JP5954708B2 - Center of mass measuring machine - Google Patents

Description

  The present invention relates to a center-of-mass measuring machine for measuring the center of mass of a rotating body to be centered.

The center-of-mass measuring machine is a machine also referred to as a mass centering device, a mass centering machine, or the like. It is a device that can measure the deviation.
The center-of-mass measuring machine is usually provided with a pair of rotating body gripping disks that grip and rotate synchronously with the material surfaces of the rotating shafts at both the left and right ends of the rotating body to be centered. Each of the pair of rotating body gripping disks is provided with a bearing device for receiving the shaft end portion of the rotating body and a clamp device for fixing the shaft end portion received by the bearing device. .

When the rotating body to be centered is a symmetric rotating body such as a four-cylinder crankshaft, for example, both ends thereof are fixed by a bearing device and a clamping device of the rotating body gripping disk, respectively, and a pair of rotations are performed. If it is rotated by the body gripping disk, it is possible to measure an inertia main axis (mass axis) of the rotating body to be centered or a rotation axis that is convenient for correcting unbalance.
However, when the rotating body to be centered is an asymmetric rotating body such as a three-cylinder crankshaft, for example, the axis of the rotating body and the inertial main axis (mass axis) have a constant inclination angle in the axial direction. There is a relationship. For this reason, conventionally, it has been difficult to center the mass of an asymmetric rotator, and it has often not been performed.

On the other hand, in the case of the apparatus described in Patent Document 1, for example, when measuring the center of mass of an asymmetric three-cylinder crankshaft, this corresponds to the weight of the connecting rod and piston added when the three-cylinder crankshaft rotates in an actual engine. A method is used in which a compensation weight is attached and measurement is performed.
For example, the compensation weight is not attached to the rotating body (for example, a three-cylinder crankshaft) to be measured, but attached to the rotating body gripping disk or the like.

Japanese Patent No. 3432429

However, in the conventional center-of-mass measuring machine, the rotating body to be centered is symmetrical, for example, every time the symmetric four-cylinder crankshaft is switched from the symmetric four-cylinder crankshaft or vice versa. Every time the mold is switched, it is necessary to attach or remove the compensation weight, and there is a problem that time and labor are required for the setup change.
The present invention has been made in order to solve such a problem. When the rotating body to be centered is changed from a symmetric type to an asymmetric type and vice versa, the setup is changed. The main object is to provide a center-of-mass measuring machine that can be easily performed.

  In addition, the present invention provides a center-of-mass measuring machine that includes a compensation weight for canceling even imbalance occurring when measuring an asymmetric rotating body and can switch whether or not the compensation weight is applied. For other purposes.

  The invention according to claim 1 for solving the above-mentioned problems is a vibration frame and a pair of rotating bodies that are provided on the vibrating frame and that rotate synchronously by gripping the material surfaces on the left and right sides of the rotating body to be centered. A center-of-mass measuring machine including a gripping disk and a spindle provided in at least one of the pair of rotating body gripping disks and extending in the direction of the rotation axis concentrically with the rotation axis of the rotating body gripping disk. When the rotating body to be centered is an asymmetric rotating body, the compensating weight mechanism is provided on the rotating body gripping disk side, and cancels even and unbalanced inherent to the rotating body. 1 having a first fixed weight disposed on the rotating body gripping disk and a second fixed weight attached to the spindle at a predetermined distance from the rotating body gripping disk in the rotation axis direction. A fixed even and unbalanced compensation weight, a first movable weight disposed on the rotating body gripping disk, and a second movable weight provided at a predetermined distance in the rotational axis direction from the rotating body gripping disk. A set of movable even unbalance compensation weights capable of changing the mounting angle position with respect to the rotating body gripping disk and the spindle, and the set of movable even unbalance compensation weights at a predetermined angular position. By being fixed, it is added to the set of fixed even unbalance compensation weights, and the compensation weight mechanism is operated.

  According to a second aspect of the present invention, the set of movable even-balance compensating weights includes a first movable weight provided on the rotating body gripping disk and a second movable weight provided at a predetermined position of the spindle. Are connected by a connecting shaft extending concentrically with the spindle, and by rotating the second movable weight with respect to the spindle, the first movable weight is moved relative to the rotating body gripping disk. 2. The center-of-mass measuring machine according to claim 1, wherein the center-of-mass measuring machine is configured to rotate.

