JP2021135244A - Top dead center position evaluation device - Google Patents

Abstract

To provide a top dead center position evaluation device for evaluating an accurate top dead center position of a piston according to an engine type.SOLUTION: A top dead center position evaluation device for evaluating a rotation angle corresponding to a top dead center of a piston equipped with a driving device for rotating a crankshaft of an engine at a constant speed and a rotation angle measurement device for measuring the rotation angle, includes: a plurality of first measurement sensors arrayed in one row in a first direction in order to measure a plurality of deck surface positions of a cylinder block; a plurality of second measurement sensors arrayed in two rows in parallel with the first direction in order to measure a plurality of top surface positions of the piston separated in a second direction orthogonal to the first direction; an engine type detection device; first and second interval adjustment devices for adjusting intervals in the first direction of the plurality of first and second measurement sensors according to an engine type and intervals in the second direction of the plurality of second measurement sensors, respectively; and a calculation device for calculating a rotation angle corresponding to the top dead center of each piston on the basis of the rotation angle, the top surface position and the plurality of deck surface positions.SELECTED DRAWING: Figure 6

Description

The present invention relates to an evaluation device for the top dead center position of each cylinder in an in-line multi-cylinder engine.

Engines mounted on vehicles and the like are required to precisely control combustion in a combustion chamber in order to improve output performance and environmental performance. For that purpose, it is important to accurately determine the top dead center position of the piston, which is the reference for control in the engine.

Conventionally, the top dead center position of each piston of a multi-cylinder engine is measured by manually applying a measurement tool for manually measuring the top surface position of the piston to the piston that is stationary near the top dead center, and the crankshaft. Was swung around the axis. Therefore, the measured values may vary among the measurers.

In addition, the stationary piston is equivalent to the clearance at the connecting portion between the piston and the connecting rod by the piston pin, the connecting portion between the connecting rod and the crank pin of the crankshaft, and the connecting portion between the crank journal of the crankshaft and the bearing of the crankcase. Only lowered by gravity. Therefore, the measured value in the stationary state lacked accuracy with respect to the position of the top surface of the piston when the engine was driven.

Therefore, for example, as in Patent Document 1, a technique is known in which a crankshaft is rotated by a motor and the position of the top surface of a piston that moves up and down is measured by using a laser beam. The top surface of the piston, which has been lowered by the amount equivalent to the above clearance, moves upward due to the inertial force of the piston near the top dead center, and the position of the top surface of the piston can be measured by reproducing the state of the piston when the engine is driven. This makes it possible to suppress variations in measured values among measurers.

Japanese Unexamined Patent Publication No. 8-212130

However, when the crankshaft is rotated to move the piston up and down, the piston tilts around the piston pin due to the clearance between the cylinder and the piston. Therefore, in the technique of Patent Document 1, the position of the top surface of the piston is measured. There was a risk that the error would increase. In addition, when the crankshaft is rotated to reciprocate the piston up and down, the engine vibrates, and this vibration causes a measurement error in the position of the top surface of the piston, making it impossible to accurately evaluate the top dead center position. There was a risk. Moreover, it has not been easy to support various engine models with different cylinder diameters, cylinder spacings, piston shapes, and the like.

An object of the present invention is to provide a top dead center position evaluation method and a top dead center position evaluation device capable of accurately evaluating the top dead center position of a piston corresponding to an engine model.

The top dead point position evaluation device of the invention of claim 1 includes a drive device that rotates the crankshaft of an engine at a predetermined speed and a rotation angle measuring device that measures the rotation angle of the crankshaft, and rotates the crankshaft at a predetermined speed. In the top dead point position evaluation device that evaluates the rotation angle corresponding to the top dead point of the piston connected to the crankshaft while rotating with, the deck surface of the cylinder block, along the axis of the crankshaft. A plurality of first measurement sensors arranged in a row to measure the positions of a plurality of deck surfaces outside the cylinder along the center line of the cylinder in the first direction, and the top of the piston reciprocating in the cylinder. A plurality of second measurement sensors arranged in two rows parallel to the first direction in order to measure the positions of a plurality of top surfaces which are surfaces and are separated from each other in a second direction orthogonal to the first direction of the piston. A model detection device that detects the engine model, and a first interval adjusting device that adjusts the intervals of the plurality of first measurement sensors and the plurality of second measurement sensors in the first direction according to the engine model. Based on the second interval adjusting device that adjusts the interval of the plurality of second measurement sensors in the second direction according to the engine model, the rotation angle, the top surface position, and the plurality of deck surface positions. It is characterized by having a calculation device for calculating the top dead point position of the piston.

According to the above configuration, the top dead center position evaluation device adjusts the interval between the plurality of first measurement sensors and the plurality of second measurement sensors in the first direction and the interval in the second direction according to the engine model to be measured. .. Therefore, the top dead center position evaluation device can be made compatible with various engine models. Further, while rotating the crankshaft of the engine at a predetermined speed by a drive device, the rotation angle of the crankshaft and the position of the top surface of the piston connected to the crankshaft are measured, and the rotation angle corresponding to the top dead center of the piston is determined. That is, the top dead center position is evaluated. Therefore, the top dead center position can be evaluated by reproducing the position of the top surface of the piston when the engine is driven. At the time of measurement, the positions of the plurality of deck surfaces outside the cylinder along the center line of the cylinder in the first direction are measured by the plurality of first measurement sensors, and the position of the top surface of the piston is measured by the plurality of second measurement sensors. measure. Therefore, the influence of the engine vibration due to the rotation of the crankshaft and the reciprocating movement of the piston can be eliminated, and the top surface position can be accurately measured. In addition, at the time of evaluation, the rotation angle, the top surface position, and the rotation angle corresponding to the top dead center of the piston are calculated by the calculation device based on the positions of the plurality of deck surfaces, so that the accurate top dead center position of the piston can be obtained. Can be evaluated.

In the invention of claim 1, the top blind point position evaluation device of the second aspect of the present invention is the first interval adjusting device so that the intervals of the plurality of first measurement sensors in the first direction are equal to each other. A row symmetrically from the center of the row of the plurality of first measurement sensors and the center of the row of the plurality of second measurement sensors in the first direction so that the intervals of the plurality of second measurement sensors in the first direction are equal. The first and second measurement sensors farther from the center are moved larger, and the second interval adjusting device makes the plurality of second measurement sensors arranged in two rows symmetrical with respect to the center line in the second direction. It is characterized by moving it equally.
According to the above configuration, it is not necessary to individually specify the positions of the plurality of first measurement sensors and the plurality of second measurement sensors, and it is possible to easily correspond to various engine models.

