Throttle Control System

Abstract

To determine abrasion of a gear in a gear mechanism.SOLUTION: A CPU performs drive processing in step S11. The drive processing is to drive an electric motor so that a target angular position of a specific gear continues to increase across from an initial position. Then in step S12, the CPU performs determination processing. In the determination processing, the CPU determines abrasion has occurred in a gear mechanism on the basis of a fact that a non-rotation time NRT is equal to or higher than a specified time ST.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a throttle control system. [Background technology]

[0002] Patent Document 1 describes a throttle control device that controls a throttle device. The throttle device includes an electric motor having a drive shaft, a gear mechanism having multiple gears, a driven shaft rotated by the gear mechanism, and a throttle valve that is opened and closed by the rotation of the driven shaft. The gear mechanism is driven by the rotation of the drive shaft. The throttle control device drives the electric motor to open and close the throttle valve according to the opening degree of the accelerator pedal. If the opening degree of the throttle valve does not change despite the change in the opening degree of the accelerator pedal, the throttle control device determines that an abnormality has occurred in which the throttle valve is stuck. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-117500 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the gear mechanism of the throttle device described in Patent Document 1, torque is applied to each gear by opening and closing the throttle valve. Therefore, when the gear mechanism is repeatedly driven, each gear wears. However, the throttle control device described in Patent Document 1 does not take gear wear into consideration at all. In other words, the throttle control device described in Patent Document 1 cannot determine the wear of the gears of the gear mechanism. [Means for solving the problem]

[0005] In order to solve the above problems, the present invention is a throttle control system having a throttle device and a control device that controls the throttle device, wherein the throttle device comprises an electric motor having a drive shaft, a gear mechanism having a plurality of gears and driven by rotation of the drive shaft, a driven shaft rotated by the gear mechanism, a throttle valve opened and closed by rotation of the driven shaft, a rotation sensor that acquires the angular position of a specific gear that is one of the plurality of gears, and a spring mechanism that biases the angular position of the specific gear to a predetermined initial position when no torque is acting from the electric motor and the driven shaft, and the control device executes a drive process that drives the electric motor so that a target angular position of the specific gear continues to increase or decrease across the initial position, and a determination process that determines that wear has occurred in the gear mechanism based on the fact that a non-rotation time during which the angular position detected by the rotation sensor does not change during execution of the drive process is equal to or longer than a predetermined specified time.

[0006] According to the above configuration, the gap between each gear from the electric motor to the specific gear is detected based on the length of the non-rotation time. The gap between each gear almost directly reflects the wear of each gear. Therefore, according to the above configuration, wear in the gear mechanism can be accurately determined.

[0007] In the throttle control system, the specific gear may be a gear that rotates integrally with the driven shaft. According to the above configuration, a sensor for acquiring the opening degree of the throttle valve can be used as the rotation sensor. Therefore, it is not necessary to provide a new sensor just for detecting the angular position of the specific gear.

[0008] According to the above configuration, the specific gear is located at the most downstream side of the torque transmission path from the electric motor to the driven shaft, and therefore, even if any of the multiple gears of the gear mechanism is worn, it can be determined that the gear mechanism is worn in the determination process.

[0009] In the above throttle control system, among the plurality of gears, a gear located between the specific gear and the electric motor on a torque transmission path from the electric motor to the driven shaft, and one or more gears selected from the specific gears may be made of a synthetic resin.

[0010] In the above configuration, the gears made of synthetic resin are relatively susceptible to wear, and it is particularly suitable to be able to determine the wear of the gear mechanism by targeting such gears that are susceptible to wear. In the above throttle control system, the control device may further execute an alarm process of outputting an alarm signal when it is determined in the determination process that wear has occurred in a plurality of the gears.

[0011] According to the above-described configuration, a warning signal is output by the warning process, so that a user or the like can be notified that a gear is worn. In the above throttle control system, the control device may store a predetermined number of no-rotation times when the drive process is executed, starting with the most recent, and in the judgment process, may determine that wear has occurred in the gear mechanism based on the fact that the average value of the stored no-rotation times is equal to or longer than the specified time.

