Method and apparatus for inspecting rotating bodies

Abstract

To provide a rotating body inspection method and a rotating body inspection apparatus capable of accurately detecting the presence or absence of a rotation failure of a rotating body.SOLUTION: The rotating body inspection method for inspecting the rotating operation of a rotating body 50 rotating around a rotating shaft 54 includes: a step of rotating the rotating body 50 in reverse rotation after forward rotation to detect a difference value between a torque value at the time of the forward rotation and a torque value at the time of the reverse rotation of the rotating body 50 and / or an inertia force at the time of switching the rotating body 50 from the forward rotation to the reverse rotation; and a step of determining the presence or absence of a rotation failure of the rotating body based on the detected value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for inspecting a rotating body and an apparatus for inspecting a rotating body that rotates around a rotation axis. [Background technology]

[0002] A rotating body that rotates around a rotation axis, such as a camshaft in an engine, is a crucial component for opening and closing the intake and exhaust valves at the appropriate timing through its rotational motion. From the perspective of fuel efficiency, it is required to rotate smoothly with minimal resistance.

[0003] Patent Document 1 describes an inspection method for determining whether the rotation of a rotating body is smooth, which involves detecting the rotational torque when a camshaft, a rotating body, is rotated, and using the detected torque value to determine whether the rotation of the camshaft is normal.

[0004] In this inspection method, the camshaft, which is a rotating body, is forced to rotate, and a torque detector is used to detect the lower limit of the rotational torque of the camshaft. Next, the lower limit detected by the torque detector is compared with a preset lower limit, and if the detected lower limit is higher than the preset lower limit, it is determined that there is an abnormality in the valve train, including the camshaft.

[0005] This inspection method allows for the simple detection of rotational malfunctions by comparing the lower limit of rotational torque with a preset lower limit. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 11-281532 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, in the conventional method of making a determination based on the lower limit value of the rotational torque, since the difference in torque values that occurs between normal products and defective products is slight, accurate determination may not be possible when noise is included in the torque value due to external disturbance effects.

[0008] The present invention has been made in view of the above problems, and an object thereof is to provide a method for inspecting a rotating body and an apparatus for inspecting a rotating body that can accurately detect the presence or absence of a rotation failure of the rotating body.

Means for Solving the Problems

[0009] In order to achieve the above object, an embodiment of the present invention is a method for inspecting a rotating body that inspects the rotational operation of a rotating body that rotates about a rotation axis, wherein the rotating body is rotated forward and then rotated backward, and the difference value between the torque value during the forward rotation of the rotating body and the torque value during the reverse rotation, and / or, a step of obtaining an inertial force when the rotating body switches from forward rotation to reverse rotation; and a step of determining the presence or absence of a rotation failure of the rotating body based on the obtained value and a preset threshold value.

[0010] Further, an embodiment of the present invention is an apparatus for inspecting a rotating body that inspects the rotational operation of a rotating body that rotates about a rotation axis, wherein a drive unit capable of rotating the rotating body in a forward rotation direction and a reverse rotation direction; a detector that detects the rotational torque and / or inertial force of the rotating body; and a determination unit that determines the presence or absence of a rotation failure of the rotating body based on the difference value between the torque value during the forward rotation of the rotating body and the torque value during the reverse rotation, and / or, the inertial force when the rotating body switches from forward rotation to reverse rotation, which is obtained based on the detection value of the detector.

Advantages of the Invention

[0011] According to the method for inspecting a rotating body and the apparatus for inspecting a rotating body according to the present invention, the presence or absence of a rotation failure of the rotating body can be accurately detected.

Brief Description of the Drawings

[0012] [Figure 1] It is a schematic explanatory view of an inspection device for a rotating body which is an embodiment of the present invention. [Figure 2] It is a graph showing the time change of the torque value when the rotating body is a non-defective product. [Figure 3] It is a graph showing the time change of the torque value when the rotating body is a defective product. [Figure 4] It is a flowchart diagram of an inspection method for a rotating body executed using the inspection device. [Figure 5] It is a diagram for explaining a conventional inspection method, and is a graph showing the time change of the torque value when a rotating body which is a non-defective product is rotated forward. [Figure 6] It is a diagram for explaining a conventional inspection method, and is a graph showing the time change of the torque value when a rotating body which is a defective product is rotated forward.

