as 9 is detected, and the rotation detection signal is output to the controller 21 shown in FIG.

Reference numeral 21 denotes a controller as a leakage diagnostic means constituted by a microcomputer or the like. As shown in FIG. 2, the controller 21 comprises a signal processing circuit 21A, a storage circuit 21B, a judgment circuit 21C, and the like. The input side is connected to the pressure sensor 17, the rotation sensor 20, and the like. Then, the signal processing circuit 21A
Calculates the rotation frequency of the cylinder block 9 as the specific frequency fn as shown in step 2 in FIG. 6 according to the rotation detection signal (rotation speed N) of the rotation sensor 20.

The signal processing circuit 21A also has a function of frequency-analyzing the pressure detection signal (the internal pressure Px shown in FIG. 4) from the pressure sensor 17 as a characteristic line 22 shown in FIG. 5 by a fast Fourier transform generally called FFT. have.
Then, the signal processing circuit 21A is connected to the characteristic line 22 shown in FIG.
The pressure pulsation in the casing 3 whose frequency has been analyzed as shown in FIG.
, That is, a function of calculating how much the pressure fluctuation width is.

On the other hand, the storage circuit 21B stores a program for operating state diagnosis processing shown in FIG. 6 and also stores a judgment value Pb of the pressure pulsation level Pa and the like.
b is predetermined according to the characteristics of the hydraulic pump based on experimental data and the like, and slightly increases or decreases depending on the rotation speed N.

Further, the output side of the determination circuit 21C is connected to a display 23 such as a display and an alarm 24 such as a buzzer and a lamp, which constitute the notification means.
By comparing the pressure pulsation level Pa output from 1A with the determination value Pb, it has a function of determining whether or not the amount of leaked oil in the drain oil chamber 6 exceeds a normal range.

The device for diagnosing the operating state of the hydraulic pump 1 according to the present embodiment has the above-described configuration. Next, the operation thereof will be described.

First, when the rotating shaft 8 is driven to rotate by a prime mover such as a diesel engine, the cylinder block 9 rotates integrally with the rotating shaft 8 in the casing 3.
The piston 11 repeats reciprocating motion in the cylinder 10, and the suction stroke and the discharge stroke are sequentially performed.

In the suction stroke of the piston 11, the oil liquid in the tank 2 is sucked into the cylinder 10 from the supply / discharge passage 16A side, and in the discharge stroke, the oil liquid in the cylinder 10 is pressurized as high-pressure oil. The pressure oil is discharged from the supply / discharge passage 16B toward an external hydraulic actuator.

In this case, a part of the pressure oil generated in the cylinder 10 leaks into the drain oil chamber 6 of the casing 3 through a minute gap between the cylinder 10 and the piston 11. In the suction stroke of the piston 11, the piston 1
A sliding force generated between the cylinder block 1 and the cylinder 10 generates a separating force in a direction in which the cylinder block 9 is separated from the valve plate 15, and the separating force causes the sliding contact between the cylinder block 9 and the valve plate 15. Pressure oil leaks into the drain oil chamber 6 from the surface side.

[0051] Such leakage oil is supplied to the drain oil chamber 6.
Usually, it is discharged to the tank 2 side through the drain pipe 7 while being temporarily stored in the tank. However, cylinder 10
When the amount of leaked oil increases sharply due to wear, galling, etc. between the piston and the piston 11, a large amount of oil flows into the drain pipe 7, so Throttling resistance causes the internal pressure Px of the casing 3 to rise rapidly, and if left unchecked, this may cause cracks or cracks in the casing 3 of the hydraulic pump 1 or the like.

Therefore, in the present embodiment, the operation state diagnosis process of the hydraulic pump 1 by the controller 21 is performed as shown in the program of FIG. Can be simplified.

That is, the signal processing circuit 2 of the controller 21
When the processing operation is started by starting the engine, 1A reads the internal pressure Px of the casing 3 from the pressure sensor 17 and reads the rotation speed N of the rotating shaft 8 from the rotation sensor 20 in step 1. In step 2, an operation for specifying the rotation frequency of the cylinder block 9 or the like is performed based on the rotation speed N, and this is calculated as the specific frequency fn.

Next, in step 3, the internal pressure Px as shown in FIG. 4 read from the pressure sensor 17 by the fast Fourier transform generally called FFT is applied to the characteristic line 22 shown in FIG.
The frequency analysis of the casing 3
Of the pressure pulsation in the inside at a specific frequency fn based on the rotation speed N is calculated.