[0012] According to the above configuration, it is determined that the gear mechanism is worn out when the average value of the no-rotation time is equal to or longer than a specified time, so that the effect of variation in the no-rotation time on one drive process can be reduced compared to when it is determined that the gear mechanism is worn out when one no-rotation time is equal to or longer than a specified time. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram of a vehicle. [Diagram 2] FIG. 2 is an exploded perspective view of the throttle device. [Diagram 3] FIG. 3 is a flowchart of a series of processes for determining wear of the gear mechanism in the first embodiment. [Figure 4]FIG. 4 is a time chart of the angular position during the execution of the drive process. [Diagram 5] FIG. 5 is a schematic diagram showing a meshing state between the throttle gear and the intermediate gear. [Figure 6] FIG. 6 is a schematic diagram showing a meshing state between the throttle gear and the intermediate gear. [Figure 7] FIG. 7 is a flowchart of a series of processes for determining wear of a gear mechanism in the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] First Embodiment A first embodiment of a throttle control system will now be described with reference to the drawings. The throttle control system is applied to a vehicle.

[0015] (General vehicle configuration) As shown in FIG. 1, a vehicle 500 includes an internal combustion engine 100, an intake passage 101, and an exhaust passage .

[0016] The internal combustion engine 100 is connected to an intake passage 101, which is a passage for introducing intake air from outside the vehicle 500. The internal combustion engine 100 is also connected to an exhaust passage 102, which is a passage for discharging exhaust gas to the outside of the vehicle 500.

[0017] The vehicle 500 is equipped with a throttle control system 300. The throttle control system 300 is equipped with a throttle device 10 and a control device 200. The throttle device 10 is located midway through an intake passage 101. The throttle device 10 adjusts the amount of intake air flowing into the internal combustion engine 100.

[0018] The vehicle 500 is equipped with an accelerator pedal 90 and an accelerator pedal sensor 91. The accelerator pedal sensor 91 is disposed in the vicinity of the accelerator pedal 90. The accelerator pedal sensor 91 outputs a signal indicative of an accelerator opening degree ACC, which is the amount of depression of the accelerator pedal 90.

[0019] The vehicle 500 includes an ignition switch 92. The ignition switch 92 is disposed near the driver's seat of the vehicle 500. The ignition switch 92 transmits a start request R1 when the ignition switch 92 is turned on while the internal combustion engine 100 is stopped. The ignition switch 92 transmits a stop request R2 when the ignition switch 92 is turned off while the internal combustion engine 100 is running.

[0020] (About the throttle device) As shown in FIG. 2, the throttle device 10 includes a valve mechanism 20 and an electric motor 70.

[0021] The valve mechanism 20 has a housing 21 and a cover 31. The housing 21 defines a valve accommodating space 21A. The valve accommodating space 21A is a cylindrical space. Both ends of the valve accommodating space 21A are open. The valve accommodating space 21A constitutes a part of the intake passage 101. Therefore, the intake air flows through the valve accommodating space 21A.

[0022] The housing 21 defines a motor accommodating space 21B. The motor accommodating space 21B is a cylindrical space. The central axis of the motor accommodating space 21B is perpendicular to the central axis of the valve accommodating space 21A. The motor accommodating space 21B is a separate space from the valve accommodating space 21A. Therefore, the motor accommodating space 21B does not communicate with the valve accommodating space 21A. A first end of the motor accommodating space 21B is closed. A second end of the motor accommodating space 21B is open toward the outside of the housing 21.

[0023] The housing 21 defines a shaft hole 21C. The shaft hole 21C is a cylindrical space. The central axis of the shaft hole 21C is perpendicular to the central axis of the valve accommodating space 21A. The central axis of the shaft hole 21C also intersects with the central axis of the valve accommodating space 21A. A first end of the shaft hole 21C opens toward the valve accommodating space 21A. A second end of the shaft hole 21C opens toward the outside of the housing 21. The second end of the shaft hole 21C is located on the same side as the second end of the motor accommodating space 21B.

[0024] The cover 31 covers a portion of the housing 21. The cover 31 covers the motor accommodating space 21B and the opening of the shaft hole 21C. Additionally, the cover 31, together with the housing 21, defines the gear accommodating space 21D. The gear accommodating space 21D is connected to both the motor accommodating space 21B and the shaft hole 21C.

[0025] The valve mechanism 20 has a driven shaft 22. The driven shaft 22 is rod-shaped. The driven shaft 22 passes through a shaft hole 21C. Although not shown, the driven shaft 22 is supported by the housing 21 via a bearing and is rotatable relative to the housing 21.

