Clearance evaluation device and clearance evaluation method

Abstract

To accurately evaluate a clearance between a link component and a shaft body.SOLUTION: A clearance evaluation device 1 includes: a multi-joint robot 10 that moves a link component by moving a hand 12; and an evaluation section 30 that evaluates a clearance between the link component and a shaft body on the basis of information from the multi-joint robot 10. The multi-joint robot 10 moves the link component to one end of the shaft body, and moves the link component to the other end of the shaft body after moving the link component to the one end. The evaluation section 30 evaluates the clearance on the basis of a movement amount of the hand 12 while moving the link component from one end to the other end or a movement amount of the link component.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a clearance evaluation device and a clearance evaluation method. [Background technology]

[0002] An internal combustion engine includes a mechanism in which a link component rotates relative to a shaft inserted into a hole in the link component, and in order to ensure the operating performance of the internal combustion engine, it is necessary to ensure an appropriate clearance between the inner peripheral surface of the link component and the outer peripheral surface of the shaft.

[0003] Patent Document 1 discloses a clearance measurement method for measuring the clearance between the tip of a turbine rotor and a shroud wall surface provided adjacent to the tip of a turbine rotor during operation of an axial-flow turbine of a gas turbine engine. In this measurement method, the clearance is measured by measuring the gas temperature near the shroud wall surface a specified distance downstream from the turbine rotor outlet using a temperature sensor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 59-220609 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the invention described in Patent Document 1 is a technology that measures the clearance by measuring the temperature change caused by the rotation of the turbine, and therefore cannot measure the clearance in a mechanism that does not cause a temperature change.

[0006] The present invention has been made in consideration of the above, and an object of the present invention is to provide a method for accurately evaluating the clearance between a link component and a shaft body. [Means for solving the problem]

[0007] A clearance evaluation device according to one aspect of the present invention includes an instrument that moves a link component by moving a gripping mechanism that grips the link component, and an evaluation unit that evaluates a clearance between the link component and a shaft body based on information from the instrument. The instrument moves the link component to one end of the shaft body, and then moves the link component to the other end of the shaft. The evaluation unit evaluates the clearance based on the amount of movement of the gripping mechanism or the amount of movement of the link component while moving the link component from the one end to the other end. Effect of the Invention

[0008] According to the present invention, the clearance between the link component and the shaft body can be evaluated with high accuracy. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram showing the configuration of a clearance evaluation device according to this embodiment. [Diagram 2] FIG. 2 is a cross-sectional view illustrating a control link and a control shaft. [Diagram 3] FIG. 3 is a side view illustrating the control link and the control shaft. [Figure 4] FIG. 4 is an explanatory diagram showing a main part of the articulated robot. [Diagram 5] FIG. 5 is a flowchart showing the clearance evaluation method according to this embodiment. [Figure 6] FIG. 6 is a flowchart showing the clearance evaluation method according to this embodiment. [Figure 7] FIG. 7 is a diagram for explaining an outline of the measurement in the clearance evaluation method. [Figure 8] FIG. 8 is an explanatory diagram showing a transition of the longitudinal force detected by the sensor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A clearance evaluation device and a clearance evaluation method according to an embodiment of the present invention will be described below with reference to the drawings.

[0011] 1, the clearance evaluation device 1 includes an articulated robot 10, a robot control device 20, and an evaluation unit 30. In this embodiment, the details of the clearance evaluation will be described using a variable compression ratio mechanism of an internal combustion engine as an example.

[0012] The variable compression ratio mechanism of the internal combustion engine includes a lower link rotatably connected to the crankshaft and an upper link connecting the lower link and the piston. The variable compression ratio mechanism also includes a control shaft disposed below the crankshaft and a control link connecting the control shaft and the lower link. This variable compression ratio mechanism allows the compression ratio of the internal combustion engine to be continuously changed according to the rotational position of the control shaft.

