Deterioration determination device for drive mechanism for auxiliary machinery

Abstract

To provide a deterioration estimation device that can accurately determine the degree of decline in the durability of a drive mechanism for an auxiliary machinery.SOLUTION: A deterioration determination device for a drive mechanism for an auxiliary machinery has: a drive pulley that is integrated with a drive shaft to which power of an engine is transmitted; a driven pulley that is integrated with a driven shaft that drives an auxiliary machinery; and an auxiliary machinery belt that is wound around the drive pulley and the driven pulley. The deterioration determination device comprises: a first rotation speed detection unit that detects a rotation speed of the drive shaft; a second rotation speed detection unit that detects a rotation speed of the driven shaft; a speed difference determination unit that determines whether or not a rotation speed difference between the drive shaft and the driven shaft is equal to or more than a predetermined threshold; a number-of-times integration unit that integrates the number of times that the speed difference is equal to or more than the predetermined threshold in a predetermined period; and a durability determination unit that, when the number of times that the speed difference is equal to or more than the predetermined threshold is equal to or more than a predetermined number of times, makes a determination that the drive mechanism for the auxiliary machinery is in a deteriorated state.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an apparatus for determining a deterioration state of an accessory drive mechanism for transmitting engine power to an accessory mounted on a vehicle. [Background technology]

[0002] Patent Document 1 discloses a device for diagnosing the remaining life of a V-ribbed belt constituting such an auxiliary drive mechanism. The device of Patent Document 1 records the engine speed and load factor until the mileage reaches a predetermined distance, and creates a frequency map based on them. The frequency map has the engine speed on the horizontal axis and the engine load factor on the vertical axis, and the number of times the vehicle is operated (operating frequency) at an operating point determined by these is expressed by shading. The frequency map is compared with a plurality of pre-stored judgment maps for the shape and shading of the operating points. The judgment map is a map showing the frequency distribution of operating points determined in advance by experiments, analysis, etc., and is a map determined based on the relationship between the operating points and the deterioration rate of the V-ribbed belt, such as by making the operating points in which the belt deteriorates faster darker than the other points. The frequency map and the judgment map are judged to have the same characteristics based on image recognition processing by artificial intelligence. If they match, it is judged that the deterioration rate of the V-ribbed belt is the deterioration rate corresponding to the judgment map. If so, the vehicle's possible driving distance is calculated based on the deterioration rate, and the remaining life is set according to the vehicle's total driving distance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-51339 A Summary of the Invention [Problem to be solved by the invention]

[0004] The device in Patent Document 1 estimates the degree of deterioration of the V-ribbed belt according to the engine speed and load factor, and is therefore said to be able to accurately diagnose the remaining life of the V-ribbed belt. However, because the estimation is based on the engine operating point, there is a possibility that a notification urging replacement may be issued to the driver even when durability has not actually decreased, or conversely, the V-ribbed belt may not be replaced even when durability has significantly decreased and power transmission efficiency has decreased.

[0005] The present invention has been made in response to the above-mentioned technical problems, and aims to provide a deterioration determination device that can accurately determine the degree of deterioration in durability of an accessory drive mechanism. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the present invention provides a deterioration determination device for an accessory drive mechanism having a drive pulley integrated with a drive shaft to which engine power is transmitted, a driven pulley integrated with a driven shaft for driving an accessory operated by the engine power, and an accessory belt wound around the drive pulley and the driven pulley, the device comprising a controller for determining whether the accessory drive mechanism is in a deteriorated state, the controller comprising a first rotational speed detection unit for detecting the rotational speed of the drive shaft, a second rotational speed detection unit for detecting the rotational speed of the driven shaft, a speed difference determination unit for determining whether the speed difference between the detected rotational speed of the drive shaft and the rotational speed of the driven shaft is equal to or greater than a predetermined threshold, a number accumulating unit for accumulating the number of times that the speed difference is equal to or greater than the predetermined threshold within a predetermined period, and a durability determination unit for determining that the accessory drive mechanism is in the deteriorated state when the number of times that the speed difference is equal to or greater than the predetermined threshold becomes equal to or greater than a predetermined number of times. Effect of the Invention