[0026] The valve mechanism 20 has a throttle valve 23. The throttle valve 23 is located in the valve accommodating space 21A. The throttle valve 23 is disk-shaped. The diameter of the throttle valve 23 is slightly smaller than the inner diameter of the valve accommodating space 21A. The throttle valve 23 is fixed to the driven shaft 22. The throttle valve 23 rotates together with the driven shaft 22. Therefore, the throttle valve 23 is opened and closed by the rotation of the driven shaft 22.

[0027] The valve mechanism 20 has a spring mechanism 25. The spring mechanism 25 is composed of a joint 26, a first spring 27, and a second spring 28. The joint 26 is substantially cylindrical. One side of the joint 26 is open, and the other side is closed. That is, the joint 26 has a bottom surface. The driven shaft 22 described above penetrates the bottom surface of the joint 26. The joint 26 is held by the driven shaft 22. The first spring 27 is located inside the joint 26. The first spring 27 is a coil spring. The first spring 27 applies a torque in one direction to the joint 26. The second spring 28 is located outside the joint 26. The second spring 28 surrounds the joint 26. The second spring 28 applies a torque in the opposite direction to the first spring 27 to the joint 26. When no external force is acting on the valve mechanism 20, the angular position TA of the driven shaft 22 is maintained at the initial position X by the torque from the first spring 27 and the second spring 28. The initial position X is determined as the angular position TA of the driven shaft 22 for realizing an opening degree of the throttle valve 23 that allows the intake air required for evacuation driving to flow through the valve accommodating space 21A. The opening degree of the throttle valve 23 when the angular position TA of the driven shaft 22 is the initial position X is, for example, several percent.

[0028] The electric motor 70 is located in the motor accommodating space 21B. The electric motor 70 has a drive shaft 71. The drive shaft 71 is located in the gear accommodating space 21D. The drive shaft 71 extends parallel to the driven shaft 22. The electric motor 70 transmits torque to the driven shaft 22 via the gear mechanism 50. That is, the electric motor 70 is a drive source for the throttle valve 23. The electric motor 70 is connected to a battery (not shown).

[0029] The throttle device 10 includes a gear mechanism 50. The gear mechanism 50 has a plurality of gears and is driven by the rotation of a drive shaft 71. Specifically, the gear mechanism 50 includes a drive gear 51, a support shaft 52, a first driven gear 53, and a second driven gear 54. The drive gear 51 is a spur gear. The drive gear 51 is held by the drive shaft 71. The drive gear 51 rotates integrally with the drive shaft 71. The drive gear 51 is made of metal.

[0030] The support shaft 52 extends from the housing 21. The support shaft 52 extends parallel to the drive shaft 71. The support shaft 52 is located between the drive shaft 71 and the driven shaft 22. The first driven gear 53 is held at the end of the support shaft 52. The first driven gear 53 has a large diameter gear 53A and a small diameter gear 53B. The large diameter gear 53A and the small diameter gear 53B are both spur gears. The outer diameter of the large diameter gear 53A is larger than the outer diameter of the drive gear 51. The outer diameter of the large diameter gear 53A is larger than the outer diameter of the small diameter gear 53B. The large diameter gear 53A is located coaxially with the small diameter gear 53B. The large diameter gear 53A is integrated with the small diameter gear 53B. The large diameter gear 53A is engaged with the drive gear 51. The first driven gear 53 decelerates and outputs the rotation of the drive gear 51. The material of the first driven gear 53 is synthetic resin.

[0031] The second driven gear 54 is a spur gear. The second driven gear 54 meshes with the small diameter gear 53B. The second driven gear 54 is held by the driven shaft 22. Therefore, the second driven gear 54 rotates integrally with the driven shaft 22. In other words, the driven shaft 22 rotates by the gear mechanism 50. The second driven gear 54 is made of a synthetic resin.

[0032] In this way, torque is transmitted from the drive shaft 71 of the electric motor 70 to the driven shaft 22 to which the throttle valve 23 is fixed via the three gears of the gear mechanism 50. As described above, the order of the gears on the torque transmission path from the electric motor 70 to the driven shaft 22 is, from the upstream side, the drive gear 51, the large diameter gear 53A, the small diameter gear 53B, and the second driven gear 54.