Mode for Carrying Out the Invention

[0013] FIG. 1 is a schematic explanatory view of an inspection device 10 for a rotating body 50 which is an embodiment of the present invention. The inspection device 10 is a device for inspecting the rotation operation of a rotating body 50 that rotates about a rotation axis 52. Specifically, the inspection device 10 is a device capable of inspecting whether the rotating body 50 is a non-defective product that rotates smoothly with a small rotational load or a defective product with a large rotational load when the rotating body 50 is rotated at a predetermined rotational speed.

[0014] In the present embodiment, the rotating body 50 to be inspected includes a cylindrical main body portion 52 and a rotation axis 54 that penetrates the central axis of the main body portion 54. The rotation axis 54 is a linear rod-shaped member, and the main body portion 52 is fixed to the rotation axis 54 and integrally formed. The material of the rotating body 50 is not specified, and for example, various materials such as a metal material or a resin material can be used. Also, the body portion 52 and the rotation axis 54 may be made of different materials. The main body portion 52 is formed of a material having the same density.

[0015] The inspection device 10 comprises a motor 20, a torque detector 30, and a control device 40. The motor 20 is a drive unit that rotates the rotating body 50, and is configured to rotate the rotating body 50 in both the forward and reverse directions. When inspecting the rotating body 50, the rotation shaft 52 of the rotating body 50 is connected to the motor 20.

[0016] The torque detector 30 is a detector that detects rotational torque, and for example, a torque transducer can be used. The torque detector 30 is connected to the rotation shaft 52 of the rotating body 50, and in this embodiment, the rotational torque of the rotating body 50 is constantly detected when the rotating body 50 is rotated.

[0017] The control device 40 is configured to include, for example, information processing means such as a central processing unit (CPU) and application-specific integrated circuits (ASICs), storage means such as RAM and ROM, and input / output interfaces. The control device 40 is electrically connected to the motor 20 and the torque detector 30, and controls the drive of the motor 20 and determines whether or not there is a rotational malfunction in the rotating body 50 based on the torque value data received from the torque detector 30. As shown in Figure 1, the control device 40 includes a storage unit 42, a calculation unit 44, a determination unit 46, and a display unit 48.

[0018] The memory unit 42 of the control device 40 stores programs for controlling the connected motor 20 and torque detector 30. It also stores a preset torque threshold T, which serves as a criterion for determining rotational malfunction of the rotating body 50. th and a preset inertial force threshold I th It is stored there.

[0019] The calculation unit 44 calculates the difference between the torque value of the rotating body 50 when it is rotating in the forward direction and when it is rotating in the reverse direction, based on the value detected by the torque detector 30. In this embodiment, the control device 40 constantly receives torque value data from the torque detection value 30, and the calculation unit 44 calculates the difference between the torque values ​​when it is rotating in the forward direction and when it is rotating in the reverse direction from the received torque value data.

[0020] FIG. 2 and FIG. 3 are graphs showing the time variation of the torque value of the rotating body 50, respectively, and show the state in which the rotating body 50 is rotated forward, then rotated backward, and then rotated forward again. FIG. 2 shows a graph of a normal product with a small rotational load of the rotating body 50, and FIG. 3 shows a graph of a defective product with a large rotational load of the rotating body 50. The inspection device 10 continuously rotates the rotating body 50 forward and backward by driving the motor 20. As shown in FIGS. 2 and 3, the torque value fluctuates greatly when the rotation direction of the rotating body 50 is changed. Therefore, after rotating the rotating body 50 in the forward rotation direction or the reverse rotation direction, the calculation unit 44 adopts the torque value in a state where the torque value has stabilized after a predetermined time has elapsed, and calculates the difference value.