The top dead point position evaluation device according to the third aspect of the present invention is the first linear motion of the first interval adjusting device according to the second aspect of the present invention, in which the plurality of first measurement sensors are moved symmetrically in the first direction. The first linear motion mechanism and the first linear motion mechanism, which have a mechanism and a second linear motion mechanism for moving the plurality of second measurement sensors symmetrically in the first direction, and which are arranged in parallel with the first direction, respectively. The two linear motion mechanisms are characterized in that they are interlocked and driven by a first interlocking mechanism provided with a first driving device.
According to the above configuration, a plurality of first measurement sensors and a plurality of second measurement sensors can be simultaneously and symmetrically moved in the first direction by driving the first drive device, so that various engine models can be used with a simple configuration. It can be made to correspond.

According to the invention of claim 4, in the invention of claim 3, a plurality of screw shafts having different leads are coaxially connected to each of the first linear motion mechanism and the second linear motion mechanism. It has two ball screw linear motion mechanisms provided with a rotating shaft, and is characterized in that the two ball screw linear motion mechanisms are configured to be driven in opposite directions via gears.
According to the above configuration, a plurality of first measurement sensors and a plurality of second measurement sensors can be simultaneously and symmetrically moved in the first direction by driving the first drive device, so that various engine models can be used with a simple configuration. It can be made to correspond.

In the invention of claim 4, the top dead point position evaluation device of the invention of claim 5 is such that the rotation shaft of the first linear motion mechanism is stepwise away from the gear with respect to the lead of the gear side portion. The lead is set so as to be an integral multiple of the lead, and the rotating shaft of the second linear motion mechanism has a lead that is gradually increased to an odd multiple in the direction away from the gear with respect to the lead of the gear side portion. It is characterized by being set.
According to the above configuration, the intervals are adjusted while the intervals in the first direction of the plurality of first measurement sensors are equal, and the intervals are adjusted while the intervals in the first directions of the plurality of second measurement sensors are equal. It can be made compatible with various engine models with a simple configuration.

The top dead point position evaluation device of the invention of claim 6 is the invention of claim 2, wherein the second interval adjusting device includes a pair of third linear motion mechanisms arranged in parallel with the second direction. It has a second interlocking mechanism provided with a second driving device, and is interlocked and driven so as to move the plurality of second measurement sensors arranged in two rows symmetrically with respect to the center line in the second direction. It is characterized by that.
According to the above configuration, since a plurality of second measurement sensors can be moved symmetrically in the second direction at the same time by driving the second drive device, it is possible to correspond to various engine models with a simple configuration.

In the invention of any one of claims 1 to 6, the first measurement sensor and the second measurement sensor are contact-type linear sensors, and the top blind point position evaluation device of the invention of claim 7 is the first measurement sensor. It is characterized by having a master plate for learning the measurement reference position of one measurement sensor and the second measurement sensor before measurement.
According to the above configuration, since a contact type linear sensor in which the measurement reference position is learned before measurement is used, the top surface position of the piston is accurately measured even if each piston is tilted, and the top surface position of each piston is measured. The dead center position can be evaluated accurately.

The top blind point position evaluation device of the invention of claim 8 is the invention of claim 7, wherein the plurality of first measurement sensors and the plurality of second measurement sensors are the first interval adjustment device and the second interval adjustment. The device is equipped in a state of projecting downward from the base member on which the device is arranged, and the base member has a plurality of legs projecting downward to abut the master plate when learning the measurement reference position. At the time of measurement, the plurality of legs are brought into contact with the deck surface.
According to the above configuration, since the lower end of the leg portion that has become the measurement reference position is brought into contact with the deck surface for measurement, it is possible to suppress the occurrence of measurement error.

According to the top dead center position evaluation method and the top dead center position evaluation device of the present invention, it is possible to accurately evaluate the top dead center position of the piston corresponding to the engine model.

It is a front view of the top dead center position evaluation apparatus which concerns on embodiment of this invention. It is a block diagram of the control part of the top dead center position evaluation apparatus. It is explanatory drawing of the measurement part which concerns on embodiment of this invention. It is sectional drawing of the main part of line IV-IV of FIG. It is sectional drawing of the main part of VV line of FIG. It is a main part plan view of the measuring apparatus which concerns on embodiment of this invention. It is a main part plan view which shows the 1st and 2nd interval adjustment apparatus of a measuring apparatus. It is explanatory drawing of the interval adjustment in the 1st direction of a measuring device. It is explanatory drawing of the interval adjustment in the 2nd direction of a measuring device. It is a main part exploded plan view of the support member of the 2nd measurement sensor pair. It is a main part plan view of the measuring apparatus which increased the interval in the 1st and 2nd directions. It is explanatory drawing of learning of the measurement reference position which concerns on embodiment of this invention. It is a block diagram which shows the process of the top dead center position evaluation which concerns on embodiment of this invention. It is explanatory drawing of the action of the inertial force in a piston. It is explanatory drawing of the relationship between the ascending distance of the top surface and the sensor followability with respect to the crankshaft rotation speed. It is explanatory drawing of the top dead center position evaluation result which concerns on embodiment of this invention.

Hereinafter, modes for carrying out the present invention will be described. The following description of preferred embodiments is merely exemplary and is not intended to limit the invention, its applications or its uses.

First, the top dead center position evaluation device 1 will be described.
As shown in FIG. 1, the top dead center position evaluation device 1 is arranged above the stage 3 on which the engine 10 to be evaluated is placed and above the stage 3 in order to measure the height of a predetermined measurement point of the engine 10. The measuring device 20, the support frame 30 that movably supports the measuring device 20 in three directions of up and down, front and back, and left and right, the drive device 5 that rotates the crankshaft 11 of the engine 10, and the rotated crankshaft 11. It has a rotation angle measuring device 6 and the like for measuring a rotation angle.

The drive device 5 is, for example, an electric motor that rotates the crankshaft 11 at a constant speed. Further, the rotation angle measuring device 6 is a high-resolution crank angle sensor that detects a rotation angle (crank angle) in increments of, for example, 0.1 degrees. The measuring device 20 is equipped with first measuring sensors 21a to 21g as a plurality of first measuring sensors and a plurality of second measuring sensor pairs 22a to 22f as a plurality of second measuring sensors. The second measurement sensor pairs 22a to 22f are each composed of two second measurement sensors.