[0033] The throttle device 10 includes a rotation sensor 60. The rotation sensor 60 is a sensor that acquires an angular position TA of a specific gear SG, which is one of a plurality of gears included in the gear mechanism 50. In this embodiment, the specific gear SG is the second driven gear 54. Therefore, the rotation sensor 60 is a sensor that acquires the angular position TA of the second driven gear 54.

[0034] The rotation sensor 60 is built into the cover 31. The rotation sensor 60 is located around the driven shaft 22. The rotation sensor 60 is a so-called Hall type non-contact sensor that detects the angular position TA of the driven shaft 22 as a change in a magnetic field. As described above, since the second driven gear 54 rotates integrally with the driven shaft 22, the angular position TA of the driven shaft 22 is equal to the angular position TA of the second driven gear 54. That is, in this embodiment, the angular position TA of the second driven gear 54 is obtained by obtaining the angular position TA of the driven shaft 22.

[0035] (Regarding the control device) The control device 200 controls the throttle device 10. As shown in Fig. 1, the control device 200 acquires an accelerator opening degree ACC output by an accelerator pedal sensor 91. The control device 200 acquires a start request R1 and a stop request R2 transmitted from an ignition switch 92. The control device 200 acquires an angular position TA output by a rotation sensor 60. In the following description, the angular position TA is set to zero when the throttle valve 23 is in a fully closed state. The angular position TA is assumed to increase as the opening degree of the throttle valve 23 increases.

[0036] The control device 200 includes a CPU 201, a peripheral circuit 202, a ROM 203, a storage device 204, and a bus 205. The bus 205 connects the CPU 201, the peripheral circuit 202, the ROM 203, and the storage device 204 so that they can communicate with each other. The peripheral circuit 202 includes a circuit that generates a clock signal that regulates the internal operation, a power supply circuit, a reset circuit, and the like. The ROM 203 stores various programs in advance for the CPU 201 to execute various controls. The CPU 201 controls the throttle device 10 by executing the various programs stored in the ROM 203. The ROM 203 stores a normal program P1 and a gear wear determination program P2.

[0037] When the CPU 201 acquires a start request R1, it repeatedly executes the normal program P1. The CPU 201 calculates a target angular position TTA according to the magnitude of the acquired accelerator opening ACC. The CPU 201 calculates the target angular position TTA such that the target throttle opening increases as the accelerator opening ACC increases. The CPU 201 supplies the electric motor 70 with a current IM according to the calculation result. Then, when the CPU 201 acquires a stop request R2, it stops the execution of the normal program P1. That is, the CPU 201 repeatedly executes the normal program P1 while the internal combustion engine 100 is operating.

[0038] When the deviation between the target angular position TTA and the angular position TA becomes larger than a predetermined amount, the CPU 201 controls the electric motor 70 to reduce the deviation. For example, when the angular position TA becomes smaller than the target angular position TTA, the CPU 201 controls the current IM supplied to the electric motor 70 to increase the angular position TA.

[0039] (A series of processes to determine wear on the gear mechanism) When the CPU 201 receives the stop request R2, it executes the gear wear determination program P2 once.

[0040] 3, when the gear wear determination program P2 is started, the CPU 201 first performs the process of step S11. In step S11, the CPU 201 performs the drive process. The drive process is a process for driving the electric motor 70 at a constant speed so that the target angular position TTA of the specific gear SG continues to increase across the initial position X.

[0041] Specifically, as shown in FIG. 4, the CPU 201 drives the electric motor 70 so that the angular position TA becomes a first position TA1 that is a predetermined amount smaller than the initial position X. Next, the CPU 201 drives the electric motor 70 at a constant speed so that the target angular position TTA becomes a second position TA2 that is a predetermined amount larger than the initial position X. Then, the CPU 201 stores in the storage device 204 time series data of the angular position TA from when the target angular position TTA of the specific gear SG becomes the first position TA1 to the second position TA2. Note that the constant speed here allows for speed changes due to control errors, etc. Thereafter, as shown in FIG. 3, the CPU 201 advances the process to step S12.