[0021] In the example shown in FIG. 2, from the torque value T1 (T1 is a positive number) during forward rotation and the torque value -T1 during reverse rotation, the difference value ΔT a is calculated. Here, when the torque value detected by the torque detector 30 includes noise N1 due to external disturbance factors, the detected torque value during forward rotation is (T1 + N1), and the torque value during reverse rotation is (-T1 + N1). The difference value ΔT a calculated from the detection value of the torque detector 30 is ΔT a =(T1 + N1)-(-T1 + N1)=2T1 and the influence of the noise N1 can be eliminated.

[0022] In the example shown in FIG. 3, from the torque value T2 (T2 is a positive number and T1 < T2) during forward rotation and the torque value -T2 during reverse rotation, the difference value ΔT b is calculated. Here, when the torque value detected by the torque detector 30 includes noise N2 due to external disturbance factors, the detected torque value during forward rotation is (T2 + N2), and the torque value during reverse rotation is (-T2 + N2). The difference value ΔT b calculated from the detection value of the torque detector 30 is ΔT b =(T2 + N2)-(-T2 + N2)=2T2 and the influence of the noise N2 can be eliminated.

[0023] Furthermore, the calculation unit 44 calculates the inertial force of the rotating body 50 based on the torque value detected by the torque detector 30. The value of the inertial force can be calculated, for example, by taking the second derivative of the change in torque value with respect to time. The calculation unit 44 further calculates the difference (inertial force difference) between the inertial force immediately before the rotating body 50 switches from forward rotation to reverse rotation and the inertial force immediately after the switch.

[0024] In the graphs shown in Figures 2 and 3, the rotating body 50 switches from forward rotation to reverse rotation at torque values ​​of -T3 and -T4. Here, T3 and T4 are positive numbers greater than T2. ​​In Figure 2, the inertial force immediately before the rotating body 50 switches from forward rotation to reverse rotation is the inertial force when the torque value drops sharply from T1, enclosed by the dashed line, and the inertial force immediately after the switch is the inertial force when the torque value rises from -T3 and reaches -T1, enclosed by the dashed line. In Figure 3, the inertial force immediately before the rotating body 50 switches from forward rotation to reverse rotation is the inertial force when the torque value drops sharply from T2, enclosed by the dashed line, and the inertial force immediately after the switch is the inertial force when the torque value rises from -T4 and reaches -T2, enclosed by the dashed line.

[0025] If the rotating body 50 is a defective product with a large rotational load, the inertial force immediately after switching from forward rotation to reverse rotation will be absent or small. In other words, in a defective product, the absolute value of the inertial force immediately after switching from forward rotation to reverse rotation will be smaller than that of a normal product. This difference in the magnitude of the inertial force is shown in Figure 3 by the fact that the angle β2 immediately after the rotation direction switches, enclosed by the dashed line, is larger than the angle β1 immediately before the rotation direction switches, enclosed by the dashed line in Figure 3, and also larger than the angles α1 and α2 immediately before and after the rotation direction switches, enclosed by the dashed line in Figure 2.

[0026] In this embodiment, as an example, the calculation unit 44 calculates the difference in inertial force between the moment immediately before and immediately after the rotation direction changes, assuming that (difference in inertial force) ≈ (change in torque value). For example, in the rotating body 50 shown in Figure 2, if the torque value detected by the torque detector 30 contains noise N1 due to external disturbances, the amount of change in the torque value immediately before switching from forward rotation to reverse rotation is: (T1+N1)-((-T3)+N1)=T1+T3 This is the result. Furthermore, immediately after switching from forward rotation to reverse rotation, if noise N1 due to external disturbances is present, the change in torque value is: (-T3+N1)-((-T1)+N1)=T1-T3 This is the result. Combining these, the difference between the inertial force of the rotating body 50 immediately before it switched from forward rotation to reverse rotation and the inertial force immediately after the switch is: (T1+T3)+(T1-T3)=2T1 This is the result.

[0027] Similarly, in the rotating body 50 shown in Figure 3, if the torque value detected by the torque detector 30 contains noise N2 due to external disturbances, the amount of change in the torque value immediately before switching from forward rotation to reverse rotation is: (T2+N2)-((-T4)+N2)=T2+T4 This is the result. The change in torque value immediately after switching from forward rotation to reverse rotation, if noise N1 due to external disturbances is included, (-T4+N2)-((-T2)+N2)=T2-T4 This is the result. Combining these, the difference in inertial force immediately before and immediately after the rotation of the rotating body 50 switches from forward rotation to reverse rotation is: (T2 + T4) + (T2 - T4) = 2T2 This is the result.