[0007] According to the deterioration determination device for an accessory drive mechanism of the present invention, the rotation speed of a drive shaft connected to a drive pulley and the rotation speed of a driven shaft connected to a driven pulley are detected. Then, the number of times that the difference between the speeds is equal to or greater than a predetermined threshold value in a predetermined period is accumulated, and if the number is equal to or greater than a predetermined number of times, it is determined that the accessory drive mechanism is in a predetermined deterioration state. In other words, the degree of deterioration of the durability of the accessory drive mechanism is determined based on the speed difference, which is the slippage actually occurring between each pulley and the transmission belt. In other words, since the state of the accessory drive mechanism can be directly detected, it is possible to accurately determine whether the durability of the accessory drive mechanism has deteriorated. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram illustrating an example of a deterioration determination device for an accessory drive mechanism according to an embodiment of the present invention. [Diagram 2] These are diagrams used when determining the deterioration state of an accessory drive mechanism, where FIG. 2(a) shows the change over time in the rotational speeds of the crankshaft (drive shaft) and the driven shaft, and FIG. 2(b) shows the change over time in the rotational speed difference between the crankshaft (drive shaft) and the driven shaft. [Diagram 3] 4 is a flowchart showing an example of control for determining a deterioration state of an accessory drive mechanism executed by the deterioration estimation device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The present invention will be described below based on the embodiments shown in the drawings. Note that the embodiments described below are merely examples of the present invention and are not intended to limit the present invention.

[0010] Fig. 1 shows an example of an accessory drive mechanism 1 and a controller 2 which is a deterioration determination device in an embodiment of the present invention. The accessory drive mechanism 1 shown in Fig. 1 is mounted on a vehicle (not shown), has a plurality of pulleys (described later) and a transmission belt 3 made of a rubber material such as synthetic rubber, and is a device for transmitting power from an engine 4 to peripheral devices (auxiliaries) 5 such as an alternator and an oil pump.

[0011] The engine 4 is configured in the same manner as a conventional gasoline engine or diesel engine. That is, the engine 4 is configured to generate torque by combusting a mixture of air and fuel that is supplied to it. The engine 4 has a plurality of cylinders, and the intake, compression, combustion (expansion), and exhaust strokes are performed in the plurality of cylinders. As a result, the reciprocating motion of the pistons pushed down by the energy of the explosive combustion is converted into the rotational motion of the crankshaft 6 (drive shaft), and power is output.

[0012] A part of the power output from the engine 4 is transmitted to the accessory drive mechanism 1. As shown in Fig. 1, the accessory drive mechanism 1 mainly comprises a transmission belt 3 for transmitting the power, a crank pulley (drive pulley) 7 attached to the end of a crankshaft 6, an idler pulley 8 for guiding the drive of the transmission belt 3, and an accessory pulley 10 (driven pulley) integrated with a driven shaft 9 for driving the accessories. That is, a part of the power of the engine 4 is transmitted to the crank pulley 7 via the crankshaft 6. Then, the power is transmitted to the accessory 5 via the driven shaft 9 by the transmission belt 3 wound around the outer periphery of the crank pulley 7, the idler pulley 8, and the accessory pulley 10. Although not shown in FIG. 1, the accessory drive mechanism 1 further has a number of other pulleys, such as a pulley connected to a shaft for transmitting power to other accessories such as the alternator and oil pump described above, and a tensioner pulley (auto tensioner) for maintaining the tension of the transmission belt 3.