[0042] In step S12, the CPU 201 performs a calculation process of a non-rotation time NRT. As shown in FIG. 4, the non-rotation time NRT is a time during which the angular position TA detected by the rotation sensor 60 does not change during the execution of the drive process. The CPU 201 calculates the non-rotation time NRT based on the time series data of the angular position TA stored in the storage device 204. For example, the CPU 201 determines the time when the angular position TA becomes the initial position X for the first time during the execution of the drive process as a first time T1. Next, the CPU 201 determines the time when the angular position TA becomes larger than the initial position X after the first time T1 as a second time T2. The CPU 201 then calculates the time from the first time T1 to the second time T2 as the non-rotation time NRT.

[0043] When the angular position TA is within a predetermined range including the initial position X, the CPU 201 determines that the angular position TA has not changed from the initial position X. The CPU 201 then determines the timing at which the angular position TA exceeds the predetermined range after the first time T1 as the second time T2. The predetermined range is determined as a range in which a change in the angular position TA caused by noise or the like being superimposed on the output signal of the rotation sensor 60 can be distinguished from a change in the angular position TA caused by the actual rotation of the second driven gear 54. Thereafter, as shown in FIG. 3, the CPU 201 advances the process to step S13.

[0044] In step S13, the CPU 201 executes a determination process to determine whether or not wear has occurred in the gear mechanism 50. The CPU 201 determines whether or not wear has occurred in the gear mechanism 50 based on the fact that the non-rotation time NRT calculated in the calculation process in step S12 is equal to or greater than a predetermined specified time ST. Specifically, the CPU 201 determines that wear has occurred in the gear mechanism 50 when the non-rotation time NRT is equal to or greater than the specified time ST. On the other hand, the CPU 201 determines that wear has not occurred in the gear mechanism 50 when the non-rotation time NRT is less than the specified time ST. The specified time ST is determined in advance by a test or a simulation. Specifically, the non-rotation time NRT is actually measured when a drive process is performed in a state in which a predetermined amount of wear has occurred in the gear mechanism 50. Then, the specified time ST is determined based on the actually measured non-rotation time NRT.

[0045] When the CPU 201 determines that the gear mechanism 50 is not worn (S13: NO), the CPU 201 ends the processing of the gear wear determination program P2. On the other hand, when the CPU 201 determines that the gear mechanism 50 is not worn (S13: YES), the CPU 201 advances the processing to step S14.

[0046] In step S14, the CPU 201 executes an alarm process. In the alarm process, the CPU 201 outputs an alarm signal. Then, the CPU 201 turns on an alarm lamp indicating that the gear mechanism 50 is worn, for example. After that, the CPU 201 ends the process of the gear wear determination program P2.

[0047] (Operation of the First Embodiment) The contact state between the teeth of the second driven gear 54 and the teeth of the small diameter gear 53B during the drive process will be described. The rotation direction of the second driven gear 54 when rotating to reduce the angular position TA is defined as a first rotation direction. The rotation direction of the second driven gear 54 when rotating to increase the angular position TA is defined as a second rotation direction D2.

[0048] As shown in Fig. 4, the time when the angular position TA of the second driven gear 54 becomes the first position TA1 is defined as the start time T0. From the start time T0 until before the first time T1, the angular position TA is smaller than the initial position X. When the angular position TA is smaller than the initial position X, the second driven gear 54 receives torque in the second rotational direction D2 from the first spring 27. Therefore, as shown in Fig. 5, the tooth surface on the side of the second driven gear 54 that advances in the second rotational direction D2 collides with the first driven gear 53.

[0049] As shown in Fig. 4, at the first time T1 when the angular position TA becomes the initial position X, the second driven gear 54 no longer receives the torque in the second rotational direction D2 from the first spring 27. On the other hand, as the target angular position TTA increases, the small diameter gear 53B rotates in the second rotational direction D2. Therefore, the tooth surface on the side of the second driven gear 54 that advances in the second rotational direction D2 separates from the small diameter gear 53B. Therefore, while the small diameter gear 53B is rotating, the second driven gear 54 is not rotating.

[0050] 6, when the small diameter gear 53B rotates and reaches the second time T2, the tooth surface of the small diameter gear 53B on the side proceeding in the second rotation direction D2 collides with the second driven gear 54. In other words, between the first time T1 and the second time T2, the small diameter gear 53B rotates while the second driven gear 54 does not rotate.

[0051] 4, after the second time T2, the CPU 201 increases the current IM supplied to the electric motor 70 because the deviation between the target angular position TTA and the angular position TA becomes large. Therefore, the angular position TA becomes larger more rapidly than the increase in the target angular position TTA.