The first and second measurement sensors are, for example, contact type linear sensors, and measure the moving distance (displacement amount) of the tip. The plurality of first measurement sensors 21a to 21g measure the position of the upper surface (deck surface 12) of the cylinder block of the engine 10. The plurality of second measurement sensor pairs 22a to 22f measure the position of the top surface of each piston of the engine 10, which will be described later.

The stage 3 is equipped with an engine model detection device 7 (model detection device) that detects the engine model. The drive device 5 and the rotation angle measuring device 6 are each configured to be movable at a position determined according to the engine model. The engine model detection device 7 reads, for example, information on a code (bar code, two-dimensional code, etc.) or RF tag attached to a predetermined position of the engine 10 to acquire information on the engine model and the like. Although not shown, the stage 3 is configured so that the position of the mounted engine 10 can be adjusted up and down, front and back, and left and right.

The support frame 30 is configured to be movable back and forth with respect to the fixed frame 31 fixed to the floor, the left and right movement frame 32 configured to be movable left and right with respect to the fixed frame 31, and the left and right movement frame 32. It has a front-back movement frame 33, a up-down movement frame 34 and the like configured to be movable up and down with respect to the front-back movement frame 33.

The left-right movement frame 32 is moved by an actuator (not shown) along a guide rail 31a extending to the left and right arranged on the fixed frame 31. The front-rear movement frame 33 is moved by an actuator (not shown) along a guide rail 32a extending back and forth arranged on the left-right movement frame 32. The vertical movement frame 34 is moved up and down by a plurality of drive cylinders 35. The measuring device 20 is fixed to the lower ends of a plurality of columnar members 36 arranged so as to extend downward on the vertically moving frame 34. Therefore, the position of the measuring device 20 can be adjusted by moving the measuring device 20 in three directions of up / down, front / back, and left / right with respect to the fixed frame.

Further, as shown in FIG. 2, the top dead center position evaluation device 1 has a control unit 90 that controls the position of the measuring device 20 and the like, the drive control of the drive device 5, and the like according to the engine model. The control unit 90 includes an arithmetic unit 91, a storage device 92, an input / output device 93, and the like, executes a predetermined control program, and evaluates the top dead center position.

During the evaluation of the top dead center position, the rotation speed information of the crankshaft 11 by the drive device 5, the rotation angle information of the crankshaft by the rotation angle measuring device 6, and the deck surface position by the plurality of first measurement sensors 21a to 21g. And the measured value of the top surface position by the plurality of second measurement sensor pairs 22a to 22f are stored in the storage device 92 via the input / output device 93. Then, based on the stored information, the arithmetic unit 91 calculates the rotation angle of the crankshaft 11 corresponding to the top dead center position of each piston.

Next, the measurement points of the engine 10 to be evaluated by the measuring device 20 will be described.
FIG. 3 is a plan view of a main part of the cylinder block of an in-line 6-cylinder engine before mounting the cylinder head as an example of the engine 10 as viewed from the deck surface 12 side. The six cylinders 13a to 13f are arranged in a row along the A1 direction (first direction) in which the axis of the crankshaft 11 extends, and the center line C1 of the cylinder row extending in parallel with the A1 direction is displayed. Further, the center lines C2a to C2f of the cylinders 13a to 13f parallel to the A2 direction (second direction) orthogonal to the A1 direction are displayed.

Pistons 14a to 14f are housed in the plurality of cylinders 13a to 13f, respectively. Although not shown, the engine 10 is equipped with a crank angle sensor for the crankshaft 11.

FIG. 4 is a cross-sectional view of a main part of the cylinder row along the center line C1 of FIG. 3, and FIG. 5 is a cross-sectional view of the cylinder 13a along the center line C2a of FIG. As shown in FIGS. 3 to 5, the plurality of first measurement sensors 21a to 21g are the measurement points Da to Dg of the corresponding deck surface positions on the center line C1 outside the cylinders 13a to 13f along the cylinder row. To measure.

The plurality of second measurement sensor pairs 22a to 22f are located at two top surface positions on the center lines C2a to C2f symmetrically with respect to the center line C1 and separated in the A2 direction in the vicinity of the outer edge of the top surface in the corresponding pistons 14a to 14f. Measurement points Ta1, Ta2-Tf1, Tf2 are measured. When a cylinder head (not shown) is mounted, the measurement points Ta1 to Tf1 are on the intake port side of the cylinder head, and the measurement points Ta2 to Tf2 are on the exhaust port side.

The portion near the outer edge of the top surface of each piston 14a to 14f separated in the A2 direction is formed flat as a squish area for compressing the air-fuel mixture in the combustion chamber with the cylinder head (not shown), so that the top surface is formed. Suitable for position measurement. On the other hand, on the radial inside of the top surface of each piston 14a to 14f, unevenness (not shown) that differs depending on the engine model may be provided for controlling the air-fuel mixture in the firing chamber. Therefore, the position of the top surface is measured. It is difficult. Therefore, the measurement points for the top surface position are set at two points corresponding to the squish area that is commonly formed in all engine models. The tips of the second measurement sensor pairs 22a to 22f are separated from the pistons 14a to 14f except near the top dead center.

Further, since there is a clearance between the piston 14a and the cylinder 13a, the piston 14a swings around the piston pin 15a, the top surface is tilted, and the measured values at the two measurement points Ta1 and Ta2 are maximum, for example. It may differ by several hundred μm. Therefore, the arithmetic unit 91 calculates the average value of the measured values of the two measurement points Ta1 and Ta2 symmetrically separated from the center line C1 in the A2 direction as the top surface position of the piston 14a. Then, the arithmetic unit 91 calculates the average value of the measured values of the measurement points Da and Db outside the cylinder 13a as the deck surface position of the cylinder 13a. The other cylinders 13b to 13f and the pistons 14b to 14f are the same as the cylinders 13a and the pistons 14a.

Next, the measuring device 20 will be described.
As shown in FIG. 6, the measuring device 20 includes, for example, seven first measurement sensors 21a to 21g as a plurality of first measurement sensors and, for example, six pairs of second measurement sensor pairs 22a to 22f as a plurality of second measurement sensors. It has an equipped rectangular and flat plate-shaped base member 23. For example, for an in-line 6-cylinder engine 10 mounted on the stage 3, the measurement points Da to Dg of the corresponding deck surface positions and the top surface positions are set by the first measurement sensors 21a to 21g and the second measurement sensor pairs 22a to 22f. Measurement points Ta1, Ta2-Tf1, Tf2 are measured.