Next, at step 4, the judgment value Pb stored in advance in the storage circuit 21B is read, and the routine proceeds to step 5 where the pressure pulsation level Pa is compared with the judgment value Pb, and the amount of oil leakage in the drain oil chamber 6 is determined. It is determined whether it is within the normal range.

In this case, the characteristic line 22 shown by a solid line in FIG.
When the pressure pulsation level Pa at the specific frequency fn is smaller than the determination value Pb, the pressure pulsation level Pa is within the range of the normal level while the rotating shaft 8 is driven to rotate at the rotation speed N, and Since it can be determined that the amount of leaked oil in the oil chamber 6 is within the normal range, the process proceeds to step 6, where the display 23 indicates that the hydraulic pump 1 is operating normally, and the processing after step 1 is repeated. To

The characteristic line 22A shown by a virtual line in FIG.
When the pressure pulsation level Pa at the specific frequency fn exceeds the determination value Pb, the pressure pulsation level Pa abnormally rises while the rotating shaft 8 is being driven to rotate at the rotation speed N. Cylinder 10 and piston 11 of pump 1
It is possible to determine that the amount of leaked oil in the drain oil chamber 6 suddenly increases due to abrasion, galling, etc. during this period, and that this oil amount exceeds the normal range.

Therefore, in this case, the process proceeds to step 7 to display an abnormality on the display 23 to inform the operator of the occurrence of wear, galling, etc. between the cylinder 10 and the piston 11 of the hydraulic pump 1. In step 8, the alarm 24 is actuated, and the abnormality is notified by, for example, a buzzer sound or an alarm lamp.

Thus, in the present embodiment configured as described above, the pressure sensor 17 for detecting the internal pressure Px of the casing 3 and the rotation sensor 2 for detecting the rotation speed N of the rotating shaft 8
And the controller 21 according to the detection signals from the pressure sensor 17 and the rotation sensor 20.
It is determined whether or not the amount of leaked oil is within a normal range in accordance with the rotation state of the cylinder block 9.

In the signal processing circuit 21 A of the controller 21, the specific frequency f based on the rotation speed N of the cylinder block 9 is determined according to the rotation detection signal from the rotation sensor 20.
n and frequency analysis of the fluctuation of the internal pressure Px by the pressure sensor 17, the pressure pulsation in the casing 3 can be reduced by the pressure pulsation level P at a specific frequency fn.
a, and the judgment circuit 21C is configured to compare the pressure pulsation level Pa with the judgment value Pb.

As a result, it can be determined at an early stage whether or not the amount of oil leaking from the casing 3 exceeds the normal range. For example, an initial abnormality in the sliding surface between the cylinder 10 and the piston 11 can be detected at an early stage. Can be prevented from spreading further on the sliding surface. Then, when an initial abnormality occurs, the alarm 24 is activated by a control signal from the controller 21 so that the nearby workers can be notified of the abnormality at an early stage, and the maintenance work such as repair and inspection can be quickly performed. It can be carried out.

That is, in the prior art, since the amount of leakage is detected only by the output from the pressure sensor, an abnormality judgment due to wear, damage, etc. of the hydraulic pump is taken into account in consideration of a change in the amount of leakage which increases or decreases according to the load pressure of the hydraulic pump. Had to do. On the other hand, in the present embodiment, the frequency fluctuation of the internal pressure Px of the casing 3 is analyzed to determine the pressure fluctuation width (the pressure pulsation level P) at the specific frequency fn corresponding to the rotation speed N.
In a), the amount of leakage can be captured.

Therefore, according to the present embodiment, the cylinder 10 and the piston 11 are not connected to each other on the basis of the internal pressure change of the casing 3 corresponding to the rotation state of the cylinder block 9 but of the absolute amount of the leakage oil generated in the casing 3. Wear during,
Galling etc. can be detected at an early stage, maintenance work etc. after abnormality detection can be simplified, and further generation of abrasion powder and the like can be suppressed, and each of the cylinder block 9, the piston 11, the swash plate 13, the valve plate 15, etc. The durability and life of the components can be reliably extended.

In the above embodiment, the rotation sensor 2
Although it has been described that the rotation of the rotation shaft 8 is detected by 0, the present invention is not limited to this. For example, as shown by a virtual line in FIG. 3 etc., and this rotation sensor 2
The rotation of the cylinder block 9 may be detected based on 0 '.

Further, in the above-described embodiment, the variable displacement type swash plate type hydraulic pump 1 has been described as an example of the hydraulic rotary machine. However, the present invention is not limited to this. It may be applied to a hydraulic pump of a type, a radial piston type hydraulic pump, or the like, or may be applied to a fixed displacement type hydraulic pump. The present invention is also applicable to a variable displacement or fixed displacement hydraulic motor.