[0052] However, even if none of the gears are worn, there are still some gaps between the gears. Therefore, the state in which the small diameter gear 53B rotates while the second driven gear 54 does not rotate occurs even if none of the gears in the gear mechanism 50 are worn. However, if any of the gears in the gear mechanism 50 are worn, the gap between that gear and the gear meshing with that gear becomes larger than when there is no wear. Accordingly, if any of the gears in the gear mechanism 50 are worn, the non-rotation time NRT from the first time T1 to the second time T2 becomes longer.

[0053] For example, when wear occurs in the second driven gear 54, the gap between the teeth of the second driven gear 54 and the teeth of the small diameter gear 53B becomes larger. Therefore, the time when the tooth surface of the small diameter gear 53B on the side advancing in the second rotation direction D2 collides with the second driven gear 54 becomes later. In other words, the time when the second time T2 occurs becomes later compared to when no wear occurs in the second driven gear 54. As a result, the non-rotation time NRT from the first time T1 to the second time T2 becomes longer.

[0054] (Effects of the first embodiment) (1-1) According to the first embodiment, the gap between each gear from the electric motor 70 to the second driven gear 54, which is the specific gear SG, is detected based on the length of the non-rotation time NRT. The gap between each gear almost directly reflects the wear of each gear. Therefore, according to the above series of processes of the first embodiment, it is possible to accurately determine that wear has occurred in the gear mechanism 50.

[0055] (1-2) According to the first embodiment, the specific gear SG is the second driven gear 54 which rotates integrally with the driven shaft 22. Therefore, a sensor for acquiring the opening degree of the throttle valve 23 can be used as the rotation sensor 60. Therefore, it is not necessary to provide a new sensor just for detecting the angular position TA of the specific gear SG.

[0056] According to the first embodiment, the specific gear SG is located at the most downstream side of the torque transmission path from the electric motor 70 to the driven shaft 22. Therefore, regardless of which gear among the multiple gears of the gear mechanism 50 is worn, it can be determined by the determination process that wear has occurred in the gear mechanism 50.

[0057] (1-3) According to the first embodiment, the material of the first driven gear 53 and the second driven gear 54 is synthetic resin. In other words, both the first driven gear 53, which is a gear between the specific gear SG and the electric motor 70, and the second driven gear 54, which is also the specific gear SG, are prone to wear to a certain extent. According to the above embodiment, since the angular position TA of the second driven gear 54 is detected, wear of the gear mechanism 50 can be detected for the first driven gear 53 and the second driven gear 54, which are prone to wear.

[0058] (1-4) According to the first embodiment, the CPU 201 outputs a warning signal by performing warning processing. Then, by operating a warning lamp based on the warning signal, it is possible to notify a user or the like that wear has occurred in the gear mechanism 50.

[0059] <Second embodiment> A second embodiment of the throttle control system will be described below with reference to the drawings. Descriptions of configurations similar to those of the first embodiment will be simplified or omitted. In the second embodiment, compared to the first embodiment, the processing performed when the gear wear determination program P2 is executed is partially different. The following description will focus on this point.

[0060] (A series of processes to determine wear on the gear mechanism) In the second embodiment, when the CPU 201 acquires the stop request R2, it executes the gear wear determination program P2 once.

[0061] As shown in Fig. 7, when the gear wear determination program P2 is started, the CPU 201 first performs the process of step S11. The drive process of step S11 is the same as that of the first embodiment. After the drive process, as shown in Fig. 7, the CPU 201 advances the process to step S12.

[0062] In step S12, the CPU 201 performs a calculation process for the non-rotation time NRT. The calculation process is similar to that in the first embodiment. After performing the calculation process, the CPU 201 advances the process to step S23.

[0063] In step S23, the CPU 201 executes a storage process. The storage process is a process for storing a predetermined number of non-rotation times NRT calculated in step S12 in order from the most recent. Specifically, the CPU 201 updates the data of the non-rotation times NRT stored in the storage device 204. First, the CPU 201 stores the non-rotation time NRT calculated in the immediately preceding calculation process as the most recent. Next, the CPU 201 updates each of the data of the non-rotation times NRT stored in the previous storage process, except for the oldest data, by one time older. As a result, the CPU 201 stores the data of the non-rotation times NRT in order from the most recent in the storage device 204. Thereafter, the CPU 201 advances the process to step S24. The number of times is, for example, 25 times.

