JP2018080994A - Crank shaft shape measuring machine, and crank shaft shape measuring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crank shaft shape measuring machine and crank shaft shape measuring method that can highly accurately measure an outer shape of each counterweight of a material crank shaft.SOLUTION: A crank shaft shape measuring machine 100 comprises: first and second chunk devices 10 and 20 that clamp either end part of a material crank shaft 1; a non-contact displacement meter 40 that measures an outer shape of the material crank shaft 1; and a control unit 50 that controls the non-contact displacement meter 40. The control unit has: a deviation-amount calculation unit; a correction-amount calculation unit; an NC program amendment unit; and a non-contact displacement meter control unit. The deviation-amount calculation unit is configured to: calculate an amount of deviation β in a longitudinal direction of the material crank shaft between an actual center and a design center in the longitudinal direction thereof, and the correction-amount calculation unit is configured to calculate an amount of correction γ of a measurement position of the non-contact displacement meter as to each of counterweights CW1 to CW8 on the basis of the amount of deviation β. The NC program amendment unit is configured to amend an NC program on the basis of the amount of correction γ.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a crankshaft shape measuring machine and a crankshaft shape measuring method.

  Since the crankshaft is used by being incorporated in an engine, if there is a rotational unbalance amount, problems such as vibrations occur during engine rotation. For this reason, it is necessary to suppress the amount of unbalanced rotation of the crankshaft.

  In order to reduce the amount of unbalanced rotation of the crankshaft, a center line that is optimally balanced in the finished product state in the state of the material crankshaft before processing is calculated, and the center that is the processing reference for the material crankshaft is calculated on the calculated centerline. It is important to form a hole.

  Here, the center line of the crankshaft is determined based on shape data indicating the outer shape of each counterweight in the material crankshaft (see Patent Document 1). The outer shape of each counterweight is acquired by a non-contact displacement meter.

International Publication No. 2009/016988

  Since the measurement position of the non-contact displacement meter in the longitudinal direction is determined by the NC program, if the longitudinal position of each counterweight is deviated for each material crankshaft, the measurement position of the non-contact displacement meter is deviated. The outer shape of each counterweight cannot be measured with high accuracy.

  The present invention has been made in view of the above situation, and an object of the present invention is to provide a crankshaft shape measuring machine and a crankshaft shape measuring method capable of accurately measuring the outer shape of each counterweight in a material crankshaft. And

  A crankshaft shape measuring machine according to the present invention includes a pair of chuck devices that grip both ends of a material crankshaft having a plurality of counterweights, a noncontact displacement meter that measures the outer shape of the material crankshaft, and a noncontact displacement And a control unit for controlling the meter. The control unit includes a deviation amount calculation unit, a correction amount calculation unit, an NC program correction unit, and a non-contact displacement meter control unit. The deviation amount calculation unit calculates the deviation amount in the longitudinal direction between the actual center in the longitudinal direction of the material crankshaft gripped by the pair of chuck devices and the design center in the longitudinal direction on the design data of the material crankshaft. The correction amount calculation unit calculates the correction amount of the measurement position of the non-contact displacement meter for each of the plurality of counter weights based on the calculated deviation amount. The NC program correcting unit corrects the NC program for controlling the operation of the non-contact displacement meter based on the calculated correction amount. The non-contact displacement meter control unit controls the operation of the non-contact displacement meter so as to measure the outer shape of each of the plurality of counterweights in the material crankshaft based on the modified NC program.

  ADVANTAGE OF THE INVENTION According to this invention, the crankshaft shape measuring machine and crankshaft shape measuring method which can measure the external shape of each counterweight among raw material crankshafts accurately can be provided.

External perspective view of material crankshaft 1 The side view which shows the structure of the crankshaft shape measuring machine which concerns on 1st Embodiment. The front view of the 1st chuck device concerning a 1st embodiment. The block diagram which shows the structure of the control part which concerns on 1st Embodiment. The flowchart for demonstrating the crankshaft shape measurement operation | movement by the control part which concerns on 1st Embodiment. The schematic diagram which shows the external shape of the raw material crankshaft which concerns on 1st Embodiment The schematic diagram which shows the external shape of the 1st thru | or 4th area | region which concerns on 1st Embodiment. Part of the operating conditions of the non-contact displacement meter defined in the NC program according to the first embodiment The block diagram which shows the structure of the control part which concerns on 2nd Embodiment. The flowchart for demonstrating the crankshaft shape measurement operation | movement by the control part which concerns on 2nd Embodiment. The schematic diagram for demonstrating the measuring method of the external shape of the raw material crankshaft and 1st and 2nd chuck apparatus which concern on 2nd Embodiment. The schematic diagram which shows the external shape of the raw material crankshaft 1 which concerns on 2nd Embodiment, and the 1st and 2nd chuck devices 10 and 20. FIG. The schematic diagram which shows the external shape of the 1st thru | or 4th area | region and 1st and 2nd chuck | zipper apparatus which concern on 2nd Embodiment.