[0028] The determination unit 46 determines whether or not there is a rotational malfunction in the rotating body 50 based on the difference between the torque value of the rotating body 50 when it is rotating in the forward direction and the torque value when it is rotating in the reverse direction, and the difference between the inertial force of the rotating body 50 just before it switches from forward rotation to reverse rotation and the inertial force immediately after it switches, which are calculated by the calculation unit 44 based on the value detected by the torque detector 30.

[0029] The determination unit 46 compares the difference value of the torque value calculated by the calculation unit 44 with the torque threshold value T stored in the storage unit 42 th and determines that it is normal when the difference value is less than or equal to the torque threshold value T th and determines that there is a rotation failure when the difference value is greater than the torque threshold value T th . Also, the determination unit 46 compares the inertial force difference calculated by the calculation unit 44 with the inertial force threshold value I stored in the storage unit 42 th and determines that it is normal when the inertial force difference is less than or equal to the inertial force threshold value I th and determines that there is a rotation failure when the difference value is greater than the inertial force threshold value I th .

[0030] The display unit 48 can display information visually and / or aurally, and can be composed of, for example, a display, a speaker, etc. The calculation result by the calculation unit 44 and the determination result by the determination unit 46 can be displayed on the display unit 48. In the present embodiment, when it is determined by the determination unit 46 that both the difference value of the torque value and the inertial force difference are normal, a determination result indicating that the rotating body 50 is normal is displayed. Also, when it is determined that at least one of the difference value of the torque value and the inertial force difference is a rotation failure, a determination result indicating a rotation failure is displayed. It is also possible to display the detected torque value data, the calculation result by the calculation unit 44, etc. on this display unit 48

[0031] Next, a method for inspecting the rotation operation of the rotating body 50 using the inspection device 10 described above will be described. FIG. 4 is a flowchart of a method for inspecting a rotating body executed using the inspection device 10

[0032] First, the control device 40 operates the motor 20 to rotate the rotating body 50 in the forward rotation direction at a predetermined rotation speed (step S10), and then continuously rotates the rotating body 50 in the reverse rotation direction at a predetermined rotation speed (the same rotation speed as the forward rotation direction) (step S11). The torque detector 30 constantly detects the torque value during the rotation of the rotating body 50, and the data of the detected torque value is transmitted to the control device 40

[0033] The calculation unit 44 of the control device 40 calculates the difference between the torque value of the rotating body 50 when it is rotating in the forward direction and the torque value when it is rotating in the reverse direction, based on the received torque value data (step S12). The calculation unit 44 also calculates the difference between the inertial force of the rotating body 50 immediately before it switches from forward rotation to reverse rotation and the inertial force immediately after the switch, based on the received torque value data (step S13). In the inspection method of this embodiment, steps S10 to S13 correspond to the process of acquiring the difference in torque values ​​and the inertial force.

[0034] Next, the determination unit 46 of the control device 40 determines whether or not there is a rotational malfunction in the rotating body 50 based on the value calculated by the calculation unit 44 (step S14). Specifically, the determination unit 46 determines whether or not there is a rotational malfunction in the rotating body 50 based on the difference value of the calculated torque value and a preset torque threshold T th The difference in torque values ​​is compared with the torque threshold T. th If it is greater than the torque threshold T, it is determined that there is a rotational malfunction, and the torque threshold T is used. th The following conditions determine that it is normal. Furthermore, the determination unit 46 considers the calculated inertial force difference and the preset inertial force threshold I. th By comparing the two, the difference in inertial force is the inertial force threshold I th If it is greater than the inertia force threshold I, it is determined that there is a rotational malfunction, and the inertia force threshold I th The following conditions will be considered normal:

[0035] The determination unit 44 determines that both the difference in torque values ​​and the difference in inertial force meet the threshold T. th ,I th If the comparison with the other determines that it is normal, the rotating body 50 is determined to be a normal product. In addition, the determination unit 44 determines that at least one of the difference in torque value and the difference in inertial force is within the threshold T th ,I th If a rotational malfunction is determined through comparison with the other components, the rotating body 50 is determined to be a defective product.

