Grease supply method and grease supply system

Abstract

To provide a grease supply method which enables improvement of durability of a slide bearing, and to provide a grease supply system.SOLUTION: In a grease supply method, grease 12 for replacing existing grease filling a clearance 11 between a rotary shaft 23 and a slide bearing 1 of the rotary shaft 23 is supplied. In the grease supply method, the clearance 11 and a supply pump P for sending the grease 12 to the clearance 11 communicate with each other through a supply pipe S with a chamber C provided in its middle part. A supply amount of the grease 12 is adjusted based on a measured internal pressure of the chamber C.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a grease supplying method and a grease supplying system. [Background technology]

[0002] Conventionally, there has been a method of managing the lubrication of sliding bearings in construction machinery, in which the sliding bearings provided in the joints of the articulated front of the construction machinery are intermittently lubricated (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-162944 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional lubrication methods are premised on using a special sliding bearing with an embedded temperature sensor to directly detect the temperature of the sliding bearing.

[0005] An object of the present invention is to provide a grease supplying method and a grease supplying system that can increase the durability of a sliding bearing. [Means for solving the problem]

[0006] The present invention has the following aspects. (1) One embodiment of the grease supply method according to the present invention is a grease supply method for supplying grease to replace existing grease filled in a clearance between a rotating shaft and a sliding bearing of the rotating shaft, the clearance and a supply pump that delivers the grease to the clearance are connected by a supply pipe with a chamber installed midway, and the amount of grease supplied is adjusted based on the measured internal pressure of the chamber. (2) One embodiment of the grease supply system of the present invention is a grease supply system that supplies grease to replace existing grease filled in a clearance between a rotating shaft and a sliding bearing of the rotating shaft, and includes a supply pump that delivers the grease to the clearance, a supply pipe that connects the clearance and the supply pump, a chamber provided midway through the supply pipe, a pressure gauge that measures the internal pressure of the chamber, and a control device that controls the supply pump, and the control device controls the supply pump based on the internal pressure. (3) In the above (2), the supply pump is a positive displacement pump that intermittently pumps the grease, and the control device may control the amount of grease supplied per pumping so that the increment in the internal pressure per pumping of the grease does not exceed an increment threshold. (4) In the above (2) or (3), the supply pump is a volumetric pump that intermittently pumps the grease, and the control device may control the amount of grease supplied per pumping so that the maximum value of the internal pressure per pumping of the grease does not exceed an internal pressure threshold value. (5) In the above (2), the control device may control the supply flow rate of the grease so that the increase in the internal pressure does not exceed an increase threshold value. Effect of the Invention

[0007] According to the present invention, it is possible to provide a grease supplying method and a grease supplying system that can increase the durability of a sliding bearing. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is an explanatory diagram of a grease supply system according to an embodiment. [Diagram 2] FIG. [Diagram 3] FIG. 4 is a diagram showing the relationship between the temperature of the plain bearing and the internal pressure of the chamber. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [Embodiment] A grease supplying method and a grease supplying system 100 according to an embodiment will be described below. Fig. 1 is an explanatory diagram of the grease supplying system 100 according to an embodiment. Fig. 2 is an explanatory diagram of a plain bearing 1. Fig. 3 is a diagram showing the relationship between the temperature of the plain bearing 1 and the internal pressure of a chamber.

[0010] (Grease supply method) As shown in FIG. 1, the grease supplying method according to the embodiment can be applied to a pump 200, such as a water pump that pumps up a fluid such as water against gravity. The pump 200 includes a pipe 20 through which a fluid such as water flows, a rotating shaft 23 that extends along the pipe axis 21 of the pipe 20 and has an impeller 22, and a motor 24 that rotates the rotating shaft 23. The rotating shaft 23 is rotatably supported by a plain bearing 1. The clearance between the rotating shaft 23 and the plain bearing 1 is filled with an existing grease. In the following, the term "grease" refers to a semi-solid or solidified product made by dispersing a soap-based or non-soap-based thickener in a raw material base oil.