The base member 23 has a pair of rectangular openings 24 that communicate in the thickness direction (vertical direction). On the upper surface side of the base member 23, a plurality of elongated rectangular plate-shaped support members 25a to 25c, 25e to 25g, 26a are partially cut out so as to be erected in a pair of openings 24 parallel to the A2 direction. ~ 26f are arranged. The support members 25a to 25c support the corresponding first measurement sensors 21a to 21c. The support members 25e to 25g support the corresponding first measurement sensor 21e to 21g. The support members 26a to 26f support the corresponding second measurement sensor pairs 22a to 22f.

Between the pair of openings 24, a cross-linked portion 23a bridged in parallel with the A2 direction is provided. A first measurement sensor 21d for measuring the measurement point Dd at the deck surface position in the center of the cylinder row is provided in the central portion of the bridge portion 23a in the A2 direction so as to project downward from the base member 23.

A plurality of support members 25a to 25c and 25e to 25g are arranged so that the first measurement sensors 21a to 21g are arranged in a row in the A1 direction, including the first sensor 21d of the cross-linking portion 23a. A plurality of support members 26a to 26f are arranged so that one second measurement sensor pair 22a to 22f is arranged between the first measurement sensors 21a to 21g arranged in a row. The plurality of first measurement sensors 21a to 21c, 21e to 21g and the plurality of second measurement sensor pairs 22a to 22f supported by the plurality of support members 25a to 25c, 25e to 25g, 26a to 26f are base members from the opening 24. It is equipped in a state of protruding downward of 23.

As shown in FIGS. 6 to 8, a pair of first guide rails 28 are arranged on the base member 23 so as to sandwich the opening 24 in parallel with the A1 direction, and the opening 24 is provided in parallel with the A2 direction. A pair of second guide rails 29 are arranged so as to sandwich the second guide rails 29. The pair of first guide rails 28 is for smoothly guiding the movement of the plurality of support members 25a to 25c, 25e to 25g, and 26a to 26f in the A1 direction while maintaining a posture parallel to the A2 direction. .. The movement of the plurality of support members 25a to 25c, 25e to 25g, and 26a to 26f in the A1 direction is performed by the first interval adjusting device 41.

The first interval adjusting device 41 moves the first linear motion mechanism 42 that moves the plurality of support members 25a to 25c and 25e to 25g symmetrically in the A1 direction, and the plurality of support members 26a to 26f symmetrically in the A1 direction. It has a second linear motion mechanism 52 and a first interlocking mechanism 62 including a first drive device 61. The first linear motion mechanism 42 is arranged parallel to the A1 direction on one end side portion of the base member 23 in the A2 direction, and the second linear motion mechanism 52 is parallel to the other end side portion of the base member 23 in the A2 direction in the A1 direction. It is arranged in.

The first linear motion mechanism 42 has a pair of ball screw linear motion mechanisms 43a and 43b. The pair of ball screw linear motion mechanisms 43a and 43b each have a rotary shaft 44 in which a plurality of screw shafts having different leads are coaxially connected via a connecting member 44a, and a gear 45 that rotates together with the rotary shaft 44. The rotary shaft 44 is rotatably supported by a plurality of support shaft members 46 fixed to the base member 23.

The lead of the rotating shaft 44 is set so as to be an integral multiple of the lead of the gear 45 side portion in a stepwise direction away from the gear 45. For example, the lead Lc1 of the gear 45 side portion corresponding to the support members 25c and 25e is set to 2 mm, respectively, and the lead Lb1 of the portion corresponding to the support members 25b and 25f is set to 4 mm (twice the lead Lc1), respectively. The lead La1 of the portion corresponding to the support members 25a and 25g is set to 6 mm (three times the lead Lc1), respectively. In this way, based on the distance between the measurement points Dd and Dc, the distance between the measurement points Dd and Db and the distance between the measurement points Dd and Da are doubled and tripled, respectively, regardless of the size of the cylinder. It corresponds. The same applies to the distances between the measurement points Dd-De, Dd-Df, and Dd-Dg.

The first linear motion mechanism 42 is configured such that a pair of ball screw linear motion mechanisms 43a and 43b are driven in opposite directions via a gear 45. In the nut units 47a to 47c corresponding to the leads La1 to Lc1 portions of the rotating shafts 44 of the pair of ball screw linear motion mechanisms 43a and 43b, the corresponding support members 25a to 25c and the support members 25e to 25g are A2. Each is fixed in a posture parallel to the direction. The support members 25a to 25c and the support members 25e to 25g are moved in the opposite directions in parallel with the A1 direction while maintaining a posture parallel to the A2 direction by the pair of the first guide rails 28 and the first linear motion mechanism 42. Will be done.

The second linear motion mechanism 52 has a pair of ball screw linear motion mechanisms 53a and 53b. The pair of ball screw linear motion mechanisms 53a and 53b each have a rotary shaft 54 in which a plurality of screw shafts having different leads are coaxially connected via a connecting member 54a, and a gear 55 that rotates together with the rotary shaft 54. The rotary shaft 54 is rotatably supported by a plurality of support shaft members 56 fixed to the base member 23.

The lead of the rotating shaft 54 is set so that the lead of the gear 55 side portion is gradually increased to an odd number in the direction away from the gear 55. For example, the lead Lc2 of the gear side 55 portion corresponding to the support members 26c and 26d is set to 1 mm, respectively, and the lead Lb2 of the portion corresponding to the support members 26b and 26e is set to 3 mm (three times Lc2), respectively, to support. The lead La2 of the portion corresponding to the members 26a and 26f is set to 5 mm (5 times Lc2), respectively. In this way, based on the distance from the measurement point Dd to the center of the cylinder 13c, the distance from the measurement point Dd to the center of the cylinder 13b and the distance from the measurement point Dd to the center of the cylinder 13a are different regardless of the size of the cylinder. It corresponds to 3 times and 5 times. The same applies to the cylinders 13d, 13e and 13f.

The second linear motion mechanism 52 is configured such that a pair of ball screw linear motion mechanisms 53a and 53b are driven in opposite directions via the gear 55. In the nut units 57a to 57c corresponding to the leads La2 to Lc2 portions of the rotating shafts 54 of the pair of ball screw linear motion mechanisms 53a and 53b, the corresponding support members 26a to 26c and the support members 26d to 26f are A2. Each is fixed in a posture parallel to the direction. The support members 26a to 26c and the support members 26d to 26f are moved in the opposite directions in parallel with the A1 direction while maintaining a posture parallel to the A2 direction by the pair of the first guide rail 28 and the second linear motion mechanism 52. Will be done.