[0013] 2 and 3, the control link 60 has a hole 61 through which the eccentric shaft portion 50 of the control shaft is inserted. The control link 60 is rotatable relative to the eccentric shaft portion 50 of the control shaft inserted into the hole 61. Support portions for supporting the control shaft are located on both sides of the eccentric shaft portion 50 in the front-to-rear direction. A front end 55 of the eccentric shaft portion 50 is defined by the front support portion, and a rear end 56 of the eccentric shaft portion 50 is defined by the rear support portion.

[0014] The clearance evaluation device 1 according to this embodiment evaluates the clearance between the inner circumferential surface 60 a of the hole 61 of the control link 60 and the outer circumferential surface 50 a of the eccentric shaft portion 50 .

[0015] 2 and 3, one control link 60 and one eccentric shaft portion 50 of the control shaft are illustrated, but the control shaft is provided with a plurality of eccentric shaft portions 50 corresponding to a plurality of cylinders and a plurality of control links 60. In the following description, the eccentric shaft portion 50 will be simply referred to as the control shaft 50.

[0016] In addition, although three axial directions including the up-down, left-right, and front-rear directions are shown in Figures 2 and 3, it should be noted that these directions are based on the three axial directions of the articulated robot 10 at the time of clearance evaluation and do not coincide with the three axial directions of the internal combustion engine when mounted on a vehicle.

[0017] Please refer to Fig. 1 again. The articulated robot 10 has a plurality of arms, joints that connect the arms together, and a drive means that drives the joints. As shown in Fig. 4, a hand 12 for holding a control link 60 is attached to an arm 11 located at the very tip. The hand 12 opens and closes by an actuator 13 such as an air cylinder, and is able to hold the control link 60 by this opening and closing movement.

[0018] The articulated robot 10 can move the hand 12 in three axial directions including the up-down direction, the left-right direction, and the front-rear direction. The articulated robot 10 can move the control link 60 by moving the hand 12 while holding the control link 60.

[0019] A sensor 15 is provided between the hand 12 and the arm 11. The sensor 15 is a so-called force sensor, and detects a force (load) acting on the hand 12. The sensor 15 can detect forces along at least three axial directions including the up-down direction, the left-right direction, and the front-rear direction. The sensor 15 can also detect torque acting around an axis in the three axial directions including the up-down direction, the left-right direction, and the front-rear direction.

[0020] 1, the robot control device 20 is mainly composed of a hardware processor such as a CPU (Central Processing Unit), a memory, and various interfaces. The memory and various interfaces are connected to the hardware processor via a bus.

[0021] A specific computer program is installed in the computer, and the computer functions as the robot control device 20 according to this embodiment as a result of the hardware processor executing the computer program.

[0022] The robot controller 20 is connected to the articulated robot 10 and controls the operation of the articulated robot 10. The robot controller 20 controls the articulated robot 10 to move the hand 12 in three axial directions including the up-down direction, the left-right direction, and the front-rear direction. The robot controller 20 also controls the actuator 13 to control the opening and closing of the hand 12.

[0023] The evaluation unit 30 is mainly composed of a hardware processor such as a CPU (Central Processing Unit), a memory, and various interfaces. The memory and various interfaces are connected to the hardware processor via a bus.

[0024] A specific computer program is installed in the computer, and the computer functions as the evaluation unit 30 according to this embodiment as a result of the hardware processor executing the computer program.

[0025] The evaluation unit 30 is connected to the articulated robot 10 and the robot controller 20, and evaluates the clearance between the inner circumferential surface 60a of the hole 61 of the control link 60 and the outer circumferential surface 50a of the control shaft 50 based on information from the articulated robot 10 and the robot controller 20. The evaluation unit 30 receives input of information on the coordinate position of the hand 12 in the three axial directions and sensor detection values ​​detected by the sensor 15 from the articulated robot 10 and the robot controller 20.

[0026] The clearance evaluation method according to this embodiment will be described below with reference to Fig. 5 to Fig. 7. The target of clearance evaluation is the clearance between the control link 60 and the control shaft 50, as shown in Fig. 2. The front-rear direction of the articulated robot 10 corresponds to the axial direction of the control shaft 50, and the left-right direction and the up-down direction of the articulated robot 10 correspond to two orthogonal axial directions included in a plane orthogonal to the axial direction of the control shaft 50.