[0064] In step S24, the CPU 201 executes an averaging process. An average time Tave is calculated, which is the average value of the multiple non-rotation times NRT stored in step S23. The average time Tave is the arithmetic mean of the multiple non-rotation times NRT. If the number of stored non-rotation times NRT does not reach the predetermined number, the arithmetic mean of all the stored non-rotation times NRT is set as the average time Tave. After that, the CPU 201 advances the process to step S25.

[0065] In step S25, the CPU 201 executes a determination process to determine whether or not wear has occurred in the gear mechanism 50. The CPU 201 determines whether or not wear has occurred in the gear mechanism 50 by comparing the average time Tave calculated in the averaging process in step S24 with the specified time ST. Specifically, the CPU 201 determines that wear has occurred in the gear mechanism 50 when the average time Tave is equal to or greater than the specified time ST. On the other hand, the CPU 201 determines that wear has not occurred in the gear mechanism 50 when the average time Tave is less than the specified time ST. Note that when the average time Tave is equal to or greater than the specified time ST, some of the non-rotation times NRT among the multiple times are equal to or greater than the specified time ST. In other words, the CPU 201 determines that the average time Tave is equal to or greater than the specified time ST based on the non-rotation time NRT being equal to or greater than the specified time ST.

[0066] When the CPU 201 determines that the gear mechanism 50 is not worn (S25: NO), the CPU 201 ends the processing of the gear wear determination program P2. On the other hand, when the CPU 201 determines that the gear mechanism 50 is not worn (S25: YES), the CPU 201 advances the processing to step S14. Step S14 is a warning processing similar to that of the first embodiment. After the warning processing, the CPU 201 ends the processing of the gear wear determination program P2.

[0067] (Effects of the second embodiment) (2-1) According to the second embodiment, when the average time Tave, which is the average value of the no-rotation times NRT, is equal to or greater than the specified time ST, it is determined that wear has occurred in the gear mechanism 50. Therefore, it is possible to reduce the effect of variation in each no-rotation time NRT on one drive process, compared to when it is determined that wear has occurred in the gear mechanism 50 when one no-rotation time NRT is equal to or greater than the specified time ST.

[0068] <Other embodiments> The above-described embodiments can be modified as follows: Each embodiment and the following modifications can be combined with each other to the extent that no technical contradiction occurs.

[0069] The valve mechanism 20 is not limited to the examples of the above-described embodiments. For example, the housing 21 may not define the motor accommodating space 21B, and a separate housing may be provided that defines the motor accommodating space 21B.

[0070] The spring mechanism 25 only needs to bias the angular position TA of the specific gear SG to the initial position X when no torque is applied from the electric motor 70 and the driven shaft 22. For example, another member may be interposed between the first spring 27 and the joint 26, or the first spring 27 may bias the first driven gear 53.

[0071] The number of gears in the gear mechanism 50 may be two, or may be four or more. The material of each gear of the gear mechanism 50 is not limited to the examples of the above-mentioned embodiments. For example, the material of the first driven gear 53 and the second driven gear 54 may be a metal such as carbon steel or stainless steel. Among the multiple gears, the gear between the specific gear SG and the electric motor 70 on the torque transmission path from the electric motor 70 to the driven shaft 22, and one or more gears selected from the specific gears SG may be made of synthetic resin. In this case, the gears whose wear can be determined based on the no-rotation time NRT include gears made of synthetic resin, which are relatively susceptible to wear.

[0072] The specific gear SG does not have to be the second driven gear 54. The specific gear SG may be the first driven gear 53 or the drive gear 51. In this case, it is sufficient that the rotation sensor 60 has a sensor that acquires the angular position TA of the specific gear SG.

[0073] The control device 200 may be configured as a circuit including one or more processors that execute various processes according to a computer program (software). The control device 200 may be configured as a circuit including one or more dedicated hardware circuits, such as an application specific integrated circuit (ASIC), that execute at least some of the various processes, or a combination thereof. The processor includes a CPU and memory such as RAM and ROM. The memory stores program code or instructions configured to cause the CPU to execute processes. The memory, i.e., computer-readable medium, includes any available medium that can be accessed by a general-purpose or special-purpose computer.