[0011] 1 and 2, the grease supplying method according to the embodiment supplies grease 12 to replace the existing grease filled in the clearance 11 between a rotating shaft 23 and a sliding bearing 1 of the rotating shaft 23. The grease supplying method first connects the clearance 11 to a supply pump P that delivers the grease 12 to the clearance 11 through a supply pipe S with a chamber C provided midway.

[0012] Here, the relationship between the temperature of the sliding bearing 1 and the internal pressure of the chamber C was examined. Fig. 3 is a diagram showing the relationship between the temperature of the sliding bearing 1 and the internal pressure of chamber C. In Fig. 3, the horizontal axis is time t (hours:minutes:seconds), the left vertical axis is the amount of temperature rise ΔT (°C), and the right vertical axis is the internal pressure (kPa) of chamber C. In Fig. 3, the thick line represents the temperature of the sliding bearing 1 (the temperature of the grease filled in the clearance 11), and the thin line represents the internal pressure of chamber C. While the rotating shaft 23 supported by the plain bearing 1 was rotating at a constant rotation speed, the temperature of the grease filled in the clearance 11 of the plain bearing 1 was measured with a thermocouple, and the internal pressure of chamber C was measured with a Bourdon tube pressure gauge. First, the supply amount of grease 12 per delivery was set to a first supply amount (e.g., 200 cc) by the delivery pump P, which is a positive displacement pump, and delivery was started from 0 hours 12 minutes 00 seconds (S1). Then, the grease 12 was delivered intermittently once every 6 minutes until 1 hour 42 minutes 00 seconds (S2). After that, the pressure was reduced (S3). Next, the amount of grease 12 supplied per one delivery was set to a second delivery amount (e.g., 400 cc) that was twice the first delivery amount, and delivery was started at 2 hours 12 minutes 00 seconds (S4). Grease 12 was then intermittently delivered once every 6 minutes until 2 hours 48 minutes 00 seconds (S5). Thereafter, the pressure was reduced (S6). As a result, it was confirmed that there is a positive correlation between the temperature of the sliding bearing 1 and the internal pressure of the chamber C (or the maximum value of the internal pressure per discharge), as shown in Figure 3. It was also confirmed that when the first supply amount is supplied at a predetermined frequency, the temperature rise can be suppressed compared to when the second supply amount is supplied at the same frequency. In this way, it was discovered that when grease 12 is supplied to clearance 11 filled with existing grease, there is a positive correlation between the temperature of sliding bearing 1 and the internal pressure of chamber C. Therefore, it was found that in order to prevent a large increase in the temperature of sliding bearing 1, the supply amount or supply flow rate of grease 12 should be adjusted so that the internal pressure of chamber C does not increase significantly.

[0013] Therefore, the grease supplying method according to the embodiment adjusts the amount of grease 12 supplied based on the measured internal pressure of the chamber C. For example, if the internal pressure of the chamber C becomes high when supplying grease 12, the temperature of the plain bearing 1 is high, and therefore, in order to maintain the temperature of the plain bearing 1 at or below a desired temperature, the amount of grease 12 supplied is reduced by, for example, changing the amount (volume) of grease 12 supplied per delivery from the supply pump P to a smaller amount. In this way, in the grease supply method according to the embodiment, the amount of grease 12 supplied is adjusted based on the internal pressure of the chamber C, which has a positive correlation with the temperature of the plain bearing 1. Therefore, it is not necessary to directly measure the temperature of the plain bearing 1. Therefore, the plain bearing 1 does not need to be special, such as having a temperature sensor embedded therein, and the structure can be simplified and the risk of failure can be reduced. In addition, the amount of grease 12 to replace the existing grease filled in the clearance 11 can be adjusted to an appropriate amount and sent out by the supply pump P. Therefore, adverse effects caused by a temperature rise in the plain bearing 1, including seizure of the rotating shaft 23 and a decrease in the life of the oil seal, can be suppressed. Therefore, a grease supply method capable of increasing the durability of the plain bearing 1 can be provided.