[0027] 5, the robot control device 20 controls the actuator 13 to cause the hand 12 to grip the control link 60 (S10). The robot control device 20 controls the articulated robot 10 to move the hand 12 in the forward direction. The articulated robot 10 moves the hand 12 linearly along the front-rear direction to move the control link 60 to the front end 55 (S11).

[0028] The robot control device 20 judges whether or not the detection value of the sensor 15, specifically, the absolute value of the force acting on the hand 12 in the front-rear direction (hereinafter referred to as "front-rear force"), has reached a first judgment value (S12). As shown in Figures 7 and 8, when the control link 60 held by the hand 12 reaches the front end 55, the forward movement of the control link 60 is restricted. When the hand 12 continues to move forward, a reaction force acts on the hand 12 when the control link 60 is pressed against the front end 55.

[0029] 5, if the absolute value of the longitudinal force has not reached the first judgment value (S12: No), the robot controller 20 continues moving the hand 12 (S11). On the other hand, if the absolute value of the longitudinal force has reached the first judgment value (S12: Yes), the robot controller 20 stops moving the hand 12 (S13).

[0030] The hand 12 grasps the control link 60 at a position offset from the axial center of the control shaft 50. When the control link 60 is pressed against the front end 55, the control link 60 assumes an attitude inclined with respect to the perpendicular direction of the control shaft 50, as shown in Fig. 7. The greater the clearance between the control link 60 and the control shaft 50, the greater the amount of this inclination.

[0031] As shown in Fig. 5, the evaluation unit 30 performs a clearance measurement process (S14). Specifically, the evaluation unit 30 acquires the coordinate position of the hand 12 in the front-rear direction at the position where the absolute value of the front-rear force becomes the first judgment value, that is, the first judgment position P1 where the movement of the hand 12 stops (see Figs. 7 and 8). This coordinate position becomes the starting point for measuring the movement amount of the hand 12.

[0032] The robot control device 20 controls the articulated robot 10 to move the hand 12 backward. The articulated robot 10 moves the hand 12 linearly in the front-to-rear direction at a constant speed, thereby moving the control link 60 backward (S15).

[0033] The robot control device 20 judges whether or not the detection value of the sensor 15, specifically, the absolute value of the longitudinal force, has reached a second judgment value (S16). This second judgment value is a value for judging whether or not the longitudinal force acting on the hand 12 has been released, and is set to a value smaller than the first judgment value.

[0034] If the absolute value of the longitudinal force has not decreased to the second determination value (S16: No), the robot controller 20 continues the movement of the control link 60 (S15).

[0035] When the absolute value of the longitudinal force becomes the second judgment value (S16: Yes), the evaluation unit 30 performs a clearance measurement process (S17). Specifically, the evaluation unit 30 acquires the longitudinal force and the coordinate position of the hand 12 in the longitudinal direction at the first reference position P2, which is the position where the absolute value of the longitudinal force becomes the second judgment value (see Figs. 7 and 8). The longitudinal force and the coordinate position become the starting point for measuring the amount of change in the longitudinal force.

[0036] The robot control device 20 moves the hand 12 backward, thereby moving the control link 60 to the rear end 56 (S18).

[0037] 6, the robot control device 20 refers to the detection value from the sensor 15 and determines whether or not forces in the left-right and up-down directions have been detected (S19). When the inner peripheral surface 60a of the hole 61 and the outer peripheral surface 50a of the control shaft 50 interfere with each other while the control link 60 is moving to the rear end 56, forces in the front-rear and up-down directions are detected.

[0038] When a force in the left-right direction and the up-down direction is detected (S19: Yes), the robot control device 20 moves the hand 12 in the direction opposite to the direction in which the force is acting (S20). At this time, the articulated robot 10 continues to move the hand 12 at a constant speed in the forward and backward directions.

[0039] If no forces in the left-right and up-down directions are detected (S19: No), the robot controller 20 judges whether the movement amount of the hand 12 from the first reference position P2 reaches a specified amount (S21). This specified amount is set to a distance such that the control link 60 reaches just before the rear end 56.