1. First embodiment (Material crankshaft 1)
First, the material crankshaft 1 (hereinafter referred to as “material crankshaft 1”) that is a measurement target of the crankshaft shape measuring machine 100 according to the first embodiment will be described. In the following, the material crankshaft 1 for an in-line four-cylinder engine will be described, but the engine type to be used is not limited to this.

  FIG. 1 is an external perspective view of the material crankshaft 1.

  The material crankshaft 1 includes a main journal J (J1 to J5), a pin journal P (P1 to P4), and a counterweight CW (CW1 to CW8). In the material crankshaft 1, the main journal J1, the counter weight CW1, the pin journal P1, the counter weight CW2, the main journal J2, the counter weight CW3, the pin journal P2, the counter weight CW4, the main journal J3 in the longitudinal direction (Z-axis direction). The counter weight CW5, the pin journal P3, the counter weight CW6, the main journal J4, the counter weight CW7, the pin journal P4, the counter weight CW8, and the main journal J5 are arranged in this order.

  The material crankshaft 1 is manufactured, for example, by casting using a mold or by forging using a forging die. In such a material crankshaft 1, the positions of the counterweights CW1 to CW8 in the longitudinal direction are slightly shifted for each material crankshaft 1. Therefore, as will be described later, in the crankshaft shape measuring machine 100 according to the first embodiment, the positions for measuring the outer shapes of the counterweights CW1 to CW8 are corrected for each material crankshaft 1.

(Crankshaft shape measuring machine 100)
FIG. 2 is a side view showing the configuration of the crankshaft shape measuring machine 100 according to the first embodiment. FIG. 3 is a front view of the first chuck device 10.

  The crankshaft shape measuring machine 100 includes a first chuck device 10, a second chuck device 20, a longitudinal clamp device 30, a phase clamp device 35, a non-contact displacement meter 40 and a control unit 50.

  The first chuck device 10 and the second chuck device 20 grip both ends of the material crankshaft 1.

  The first chuck device 10 includes a first main body portion 11, a pair of first receiving portions 12, and a first rotating chuck portion 13. The 1st main-body part 11 can rotate centering | focusing on the central axis CL. The pair of first receiving portions 12 and the first rotating chuck portion 13 are attached to the first main body portion 11. When the material crankshaft 1 is input from a loader (not shown), the main journal J1 of the material crankshaft 1 is disposed on the pair of first receiving portions 12. The pair of first receiving portions 12 supports the main journal J1 from below. The first rotating chuck portion 13 is rotatable around an axis AX that is parallel to the central axis CL. The rotation operation of the first rotary chuck unit 13 is controlled by the control unit 50 described later. The first rotating chuck portion 13 includes the main journal J1 after the material crankshaft 1 is disposed on the pair of first receiving portions 12 and the material crankshaft 1 is positioned by a longitudinal clamp device 30 and a phase clamp device 35 described later. Is chucked from above. As a result, one end of the material crankshaft 1 is gripped by the first chuck device 10.

  The second chuck device 20 includes a second main body portion 21, a pair of second receiving portions 22, and a second rotating chuck portion 23. The pair of second receiving portions 22 and the second rotating chuck portion 23 are attached to the second main body portion 21. When the material crankshaft 1 is loaded from the loader, the main journal J5 of the material crankshaft 1 is disposed on the pair of second receiving portions 22. The pair of second receiving portions 22 supports the main journal J5 from below. The second rotary chuck portion 23 can rotate around an axis (not shown) parallel to the central axis CL. The rotation operation of the second rotary chuck unit 23 is controlled by the control unit 50. The second rotating chuck portion 23 has the material crankshaft 1 disposed on the pair of second receiving portions 22, and after the material crankshaft 1 is positioned by the longitudinal clamp device 30 and the phase clamp device 35, the main journal J5 is moved upward. Chuck from. As a result, the other end of the material crankshaft 1 is gripped by the second chuck device 20.