  According to a third aspect of the present invention, when the rotating body to be centered is an asymmetric rotating body, the second movable weight is fixed at the same angular position as the second fixed weight, and in this case, the first moving weight is fixed. The movable weight is at the same angular position as the first fixed weight. In this case, the one set of movable even unbalance compensation weights is added to the one set of fixed even unbalance compensation weights, and the rotation to be centered. When the body is a symmetrical rotating body, the second movable weight is moved and fixed at an angular position different from the second fixed weight by 180 °, whereby the first movable weight is fixed to the first fixed weight. In this state, the one set of fixed even unbalance compensation weights is canceled by the one set of movable even unbalance compensation weights and does not act. Item 2 This is a center-of-mass measuring machine.

  According to the present invention, the changeover of the center-of-mass measuring machine can be performed in a short time when the rotating body to be centered is switched. That is, even if the rotating body to be centered is a symmetric type rotating body or an asymmetric type rotating body, an even unbalance occurs in the latter. It can be in a working state. In addition, when it is not necessary to operate the compensation weight, switching can be performed so that the compensation weight does not operate.

  Furthermore, according to the present invention, not only the amount of even unbalance generated by the compensation weight is varied in the case of measuring the center of mass of the symmetric type rotator and the case of measuring the center of mass of the asymmetric type rotator, It is also possible to provide a center-of-mass measuring machine capable of switching the compensation weight for canceling the even-balanced occurrence when measuring the center-of-mass of two types of asymmetric rotators with different even-balanced amounts. . That is, even when the rotating body to be centered is an asymmetric rotating body with a different compensation amount to compensate for even unbalance, the center of mass is appropriately set for the two types of asymmetric rotating bodies by switching the compensation weight mechanism. It can be set as the mass center measuring machine which can be measured.

  Furthermore, by providing a compensation weight mechanism on the two left and right bearing mounts, the measuring machine should be capable of easy setup change so that the mass center of various types of symmetric and asymmetric rotators can be measured. You can also.

FIG. 1 is a front view of a center-of-mass measuring instrument 10 according to an embodiment of the present invention. FIG. 2 is a diagram in which the right gantry 15 and the rotating body 26 are extracted from the center-of-mass measuring instrument 10 shown in FIG. FIG. 3 is a view of the right gantry 15 and the rotator 26 taken out of the center-of-mass measuring instrument 10 shown in FIG. 1 in the same manner as FIG. 2. The rotator to be centered is a symmetrical rotator (four-cylinder crank). It is a figure in the case of 260). FIG. 4 is a partial longitudinal sectional view showing a specific configuration of the rear end portion of the spindle 24 of the right gantry 15 in FIGS. 1 to 3. FIG. 5 is a view of FIG. 4 viewed from the right side. FIG. 6 is an illustrative view showing an example of a configuration for automatically switching the angular position of the compensation weight mechanism 80.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a front view of a center-of-mass measuring instrument 10 according to an embodiment of the present invention. The center-of-mass measuring machine 10 has a vibration frame 13 supported on a base 11 by a plurality of springs 12. On the vibration frame 13, a left frame 14 and a right frame 15 are provided on the left and right. The left gantry 14 and the right gantry 15 have a symmetric structure, and both are the same except that the right gantry 15 is provided with a compensation weight mechanism for compensating for even unbalance described later. It has a configuration.

That is, the left gantry 14 and the right gantry 15 are mounted on a guide rail 16 provided on the left upper surface of the vibration frame 13 and a guide rail 16 provided on the right upper surface of the vibration frame 13, respectively. It is slidable and can be positioned and fixed at any position.
The left gantry 14 and the right gantry 15 respectively include a base 17 that engages with the guide rail 16, a spindle unit 18 provided on the base 17, and a vertical frame 19 that is attached to the rear portion of the spindle unit 18 and extends upward. And a motor 20 attached to the upper part of the vertical frame 19. The rotational force of the motor 20 is transmitted from the motor-side pulley 21 to the spindle-side pulley 23 via the belt 22, and the spindle 24 extending horizontally in the left-right direction in the spindle unit 18 can be rotated.