[0040] If the movement amount of the hand 12 has not reached the specified amount (S21: No), the robot control device 20 continues the movement of the hand 12 (S18).

[0041] When the movement amount of the hand 12 reaches the specified amount (S21: Yes), the evaluation unit 30 performs a clearance measurement process (S22). Specifically, the evaluation unit 30 acquires the front-rear force and the coordinate position of the hand 12 in the front-rear direction at the second reference position P3, which is the position where the movement amount of the hand 12 reaches the specified amount (see FIGS. 7 and 8).

[0042] Similar to the process of step S19, the robot controller 20 refers to the detection value from the sensor 15 and determines whether or not forces in the left / right and up / down directions have been detected (S23).

[0043] When a force in the left-right direction and the up-down direction is detected (S23: Yes), the robot control device 20 moves the hand 12 in the direction opposite to the direction in which the force is acting (S24). At this time, the articulated robot 10 continues to move the hand 12 at a constant speed in the front-rear direction.

[0044] The robot control device 20 judges whether the absolute value of the longitudinal force has reached a first judgment value (S27). As shown in Fig. 7 and Fig. 8, when the control link 60 held by the hand 12 reaches the rear end 56, the rearward movement of the control link 60 is restricted. When the hand 12 continues to move rearward, a reaction force generated when the control link 60 is pressed against the rear end 56 acts on the hand 12 as a longitudinal force.

[0045] If the absolute value of the longitudinal force has not reached the first judgment value (S25: No), the robot controller 20 continues the movement of the hand 12 and returns to the process of step S23. On the other hand, if the absolute value of the longitudinal force has reached the first judgment value (S25: Yes), the robot controller 20 stops the movement of the hand 12 (S26).

[0046] The evaluation unit 30 performs a clearance measurement process (S27). Specifically, the evaluation unit 30 acquires the coordinate position of the hand 12 in the front-rear direction at the position where the absolute value of the front-rear force becomes the first judgment value, that is, the second judgment position P4 where the movement of the hand 12 is stopped (see FIGS. 7 and 8).

[0047] The evaluation unit 30 evaluates the clearance between the control link 60 and the control shaft 50 based on the first and second conditions described below (S28). <First condition> The distance from the first determination position P1 to the second determination position P4 is greater than a predetermined reference distance. <Second condition> The amount of change in the longitudinal force when moving from the first reference position P2 to the second reference position P3 is greater than a predetermined reference amount of change.

[0048] Specifically, when both the first condition and the second condition are satisfied, the evaluation unit 30 evaluates that there is sufficient clearance between the control link 60 and the control shaft 50. On the other hand, when either or both of the first condition and the second condition are not satisfied, the evaluation unit 30 evaluates that there is not sufficient clearance between the control link 60 and the control shaft 50.

[0049] This series of processes makes it possible to evaluate the clearance between the control link 60 and the control shaft 50. The robot control device 20 controls the articulated robot 10 to perform the above processes for each cylinder, allowing the clearance evaluation device 1 to evaluate the clearance of the control link 60 provided for each cylinder.

[0050] According to the clearance evaluation device 1 and clearance evaluation method of the present embodiment, the control link 60 is moved from the front end 55 to the rear end 56 by the hand 12. As shown in FIG. 7, the larger the clearance between the control link 60 and the control shaft 50, the more the control link 60 is inclined at the front end 55 and the rear end 56. Therefore, the larger the clearance, the larger the movement amount of the hand 12 when the control link 60 is moved from the front end 55 to the rear end 56. In this way, by moving the control link 60 from the front end 55 to the rear end 56 and specifying the movement amount of the hand 12 at that time, the clearance can be evaluated with high accuracy.

[0051] In this embodiment, the articulated robot 10 further includes a sensor 15 that detects a longitudinal force, that is, a force acting on the hand 12 along the axial direction of the control shaft 50. This makes it possible to accurately evaluate the clearance.