  The longitudinal clamp device 30 determines a position in the longitudinal direction of the material crankshaft 1 (hereinafter referred to as “longitudinal position”). The longitudinal clamp device 30 includes a first clamper 31, a second clamper 32, and a base portion 33. The first clamper 31 and the second clamper 32 are supported by the base 33 so as to be movable in the longitudinal direction. When the material crankshaft 1 is disposed on the pair of first receiving portions 12 and the pair of second receiving portions 22, the first clamper 31 is brought into contact with the counterweight CW4 and the second clamper 32 is set to the counterweight CW5. Abut. The clamping operation of the first clamper 31 and the second clamper 32 is controlled by the control unit 50.

  The phase clamp device 35 determines the position of the material crankshaft 1 in the circumferential direction around the central axis CL (hereinafter referred to as “phase position”). The phase clamp device 35 is provided so as to be movable in a radial direction perpendicular to the longitudinal direction. In the present embodiment, the phase position of the material crankshaft 1 is determined by the phase clamp device 35 coming into contact with the pin journal P4.

  The non-contact displacement meter 40 measures the outer shape of the material crankshaft 1. As the non-contact displacement meter 40, for example, a laser displacement meter, an infrared displacement meter, an LED displacement sensor, or the like is used. The non-contact displacement meter 40 is attached to a rail 41 arranged along the central axis CL. The non-contact displacement meter 40 can move left and right along the longitudinal direction. The measurement operation of the non-contact displacement meter 40 is controlled by the control unit 50.

  The control unit 50 controls the operations of the first chuck device 10, the second chuck device 20, the longitudinal clamp device 30, the phase clamp device 35, and the non-contact displacement meter 40.

  FIG. 4 is a block diagram illustrating a configuration of the control unit 50. FIG. 5 is a flowchart for explaining the crankshaft shape measurement operation by the control unit 50. The control unit 50 includes a longitudinal clamp control unit 51a, a phase clamp control unit 51b, a chuck control unit 52, a non-contact displacement meter control unit 53, a deviation amount calculation unit 54, a correction amount calculation unit 55, and an NC program modification unit 56. Hereinafter, the function of the control unit 50 will be described with reference to the flowchart of FIG.

  In step S1, when the material crankshaft 1 is inserted, the phase clamp control unit 51b positions the material crankshaft 1 in the circumferential direction (phase clamp) by the phase clamp device 35.

  In step S <b> 2, the longitudinal clamp control unit 51 a positions the material crankshaft 1 in the longitudinal direction (longitudinal clamp) by the longitudinal clamp device 30. At this time, the first clamper 31 is brought into contact with the counterweight CW4 and the second clamper 32 is brought into contact with the counterweight CW5.

  In step S <b> 3, the chuck control unit 52 grips both ends of the material crankshaft 1 with the first chuck device 10 and the second chuck device 20.

  In step S4, the longitudinal clamp controller 51a retracts the longitudinal clamp device 30 (longitudinal unclamping).

  In step S5, the phase clamp control unit 51b retracts (phase unclamps) the phase clamp device 35.

  In step S <b> 6, the chuck controller 52 moves the non-contact displacement meter 40 in the longitudinal direction while appropriately rotating the material crankshaft 1. Thereby, measurement data indicating the outer shape over the entire length of the material crankshaft 1 is acquired. FIG. 6 is a schematic diagram showing the outer shape of the material crankshaft 1.

  In step S7, as shown in FIG. 6, the deviation amount calculation unit 54 has the X coordinate value in the radial direction perpendicular to the longitudinal direction of the measurement data indicating the outer shape over the entire length of the material crankshaft 1 equal to or greater than the threshold value TH. The measurement data indicating the outer shape of the first to fourth regions R1 to R4 is acquired by extracting the measurement data. The first area R1 includes a counter weight CW1, a pin journal P1, and a counter weight CW2. The second area R2 includes a counter weight CW3, a pin journal P2, and a counter weight CW4. The third region R3 includes a counter weight CW5, a pin journal P3, and a counter weight CW6. The fourth area R4 includes a counter weight CW7, a pin journal P4, and a counter weight CW8. FIG. 7 is a schematic diagram showing the outer shape of the first to fourth regions R1 to R4. In FIG. 7, the design shape which is the external shape on the design data of the first to fourth regions R1 to R4 is shown by a solid line.