A rotating body gripping disk 25 that is rotated by the spindle 24 is provided at the tip of the spindle 24 that protrudes from the tip of the spindle unit 18.
On the front surface side of the rotating body gripping disk 25, that is, on the front surface side facing each other, the end of a rotating body 26 to be centered, for example, an engine crankshaft 26 integrally formed by casting or forging is received. And a clamp unit 28 for pressing and fixing an end of a rotating body (for example, a crankshaft) 26 received by the bearing unit 27 in the direction of the bearing unit 27.

  In the center-of-mass measuring instrument 10, one end (left end) of a rotating body (for example, crankshaft) 26 to be centered is placed on a bearing unit 27 provided on the rotating body gripping disk 25 of the left gantry 14, and the others. The end (right end) is placed on a bearing unit 27 provided in the rotating body gripping disk 25 of the right gantry 15. One end and the other end of the rotating body 26 are clamped by a clamp unit 28 provided on each rotating body gripping disk 25.

  In this state, the motors 20 of the left gantry 14 and the right gantry 15 are synchronously rotated, whereby the spindles 24 of the spindle units 18 of the left and right gantry 14, 15 are synchronously rotated, and the rotating body gripping disk 25 of the left gantry 14 and The rotating body gripping disk 25 of the right gantry 15 rotates synchronously. That is, both ends of the rotating body (crankshaft) 26 are gripped by the pair of rotating body gripping disks 25 and rotated together with the pair of rotating body gripping disks 25.

At this time, if there is a deviation between the center of inertia of the rotating body (crankshaft) 26 and the center of rotation, an unbalance proportional to the amount of deviation occurs, and the vibration frame 13 vibrates. The vibration of the vibration frame 13 is detected by a vibration detector (pickup) (not shown), and the amount of deviation between the center of inertia of the rotating body (crankshaft) 26 and the rotation center can be measured.
By the way, in the case where the rotating body 26 whose center of mass is to be measured by the center-of-mass measuring instrument 10 is, for example, an asymmetric type rotating body 26 as shown in FIG. Is a relationship in which the axis of the crankshaft 26 and the inertial main axis (mass axis) have a constant inclination angle in the axial direction. For this reason, when the three-cylinder crankshaft 26 is rotated, a vibration based on the even unbalance of the three-cylinder crankshaft 26 appears. Therefore, in the center-of-mass measuring instrument 10 according to this embodiment, a compensation weight mechanism 80 for canceling even disparity is incorporated in the right frame 15.

Hereinafter, the configuration and operation of the compensation weight mechanism 80 will be described in detail.
FIG. 2 is a diagram in which the right platform 15 and the rotating body (three-cylinder crankshaft) 26 are extracted from the center-of-mass measuring instrument 10 shown in FIG. The right pedestal 15 is shown in a vertical cross-sectional configuration, and the vertical frame 19, the motor 20, the motor-side pulley 21 and the belt 22 are omitted.

  Referring to FIG. 2, the compensation weight mechanism 80 provided on the right frame 15 is attached to the first fixed weight 81 attached to the lower end portion of the front surface of the rotating body gripping disk 25 and the spindle-side pulley 23. And a second fixed weight 82. The first fixed weight 81 and the second fixed weight 82 are at positions where the angular positions differ from the rotation axis A of the rotating body gripping disk 25 and the spindle 24 by 180 °, that is, opposite to the rotation axis A. It is fixed at an angular position in the direction (for example, a position of 0 ° and a position of 180 °).

  Further, the compensation weight mechanism 80 provided on the right gantry 15 is provided at the rear end portion (right end portion in FIG. 2) of the first movable weight 83 and the spindle 24 provided at the center of the front surface of the rotating body gripping disk 25. A second movable weight 84 is provided. The first movable weight 83 and the second movable weight 84 are both eccentric disc weights that are eccentric with respect to the rotation axis A, and are provided concentrically with the spindle 24 so as to be rotatable with respect to the spindle 24. The connecting shaft 85 is connected. The first movable weight 83 and the second movable weight 84 are distributed with respect to the rotational axis A at angular positions that are 180 degrees different from each other. Then, by operating the operation handle 86 provided in association with the second movable weight 84, the second movable weight 84 (the center of gravity thereof) faces directly above (the angular position is 0 °), and the first The two movable weights 83 and 84 can be fixed to the rotating body gripping disk 25 and the spindle 24 in a state where the movable weight 83 (the center of gravity thereof) faces directly below (angular position 180 °).