[0014] When the supply pump P is a positive displacement pump and the volume per discharge by the positive displacement pump is fixed, the supply amount of the grease 12 may be adjusted by changing the discharge frequency obtained by dividing the number of discharges by time. When the supply pump P is a positive displacement pump and the frequency of delivery by the positive displacement pump is fixed, the amount of grease 12 supplied may be adjusted by changing the volume per delivery by the positive displacement pump. When the supply pump P is a variable flow rate pump, the supply amount of the grease 12 may be adjusted by changing the flow rate of the grease 12.

[0015] (Grease supply system) Next, the grease supply system 100 according to the embodiment will be described. 1, a grease supply system 100 according to an embodiment can be applied to a pump 200, such as a water pump that pumps up a fluid such as water against gravity. The pump 200 includes a pipe 20 through which a fluid such as water flows, a rotating shaft 23 that extends along a pipe axis 21 of the pipe 20 and has an impeller 22, and a motor 24 that rotates the rotating shaft 23.

[0016] 1 and 2, a rotating shaft 23 is rotatably supported by a plain bearing 1. The plain bearing 1 receives a radial force from the rotating shaft 23. In addition to being supported by the plain bearing 1, the rotating shaft 23 may be supported by a bearing other than the plain bearing 1 as appropriate.

[0017] 1 and 2, the grease supply system 100 supplies grease 12 to replace the existing grease filled in the clearance 11 between a rotating shaft 23 and a sliding bearing 1 of the rotating shaft 23. The grease supply system 100 includes a supply pump P that sends the grease 12 to the clearance 11, a supply pipe S that connects the clearance 11 and the supply pump P, a chamber C provided midway through the supply pipe S, a pressure gauge B that measures the internal pressure of the chamber C, and a control device 30 that controls the supply pump P.

[0018] The plain bearing 1 comprises a casing 13 disposed in a flow path inside a pipe 20 and supported by the pipe 20 or the like, a bushing 14 provided on the inner surface of the casing 13 and facing the rotating shaft 23 across a minute clearance 11 filled with grease 12, and a seal 15 that provides a seal between both axial ends of the casing 13 and the rotating shaft 23.

[0019] The casing 13 and the bush 14 each have a through hole 16 that penetrates from the supply pipe S to the clearance 11. Note that a plurality of through holes 16 may be provided, for example, at equal intervals in the circumferential direction of the plain bearing 1. Note that when there are a plurality of through holes 16, the supply pipe S may be provided so as to branch into a plurality of pipes from the chamber C in correspondence with the respective through holes 16.

[0020] Since the sliding bearing 1 has the structure described above, the grease 12 supplied from the supply pipe S passes through the through hole 16, as shown by the arrow in Figure 3, and pushes the existing grease out of the gap between the seal 15 and the rotating shaft 23, replacing the existing grease, and filling the clearance 11.

[0021] The grease 12 is a semi-solid or solidified grease obtained by dispersing a soap-based or non-soap-based thickener in a raw base oil. The grease 12 fills the flow path from the clearance 11 to the chamber C.

[0022] The supply pipe S communicates with the chamber C and a through hole 16 provided in the casing 13 of the plain bearing 1. Note that there may be multiple supply pipes S depending on the number of through holes 16. The supply pipe S may be branched into multiple pipes depending on the number of through holes 16.

[0023] The chamber C is a room having an internal space that is continuous with the flow path of the supply pipe S. The chamber C is provided midway through the supply pipe S, that is, between the supply pump P and the plain bearing 1.

[0024] The pressure gauge B measures the internal pressure of the chamber C. The pressure gauge B is, for example, a Bourdon tube type pressure gauge. Since the pressure gauge B measures the internal pressure of the chamber C, it can measure the pressure of the grease 12 filled in the flow path from the clearance 11 of the plain bearing 1 to the chamber C. Data on the internal pressure of the chamber C measured by the pressure gauge B is sent to the control device 30.

[0025] The supply pump P is a pump that supplies the grease 12 to the sliding bearing 1. The supply pump P may be, for example, a positive displacement pump, a non-positive displacement pump, or a variable flow rate pump. The supply pump P can adjust the supply amount or supply flow rate of the grease 12 by, for example, changing the structure of the supply pump P (such as the volume corresponding to the supply amount per delivery) and the supply speed (such as the delivery pitch and rotation speed). The supply pump P may be configured so that the supply amount or supply flow rate of the grease 12 can be controlled by the control device 30.