The first interlocking mechanism 62 includes a drive shaft 61a coaxially connected to the rotary shaft 44 of the ball screw linear motion mechanism 43a and a drive shaft 61b coaxially connected to the rotary shaft 54 of the ball screw linear motion mechanism 53a. It has a transmission mechanism 63 that transmits the driving force of the first driving device 61 transmitted to the driving shaft 61a to the driving shaft 61b. The transmission mechanism 63 is, for example, a belt drive or a chain drive.

The first interlocking mechanism 62 includes the first and second linear motion mechanisms 42, so that when the support members 26c and 26d are moved by, for example, a distance M, the support members 25c and 25e are moved by a distance of 2M, which is twice that distance. The relationship between the leads Lc1 and Lc2 of the rotating shafts 44 and 54 of 52 and the first interlocking mechanism 62 is set. For example, the lead Lc1 of the first linear motion mechanism 42 is set to twice the lead Lc2 of the second linear motion mechanism 52, and the first interlocking mechanism 62 causes the first and second linear motion mechanisms 42 and 52 to rotate at the same rotation speed. It is rotated. The distance between the measurement points Dd and Dc is made to be twice the distance from the measurement point Dd to the center of the cylinder 13c regardless of the size of the cylinder.

As shown in FIGS. 6, 7, and 9, the pair of second guide rails 29 parallel to the A2 direction are the pair of power transmission plates 70a and 70b bridged in parallel with the A1 direction in the A2 direction. It is for guiding the movement smoothly. The movement of the pair of power transmission plates 70a and 70b in the A2 direction is performed by the second interval adjusting device 71.

The second interval adjusting device 71 has a second interlocking mechanism 73 including a second driving device 72 and a pair of third linear motion mechanisms 74 and 75. The pair of third linear motion mechanisms 74 and 75 each have a pair of ball screw linear motion mechanisms 76a and 76b. The pair of ball screw linear motion mechanisms 76a and 76b each have a rotation shaft 77 in which the same lead is set and a gear 78 that rotates together with the rotation shaft 77. The rotary shaft 77 is rotatably supported by a plurality of support shaft members 79 fixed to the base member 23.

The pair of third linear motion mechanisms 74 and 75 are configured so that the pair of ball screw linear motion mechanisms 76a and 76b are driven in opposite directions via the gear 77, respectively. The corresponding power transmission plates 70a and 70b are fixed to the nut units 80a and 80b corresponding to the respective rotation shafts 77 of the pair of ball screw linear motion mechanisms 76a and 76b in a posture parallel to the A1 direction.

The second interlocking mechanism 73 is a drive shaft 81 coaxially connected to a rotation shaft 77 of the ball screw linear motion mechanism 76b of the third linear motion mechanism 74, and a ball screw linear motion mechanism 76b of the third linear motion mechanism 75. It has a drive shaft 82 coaxially connected to the rotating shaft 77, and a transmission mechanism 83 that transmits the driving force of the second drive device 72 transmitted to the drive shaft 81 to the drive shaft 82. The transmission mechanism 83 is, for example, a belt drive or a chain drive.

The pair of third linear motion mechanisms 74 and 75 are moved in the opposite directions to each other by the same distance in parallel with the A2 direction while maintaining the posture parallel to the A1 direction of the power transmission plates 70a and 70b. It is rotated at the same rotation speed by the interlocking mechanism 73.

The plurality of support members 26a to 26f support the second measurement sensors constituting the second measurement sensor pairs 22a to 22f so as to be movable in the A2 direction. For example, as shown in FIG. 10, the support member 26a has a pair of rectangular through holes 85a and 85b formed side by side in the A2 direction in the central portion in the A2 direction and a pair of through holes 85a and 85b in the A2 direction. It has a pair of slide guides 86a and 86b extending in parallel with the A2 direction on the outside. In the pair of slide guides 86a and 86b, a pair of rectangular slide plates 87a and 87b are supported so as to be slidable along the pair of slide guides 86a and 86b.

The two second measurement sensors of the second measurement sensor pair 22a are fixed to the pair of slide plates 87a and 87b in a state of being inserted into the pair of through holes 85a and 85b, respectively. Further, the pair of slide plates 87a and 87b are equipped with engaging members 88a and 88b that engage with the corresponding power transmission plates 70a and 70b in the A2 direction and do not engage in the A1 direction. The other support members 26b to 26f are the same as the support members 26a, and the description thereof will be omitted.

The second drive device 72 rotates each rotation shaft 77 of the third linear motion mechanism 74 at the same rotation speed in opposite directions, and each nut unit is symmetrically moved along the A2 direction. The other third linear motion mechanism 75 is similarly driven by the second interlocking mechanism 73. Therefore, the power transmission plates 70a and 70b are symmetrically moved in the opposite direction to each other in parallel with the A2 direction while maintaining the posture parallel to the A1 direction.

Since the slide plates 87a and 87b are engaged with the power transmission plates 70a and 70b in the A2 direction, respectively, they are symmetrically moved along the A2 direction together with the power transmission plates 70a and 70b. Therefore, the distance between the second measurement sensors of the second measurement sensor pair 21a fixed to the pair of slide plates 87a and 87b in the A2 direction is adjusted. The other second measurement sensor pairs 21b to 21f are also adjusted to have the same A2 direction spacing as the second measurement sensor pair 21a. On the other hand, since the power transmission plates 70a and 70b are not engaged in the A1 direction, the movement of the support members 26a to 26f in the A1 direction is not hindered.

By moving a plurality of support members 25a to 25c, 25e to 25g, and 26a to 26f by the first interval adjusting device 41 according to the engine model, the intervals of the first measurement sensors 21a to 21g in the A1 direction and the first interval. The distance between the two measurement sensor pairs 22a to 22f in the A1 direction can be adjusted at the same time. Further, the distance between the second measurement sensor pairs 22a to 22f in the A2 direction can be adjusted by the second distance adjustment device 71 according to the engine model. FIG. 11 shows a state in which the engine is adjusted to a larger interval by the first interval adjusting device 41 and the second interval adjusting device 71 in order to measure an engine having a cylinder diameter larger than that of FIG.

As shown in FIG. 1, the base member 23 is equipped with a plurality of leg portions 27 projecting downward so that the lower ends of the leg portions 27 are aligned at the same height. The lower ends (tips) of the plurality of first measurement sensors 21a to 21g and the plurality of second measurement sensor pairs 22a to 22f are substantially the same height as the lower ends of the plurality of legs 27, but are higher than the lower ends of the plurality of legs 27. Also extends downward.