  In step S <b> 8, the shift amount calculation unit 54 performs the best fit of the outer shape to the design shape for each of the first to fourth regions R <b> 1 to R <b> 4, so that the profile in the longitudinal direction of each of the first to fourth regions R <b> 1 to R <b> 4. Get the error α. To best fit the outer shape to the design shape, move the outer shape of each of the first to fourth regions R1 to R4 in the vertical and horizontal directions, and correspond to the coordinates after the movement and the coordinates. A method (so-called least square method) for detecting a position where the sum of the square errors of the Z-axis coordinate values with the coordinates of the design shape to be minimized can be used. In the table of FIG. 7, the profile error α is exemplified with the first chuck device 10 side being plus (+) and the second chuck device 20 side being minus (−).

  In step S9, the deviation amount calculation unit 54 determines the actual center Rc in the longitudinal direction of the material crankshaft 1 based on the outer shapes of the second region R2 and the third region R3 with which the longitudinal clamping device 30 is in contact in step S1. And “deviation amount β” in the longitudinal direction with respect to the design center Dc in the longitudinal direction on the design data of the material crankshaft 1 is calculated. Specifically, the shift amount β is an arithmetic average value of the profile error α of the second region R2 and the profile error α of the third region R3. In the table of FIG. 7, since the profile error α of the second region R2 is −0.2 and the profile error α of the third region R3 is +0.3, the shift amount β is +0.05. The actual center Rc of the material crankshaft 1 is a mechanical center in the longitudinal direction of the material crankshaft 1 in a state where both ends are gripped by the first chuck device 10 and the second chuck device 20.

  In step S10, the correction amount calculation unit 55 calculates the correction amount γ of the measurement position of the non-contact displacement meter 40 for each of the first to fourth regions R1 to R4 based on the calculated shift amount β. Specifically, the correction amount γ is a value obtained by subtracting the shift amount β from the profile error α of each of the first to fourth regions R1 to R4. In the table of FIG. 7, the correction amount γ in each of the first to fourth regions R1 to R4 is shown with the first chuck device 10 side being plus (+) and the second chuck device 20 side being minus (−). Yes.

  In step S11, the NC program correcting unit 56 corrects the NC program for controlling the operation of the non-contact displacement meter 40 based on the calculated correction amount γ. FIG. 8 shows part of the operating conditions of the non-contact displacement meter 40 defined in the NC program. The NC program correcting unit 56 designates the correction amount γ of the first region R1 in (# 101) shown in FIG. 8 to thereby perform non-contact displacement in each of the counter weight CW1 and the counter weight CW2 included in the first region R1. A total of 40 measurement positions are corrected. Similarly, the NC program correcting unit 56 specifies the correction amount γ of each of the second to fourth regions R2 to R4 to a predetermined position in the NC program, thereby measuring the non-contact displacement meter 40 with the counterweights CW3 to CW8. The position is corrected.

  In step S12, the non-contact displacement meter control unit 53 controls the non-contact displacement meter 40 to measure the outer shapes of the counterweights CW1 to CW8 in the material crankshaft 1 based on the modified NC program. At this time, since the measurement position in the longitudinal direction of the non-contact displacement meter 40 is corrected for each counterweight CW, the outer shape of each of the counterweights CW1 to CW8 is accurately measured.

2. Second Embodiment Next, a crankshaft shape measuring machine 101 according to a second embodiment will be described. The difference from the crankshaft shape measuring machine 100 according to the first embodiment is a method of calculating the “deviation amount β” between the actual center Rc and the design center Dc. In the following, differences from the first embodiment will be mainly described.

  FIG. 9 is a block diagram illustrating a configuration of the control unit 50. FIG. 10 is a flowchart for explaining the crankshaft shape measurement operation by the control unit 50. The control unit 50 includes a longitudinal clamp control unit 51a, a phase clamp control unit 51b, a chuck control unit 52, a non-contact displacement meter control unit 53, a deviation amount calculation unit 54, a correction amount calculation unit 55, and an NC program modification unit 56. Hereinafter, the function of the control unit 50 will be described with reference to the flowchart of FIG.