[0036] When the determination unit 44 determines whether the rotating body 50 is a normal product or a defective product, the control device 40 displays the determination result on the display unit 48 (step S15).

[0037] In the inspection method described above, when inspecting for rotational defects in the rotating body 50, the difference in torque values ​​between forward and reverse rotation, and the inertial force value generated when switching from forward to reverse rotation, can be used to accurately detect whether or not there are rotational defects in the rotating body.

[0038] For example, if the torque value detected by the torque detector 30 contains noise due to external disturbances, the conventional method of determining whether or not there is a rotational malfunction based only on the torque value during forward rotation may not be able to make an accurate determination due to the influence of noise. In the conventional inspection method, the detected torque value is a preset threshold T'. th The following conditions are considered normal, threshold T' th A rotational malfunction was determined when the value exceeded a certain threshold. Figures 5 and 6 are graphs showing the change in torque value over time when the rotating body 50 is rotated in the forward direction. Figure 5 shows the case when the rotating body 50 is a normal product, and Figure 6 shows the case when the rotating body 50 is a defective product. The torque value of the rotating body 50 shown in Figure 5 is T1 = 0.2 (N·m), and the torque value of the rotating body 50 shown in Figure 6 is T2 = 0.4 (N·m). The threshold T' used to determine a rotational malfunction is used. th When set to =0.3(N·m), the torque values ​​T1, T2 and the threshold T' are as follows: th The difference is T1-T' when there is no noise influence. th = 0.1(N·m), T' th -T2 = -0.1 (N·m) is very small. Here, the detected torque value includes noise N due to external disturbances. When the noise N = 0.3 (N·m), the rotating body 50 shown in Figure 5 has a detected torque value of T1 + N = 0.2 + 0.3 = 0.5 (N·m), and despite being a normal product, it is judged to be malfunctioning. Also, when the noise N = -0.3 (N·m), the rotating body 50 shown in Figure 6 has a detected torque value of T2 + N = 0.4 - 0.3 = 0.1 (N·m), and despite being a defective product, it is judged to be a normal product.

[0039] In contrast, the inspection method of this embodiment suppresses the influence of noise, increases the numerical difference between normal and defective products, and enables highly accurate judgment.

[0040] For example, if the torque value T1 = 0.2 (N·m) of the rotating body 50 shown in Figure 2 and the torque value T2 = 0.4 (N·m) of the rotating body 50 shown in Figure 3, the torque threshold T used to determine if rotation is faulty is... th Let = 0.6 (N·m). In the rotating body 50 shown in Figure 2, as described above, regardless of noise, the difference value ΔT of the torque value remains constant. a =2T1=0.4, and the torque threshold T th The difference is 0.6 - 0.4 = 0.2 (N·m). Also, in the rotating body 50 shown in Figure 3, as described above, regardless of noise, the difference value ΔT of the torque value is... b =2T2=0.8, and the torque threshold T th The difference is 0.6 - 0.8 = -0.2 (N·m). Thus, in the inspection method of this embodiment, the effect of noise is suppressed and the threshold T th By increasing the difference between the two, a more accurate judgment can be made.

[0041] Furthermore, in this embodiment, a more accurate determination can be made by using the difference in inertial force. For example, the inertial force threshold I th Assuming = 0.6, the torque values ​​of the rotating body 50 shown in Figure 2 are T1 = 0.2 (N·m) and T3 = 0.8 (N·m), and the torque values ​​of the rotating body 50 shown in Figure 3 are T2 = 0.4 (N·m) and T4 = 0.8 (N·m). In this case, the inertial force difference of the rotating body 50 shown in Figure 2 is (inertial force difference) ≈ (change in torque value), and as previously stated, regardless of noise, (inertial force difference) ≈ 2T1 = 0.4, and the inertial force threshold I th The difference is 0.6 - 0.4 = 0.2 (N·m). Also, the inertial force difference of the rotating body 50 shown in Figure 3 is (inertial force difference) ≈ 2T² = 0.8 regardless of the noise, as mentioned above, and the inertial force threshold I th The difference is 0.6 - 0.8 = -0.2 (N·m). Thus, in the inspection method of this embodiment, the effect of noise is suppressed and the threshold I th By increasing the difference between the two, a more accurate judgment can be made.