Next, a master plate 37 for learning the measurement reference positions of the plurality of first measurement sensors 21a to 21g and the plurality of second measurement sensor pairs 22a to 22f will be described.
The master plate 37 is a flat rectangular plate. As shown in FIG. 1, the master plate 37 is mounted on the top dead center position evaluation device 1 so that it can advance between the raised measuring device 20 and the engine 10 mounted on the stage 3. For example, two arms 38 each provided with guide rails 38a for guiding the master plate 37 in the front-rear direction are fixed to the fixed frame 31. Then, the master plate 37 erected on these two arms 38 advances and retracts along the guide rail 38a by an actuator (not shown).

As shown in FIG. 12, the top dead center position evaluation device 1 having the above-mentioned interval adjustment adjusted according to the engine model has a plurality of first measurement sensors 21a to 21g and a plurality of second measurement sensor pairs 22a to 22f before measurement. The measurement reference position is learned by simultaneously contacting the lower end (tip) of the master plate 37 with the upper surface of the advanced master plate 37. Since the plurality of first measurement sensors 21a to 21g and the plurality of second measurement sensor pairs 22a to 22f measure the distance from the measurement reference position when the tip is brought into contact with the measurement target, for example, due to temperature changes, mounting errors, etc. The effect is eliminated. In addition, if the output value at the measurement reference position during the current learning is significantly different from the output value at the measurement reference position during the previous learning, or if it exceeds the preset range, foreign matter adheres or fails. It can be detected as a defect such as.

When learning the measurement reference position, the lower ends of the plurality of legs 27 of the base member 23 are brought into contact with the upper surface of the master plate 37. Further, at the time of measurement, the lower ends of the plurality of legs 27 of the base member 23 are brought into contact with the deck surface 12 of the engine 10. Thereby, the deck surface 12 can be adjusted to the measurement reference position, and the fluctuation of the position of the deck surface 12 due to the vibration when the crankshaft 11 is rotated can be measured by the plurality of first measurement sensors 21a to 21g. ..

Next, the top dead center position measurement method will be described with reference to FIG.
When the engine 10 to be evaluated is mounted on the stage 3, the engine model detection device 7 detects the engine model and outputs the engine model information to the control unit 90 (model detection process). The control unit 90 adjusts the positions of the drive device 5 and the rotation angle measurement device 6 and the position of the stage 3 to predetermined measurement positions based on the engine model information, and also adjusts the position of the measurement device 20 and the interval adjustment. (Measurement preparation process).

Next, the master plate 37 is advanced, and after learning the measurement reference positions of the plurality of first measurement sensors 21a to 21g and the plurality of second measurement sensor pairs 22a to 22f equipped in the measuring device 20, the master plate 37 is predetermined. Retreat to the standby position of (learning process).

Next, the measuring device 20 is moved so that the plurality of legs 27 come into contact with the deck surface 11. Further, the plurality of first measurement sensors 21a to 21f and the plurality of second measurement sensor pairs 22a to 22f are moved so as to correspond to the measurement points Da to Dg at the deck surface position and the measurement points Ta1 to Tf2 at the top surface position. Then, in a state where the crankshaft 11 is rotated at a predetermined rotation speed (for example, 40 rpm) by the drive device 5, the decks of measurement points Da to Dg corresponding to the rotation angle of the crankshaft 11 measured by the rotation angle measuring device 6 The surface position and the top surface position of the measurement points Ta1 to Tf2 are measured by a plurality of first measurement sensors 21a to 21g and a plurality of second measurement sensor pairs 22a to 22f (measurement step).

At this time, since the piston 14a reciprocates up and down, the inertial force IF acts upward near the top dead center. As shown in FIG. 14, a connecting portion in which the piston 14a and the connecting rod 16a are connected by a piston pin 15a by an inertial force IF, a connecting portion between the connecting rod 16a and the crankpin 17a of the crankshaft 11, and a shaft of the crankshaft 11 The top surface of the piston 14a rises by the amount of CL corresponding to the clearance at the connecting portion between the (crank journal 18) and the crankcase bearing 19. Since the other pistons 14b to 14f are the same, the position of the top surface when the engine is driven is reproduced.

Further, as the rotation speed is increased, the position of the top surface rises due to the inertial force IF. The top surface rise distance becomes constant even if the rotation speed is increased. On the other hand, as the rotation speed is increased, as shown by the curve Tr, the followability of the second measurement sensor (contact type linear sensor) to the top surface of the piston 14a that moves up and down decreases. .. If the rotation speed is too high, the contact-type linear sensor cannot follow the top surface of the piston 14a and cannot measure correctly. Therefore, for example, 40 rpm is set as a predetermined rotation speed that can be increased by CL by the amount corresponding to the clearance and can be measured correctly.

The control unit 90 receives each measurement value in the measurement process, and the arithmetic unit 91 receives the top dead center of each piston 14a to 14f and the rotation angle of the crankshaft 11 corresponding to this top dead center, that is, the rotation angles of the pistons 14a to 14f. The top dead center position is calculated (evaluated) (evaluation process). For example, the position of the top surface of the piston 14a is the average of the measured values of the two measurement points Da and Db on the outer side of the cylinder 13a on which the piston 14a moves up and down from the average value of the two measured values of the measurement points T1a and T2a of the piston 14a. Calculated by subtracting the value. As a result, it is possible to eliminate the deviation of the deck surface position from the measurement reference position due to the vibration of the engine 10 included in the top surface position of the piston 14a.

Then, as shown in FIG. 16, the top surface position of the piston 14a is calculated for each rotation angle (every 0.1 degree) by the rotation angle measuring device 6, and is near the rotation angle of the mechanical top dead point (TDC). An approximate curve TL (quadratic curve) of the top surface position with respect to the rotation angle is obtained. Since the apex of the obtained approximate curve TL becomes the actual top dead center of the piston 14a, the rotation angle θmax corresponding to the position of the top surface which becomes the top dead center is calculated. For the other pistons 14b to 14f, the rotation angle θmax corresponding to the top dead center is calculated in the same manner as for the pistons 14a.

It is also possible to detect defects by determining whether or not the rotation angle θmax corresponding to the calculated top dead center is within a predetermined reference angle range, for example. Each rotation angle θmax of the crankshaft 11 corresponding to the top dead center of each piston 14a to 14f evaluated in the evaluation step is recorded as information on the unique top dead center position of the engine 10. It is also possible to make the evaluated top dead center position correspond to the output value of a crank angle sensor (not shown) mounted on the engine 10.