[0066]

As described in detail above, according to the first aspect of the present invention, the internal pressure detecting means detects a pressure change in the casing, and the rotation detecting means detects the rotation of the rotating shaft. In accordance with the detection signals output from the internal pressure detecting means and the rotation detecting means, the leak diagnosing means is configured to diagnose whether or not the leaked oil amount is within a normal range. Initial abnormalities when the amount of leaked oil increases due to wear, galling, etc. can be detected early, simplifying maintenance work etc. after abnormalities are detected, and further generating abrasion powder etc. The cylinder block,
The durability and life of each component such as the piston and the valve member can be reliably extended.

According to the second aspect of the present invention, by operating the notifying means when the amount of leaked oil is abnormally increased, the initial abnormality of the hydraulic rotary machine can be notified early.
By stopping the operation of the hydraulic rotating machine, it is possible to immediately suppress the further spread of wear, galling, etc., and it is possible to simplify subsequent repair and inspection work, and to surely reduce the burden on maintenance workers. .

According to the third aspect of the present invention,
The signal processing circuit of the leak diagnosis means specifies the rotation frequency based on the rotation detection signal from the rotation detection means, and performs frequency analysis of the pressure detection signal from the internal pressure detection means to determine the pressure pulsation level in the casing at the specific frequency. Calculated, and the calculated pressure pulsation level is compared with a predetermined determination value, so that the determination circuit determines whether or not the amount of leaked oil is within a normal range.
Without being affected by external load pressure, etc., it is possible to determine at an early stage whether or not the amount of leaked oil in the casing exceeds the normal range.For example, further wear or galling on the sliding surface between the cylinder and the piston, etc. Can be prevented from occurring, and the subsequent maintenance work can be simplified.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a hydraulic pump operating state diagnostic apparatus according to an embodiment of the present invention.

FIG. 2 is a control block diagram of the operating state diagnostic device shown in FIG.

FIG. 3 is a characteristic diagram illustrating a relationship between an external load pressure and an amount of leaked oil in a casing.

FIG. 4 is a characteristic diagram showing a variation in internal pressure of a casing.

FIG. 5 is a characteristic diagram showing a pressure pulsation level with respect to a frequency in a state where an internal pressure in a casing is subjected to frequency analysis.

FIG. 6 is a flowchart showing a process of diagnosing an operating state of a hydraulic pump by a controller.

[Explanation of symbols]

 Reference Signs List 1 hydraulic pump (hydraulic rotary machine) 3 casing 6 drain oil chamber 8 rotating shaft 9 cylinder block (rotor) 10 cylinder 11 piston 13 swash plate 15 valve plate (valve member) 15A, 15B supply / discharge port 17 pressure sensor (internal pressure detection) Means) 20 Rotation sensor (rotation detection means) 21 Controller (leakage diagnosis means) 21A Signal processing circuit 21B Storage circuit 21C Judgment circuit 23 Display (notification means) 24 Alarm (notification means)

Claims (3)

[Claims] 1. A casing, a rotating shaft rotatably provided on the casing, a rotor provided in the casing such that a plurality of cylinders are bored and rotating integrally with the rotating shaft, and the rotor A plurality of pistons reciprocally inserted into each of the cylinders, and a valve member formed with a pair of supply / discharge ports provided in the casing so as to be in sliding contact with the rotor and intermittently communicating with the respective cylinders A hydraulic rotating machine comprising: an internal pressure detecting means for detecting a pressure change in the casing due to oil leaking from each of the cylinders; a rotation detecting means for detecting rotation of the rotating shaft or the rotor; Leak diagnosis for determining whether or not the amount of the leaked oil is within a normal range according to a pressure detection signal output from the means and a rotation detection signal output from the rotation detecting means. Operating state diagnosis apparatus for hydraulic rotary machine, characterized in that a means. 2. The operating state diagnostic apparatus for a hydraulic rotary machine according to claim 1, wherein a notifying means for notifying the diagnosis result of the leak diagnosing device to the outside is provided on an output side of the leak diagnosing means. 3. The leak diagnosis unit specifies a rotation frequency of the rotor based on a rotation detection signal output from the rotation detection unit, and performs frequency analysis on a pressure detection signal output from the internal pressure detection unit. A signal processing circuit for calculating the pressure pulsation level in the casing at the specific frequency, and comparing the pressure pulsation level calculated by the signal processing circuit with a predetermined determination value, the oil amount of the leaked oil is within a normal range. The operating state diagnostic device for a hydraulic rotary machine according to claim 1, further comprising: a determination circuit that determines whether or not the hydraulic pressure is higher than the threshold value.