CN115298473A

CN115298473A - Diagnostic device for bearing device

Info

Publication number: CN115298473A
Application number: CN202180022438.8A
Authority: CN
Inventors: 长田英树
Original assignee: Isuzu Motors Ltd
Current assignee: Isuzu Motors Ltd
Priority date: 2020-03-19
Filing date: 2021-03-16
Publication date: 2022-11-04
Anticipated expiration: 2041-03-16
Also published as: JP2021148227A; WO2021187452A1; CN115298473B; JP7384085B2

Abstract

Provided is a diagnostic device for a bearing device (1) which is provided with a gear (3), a sliding bearing (4) that rotatably supports the gear, and an oil passage (6) that supplies lubricating oil to the bearing surface (5) of the sliding bearing. The diagnostic device is provided with: a first temperature sensor (51) that detects the temperature of the lubricating oil before being supplied to the bearing surface; a second temperature sensor (52) that detects the temperature of the lubricating oil after passing through the bearing surface; and a diagnostic unit (100) configured to determine that the bearing device is abnormal when a state in which the difference between the temperatures detected by the first temperature sensor and the second temperature sensor is equal to or greater than a predetermined threshold value and the difference between the temperatures is equal to or greater than the predetermined threshold value continues for a predetermined time or longer.

Description

Diagnostic device for bearing device

Technical Field

The present disclosure relates to a diagnostic device for a bearing device.

Background

For example, an internal combustion engine is provided with a power transmission mechanism that transmits power from a crankshaft to a camshaft. When the power transmission mechanism is of a gear type, the power transmission mechanism is provided with a bearing device including a gear, a sliding bearing that rotatably supports the gear, and an oil passage that supplies a lubricating oil to a bearing surface of the sliding bearing.

Documents of the prior art

Patent literature

Patent document 1: japanese unexamined patent publication No. 5-202930

Disclosure of Invention

Technical problems to be solved by the invention

If an abnormality due to poor lubrication occurs in the bearing device, a failure such as sintering of the gear and the sliding bearing may occur. It is desirable to detect an abnormality of the bearing device immediately before such a failure develops.

An object of the present disclosure is to provide a diagnostic device for a bearing device capable of immediately detecting an abnormality of the bearing device.

Means for solving the problems

A diagnostic device for a bearing device according to one aspect of the present disclosure,

the diagnostic device is a bearing device comprising a gear, a sliding bearing for rotatably supporting the gear, and an oil passage for supplying lubricating oil to a bearing surface of the sliding bearing,

the disclosed device is provided with:

a first temperature sensor that detects a temperature of the lubricating oil before the lubricating oil is supplied to the bearing surface;

a second temperature sensor that detects a temperature of the lubricating oil after passing through the bearing surface; and

and a diagnostic unit configured to determine that the bearing device is abnormal when a state in which a difference between temperatures detected by the first temperature sensor and the second temperature sensor is equal to or greater than a predetermined threshold value and the difference between the temperatures is equal to or greater than the predetermined threshold value continues for a predetermined time or longer.

Preferably, the second temperature sensor is disposed at a position where the second temperature sensor contacts the lubricant oil dropped after passing through the bearing surface.

Preferably, the bearing device is provided in a power transmission mechanism of an internal combustion engine.

Effects of the invention

According to the diagnostic device for a bearing device of the present disclosure, it is possible to immediately detect an abnormality of the bearing device.

Drawings

Fig. 1 is a schematic view showing a diagnostic apparatus for a bearing device.

FIG. 2 is a flow diagram of a diagnostic routine.

Detailed Description

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the present disclosure is not limited to the following embodiments.

Fig. 1 is a schematic view showing a diagnostic device for a bearing device according to the present embodiment. The bearing device is applied to an internal combustion engine (also referred to as an engine), and particularly to a power transmission mechanism that transmits power from a crankshaft to a camshaft in the internal combustion engine. In the present embodiment, the internal combustion engine is a diesel engine for a vehicle, and the vehicle is a large vehicle such as a truck. However, the type and use of the vehicle and the internal combustion engine are not particularly limited.

