CS226563B1 - Method of and apparatus for measuring static unbalance momentum - Google Patents

Description

BACKGROUND OF THE INVENTION The present invention relates to a method for measuring the torque of static unbalance of rotary bodies and to a device for carrying it.

Of the methods used to measure the imbalance so far, the most known methods are dynamic, i. j. those that measure the moment of imbalance as the object rotates about an axis against which the moment of imbalance should be measured. The devices used in this method of measurement are often expensive, complex and labor intensive.

From the static measurement of the unbalance moment, devices are known in which the object to be measured is inserted in a vertical position, i. j. the axis of the object against which the measurement is made, the psalm only the axis of rotation, is perpendicular to the horizontal plane. The advantage of these devices is that the direction or direction can be determined immediately. space max. imbalance, i. j. the direction of the center of gravity of the axis of rotation of the object. The value of the unbalance moment or the exact position of the center of gravity can be determined by the actual removal. The disadvantage of this method is that the axis of rotation of the object to be measured must be perpendicular to the face on which it lies. Perpendicular deviations bring inaccuracy to the measurement. A further disadvantage is that it is very difficult to measure the moment of imbalance on objects whose length is several times greater than the outer diameter. casting is also very difficult in cases where the height of the object's center of gravity is not known, i. j. the distance of the center of gravity from the front surface on which the object lies. This occurs in particular for objects with an internal cavity, e.g. for artillery shells.

Of the methods and methods of measuring static imbalances commonly used in practice, the best known method is the rolling method. The rotary object to be measured is placed on a guide, placed in a horizontal position. The heavier side of the measured object outweighs the lighter side, the object rolls. Weights are attached to the lighter side, e.g. magnets until the object is removed226 565. The accuracy of this method is low and is dependent on the quality of the rails and the quality of the object sheet that touches the rails, i. j. on the rolling friction between the object and the rails.

The aforementioned drawbacks eliminate the method and the device which together form the subject-matter of the invention.

The invention solves the measurement of the moment of static imbalance on the oscillating measuring device shown in FIG. 1. The axis of rotation of the measured object is in the horizontal position. The device is very sensitive, the measurement accuracy is high. Placing an object in the device is usually very easy to achieve in practice.

The device consists of a bearing part 8 formed by two surfaces clamping at an angle of 80 ° to 100 °, fixed at the ends by pivoting arms, provided with two prongs 2 reaching to the supports J and a deflector J firmly connected to the pivoting arms (Fig. 1).

The object to be measured is inserted into the bearing part lying flat, its axis of rotation being parallel to the longitudinal axis of the bearing part. After the oscillation has stabilized, the oscillation angle α, (relative to the index finger £) is subtracted. The object to be measured rotates about its axis of rotation by 90 °. After steady swing is read swivel angle α ₂ · From the measured values of angles and _«2 ⁸⁸ calculates the angle of rotation y:

Z = β + α, (T) where

Sin ^and 2 tg β - tg (α - α -) (2) sin. cos («i - i)

The angle γ is the angle by which the measured object must be rotated with respect to its axis of rotation to bring the center of gravity of the object Tp to a horizontal position relative to the axis of rotation. The angle γ should be measured relative to the position at which the angle r <,.

Further possible angles and values of _«2 calculate the size of the torque imbalance as:

M · (G_r + G_r). sin a, z of p s i sin «2 sin lips. cos (tg («,

TF2

Gg the mass of the pivoting parts of the device, r _{z the} distance of the horizontal axis passing through the center of gravity of the pivoting parts of the device from the axis passing through the tips 2,

Gp the mass of the measured body, r _{and the} distance of the geometry geometry axis of rotation of the measured body from the horizontal axis passing through the tips 2,

Distance of the center of gravity of the object from the vertical axis through the points 2.

Derive the relationship (2) as shown in Figure 2:

If you place the measured object on the device in any position, the whole system will deflect eg. o angle After turning the measured body, the system deflects by angle j.