Further, as shown in FIG. 3, by operating the operation handle 86, the first movable weight 83 (the center of gravity) faces directly above (angle position 0 °), and the second movable weight 84 (the center of gravity). The first movable weight 83 and the second movable weight 84 can be fixed to the rotating body gripping disk 25 and the spindle 24 in a state where the head is directly below (angular position 180 °).
Referring to FIG. 2, when the rotating body 26 to be centered is a three-cylinder crankshaft 26 as shown in FIG. 2, the three-cylinder crankshaft 26 has an asymmetric shape with respect to the rotation axis. Thus, the three-cylinder crankshaft 26 has an even unbalance U _C.

Further, the rotating body gripping disk 25 and the spindle 24 in the right gantry 15 have an even unbalance U _C1 due to the first and second fixed weights 81 and 82 described above. Furthermore, the first movable weight 83 is in the same angular position as the first fixed weight 81, and the second movable weight 84 is in the same angular position as the second fixed weight 82, so that the first and Due to the second movable weights 83 and 84, an even unbalance U _C2 appears.

Then, in this embodiment, the偶不balance U _C of 3-cylinder crankshaft, and偶不balancing U _C1 with fixed weights 81 and 82, and偶不balance U _C2 by the movable weight 83, 84,
U _C + U _C1 + U _C2 = 0
(* Each even and unbalance is shown as a vector quantity.)
The weights of the first and second fixed weights 81 and 82, the weights of the first and second movable weights 83 and 84 are set, and the first and second fixed weights 81, An interval in the direction of the rotational axis A of 82 and an interval in the direction of the rotational axis A of the first and second movable weights 83 and 84 are set.

  As a result, as shown in FIG. 2, the directions (angular positions with respect to the rotational axis A) of the two fixed weights 81 and 82 and the two movable weights 83 and 84 are made to coincide with each other. By rotating the rotating body gripping disk 25, the even unbalance generated by the three-cylinder crankshaft 26 can be canceled by the even unbalance generated by the compensating weight mechanism 80.

Next, referring to FIG. 3, when the rotating body 260 to be centered is a symmetrical rotating body as shown in FIG. 3, for example, a four-cylinder crankshaft 260, the first movable weight 83, The two movable weights 84 are fixed in a 180 ° inverted state.
That is, on the front surface of the rotating body gripping disk 25, the first movable weight 83 is rotated and fixed with respect to the first fixed weight 81 so that the center of gravity of the first movable weight 83 is directed in the opposite direction. In addition, at the rear portion of the spindle 24, the angular position is changed so that the center of gravity of the second movable weight 84 is opposite to the rotation axis A with respect to the second fixed weight 82. This change can be performed by operating the operation handle 86 and rotating the first movable weight 83 and the second movable weight 84 connected by the connecting rod 85 in conjunction with each other. Therefore, it is possible to easily change the mounting angle position of the pair of first movable weight 83 and second movable weight 84.

In the state shown in FIG. 3, the four-cylinder crankshaft 260 is a symmetric rotating body, and therefore no even disparity appears.
On the other hand, the even unbalance U _C1 caused by the first and second fixed weights 81 and 82 and the even unbalance U _C2 caused by the first and second movable weights 83 and 84 in the right frame 15 are:
U _C1 + U _C2 = 0
(* Each even and unbalance is shown as a vector quantity.)
It becomes the relationship. That is, in the right frame 15, the even unbalance between the fixed weights 81, 82 and the movable weights 83, 84 cancels out, and the right frame 15 does not have an even unbalance.

  In this embodiment, in the center-of-mass measuring instrument 10, when the rotating body 26 to be centered is an asymmetric type rotating body and has even unbalance, one bearing that receives and rotates at one end side of the rotating body. In the gantry 15, the compensation weight mechanism 80 for compensating (canceling) the even unbalance caused by the rotating body 26 to be centered is provided. Therefore, the compensating weight mechanism 80 causes the evenly generated rotating body 26 to be centered. It is possible to cancel the unbalance and perform a good centering.

Further, when the rotating body 260 to be centered does not cause even unbalance, the compensating weight mechanism 80 is rotated so that the even unbalance in the right frame 15 is eliminated. Moreover, it can be set as the mass center measuring device 10 which can respond | correspond favorably.
Further, the center-of-mass measuring device 10 determines the angular position of the pair of movable weights 83 and 84 included in the compensation weight mechanism 80 according to whether the rotating body to be centered is symmetric or asymmetric. ° Can be dealt with simply by reversing. Therefore, it can be set as the apparatus with easy setup change.