[0042] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention.

[0043] For example, the detection device 10 only needs to be configured to acquire at least the difference in torque values ​​between forward and reverse rotation of the rotating body, or the inertial force immediately after the rotating body 50 switches from forward to reverse rotation. In this case, the presence or absence of a rotational malfunction in the rotating body 50 is determined based on the acquired difference in torque values ​​or inertial force. The difference in torque values ​​between forward and reverse rotation can be acquired by the method of the embodiment described above. Furthermore, when determining a rotational malfunction based on inertial force, the device can be configured to determine that the rotation is normal if the magnitude (absolute value) of the inertial force immediately after the rotation switches exceeds a preset inertial force threshold, and that it is malfunctioning if it is below the inertial force threshold.

[0044] Furthermore, for example, the inertial force value of the rotating body 50 may be detected using a detector capable of directly detecting inertial force (for example, an inertial force sensor such as an acceleration sensor) instead of the torque detector 30.

[0045] Furthermore, in this embodiment, a method for inspecting a rotating body 50 in which a cylindrical main body 54 is attached to a rotating shaft 52 has been described as an example, but the rotating body 50 to be inspected is not limited to this. For example, the rotating body 50 may be a camshaft, which is a component of an engine mounted on a vehicle. A camshaft comprises a shaft which is the rotating axis and a plurality of cams which are the main body. When inspecting a camshaft, the configuration can be used to measure torque values ​​and inertial force values ​​in the region without cam lobes in the direction of rotation. [Explanation of Symbols]

[0046] 10 Inspection equipment 20 motors 30 Torque detector 40 Control device 42 Storage section 44 Calculation Section 46 Judgment section 48 Display section 50 Rotating Bodies 52 Rotation axis 54 Main body

Claims

1. A method for inspecting the rotational motion of a rotating body that rotates around a rotation axis, A step of rotating the rotating body in the forward direction and then in the reverse direction to obtain the difference between the torque value of the rotating body during forward rotation and the torque value during reverse rotation, and / or the inertial force when the rotating body switches from forward rotation to reverse rotation, A step of determining whether or not there is a rotational malfunction of the rotating body based on the acquired value and a preset threshold, A method for inspecting a rotating body, characterized by including the following:

2. In the process described above, the difference between the torque value of the rotating body when it is rotating in the forward direction and the torque value when it is rotating in the reverse direction is obtained. The method for inspecting a rotating body according to claim 1, characterized in that, in the determination step, the difference value of the acquired torque value is compared with a preset torque threshold, and if the difference value is greater than the torque threshold, it is determined that there is a rotational malfunction.

3. In the acquisition process described above, the difference between the inertial force of the rotating body immediately before it switches from forward rotation to reverse rotation and the inertial force immediately after the switch is acquired. The method for inspecting a rotating body according to claim 1 or 2, characterized in that, in the determination step, the difference value of the acquired inertial force is compared with a preset inertial force threshold, and if the difference value is greater than the inertial force threshold, it is determined that there is a rotational defect.

4. In a rotating body inspection device that inspects the rotational motion of a rotating body that rotates around a rotation axis, A drive unit capable of rotating the aforementioned rotating body in both the forward and reverse directions, A detector for detecting the rotational torque and / or inertial force of the rotating body, A determination unit determines whether or not there is a rotational malfunction of the rotating body based on the difference between the torque value when the rotating body is rotating in the forward direction and the torque value when it is rotating in the reverse direction, and / or the inertial force when the rotating body switches from forward rotation to reverse rotation, based on the detected value of the detector, An inspection device for rotating bodies, characterized by being equipped with the following features.

5. The detector is a torque detector that detects the rotational torque of the rotating body, The rotating body inspection apparatus according to claim 4, further comprising a calculation unit that calculates the inertial force of the rotating body based on the torque value detected by the torque detector.

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