Equations of system equilibrium are:

· R · ^r "i = ⁰ p pI from Zl ° ^r · p 2 p - ^{y G} z · Z 2 - ⁰

It follows that 'Mrs. ^G z · ^r Z2 p2

It is apparent from Figure 2 that ^Γ 81 κ sin r _z1 = r _a . sin a ₁ ^r for similar ^r z2 “ ^r z * ^sin “ 2

Furthermore, it is clear from the figure that r _s i sin «j» —— r _g] = r _g . sin a, • similar to ^r s2 “ ^r s * ^sin “ 2

For an unknown angle P, " ^r p1 ^{+ r} s1". ^{Γ Ρ1} * ^r s1 cos P ^lt?> P »--- -t p cos p sin (+ P <S) ^r * ^r p2 s2 δ '«, - _«2

226563 4 the second equation is replaced by p the first equation r_o * ^p s2 sin (β + δ) = -Σ £ -2 £ ^γ ρι + ^r s1 cos I) r _o2 ⁺ r-2 sin (Ρ + δ) s ° . cos fi ^Γ Ρ 1 ^{+ Γ} 81

1'avá the right side of the equation are divided by cos β sin (β + <5) _{R? 2} + y _{s 2} cos β r _p + r _{8 liters} layout sin (β + S) reaches sin β. cos δ + cos β. sin 8 r _p2 + r _s2 eos / J r _p , + r _{g The} left side of the equation is adjusted to ^r p2 ^{+ r} s2 tg phi. cos δ + sin δ » ^r p1 ^{+ r} s1 after adjustment tg β ^r p2 ♦ ^r s2 cos δ. (r _p , + r _s1 ) tg δ by substituting for r _p1 , r _p2 , r ₈₎ , r _g2 , r _z , ar _z2 to get tg β

G _z . r _z . sin and ₂ + r ₈ . sin and ₂ cos δ

ZG _z . r _s . sin a, * \ <-r- · '. · »tq β = (Q _z . r, + 0 _p . r ₈ ). aln _{2 2} (G _z . r _z + G _p . r _s ). you are on, . cos δ

- tg δ sin and _{2 tg} n = - tg δ sin. cos δ

To derive the relationship (3) from Figure 2:

The resulting moment of imbalance is denoted M.

M = G _p . p

^P p p1 + ^r s1

P B p cos P

After p is substituted to the previous equation * G_ ^r p1 + ^r s1

M ^F cos β

By settling for r _p , ^{8 r} s, ⁸ by adjusting the equation it gets

Μ = θ ⁸ ' ^{Γζ1 + Q} P s ^{r Sun} * 1 _Q Gp. cos β P

Sitting for r. and further editing will get the relationship

0-. r «+ G _n cos p

For cos β expressed by the tangent function, cos β ¹ - · - * \ / Y + tg ² p substitutes for tg β relation © to get cos p ± \ / Z sin “2 \ 2 \ / l + (-: - tg 5) in ssin. cos δ y

By substituting this equation into (5) and adjusting, the equation « ³ <° z · ^r z ⁺ Gp · ^r s> ♦ ^sin « 1 · l / ¹ / sin and ₂ ,, _n 2 + / - £ - / - / _{tg (ft} . _a ) and sin. cos («, -« j) / </

It follows from the description of the operation of the device that it is possible to determine the moment of imbalance and its location for each measured object, so it can be additionally statically balanced.

Said method and the device for measuring the moment of imbalance can be used in industrial areas, e.g. in the manufacture of grinding wheels, wheels of motorized and non-motorized vehicles, crankshafts, rotors, in the arms industry, but also in the manufacture of components and products of various non-rotational shape. For accelerated measurement, it is advantageous to place air, electromagnetic, oil, etc. vibration dampers on one of the pivoting parts of the device.

Claims (2)

OBJECT OF THE INVENTION Method for measuring the torque of a static imbalance, in particular of rotary bodies, characterized in that, for a measured cylindrical body mounted in a horizontal position, a first deflection angle of zero from the zero position is first detected, then the measured body is rotated by 90 ° and a second deflection angle _{α2 is determined} , whereby M - (Q _z . R _g + G _p . R _g ). sin «. where M is the moment of static imbalance, G _g weight of the swinging parts of the measuring device, r ₈ distance of the horizontal axis passing through the center of gravity of the swinging parts of the measuring device from the horizontal axis passing through the storage centers of the measuring device, Gp mass of the measured body, r _g distance of the geometric axis of rotation of the measured body from the horizontal axis passing through the tips of the measuring device. 2. Apparatus for carrying out the method according to claim 1, comprising a deflection meter, characterized in that it comprises a bearing part (4) formed by two surfaces formed at an angle of 80 ° to 100 ° fixedly connected to the ends with pivoting arms provided with yard tips (2). , abutting the supports (3).