FIG. 4 is a partial longitudinal sectional view showing a specific configuration of the rear end portion of the spindle 24 of the right gantry 15 in FIGS. 1 to 3. FIG. 5 is a view of FIG. 4 as viewed from the right side.
4 and 5, it can be understood that the second movable weight 84 is an eccentric disk-shaped weight 84 that can rotate about the connecting shaft 85 and change the angular position.
Although not shown, the first movable weight 83 also employs an eccentric disk-shaped weight that can rotate about the connecting shaft 85 and change the angular position.

In the embodiment described above, the configuration in which the operation handle 86 is switched to change the angular position of the pair of movable weights 83 and 84 included in the compensation weight mechanism 80 with respect to the rotation axis A has been described.
However, as will be described below, switching of the angular positions of the pair of movable weights 83 and 84 included in the compensation weight mechanism 80 can be automatically performed by, for example, remote operation.

FIG. 6 is an illustrative view showing one example of a configuration for automatically switching the angular positions of the movable weights 83 and 84 of the compensation weight mechanism 80. In FIG. 6, switching of the angular positions of the movable weights 83 and 84 of the compensation weight mechanism 80 is sequentially performed as (A), (B), (C), and (D).
First, as shown in FIG. 6A, the automatic switching mechanism 90 is moved toward the second movable weight 84. The automatic switching mechanism 90 includes an eccentric plate 92 that is externally fitted to a shaft 91 that extends on the rotation axis A. An air supply nozzle 93 projects from the eccentric plate 92.

  On the other hand, an air supply path 87 and a fixed pin 88 are incorporated in the second movable weight 84. The fixed pin 88 is elastically biased by a spring 89 so that its tip always protrudes toward the rear end surface (right end surface) of the spindle 24. Then, it is fitted in a first fitting hole 851 formed in the rear end surface of the spindle 24, and the angular position of the second movable weight 84 with respect to the spindle 24 is fixed to a predetermined angular position (for example, 0 ° position). ing.

  In this state, the automatic switching mechanism 90 is displaced leftward as shown in FIG. 6A, and the nozzle 93 is engaged with the air supply path 87 as shown in FIG. Then, air is supplied from the nozzle 93 to the air supply path 87. Then, the pressure of the air overcomes the elastic force of the spring 89, displaces the fixing pin 88 in the right direction, and the fixing pin 88 is detached from the first fitting hole 851. In this state, the second movable weight 84 can rotate around the connecting shaft 85.

The automatic switching mechanism 90 rotates the eccentric plate 92 around the shaft 91. As a result, the second movable weight 84 rotates as the eccentric plate 92 rotates.
In the state shown in FIG. 6C, that is, in the state where the eccentric plate 92 and the second fixed weight 82 are rotated by 180 °, the automatic switching mechanism 90 stops the supply of air and reduces the pressure. Along with this, the fixing pin 88 is pushed by the spring 89 and enters the second fitting hole 852 formed in the rear end surface of the spindle 24. As a result, the second movable weight 84 is fixed to the spindle 24 by switching the angular position to a predetermined angular position (for example, a position of 180 °).

Thereafter, as shown in FIG. 6D, the automatic switching mechanism 90 is slid to the right and retracted.
As described above, the automatic switching mechanism 90 can be used to automatically switch the angular positions of the pair of movable weights 83 and 84 included in the compensation weight mechanism 80.
The present invention is not limited to the embodiment described above. That is, in order to measure not only the angular position of the compensation weight, but also two types of asymmetric rotators with different even balance between the case of measuring a symmetric rotator and the case of measuring an asymmetric rotator. The compensation weight mechanism 80 can also be configured so that the two types of compensation amounts can be switched by switching the angular position of the compensation weight mechanism.