For convenience, the directions of the front, rear, left, right, upper, and lower are defined as shown in the drawing. However, it should be noted that these directions are only directions determined for convenience of explanation. In the case of the present embodiment, these directions coincide with the directions of the vehicle and the engine.

The bearing device 1 is provided on the rear surface portion of the engine body 2. The engine body 2 includes a cylinder block, a crankcase, and a cylinder head, and the bearing device 1 of the present embodiment is provided in the crankcase. The bearing device 1 includes a gear 3, a sliding bearing 4 that rotatably supports the gear 3, and an oil passage 6 that supplies lubricating oil (a part of which is indicated by symbol O) to a bearing surface 5 of the sliding bearing 4.

In the present embodiment, the gear 3 is an idle gear, and is disposed in mesh between the upstream gear 7 on the upstream side and the downstream gear 8 on the downstream side in the driving force transmission direction.

The sliding bearing 4 is a substantially cylindrical member also called a bushing, and is inserted through the center of the gear 3. The sliding bearing 4 has a central axis C extending in the front-rear direction, and rotatably supports an inner circumferential surface 9 of the gear 3 in the radial direction by a bearing surface 5 on the outer circumferential side thereof. These bearing surface 5 and inner circumferential surface 9 form a bearing portion 10. The sliding bearing 4 is fixed to the rear surface portion of the engine body 2 by a bolt 11 inserted through the center portion thereof. Further, the sliding bearing 4 and the engine body 2 are provided with an engagement portion (for example, a groove and a projection) that stops the sliding bearing 4 from rotating when the sliding bearing 4 is fixed by the bolt 11.

A flange portion 12 is integrally formed at the front end portion of the sliding bearing 4, and the flange portion 12 supports the front surface portion 3A of the gear 3 in the thrust direction. Further, a washer 13 is interposed between the bolt 11 and the sliding bearing 4, and the washer 13 supports the rear surface portion 3B of the gear 3 in the thrust direction.

The oil passage 6 includes an internal oil passage 14 formed inside the engine body 2 and an internal bearing oil passage 15 formed inside the sliding bearing 4. An oil passage 16 serving as a lubricant reservoir is provided on the upstream side of the internal oil passage 14 in the lubricant oil flow direction, and lubricant oil is supplied from the oil passage 16 to the internal oil passage 14. The oil passage 16 is formed inside the engine body 2 (e.g., crankcase).

The bearing internal oil passage 15 is formed in an L-shape, an upstream end thereof is connected to the internal oil passage 14, and a downstream end thereof is opened on the bearing surface 5. Thereby, the lubricating oil supplied from the oil passage 16 to the internal oil passage 14 flows through the bearing internal oil passage 15 and is supplied to the bearing portion 10. Then, the bearing portion 10 is lubricated by the lubricating oil.

Thereafter, the lubricating oil lubricates the thrust sliding portion between the front flange portion 12 and the front surface portion 3A of the gear 3, and then flows down along the front surface portion 3A of the gear 3 and drops downward as indicated by reference character O. The lubricating oil lubricates the thrust sliding portion between the rear washer 13 and the rear surface portion 3B of the gear 3, and then flows down along the rear surface portion 3B of the gear 3 to be supplied to the meshing portion with the upstream gear 7 or drops downward.

On the other hand, the diagnostic device 50 includes: a first temperature sensor 51 for detecting the temperature of the lubricating oil before being supplied to the bearing surface 5; a second temperature sensor 52 that detects the temperature of the lubricating oil after passing through the bearing surface 5; and a diagnosis unit that determines whether the bearing device 1 is abnormal. In the case of the present embodiment, the diagnostic unit is constituted by an electronic control unit (referred to as ECU) 100 for controlling the engine. The ECU100 is configured to determine that the bearing device 1 is abnormal when a state in which the difference between the temperatures detected by the first temperature sensor 51 and the second temperature sensor 52 is equal to or greater than a predetermined threshold value and the difference between the temperatures is equal to or greater than the predetermined threshold value continues for a predetermined time or longer.