Next, the operation and effect of the top dead center position evaluation device 1 according to the above embodiment will be described.
The top dead center position evaluation device 1 adjusts the distance between the plurality of first measurement sensors 21a to 21g and the plurality of second measurement sensor pairs 22a to 22f in the A1 direction and the distance in the A2 direction according to the engine model to be measured. .. Therefore, the top dead center position evaluation device 1 can be made compatible with various engine models.

Further, while rotating the crankshaft 11 of the engine 10 at a predetermined speed by the drive device 5, the rotation angle of the crankshaft 11 and the top surface positions of the plurality of pistons 13a to 13f connected to the crankshaft 11 are measured, and each of them is measured. The rotation angle corresponding to the top dead center of the pistons 13a to 13f is evaluated. Therefore, the top dead center position can be evaluated by reproducing the top surface positions of the pistons 13a to 13f when the engine 10 is driven.

At the time of measurement, the positions of the plurality of deck surfaces at the measurement points Da to Dg outside the cylinders 14a to 14f along the cylinder row are measured by the plurality of first measurement sensors 21a to 21g, and the pistons 13a to 13f are measured. The top surface position is measured by a plurality of second measurement sensor pairs 22a to 22f. Therefore, the influence of the vibration of the engine 10 due to the rotation of the crankshaft 11 and the reciprocating movement of the pistons 13a to 13f can be eliminated, and the top surface position can be accurately measured.

Moreover, at the time of evaluation, the rotation angle, the top surface position, and the rotation angle corresponding to the accurate top dead center based on the plurality of deck surface positions are evaluated for each piston 13a to 13f, so that each piston 13a to 13a is accurate. The rotation angle corresponding to the top dead center of 13f, that is, the top dead center position can be accurately evaluated.

At the time of measurement, a plurality of deck surface positions on the outside of each cylinder 14a to 14f are measured by a plurality of first measurement sensors 21a to 21g along the cylinder row, and the top surface positions of the pistons 13a to 13f are measured by a plurality of second. Since the measurement is performed by the measurement sensor pairs 22a to 22f, the influence of the vibration of the engine 10 due to the rotation of the crankshaft 11 and the reciprocating movement of the pistons 13a to 13f can be eliminated, and the top surface position can be measured correctly.

At the time of evaluation, the rotation angle corresponding to the top dead center is evaluated for each piston 13a to 13f based on the rotation angle, the top surface position, and the plurality of deck surface positions. Therefore, the top dead center position of each piston 13a to 13f is evaluated. It can be evaluated accurately.

The first interval adjusting device 41 is symmetrical from the center of the row to the center of the row of the plurality of first measuring sensors 21a to 21g in the A1 direction so that the distances of the plurality of first measuring sensors 21a to 21g in the A1 direction are equal. The farther the first measurement sensor is, the larger it is moved. At the same time, the second interval adjusting device 71 sets the plurality of second measurement sensor pairs 22a to 22f in the A2 direction with respect to the center line C1 so that the intervals in the A1 direction of the plurality of second measurement sensor pairs 22a to 22f are equal. Move symmetrically and equally. Therefore, it is not necessary to individually specify the positions of the plurality of first measurement sensors 21a to 21g and the plurality of second measurement sensor pairs 22a to 22f, and it is possible to easily correspond to various engine models.

The first interval adjusting device 41 moves the first linear motion mechanism 42 that moves the plurality of first measurement sensors 21a to 21g symmetrically in the A1 direction, and the plurality of second measurement sensor pairs 22a to 22f symmetrically in the A1 direction. It has a second linear motion mechanism 52. The first linear motion mechanism 42 and the second linear motion mechanism 52, which are arranged parallel to the A1 direction, are interlocked and driven by the first interlocking mechanism 62 provided with the first drive device 61. Therefore, by driving the first drive device 61, the plurality of first measurement sensors 21a to 21g and the plurality of second measurement sensor pairs 22a to 22f can be simultaneously and symmetrically moved in the A1 direction, and various engine models can be easily configured. Can be made to correspond to.

The first linear motion mechanism 42 has two ball screw linear motion mechanisms 43a and 43b including a rotary shaft 44 in which a plurality of screw shafts having different leads are coaxially connected, and the two ball screw linear motion mechanisms 43a. , 43b are configured to be driven in opposite directions via the gear 45. Further, the second linear motion mechanism 52 has two ball screw linear motion mechanisms 53a and 53b having a rotary shaft 54 in which a plurality of screw shafts having different leads are coaxially connected, and the two ball screw linear motion mechanisms 52. The mechanism is configured to drive in opposite directions via the gear 55. Therefore, by driving the first drive device 42, the plurality of first measurement sensors 21a to 21g and the plurality of second measurement sensor pairs 22a to 22f can be simultaneously and symmetrically moved in the A1 direction, and various engine models can be easily configured. Can be made to correspond to.

The rotation shaft 44 of the first linear motion mechanism 42 is set so that the lead is gradually multiplied by an integral multiple in the direction away from the gear 44 with respect to the lead on the gear 45 side portion. Further, the rotating shaft 54 of the second linear motion mechanism 52 is set so that the lead is gradually increased to an odd number in the direction away from the gear 55 with respect to the lead of the gear 55 side portion. Therefore, the intervals of the plurality of first measurement sensors 21a to 21g in the A1 direction are adjusted while being equal, and the intervals of the plurality of second measurement sensor pairs 22a to 22f are adjusted while being equal to each other in the A1 direction. It can be configured to support various engine models.

The second interval adjusting device 71 has a pair of third linear motion mechanisms 74 and 75 arranged in parallel in the A2 direction, and a second interlocking mechanism 73 including a second driving device 72. Then, a plurality of second measurement sensors in which the plurality of second measurement sensor pairs 22a to 22f are arranged side by side and arranged in two rows are interlocked and driven so as to move symmetrically with respect to the center line C1 in the A2 direction. Therefore, with a simple configuration, the plurality of second measurement sensor pairs 22a to 22f can be simultaneously moved symmetrically in the A2 direction by driving the second drive device 71, and can be made compatible with various engine models.

The second measurement sensor constituting the first measurement sensor 21a to 21g and the second measurement sensor pair 22a to 22f is a contact type linear sensor. Since the contact type linear sensor is used, the top surface position of each piston 14a to 14f can be accurately measured and the top dead center position can be accurately evaluated even if the pistons 14a to 14f are tilted.

The plurality of first measurement sensors 21a to 21g and the plurality of second measurement sensor pairs 22a to 22f are provided in a state of protruding downward from the base member 23 in which the first interval adjustment device 41 and the second interval adjustment device 71 are arranged. Has been done. The base member 23 has a plurality of legs 27 protruding downward to abut the master plate 37 when learning the measurement reference position, and a plurality of legs 27 abut the deck surface 12 during the measurement. Therefore, since the lower end of the leg portion 27, which is the measurement reference position, is brought into contact with the deck surface 12 for measurement, the occurrence of measurement error can be suppressed.