In the above-described embodiment, the configuration in which the compensation weight mechanism 80 is provided only on one of the bearing mounts of the center-of-mass measuring instrument 10, that is, the right mount 15 has been described. However, the compensation weight mechanism 80 may be provided not only on the right base 15 but also on the left base 14.
When the compensation weight mechanism 80 is provided on both the right gantry 15 and the left gantry 14, by switching one set of movable weights 83 and 84 in each compensation weight mechanism 80, various types of compensation amounts can be switched. For example, when the compensating weight mechanism 80 provided on the left gantry 14 causes an even unbalance V _C1 due to a fixed weight and an even unbalance V _C2 due to a movable weight,
V _C + V _C1 + V _C2 = 0 (1)
V _C1 + V _C2 = 0 (2)
(* V _C is the even unbalance of the rotating body to be centered. Each even unbalance is indicated by a vector quantity.)
As described in (1) above, the even weight disparity of the rotating body to be centered can be canceled by the compensation weight mechanism 80. Further, when the rotating body to be centered does not have even-balance, the movable weight may be switched so that the even-balance in the left gantry 14 becomes 0 as described in (2) above.

The even balance V _C of the rotating body to be centered is a value different from U _C described above, and the compensation weight mechanism 80 of the left platform 14 is activated (actuated) or the compensation weight of the right platform 15 is compensated. Depending on whether the mechanism 80 is activated (actuated), measurement of two types of asymmetric rotating bodies can be supported.
Furthermore, by activating (acting) the compensation weight mechanism 80 of the left gantry 14 and the right gantry 15 together,
X _C + U _C1 + U _C2 + V _C1 + V _C2 = 0
(* X _C is the even unbalance of the rotating body to be centered. Each even unbalance is indicated by a vector quantity.)
So on, can also be偶不balance corresponds to the measurement of another asymmetric rotator X _C.

  In addition, the present invention can be variously modified within the scope of the claims.

DESCRIPTION OF SYMBOLS 10 Mass center measuring machine 11 Base 12 Spring 13 Vibration frame 14 Left mount 15 Right mount 18 Spindle unit 24 Spindle 25 Rotating body holding disk 27 Bearing unit 28 Clamp unit 80 Compensation weight mechanism 81 1st fixed weight 82 2nd fixation Weight 83 First movable weight 84 Second movable weight 85 Connection shaft 86 Operation handle 90 Automatic switching mechanism

Claims (3)

A vibration frame;
A pair of rotating body gripping disks that are provided on the vibration frame and that rotate synchronously by gripping the material surfaces on the left and right sides of the rotating body to be centered;
A spindle that is provided in at least one of the pair of rotating body gripping disks and extends in the direction of the rotation axis concentrically with the rotation axis of the rotating body gripping disk;
In the center of mass measuring machine including
Provided on the rotating body gripping disk side provided with the spindle, when the rotating body to be centered is an asymmetric rotating body, provided with a compensation weight mechanism for canceling even unbalance inherent in the rotating body,
The compensation weight mechanism is
A set of a first fixed weight disposed on the rotating body gripping disk and a second fixed weight attached to the spindle at a position away from the rotating body gripping disk in a rotation axis direction by a predetermined distance. Fixed even disproportionate compensation weight,
A first movable weight disposed on the rotating body gripping disk; and a second movable weight provided at a position away from the rotating body gripping disk in a rotation axis direction by a predetermined distance. And a set of movable even unbalance compensation weights capable of changing the mounting angle position with respect to the spindle,
The set of movable even unbalance compensation weights is added to the set of fixed even unbalance compensation weights by being fixed at a predetermined angular position, and the compensation weight mechanism acts. Center of mass measuring machine.   The pair of movable even-balance compensating weights includes a first movable weight provided on the rotating body gripping disk and a second movable weight provided at a predetermined position of the spindle concentrically with the spindle. It is connected with an extending connecting shaft, and by rotating the second movable weight with respect to the spindle, the first movable weight rotates with respect to the rotating body gripping disk. The center-of-mass measuring machine according to claim 1, wherein When the rotating body to be centered is an asymmetric rotating body, the second movable weight is fixed at the same angular position as the second fixed weight, and in this case, the first movable weight is fixed to the first fixed weight. The same angular position as the weight, in which case the set of movable even unbalance compensation weights is added to the set of fixed even unbalance compensation weights;
When the rotating body to be centered is a symmetrical rotating body, the second movable weight is moved and fixed at an angular position different from the second fixed weight by 180 °, whereby the first movable weight is The angular position is 180 ° different from that of the first fixed weight, and in this state, the one set of fixed even unbalance compensation weights is canceled by the one set of movable even unbalance compensation weights and becomes inoperative. The center-of-mass measuring machine according to claim 2, wherein

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