The first temperature sensor 51 is provided in the oil passage 16, and detects the temperature of the lubricating oil in the oil passage 16. The second temperature sensor 52 is disposed below the bearing 10, specifically, at a position in contact with the lubricating oil O dropped from the front surface portion 3A of the gear 3 after the lubrication of the bearing 10 and the front thrust sliding portion is completed. That is, the second temperature sensor 52 is disposed directly below the front surface portion 3A of the gear 3. The second temperature sensor 52 is formed in an axial shape, is disposed in a direction perpendicular to the central axis C, and is supported by the engine body 2 at a position outside the drawing.

These first temperature sensor 51 and second temperature sensor 52 are connected to the ECU 100. Further, the ECU100 is also connected to a warning device 53 for warning a user of the vehicle or the like. The warning device 53 may be constituted by any device such as a warning lamp, an alarm, an information display, and the like.

If an abnormality due to poor lubrication occurs in the bearing device 1, a failure such as sintering of the gear 3 and the sliding bearing 4 may occur. It is desirable to detect an abnormality of the bearing device 1 immediately before such a failure progresses.

Specifically, the cause of the lubrication failure in the bearing portion 10 of the bearing device 1 is, for example, a failure in which degraded lubricating oil is used or a driven member (auxiliary equipment or the like) driven via the gear 3 is used. If this lubrication failure occurs, the amount of the lubricating oil in the bearing portion 10 decreases, the sliding resistance of the bearing portion 10 increases, and the bearing portion 10 generates heat and the temperature thereof increases. In this case, there is a possibility that the gear 3 and the sliding bearing 4 may be sintered. In addition, the engine itself may be damaged by overload due to the sintering.

In any case, if the gear 3 is sintered, it may be a serious failure to disassemble and prepare the engine or, more seriously, to replace the engine. In the present embodiment, the abnormality of the bearing device 1 is detected immediately before the serious failure progresses, thereby greatly reducing the probability of the serious failure.

When the lubrication failure of the bearing portion 10 occurs, the second temperature T2 detected by the second temperature sensor 52 is greatly increased with respect to the first temperature T1 detected by the first temperature sensor 51. This is because the lubricating oil dropped onto the second temperature sensor 52 through the bearing portion 10 is higher than that in the normal state. Therefore, in the present embodiment, when the temperature difference Δ T = T2-T1, which is the difference between the first temperature T1 and the second temperature T2, is equal to or greater than the predetermined threshold value Δ Ts, it is determined that there is a precursor of seizure, and this is used as the first condition for determining the abnormality of the bearing device 1.

On the other hand, although not abnormal, the temperature difference Δ T may temporarily reach the threshold value Δ Ts or more for some reason. In the present embodiment, in order not to make an erroneous determination in such a case, a state in which the temperature difference Δ T is equal to or greater than the threshold value Δ Ts continues for a predetermined time or longer is used as the second condition for determining an abnormality of the bearing device 1.

The threshold value Δ Ts of the temperature difference is set to a value equal to the minimum value of the temperature difference Δ T experimentally obtained when a lubrication failure occurs in the bearing portion 10, for example. The predetermined time is, for example, a time during which the temperature difference Δ T temporarily becomes equal to or greater than the threshold value Δ Ts although no lubrication failure of the bearing portion 10 occurs, and is set to a value equal to the maximum value of the experimentally determined time.

Next, a routine of diagnosis according to the present embodiment will be described with reference to fig. 2. The illustrated routine is repeatedly executed by the ECU100 for each predetermined calculation cycle τ.

In step S101, the ECU100 acquires the first temperature T1 and the second temperature T2 detected by the first temperature sensor 51 and the second temperature sensor 52, respectively.

In step S102, the ECU100 calculates a temperature difference Δ T = T2-T1 from the values of the first temperature T1 and the second temperature T2.

In step S103, the ECU100 determines whether or not the calculated temperature difference Δ T is equal to or greater than a predetermined threshold value Δ Ts.

If the threshold value is equal to or greater than the threshold value Δ Ts, the ECU100 proceeds to step S104 to count the value (timer value) TM of the internal timer.