[0013] The accessory drive mechanism 1 configured as above inevitably deteriorates due to aging, etc. As shown in FIG. 1, the controller 2 has a function as a deterioration determination device for estimating the degree of deterioration and determining whether the accessory drive mechanism 1 needs to be replaced. The controller 2 is, for example, an electronic control device mainly composed of a microcomputer. Various data detected or calculated by various sensors, etc. are input to the controller 2. The controller 2 performs calculations using the input various data and pre-stored data, calculation formulas, etc. Then, the controller 2 is configured to output the calculation results as control command signals and control the entire vehicle.

[0014] A detection device 11, which is a collective term for a plurality of devices or apparatuses for acquiring various data and information required for controlling the vehicle Ve, is electrically connected to the controller 2. The detection device 11 includes, for example, a power supply unit, a microcomputer, a sensor, and an input / output interface. As shown in FIG. 1, the detection device 11 in the embodiment of the present invention includes a crank angle sensor 12 that detects the rotation angle of the crankshaft 6, and a rotation angle sensor 13 that detects the rotation speed of the driven shaft 9 that drives the auxiliary device 5 connected to the driven pulley. The crank angle sensor 12 and the rotation angle sensor 13 are configured to output, as detection data, electric signals or the like corresponding to detection values ​​or calculated values ​​of various sensors, devices, and the like to the controller 2.

[0015] The controller 2 has a first rotational speed detection unit 14, a second rotational speed detection unit 15, a speed difference determination unit 16, a number accumulation unit 17, and a durability determination unit 18 as functional components for estimating deterioration of the accessory drive mechanism 1.

[0016] The first rotation speed detection unit 14 calculates the rotation speed (m / s) of the crankshaft 6 based on the value detected by the crank angle sensor 12. For example, when the rotation speed of the crankshaft 6 is Ncr and the pulley diameter (outer diameter) of the crank pulley 7 is Rcr, the first rotation speed detection unit 14 calculates the rotation speed (Vcr) of the crankshaft 6 corresponding to the belt movement speed on the drive side by the following formula (1): Vcr=(Ncr / 60)×2×π×Rcr...(1)

[0017] The second rotation speed detection unit 15 detects the rotation speed (m / s) of the driven shaft 9 based on the value detected by the rotation angle sensor 13. For example, when the rotation speed of the driven shaft 9 of the auxiliary equipment is Nacc, the pulley diameter (outer diameter) of the auxiliary equipment pulley 10 is Racc, and a correction term for aligning the fluctuation range of the rotation speed according to the specifications of the auxiliary equipment pulley 10 and the connected auxiliary equipment is N, the second rotation speed detection unit 15 calculates the rotation speed (Vacc) of the driven shaft 9 corresponding to the belt movement speed on the driven side by the following formula (2). Vacc=(Nacc / 60)×2×π×Racc×N (2) Based on the time-dependent changes in the rotation speed of the crankshaft 6 and the rotation speed of the driven shaft 9 calculated by the above-mentioned equations (1) and (2), waveforms such as those shown in FIG. 2(a) are created.

[0018] The speed difference determination unit 16 determines whether the speed difference between the rotation speed of the crankshaft 6 and the rotation speed of the driven shaft 9 is equal to or greater than a predetermined threshold value. Depending on the magnitude of the torque transmitted to the crank pulley 7 and the tension of the transmission belt 3, a slip relatively larger than a normal slip may instantaneously occur between the transmission belt 3 and the crank pulley 7 or the accessory pulley 10. Such a relatively large slip occurs regardless of the deterioration state of the accessory drive mechanism 1, and becomes even larger when the deterioration of the accessory drive mechanism 1 progresses. Therefore, the predetermined threshold value is set to a speed difference that can detect that the deterioration of the accessory drive mechanism 1 has progressed to the extent that replacement is necessary. Note that such a speed difference may be set based on the friction coefficients of the pulleys 7, 10 and the transmission belt 3, and is obtained in advance by performing experiments, simulations, etc. In addition, the speed difference determination unit 16 creates a waveform that represents the change in the rotation speed difference over time based on the rotation speed difference calculated based on the waveform shown in FIG. 2(a). The waveform shown in FIG. 2(b) is one example, and the speed difference determining unit 16 determines whether or not the rotation speed difference is equal to or greater than a predetermined threshold value based on the waveform shown in FIG. 2(b).