  In step S21, when the material crankshaft 1 is inserted, the phase clamp control unit 51b positions the material crankshaft 1 in the circumferential direction by the phase clamp device 35.

  In step S <b> 22, the longitudinal clamp controller 51 a positions the material crankshaft 1 in the longitudinal direction by the longitudinal clamp device 30. At this time, the first clamper 31 is brought into contact with the counterweight CW4 and the second clamper 32 is brought into contact with the counterweight CW5.

  In step S <b> 23, the chuck control unit 52 grips both end portions of the material crankshaft 1 with the first chuck device 10 and the second chuck device 20.

  In step S24, the longitudinal clamp controller 51a retracts the longitudinal clamp device 30.

  In step S25, the phase clamp controller 51b retracts the phase clamp device 35.

  In step S26, as shown in FIG. 11, the chuck controller 52 rotates the material crankshaft 1 as appropriate, and the non-contact displacement meter controller 53 moves the non-contact displacement meter 40 in the longitudinal direction. Thereby, measurement data indicating the outer shape over the entire length of the material crankshaft 1 and the outer shapes of the first and second chuck devices 10 and 20 are acquired. FIG. 12 is a schematic diagram showing the outer shape of the material crankshaft 1 and the first and second chuck devices 10 and 20.

  In step S <b> 27, the deviation amount calculation unit 54 extracts measurement data having an X coordinate value equal to or greater than a threshold value TH from measurement data indicating the outer shapes of the material crankshaft 1 and the first and second chuck devices 10 and 20. Thus, measurement data indicating the outer shape of the first to fourth regions R1 to R4 and the outer shapes of the first and second chuck devices 10 and 20 are acquired. FIG. 13 is a schematic diagram showing the outer shapes of the first to fourth regions R1 to R4 and the outer shapes of the first and second chuck devices 10 and 20, respectively. In FIG. 13, the design shape that is the outer shape of the design data of the first to fourth regions R1 to R4 and the first and second chuck devices 10 and 20 is shown by a solid line.

  In step S <b> 28, the shift amount calculation unit 54 performs the best fit of the outer shape to the design shape for each of the first to fourth regions R <b> 1 to R <b> 4, thereby creating a profile in the longitudinal direction of each of the first to fourth regions R <b> 1 to R <b> 4. Get the error α.

  In step S <b> 29, the deviation amount calculation unit 54 makes the outer shape of each of the first and second chuck devices 10, 20 best fit the design shape to the longitudinal direction of each of the first and second chuck devices 10, 20. Is obtained.

  In step S <b> 30, the deviation amount calculation unit 54 determines the actual center Rc in the longitudinal direction of the material crankshaft 1 and the design data of the material crankshaft 1 based on the outer shapes of the first and second chuck devices 10 and 20. The “deviation amount β” in the longitudinal direction from the design center Dc in the longitudinal direction is calculated. Specifically, the shift amount β is an arithmetic average value of the profile error α of the first chuck device 10 and the profile error α of the second chuck device 20. In the table of FIG. 13, since the profile error α of the first chuck device 10 is +0.1 and the profile error α of the second chuck device 20 is −0.3, the shift amount β is −0.1.

  In step S31, the correction amount calculation unit 55 calculates the correction amount γ of the measurement position of the non-contact displacement meter 40 for each of the first to fourth regions R1 to R4 based on the calculated shift amount β. Specifically, the correction amount γ is a value obtained by subtracting the shift amount β from the profile error α of each of the first to fourth regions R1 to R4.

  In step S32, the NC program correcting unit 56 corrects the NC program for controlling the operation of the non-contact displacement meter 40 based on the calculated correction amount γ (see FIG. 7).

  In step S33, the non-contact displacement meter controller 53 controls the non-contact displacement meter 40 to measure the outer shapes of the counterweights CW1 to CW8 in the material crankshaft 1 based on the modified NC program. At this time, since the measurement position in the longitudinal direction of the non-contact displacement meter 40 is corrected for each counterweight CW, the outer shape of each of the counterweights CW1 to CW8 is accurately measured.

(Other embodiments)
In the first and second embodiments, the crankshaft shape measuring machine 100 includes the rotary chuck type first chuck device 10 and the second chuck device 20, but instead of these, an automatic centering type chuck. An apparatus may be provided.