Next, in step S105, the ECU100 determines whether or not the timer value TM is equal to or greater than a predetermined value TMs corresponding to the predetermined time.

If the value is equal to or greater than the predetermined value TMs, the ECU100 proceeds to step S106 to determine that the bearing device 1 is abnormal, activates (turns on) the warning device 53, and ends the routine. This can prompt a user of the vehicle to perform inspection and repair.

By immediately performing inspection and repair in response to a warning by a user of the vehicle or the like, the cause of the abnormality can be investigated and removed before the gear 3 is actually sintered. Therefore, the cause can be eliminated before the serious failure progresses, and the probability of occurrence of the serious failure can be greatly reduced.

On the other hand, if the timer value TM is smaller than the predetermined value TMs in step S105, the ECU100 directly ends the routine. Thereby, the timer value TM is held as it is.

If the temperature difference Δ T is smaller than the threshold Δ Ts in step S103, the ECU100 proceeds to step S107, and ends the routine after resetting the timer value TM.

Until the timer value MT during counting reaches the predetermined value TMs, the temperature difference Δ T may become smaller than the threshold Δ Ts in step S103, and the timer value TM may be reset. This is a case where the temperature difference Δ T temporarily becomes equal to or greater than the threshold value Δ Ts for some reason although the bearing device 1 is normal, and then returns to be smaller than the threshold value Δ Ts. Therefore, in this case, in order to prevent erroneous determination, the timer value TM is reset, and the count of the timer value TM is also stopped.

When step S106 is not executed, the ECU100 substantially determines that the bearing device 1 is not abnormal, that is, normal.

As described above, according to the present embodiment, it is possible to immediately detect an abnormality of the bearing device 1. Further, it is possible to prevent the abnormality from developing into a serious failure.

While the embodiments of the present disclosure have been described in detail above, other various embodiments and modifications of the present disclosure are also conceivable.

(1) For example, the bearing device may be applied to a portion other than the power transmission device of the internal combustion engine, or may be applied to a mechanical device other than the internal combustion engine.

(2) The temperature detection portions of the first temperature sensor 51 and the second temperature sensor 52 are not limited to the above. For example, the first temperature sensor 51 may detect the temperature of the lubricating oil in the oil passage connecting the oil passage 16 and the internal oil passage 14, or may detect the temperature of the lubricating oil in the internal oil passage 14 or the bearing internal oil passage 15. The second temperature sensor 52 may be in contact with the lubricant oil O scattered from the rotating gear 3 to detect the temperature of the lubricant oil O. The second temperature sensor 52 may be disposed at any height position, and may be disposed in front of or behind the gear 3.

The embodiments of the present disclosure are not limited to the above-described embodiments, and all modifications, applications, and equivalents included in the idea of the present disclosure defined by the scope of protection are included in the present disclosure. Therefore, the present disclosure should not be construed as limited thereto, and can be applied to any other technique within the scope of the idea of the present disclosure.

This application is based on the Japanese patent application filed on 3/19/2020 (Japanese patent application No. 2020-049750) and the content thereof is hereby incorporated by reference.

Industrial applicability

The diagnostic device for a bearing device of the present disclosure can be widely applied to a diagnostic device that immediately detects an abnormality of a bearing device.

Description of the reference numerals

1. Bearing device

3. Gear wheel

4. Sliding bearing

5. Bearing surface

6. Oil circuit

51. First temperature sensor

52. Second temperature sensor

100. Electronic Control Unit (ECU)

O lubricating oil

Claims

1. A diagnostic device for a bearing device provided with a gear, a sliding bearing that rotatably supports the gear, and an oil passage that supplies lubricating oil to a bearing surface of the sliding bearing, the diagnostic device being characterized by comprising:

2. The diagnostic device of a bearing device according to claim 1,

the second temperature sensor is disposed at a position where the second temperature sensor contacts the lubricating oil dropped after passing through the bearing surface.

3. The diagnostic device of a bearing device according to claim 1 or 2,

the bearing device is provided in a power transmission mechanism of an internal combustion engine.