[0019] The number accumulating unit 17 accumulates the number of times when the speed difference determining unit 16 detects that the rotation speed difference between the crankshaft 6 and the driven shaft 9 is equal to or greater than a predetermined threshold. The number accumulating unit 17 is configured to reset the accumulated number and restart accumulation every time a predetermined period determined in advance by an experiment, a simulation, or the like has elapsed. By setting in this manner, a rotation speed difference caused by a disturbance and a rotation speed difference caused by deterioration can be clearly distinguished.

[0020] The durability determination unit 18 determines whether the accumulated number of times within a predetermined period is equal to or greater than a predetermined number of times. When the accumulated number of times is equal to or greater than the predetermined number of times, the durability determination unit 18 determines that a predetermined condition is satisfied. In other words, the durability determination unit 18 determines that the durability of the accessory drive mechanism 1 has decreased and that the accessory drive mechanism 1 is in a deteriorated state to the extent that replacement is required. The predetermined number of times is, for example, a plurality of times, and is determined in advance by performing experiments or simulations as a number of times that can determine that such a deteriorated state exists and can prevent a mistaken determination that replacement is required due to a large speed difference that occurs accidentally and is equal to or greater than a predetermined threshold value.

[0021] Furthermore, for the predetermined period, the position where the transmission belt 3 is wound around each of the pulleys 7 and 10 must be consistent. That is, the durability determination unit 18 aligns the predetermined period for each of the pulleys 7 and 10 so as to align the phase difference in each of the pulleys 7 and 10. For this reason, for example, when the predetermined period is t, the predetermined period in the crank pulley 7 is Tcr, the predetermined period in the accessory pulley 10 is Tacc, and the correction term for aligning the phase difference is S, the durability determination unit 18 adjusts the predetermined period t, the predetermined period Tcr in the crank pulley 7, and the value obtained by adding the correction term S to the predetermined period Tacc in the accessory pulley 10 are equal (t=Tcr=Tacc+S).

[0022] Next, a control for estimating a decrease in durability of the accessory drive mechanism 1, which is executed by the controller 2 in the embodiment of the present invention, will be described. As shown in the flowchart of Fig. 3, first, in step S1, the rotation speeds of the crankshaft 6, which is the drive shaft, and the driven shaft 9, which is the driven shaft, are detected. After the rotation speeds of the crankshaft 6 and the driven shaft 9 are detected by the above-mentioned formulas (1) and (2), the process proceeds to step S2.

[0023] In step S2, a waveform showing a change over time is created based on the rotation speed difference between the crankshaft 6 and the driven shaft 9 acquired in step S1. In step S2, as shown in Fig. 2(b), the rotation speed difference between the crankshaft 6 and the driven shaft 9 is plotted on the vertical axis and time is plotted on the horizontal axis, thereby recording the change in the speed difference. After that, the process proceeds to step S3.

[0024] In step S3, it is determined whether the rotation speed difference between the crankshaft 6 and the driven shaft 9 acquired in step S2 is equal to or greater than a predetermined threshold based on Fig. 2(b). If the speed difference is not equal to or greater than the predetermined threshold, the result of step S3 is NO, and the process proceeds to step S5, which will be described later.

[0025] On the other hand, if the speed difference is equal to or greater than the predetermined threshold, step S3 returns YES and the process proceeds to step S4. In step S4, the number of detections is incremented by stamping a timestamp or the like, and a time log is taken of the time when the speed difference became equal to or greater than the predetermined threshold.

[0026] When the process proceeds to step S5, it is determined whether a predetermined period of time has elapsed. The predetermined period of time may be started every time a predetermined time elapses, or may be started when the rotation speed difference between the crankshaft 6 and the driven shaft 9 becomes equal to or greater than a predetermined threshold. If the predetermined period of time has not elapsed, the process returns to step S3, and it is determined again whether the rotation speed difference between the crankshaft 6 and the driven shaft 9 is equal to or greater than a predetermined threshold.