  Although not particularly mentioned in the first and second embodiments, at least one of the first chuck device 10 and the second chuck device 20 may be movable in the longitudinal direction. In this case, it becomes possible to deal with the material crankshaft 1 of various lengths.

  In the first and second embodiments, the profile error α in the longitudinal direction of each of the first to fourth regions R1 to R4 is obtained by best fitting the outer shape of the first to fourth regions R1 to R4 to the design shape. However, instead of the first to fourth regions R1 to R4, the outer shapes of the counterweights CW1 to CW8 may be best fit to the design shape. However, as in the first to fourth regions R1 to R4, it is possible to achieve a best fit with accuracy by using a region including a flat pin journal as one unit.

  In the second embodiment, the crankshaft shape measuring machine 100 may not include the longitudinal clamp device 30. In this case, it is possible to prevent the actual center Rc from being displaced due to wear of the longitudinal clamp device 30, so that the outer shapes of the counterweights CW1 to CW8 can be measured with higher accuracy.

  In the second embodiment, the crankshaft shape measuring machine 100 may not include the phase clamp device 35. In this case, since the number of constituent members can be reduced, the configuration of the crankshaft shape measuring machine 100 can be further simplified.

1 material crankshaft 10 first chuck device 20 second chuck device 30 longitudinal clamp device 35 phase clamp device 40 non-contact displacement meter 50 control unit 51 clamp control unit 52 chuck control unit 53 non-contact displacement meter control unit 54 deviation amount calculation unit 55 Correction amount calculation unit 56 NC program correction unit 100 Crankshaft shape measuring machine Rc Actual center Dc Design center α Profile error β Deviation amount γ Correction amount

Claims (6)

A pair of chuck devices for gripping both ends of a material crankshaft having a plurality of counterweights;
A non-contact displacement meter for measuring the outer shape of the material crankshaft;
A control unit for controlling the non-contact displacement meter;
With
The controller is
A deviation amount calculation unit for calculating a deviation amount in the longitudinal direction between the actual center in the longitudinal direction of the material crankshaft gripped by the pair of chuck devices and the design center in the longitudinal direction on the design data of the material crankshaft. When,
A correction amount calculation unit that calculates a correction amount of the measurement position of the non-contact displacement meter for each of the plurality of counter weights based on the calculated shift amount;
An NC program correction unit for correcting an NC program for controlling the operation of the non-contact displacement meter based on the calculated correction amount;
Based on the modified NC program, a non-contact displacement meter control unit that controls the operation of the non-contact displacement meter so as to measure the outer shape of each of the plurality of counterweights of the material crankshaft;
Having
Crankshaft shape measuring machine. A longitudinal clamping device for positioning the material crankshaft in the longitudinal direction;
The deviation amount calculation unit calculates the deviation amount of the material crankshaft based on the outer shape of two or more counterweights including two counterweights that are in contact with the longitudinal clamp device among the plurality of counterweights. To
The crankshaft shape measuring machine according to claim 1. The deviation amount calculation unit calculates the deviation amount of the material crankshaft based on an outer shape of the pair of chuck devices.
The crankshaft shape measuring machine according to claim 1. Gripping both ends of a material crankshaft having a plurality of counterweights with a pair of chuck devices;
Calculating an amount of deviation in the longitudinal direction between the actual center in the longitudinal direction of the material crankshaft gripped by the pair of chuck devices and the design center in the longitudinal direction on the design data of the material crankshaft;
Calculating a correction amount of a measurement position of a non-contact displacement meter for each of the plurality of counterweights based on the calculated deviation amount;
Modifying an NC program for controlling the operation of the non-contact displacement meter based on the calculated correction amount;
Controlling the operation of the non-contact displacement meter to measure the outer shape of each of the plurality of counterweights of the material crankshaft based on the modified NC program;
A crankshaft shape measuring method comprising: Before the step of gripping the material crankshaft, comprising a step of positioning the material crankshaft by a longitudinal clamp device in the longitudinal direction,
The actual center of the material crankshaft is calculated based on an outer shape of two or more counterweights including two counterweights with which the longitudinal clamp device contacts among the plurality of counterweights.
The crankshaft shape measuring method according to claim 4. The actual center of the material crankshaft is calculated based on the outer shape of the pair of chuck devices.
The crankshaft shape measuring method according to claim 4.

Images