[0052] In this embodiment, the articulated robot 10 can determine the first determination position P1 and the second determination position P4 by referring to the detection value from the sensor 15. As shown in Fig. 7, the larger the clearance between the control link 60 and the control shaft 50, the larger the inclination amount of the control link 60 at the first determination position P1 and the second determination position P4. Therefore, the larger the clearance, the larger the distance from the first determination position P1 to the second determination position P4. By taking into account the amount of movement from the first determination position P1 to the second determination position P4, the evaluation unit 30 can accurately evaluate the clearance.

[0053] Furthermore, in this embodiment, the evaluation unit 30 evaluates the clearance based on the amount of movement from the first determination position P1 to the second determination position P4 and the amount of change in force detected by the sensor 15. This allows the clearance to be evaluated more accurately than when only the amount of movement is taken into consideration.

[0054] The evaluation unit 30 specifies the amount of change in the longitudinal force between the first reference position P2 and the second reference position P3. The articulated robot 10 moves the control link 60 along the longitudinal direction between the first reference position P2 and the second reference position P3. When the clearance between the control link 60 and the control shaft 50 is small, the control link 60 and the control shaft 50 are likely to interfere with each other, which acts as a resistance force in the longitudinal direction. Therefore, when there is a large change in force between the first reference position P2 and the second reference position P3, there is a possibility that the clearance between the control link 60 and the control shaft 50 is small. Therefore, by taking into account the amount of change in force between the first reference position P2 and the second reference position P3, the clearance can be evaluated with high accuracy.

[0055] Furthermore, when a force in the left / right or front / rear direction is detected while the articulated robot 10 is moving the control link 60 in the front / rear direction, the articulated robot 10 moves the control link 60 in the direction opposite to the direction in which the force is acting. This configuration makes it possible to prevent interference (frictional force) between the control link 60 and the control shaft 50 from acting as a force in the front / rear direction, and therefore makes it possible to appropriately evaluate the front / rear force when moving the control link 60 to the rear end 56. This makes it possible to accurately identify the second judgment position P4, and therefore to accurately evaluate the clearance.

[0056] In this embodiment, the articulated robot 10 is used as a mechanism for moving the control link 60. Therefore, by applying the hand 12 of the articulated robot 10 to each cylinder, the clearance of each control link 60 can be appropriately evaluated.

[0057] In this embodiment, the clearance between the control link 60 and the control shaft 50 is evaluated. However, the clearance evaluation device 1 and the clearance evaluation method according to this embodiment may also be applied to an internal combustion engine that includes a connecting rod attached to a crankshaft and a piston connected to the other end of the connecting rod. In other words, the clearance between the connecting rod and the crankshaft may be evaluated. Even in this case, the clearance between the connecting rod and the crankshaft can be evaluated with high accuracy.

[0058] In this embodiment, it is evaluated that the clearance is ensured when both the first condition and the second condition are satisfied. However, the evaluation unit 30 may evaluate the clearance using only the first condition.

[0059] In addition, in this embodiment, the hand 12 is moved at a constant speed from the first judgment position P1 to the second judgment position P4. Therefore, the movement amount from the first judgment position P1 to the second judgment position P4 may be treated as a movement time. Also, the distance from the first reference position P2 to the second reference position P3 is a common specified amount. Therefore, the movement amount from the first judgment position P1 to the second judgment position P4 depends on the sum of the movement amount from the first judgment position P1 to the first reference position P2 and the movement amount from the second reference position P3 to the second judgment position P4. Therefore, the movement amount from the first judgment position P1 to the second judgment position P4 may be treated as the sum of the movement amount from the first judgment position P1 to the first reference position P2 and the movement amount from the second reference position P3 to the second judgment position P4.

[0060] In the present embodiment, the evaluation unit 30 evaluates the clearance using the movement amount of the hand 12. However, the evaluation unit 30 may be provided with a sensor that detects the movement amount of the control link 60, and may evaluate the clearance using the movement amount of the control link 60 instead of the movement amount of the hand 12.