[0027] On the other hand, if the predetermined period has elapsed and thus the determination in step S5 is YES, the process proceeds to step S6. In step S6, it is determined whether or not the number of times that the rotational speed difference between the crankshaft 6 and the driven shaft 9 has become equal to or greater than the predetermined threshold value within the predetermined period has become equal to or greater than a predetermined number of times. If the number of times is less than the predetermined number of times and thus the determination in step S6 is NO, the process is temporarily terminated without executing the subsequent control.

[0028] If the answer to step S6 is YES because the number of times the speed difference has exceeded the predetermined threshold value exceeds a predetermined number of times, the process proceeds to step S7. If the process proceeds to step S7, it is determined that the accessory drive mechanism 1 is in a predetermined deteriorated state due to aging or the like, and that the accessory drive mechanism 1 needs to be replaced. In that case, the vehicle occupant is notified that it is time to replace the accessory drive mechanism 1, for example, by displaying the information on a display device mounted on the vehicle's instrument panel, and the flow chart is temporarily terminated.

[0029] As described above, in the deterioration determination device for the auxiliary drive mechanism 1 in the embodiment of the present invention, first, the rotation speed of the crankshaft 6 and the rotation speed of the driven shaft 9 are detected. Then, the number of times that the difference in rotation speed between them becomes equal to or greater than a predetermined threshold value in a predetermined period is accumulated, and if the number of times is equal to or greater than a predetermined number, it is determined that the auxiliary drive mechanism 1 is in a predetermined deterioration state and that it is necessary to replace the auxiliary drive mechanism 1. That is, the degree of deterioration of the durability of the auxiliary drive mechanism 1 is determined based on the speed difference that actually occurs between each of the pulleys 7, 10 and the transmission belt 3. That is, since the state of the auxiliary drive mechanism 1 can be directly detected, it is possible to accurately determine whether or not the durability of the auxiliary drive mechanism 1 has deteriorated. In addition, since it is determined that the auxiliary drive mechanism 1 needs to be replaced when such a speed difference that is equal to or greater than the predetermined threshold value occurs a predetermined number of times or more within a predetermined period, it is possible to suppress a mistaken determination that the auxiliary drive mechanism 1 needs to be replaced due to a large speed difference that occurs by chance. [Explanation of symbols]

[0030] 1. Accessory drive mechanism 2 Controller (deterioration determination device) 3 Transmission belt 4 Engine 5. Auxiliary Equipment 6. Crankshaft 7 Crank pulley 9 Driven axis 10 Auxiliary pulley 14 First rotation speed detector 15 Second rotation speed detector 16 Speed ​​difference determination section 17 Number of times counting unit 18 Durability judgment section

Claims

[Claim 1] 1. A deterioration determination device for an accessory drive mechanism, the accessory drive mechanism having a drive pulley integrated with a drive shaft to which engine power is transmitted, a driven pulley integrated with a driven shaft for driving an accessory operated by the engine power, and an accessory belt wound around the drive pulley and the driven pulley, a controller for determining whether the accessory drive mechanism is in a deteriorated state; The controller: A first rotation speed detection unit that detects a rotation speed of the drive shaft; A second rotation speed detection unit that detects a rotation speed of the driven shaft; a speed difference determination unit that determines whether a speed difference between the detected rotation speed of the drive shaft and the detected rotation speed of the driven shaft is equal to or greater than a predetermined threshold value; a number accumulating unit that accumulates the number of times that the speed difference is equal to or greater than the predetermined threshold value during a predetermined period of time; a durability determination unit that determines that the accessory drive mechanism is in the deteriorated state when the number of times that the speed difference is equal to or greater than the predetermined threshold value becomes equal to or greater than a predetermined number of times; A deterioration determination device for an accessory drive mechanism comprising:

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