[0026] The control device 30 controls the supply pump P to control the supply amount or supply flow rate of the grease 12. The control device 30 has a memory and a CPU. In addition to a program, a preset internal pressure threshold or increment threshold is stored in the memory. The memory temporarily stores the internal pressure measured by the pressure gauge B at a predetermined time interval. The control device 30 calls up the internal pressure and the internal pressure threshold or increment threshold from the memory according to the program, and compares the internal pressure with the internal pressure threshold. Alternatively, the control device 30 compares the internal pressure increment ΔP with the increment threshold from the memory according to the program. Then, the control device 30 controls the supply pump P based on the comparison result. For example, when the internal pressure exceeds the internal pressure threshold, the drive of the supply pump P is stopped to stop the supply of the grease 12. For example, when the internal pressure exceeds the internal pressure threshold and then falls below the internal pressure threshold, the supply pump P is driven again to resume the supply of the grease 12.

[0027] In this manner, the control device 30 controls the supply pump P based on the internal pressure of the chamber C. That is, in the grease supply system 100 according to the embodiment, the control device 30 controls the supply pump P based on the internal pressure of the chamber C, which has a positive correlation with the temperature of the plain bearing 1. Therefore, it is not necessary to directly measure the temperature of the plain bearing 1. Therefore, the plain bearing 1 does not need to be special, such as having a temperature sensor embedded therein, and the structure can be simplified, and the risk of failure can be reduced. In addition, the amount of grease 12 to replace the existing grease filled in the clearance 11 can be adjusted to an appropriate amount and delivered by the supply pump P. Therefore, adverse effects caused by a temperature rise in the plain bearing 1, including seizure of the rotating shaft 23 and a decrease in the life of the oil seal, can be suppressed. Therefore, it is possible to provide a grease supply system 100 that can increase the durability of the plain bearing 1.

[0028] The supply pump P may be a positive displacement pump that intermittently delivers the grease 12. The control device 30 may control the amount of grease supplied per delivery so that the increment ΔP (see FIG. 3) of the internal pressure of the chamber C per delivery of the grease 12 does not exceed an increment threshold. For example, the increment threshold is set in advance to 20 kPa, and the control device 30 controls the amount of grease 12 supplied per delivery by the supply pump P so that the increment ΔP of the internal pressure of the chamber C does not exceed this increment threshold. This makes it possible to supply an appropriate amount of grease 12 to the clearance 11 of the plain bearing 1 at an appropriate frequency while suppressing a temperature rise of the plain bearing 1.

[0029] The supply pump P may be a positive displacement pump that intermittently delivers the grease 12. The control device 30 may control the amount of grease supplied per delivery so that the maximum value Pmax (see FIG. 3) of the internal pressure of the chamber C per delivery of the grease 12 does not exceed the internal pressure threshold. For example, the internal pressure threshold is set in advance to 60 kPa, and the control device 30 controls the amount of grease 12 supplied per delivery by the supply pump P so that the maximum value Pmax of the internal pressure of the chamber C does not exceed this internal pressure threshold. This makes it possible to supply an appropriate amount of grease 12 to the clearance 11 of the plain bearing 1 at an appropriate frequency while suppressing a temperature rise of the plain bearing 1.

[0030] Furthermore, the control device 30 may control the supply flow rate of the grease 12 so that the increment in the internal pressure of the chamber C does not exceed an increment threshold. Here, the supply flow rate is the amount supplied per unit time. For example, the increment threshold is set in advance to 20 kPa, and the control device 30 controls the supply flow rate of the grease 12 by the supply pump P so that the increment ΔP in the internal pressure of the chamber C does not exceed this increment threshold. This makes it possible to supply the grease 12 to the clearance 11 of the plain bearing 1 at an appropriate supply flow rate while suppressing a temperature rise in the plain bearing 1, regardless of the structure of the supply pump P, such as a positive displacement type, a non-positive displacement type, or a variable displacement type.