[0061] As described above, the present embodiment has been described, but the description and drawings forming a part of this embodiment should not be understood as limiting this embodiment. Various alternative embodiments, examples and operation techniques will be apparent to those skilled in the art from this embodiment. [Explanation of symbols]

[0062] 1. Clearance evaluation device 10 Articulated robot (equipment) 12 Hand (grasping mechanism) 15 Sensors 20 Robot control device (equipment) 30 Evaluation Section 50 Control shaft / eccentric shaft 50a Outer surface 55 Front end (one end) 56 Rear end (other end) 60 Control Link 60a Inner surface 61 Hole P1 1st judgment position P2 1st reference position P3 2nd reference position P4 2nd judgment position

Claims

1. a device including a gripping mechanism for gripping a link component having a hole through which a shaft body is inserted and rotatable relative to the shaft body, and for moving the link component by moving the gripping mechanism; and an evaluation unit that evaluates a clearance between an inner circumferential surface of the hole and an outer circumferential surface of the shaft body based on information from the device, The device comprises: The link component is moved to one end of the shaft body, After the link component is moved to the one end, the link component is moved to the other end of the shaft body; The evaluation unit is evaluating the clearance based on a movement amount of the gripping mechanism or a movement amount of the link component during movement of the link component from the one end to the other end; Clearance assessment device.

2. The device further includes a sensor for detecting a force acting on the gripping mechanism along an axial direction of the shaft. The clearance evaluation device according to claim 1 .

3. The device comprises: stopping the movement of the link part toward the one end at a first determination position where an absolute value of a force detected by the sensor after starting the movement of the link part toward the one end becomes a first determination value; stopping the movement of the link component at a second determination position where an absolute value of a force detected by the sensor after starting the movement of the link component from the first determination position toward the other end portion becomes the first determination value; The evaluation unit is evaluating the clearance based on a movement amount of the gripping mechanism or a movement amount of the link component while moving the link component from the first determination position to the second determination position; The clearance evaluation device according to claim 2 .

4. The evaluation unit is evaluating the clearance based on the amount of movement and the amount of change in force detected by the sensor; The clearance evaluation device according to claim 3 .

5. The evaluation unit is determining the amount of change while the link component is moved by a specified amount from a first reference position that is located on the other end side of the first determination position; The clearance evaluation device according to claim 4.

6. The first reference position is a position at which a force detected by the sensor after the link part starts moving from the first determination position toward the other end portion becomes a second determination value for determining that a force acting on the gripping mechanism has been released. The clearance evaluation device according to claim 5 .

7. The sensor includes: Further detecting forces in two orthogonal axial directions included in a plane orthogonal to the axial direction of the shaft body; The device comprises: moving the link component at a constant speed along an axial direction of the shaft from the first reference position; When the force in the two axial directions is detected while the link part is being moved along the axial direction of the shaft body, the link part is moved in a direction opposite to a direction in which the force in the two axial directions acts. The clearance evaluation device according to claim 5 .

8. The device comprises: The robot is an articulated robot having the gripping mechanism at an arm tip. The clearance evaluation device according to any one of claims 1 to 7.

9. A variable compression ratio mechanism for varying the compression ratio of an internal combustion engine includes a lower link attached to a crankshaft, a control shaft, and a control link connecting the control shaft and the lower link, The shaft body is the control shaft, and the link component is the control link. The clearance evaluation device according to any one of claims 1 to 7.

10. The internal combustion engine includes a connecting rod attached to a crankshaft and a piston connected to the other end of the connecting rod, The shaft is the crankshaft, and the link part is the connecting rod. The clearance evaluation device according to any one of claims 1 to 7.

11. A link component having a hole through which the shaft body is inserted and rotatable relative to the shaft body is gripped by a gripping mechanism; The link component is moved to one end of the shaft by moving the gripping mechanism; After the link component is moved to one end of the shaft body, the link component is moved to the other end of the shaft body by moving the gripping mechanism; evaluating a clearance between an inner circumferential surface of the hole and an outer circumferential surface of the shaft body based on a movement amount of the gripping mechanism or a movement amount of the link part while moving the link part from the one end to the other end. Clearance assessment methods.

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