In the above embodiment, the in-line 6-cylinder engine has been described as an example, but the top dead point position is similarly evaluated in, for example, an in-line 4-cylinder engine, an in-line 3-cylinder engine, and a single-cylinder engine having a smaller number of cylinders. Can be done. In this case, the evaluation is performed without using the output values of the plurality of first and second measurement sensors that do not have the corresponding measurement points. Further, a number of measurement sensors corresponding to the number of cylinders of the engine may be equipped. In addition, a person skilled in the art can carry out the embodiment in a form in which various modifications are added to the above embodiment without deviating from the gist of the present invention, and the present invention also includes such modified forms.

1: Top dead point position evaluation device 3: Stage 5: Drive device 6: Rotation angle measurement device 7: Engine model detection device 10: Engine 11: Crank shaft 12: Deck surface 13a to 13f: Cylinder 14a to 14f: Piston 15a: Piston pin 16a: Connecting rod 17a: Crank pin 18a: Crank journal 20: Measuring device 21a to 21g: First measuring sensor 22a to 22f: Second measuring sensor pair 23: Base member 24: Opening 25a to 25c, 25e to 25f, 26a to 26f: Support member 27: Leg 30: Support frame 31: Fixed frame 32: Left / right movement frame 33: Front / rear movement frame 34: Up / down movement frame 37: Master plate 41: First interval adjusting device 42: First linear motion Mechanisms 43a, 43b: Ball screw linear motion mechanism 44: Rotating shaft 44a: Connecting member 45: Gear 46: Support shaft member 47a to 47c: Nut unit 52: Second linear motion mechanism 53a, 53b: Ball screw linear motion mechanism 54: Rotating shaft 54a: Connecting member 55: Gear 56: Supporting shaft member 57a to 57c: Nut unit 61: First drive device 61a, 61b: Drive shaft 62: First interlocking mechanism 63: Transmission mechanism 70a, 70b: Power transmission plate 71 : Second interval adjusting device 72: Second driving device 73: Second interlocking mechanism 74, 75: Third linear motion mechanism 76a, 76b: Ball screw linear motion mechanism 77: Rotating shaft 78: Gear 79: Support shaft member 80a, 80b nut units 81, 82: drive shaft 83: transmission mechanism 85a, 85b: through holes 86a, 86b: slide guides 87a, 87b: slide plates 88a, 88b: engaging members 90: control unit 91: arithmetic unit C1: center line

Claims (8)

A drive device for rotating the crankshaft of the engine at a predetermined speed and a rotation angle measuring device for measuring the rotation angle of the crankshaft are provided, and the piston connected to the crankshaft while rotating the crankshaft at a predetermined speed is provided. In the top dead point position evaluation device that evaluates the rotation angle corresponding to the top dead point,
A plurality of first deck surfaces of a cylinder block arranged in a row to measure the positions of a plurality of deck surfaces outside the cylinder along the center line of the cylinder in the first direction along the axis of the crankshaft. 1 measurement sensor and
2 in parallel with the first direction in order to measure the positions of a plurality of top surfaces of the piston that reciprocate in the cylinder and separated in a second direction orthogonal to the first direction of the piston. Multiple second measurement sensors arranged in a row,
A model detection device that detects the engine model and
A first interval adjusting device that adjusts the intervals of the plurality of first measurement sensors and the plurality of second measurement sensors in the first direction according to the engine model, and
A second interval adjusting device that adjusts the interval of the plurality of second measurement sensors in the second direction according to the engine model, and
A top dead center position evaluation device comprising a calculation device for calculating the top dead center position of the piston based on the rotation angle, the top surface position, and the plurality of deck surface positions. The first interval adjusting device includes the plurality of first measurement sensors so that the intervals in the first direction of the plurality of first measurement sensors are equal to each other and the intervals of the plurality of second measurement sensors in the first direction are equal to each other. The first and second measurement sensors, which are symmetrically symmetric in the first direction from the center of the row of the first measurement sensor and the center of the row of the plurality of second measurement sensors and farther from the center of the row, are moved larger.
The first aspect of claim 1, wherein the second interval adjusting device moves the plurality of second measurement sensors arranged in two rows symmetrically and equally in the second direction with respect to the center line. Dead center position evaluation device. The first interval adjusting device includes a first linear motion mechanism that moves the plurality of first measurement sensors symmetrically in the first direction, and a first linear motion mechanism that moves the plurality of second measurement sensors symmetrically in the first direction. The first linear motion mechanism and the second linear motion mechanism, which have two linear motion mechanisms and are arranged in parallel with the first direction, are interlocked and driven by a first interlocking mechanism provided with a first drive device. The top dead point position evaluation device according to claim 2, wherein the top blind point position evaluation device is characterized. Each of the first linear motion mechanism and the second linear motion mechanism has two ball screw linear motion mechanisms having a rotary shaft in which a plurality of screw shafts having different leads are coaxially connected, and two ball screws. The top dead point position evaluation device according to claim 3, wherein the linear motion mechanism is configured to drive in opposite directions via gears. The rotation shaft of the first linear motion mechanism is set so that the lead is gradually multiplied by an integral multiple in the direction away from the gear with respect to the lead of the gear side portion, and the rotation shaft of the second linear motion mechanism. The top dead center position evaluation device according to claim 4, wherein the lead is set so as to be an odd multiple stepwise in a direction away from the gear with respect to the lead of the gear side portion. The second interval adjusting device has a pair of third linear motion mechanisms arranged in parallel in the second direction and a second interlocking mechanism provided with a second driving device, and is arranged in two rows. The top dead point position evaluation device according to claim 2, wherein the plurality of second measurement sensors are interlocked and driven so as to move symmetrically with respect to the center line in the second direction. The first measurement sensor and the second measurement sensor are contact-type linear sensors, and are characterized by having a master plate for learning the measurement reference positions of the first measurement sensor and the second measurement sensor before measurement. The top dead center position evaluation device according to any one of claims 1 to 6. The plurality of first measurement sensors and the plurality of second measurement sensors are equipped so as to project downward from a base member in which the first interval adjustment device and the second interval adjustment device are arranged.
The base member has a plurality of legs protruding downward in order to bring them into contact with the master plate when learning the measurement reference position, and the plurality of legs are brought into contact with the deck surface during measurement. The top dead center position evaluation device according to claim 7.

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