[0031] Although the embodiment has been described above with reference to the drawings, the present invention is not limited to the above. A plurality of features given as the embodiment may be freely combined.

[0032] The grease supply method according to the present embodiment supplies grease 12 to replace the existing grease filled in the clearance 11 between the rotating shaft 23 and the sliding bearing 1 of the rotating shaft 23. In the grease supply method, the clearance 11 and the supply pump P that delivers the grease 12 to the clearance 11 are connected by a supply pipe S with a chamber C provided in the middle. Then, the amount of grease 12 supplied is adjusted based on the measured internal pressure of the chamber C. This makes it possible to simplify the structure and reduce the risk of failure without making the sliding bearing 1 special, such as by embedding a temperature sensor. In addition, the amount of grease 12 to replace the existing grease filled in the clearance 11 can be adjusted to an appropriate amount and delivered by the supply pump P. This makes it possible to suppress adverse effects caused by a rise in temperature of the sliding bearing 1, including seizure of the rotating shaft 23 and a decrease in the life of the oil seal. Therefore, it is possible to provide a grease supply method that can increase the durability of the sliding bearing 1.

[0033] The grease supply system 100 according to this embodiment supplies grease 12 to replace the existing grease filled in the clearance 11 between the rotating shaft 23 and the sliding bearing 1 of the rotating shaft 23. The grease supply system 100 includes a supply pump P that delivers the grease 12 to the clearance 11, a supply pipe S that connects the clearance 11 to the supply pump P, a chamber C provided in the middle of the supply pipe S, a pressure gauge B that measures the internal pressure of the chamber C, and a control device 30 that controls the supply pump P. The control device 30 controls the supply pump P based on the internal pressure. This makes it possible to simplify the structure of the sliding bearing 1 without making it special, such as by embedding a temperature sensor, and to reduce the risk of failure. In addition, the amount of grease 12 that replaces the existing grease filled in the clearance 11 can be controlled to an appropriate amount and delivered by the supply pump P. This makes it possible to suppress adverse effects caused by a rise in temperature of the sliding bearing 1, including seizure of the rotating shaft 23 and a decrease in the life of the oil seal. Therefore, it is possible to provide a grease supply system 100 that can increase the durability of the sliding bearing 1. [Explanation of symbols]

[0034] 1. Bearings 11 Clearance 12 Grease 13 Casing 14. Bush 15 Seal 16 through hole 20 tubes 21 Tube shaft 22 Impeller 23 Rotation axis 24 Motor 30 Control device 100 Grease Supply System 200 Pump B Pressure gauge C Chamber P Supply Pump S supply pipe

Claims

1. A grease supplying method for supplying grease to replace existing grease filled in a clearance between a rotating shaft and a sliding bearing of the rotating shaft, comprising the steps of: The clearance is connected to a supply pump that delivers the grease to the clearance through a supply pipe having a chamber provided therein; the supply pump is a positive displacement pump that intermittently delivers the grease; A grease supply method characterized by adjusting the amount of grease supplied per discharge based on the measured internal pressure of the chamber so that the increment in the internal pressure per discharge of the grease does not exceed an increment threshold value.

2. The amount of grease supplied per one discharge is adjusted so that the maximum value of the internal pressure per one discharge does not exceed the internal pressure threshold value.

2. The grease supplying method according to claim 1 .

3. A grease supply system that supplies grease to replace existing grease filled in a clearance between a rotating shaft and a sliding bearing of the rotating shaft, a supply pump for delivering the grease to the clearance; a supply pipe communicating the clearance with the supply pump; a chamber provided midway through the supply pipe; a pressure gauge for measuring an internal pressure of the chamber; A control device for controlling the supply pump, the supply pump is a positive displacement pump that intermittently delivers the grease, The control device controls the supply pump based on the internal pressure and controls the amount of grease supplied per discharge so that the increment in internal pressure per discharge of the grease does not exceed an increment threshold value.

4. the supply pump is a positive displacement pump that intermittently delivers the grease, The control device controls the amount of grease supplied per one delivery such that the maximum value of the internal pressure per one delivery does not exceed an internal pressure threshold value.

4. The grease supply system according to claim 3.

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