[0074] Based on the alarm signal, the CPU 201 may notify the user or the like that wear has occurred in the gear mechanism 50 by a separate operation. For example, when the CPU 201 acquires an alarm signal, the CPU 201 may notify a display mounted on the vehicle 500 of a message indicating that the gear mechanism 50 needs to be replaced. Also, for example, when the CPU 201 acquires an alarm signal, the CPU 201 may notify a smartphone communicating with the vehicle 500 of a message indicating that the gear mechanism 50 needs to be replaced. Also, the CPU 201 may not need to perform alarm processing.

[0075] As the drive process, the CPU 201 may drive the electric motor 70 at a constant speed so that the target angular position TTA of the specific gear SG continues to decrease across the initial position X. Even in this case, the gap between each gear of the gear mechanism 50 can be detected based on the length of the non-rotation time NRT.

[0076] The CPU 201 does not have to drive the electric motor 70 at a constant speed in the drive process. As long as the electric motor 70 is driven in the same manner in each drive process, the speed at which the drive shaft 71 rotates may change until the target angular position TTA is changed from the first position TA1 to the second position TA2.

[0077] The CPU 201 may calculate the non-rotation time NRT by a different method. For example, the CPU 201 may calculate a differential value of the time series data of the angular position TA, and determine the time when the differential value becomes zero as the first time T1. Also, the CPU 201 may determine the time when the differential value becomes a positive value from zero as the second time T2.

[0078] In the second embodiment, when the CPU 201 executes the gear wear determination program P2 once, the CPU 201 may repeat steps S11 to S23 a predetermined number of times and then proceed to step S24. In other words, the CPU 201 may execute the drive process and the calculation process multiple times when the CPU 201 acquires the stop request R2 once.

[0079] In the first embodiment, the CPU 201 may determine that wear has occurred in the gear mechanism 50 when the number of times that the no-rotation time NRT is equal to or greater than the specified time ST is greater than a predetermined number of times. For example, when the gear wear determination program P2 is executed once, steps S11 to S13 may be repeated a predetermined number of times. Also, for example, in step S13, the CPU 201 stores the number of times that the no-rotation time NRT is equal to or greater than the specified time ST in the storage device 204. Then, by executing the gear wear determination program P2 a number of times, when the number of times reaches a predetermined number of times, it may be determined that wear has occurred in the gear mechanism 50. Even in this case, the control device 200 determines that wear has occurred in the gear mechanism 50 based on the fact that the no-rotation time NRT is equal to or greater than the specified time ST. [Explanation of symbols]

[0080] 10...Throttle device 20…Valve mechanism 22...Driver axis 23...Throttle valve 25...Spring mechanism 50…Gear mechanism 51…Drive gear 53…First driven gear 54…Second driven gear 60...Rotation sensor 70...Electric motor 71...Drive shaft 100…Internal combustion engine 200...Control device 300…Throttle control system 500…Vehicle NRT…No rotation time SG: Specific gear ST…Regular time TA…Angle position TTA…Target angle position X…Initial position

Claims

1. A throttle control system having a throttle device and a control device that controls the throttle device, The throttle device is an electric motor having a drive shaft; a gear mechanism having a plurality of gears and driven by rotation of the drive shaft; A driven shaft rotated by the gear mechanism; a throttle valve that is opened and closed by rotation of the driven shaft; a rotation sensor for acquiring an angular position of a specific gear that is one of the plurality of gears; a spring mechanism that biases the angular position to a predetermined initial position when no torque is applied from the electric motor and the driven shaft, The control device includes: a drive process for driving the electric motor so that the target angular position of the specific gear continues to increase or decrease across the initial position; a calculation process of calculating a non-rotation time during which the angular position detected by the rotation sensor does not change during execution of the drive process; and executing a determination process for determining that wear has occurred in the gear mechanism when the number of times that the no-rotation time has exceeded a predetermined specified time reaches a predetermined number of times. Throttle control system.

2. The specific gear is a gear that rotates integrally with the driven shaft.

2. The throttle control system of claim 1.

3. Among the plurality of gears, a gear present between the specific gear and the electric motor on a torque transmission path from the electric motor to the driven shaft, and one or more gears selected from the specific gears are made of a synthetic resin.

3. A throttle control system according to claim 1 or 2.

4. The control device further executes an alarm process for outputting an alarm signal when it is determined in the determination process that wear has occurred in the gear mechanism. The throttle control system according to any one of claims 1 to 3.

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