GB2226866A

GB2226866A - Vibration generator

Info

Publication number: GB2226866A
Application number: GB8900094A
Authority: GB
Inventors: Alexandr Iosifovich Dryga; Vyachelsav Matveevich Alexeev; Sergei Alexeevich Polovoi
Original assignee: KRAMTORSKY IND I; Proizv Ob Nevsky Z Im V I; PROIZV OB NOVOKRAMATORSKY MASH
Current assignee: KRAMTORSKY IND I; Proizv Ob Nevsky Z Im V I; PROIZV OB NOVOKRAMATORSKY MASH
Priority date: 1989-01-04
Filing date: 1989-01-04
Publication date: 1990-07-11
Also published as: GB8900094D0; FR2641483A1; DE3900325A1

Description

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VIBRATION GENEW-POR Technical Field

The present invention relates generally to vibration engineering and more specifically, to the vibration genera5 tor for vibratory devices.

The invention may be used to best advantage for a number of applications which include vibrostabilizing treatment of components machined by pressworking or cutting as well as by welding or casting for the purpose of stabiliz- ing their geometric dimensions and shape or reducing residual stresses; vibration loading for testing the effect of vibrational overloads on the operational reliability and vibration-resistance, for example, or aircraft.

The present invention can also be employed in other fields such as vibroebrasive treatment of components, for example, in deburring or descaling machines, construction materials industry (e.g., concrete compaction ma,chines or pile driving machines), highway engineering (eog.9 asphalt or gravel compaction machines), as well as transportation devices, such as vibratory feeding or conveying apparatus.

Background of the Invention

At the present time, extending the processing capacities of vibratory equipnent under development is'an urgent problem since it allows reductions in the component machin- ing time, and consequently, in power cons= tion which leads to increased productivity per unit time and;1,nproved quality of vibration treatment. Vibration generators 2 1 I used most commonly for the generation of disturbing forces are of the mechanical inertia unbalance type which off ers simplicity in operation and fairly high disturbing forces. Under operating conditionsl a necessity may often arise for theamount of disturbing force generated by the vibratory device to be adjusted over a wide range, for example, in order to adjust the oscillation amplitude in the vibratory device.

The amount of vibratory force generated is directly proportional to the mass of unbalance weights which is arranged eccentrically with respect to the axis of rotation of the drive shafts the distance of the center of this mass from the axis of rotation of the drive shaft, and to the squared frequency of rotation (angular velocity) of the drive shaft.

By virtue of the fact that varying the frequency of rotation of the drive shaft over a wide range necessitates the use of a d.c. motor in conjunction with supply voltage regulators the simplest ways of varying the amount of the disturbing force would be either by changing the eccentric mass of the vibration generator or by altering the distance from the center of its masses to the axis of rotation of the drive shaft.

Known in the present state of the art is a vibration generator (SU9 A, 9569051) comprising a drive shaft, two unbalance weightst which a-re moanted on the drive shaft so as to be tun-rable with respect to each other, a 3 mechanism for adjusting the mutual position of the unbalance weights, which is made in the form of a rod and a hollow cylinder having helical grooves provided on its cylindrical surface, each of the grooves being adapted to interact with one of the unbalance weights. The cylinder is installed so as to be traversable lengthwise the shaft, and the'rod is connected to the cylinder. A disadvantage inherent in the device described above resides in the fact that-the mechanism for adjusting the mutual position of unbalance weights is too cumbersome and features sophisticated construction.

The closest to the herein proposed invention is a centrifugal vibration generator (DE, C, 1,297,928) comprisfixed shaft fitted in a rotary electric motor, Fixed ing a stationary on the housing of the electric motor is an unbalance weight made in the form of an are-shaped guideway supporting another movable unbalance weight made in the form. of an arc-shaped element. The unbalance weights are provided with a mechanism for adjusting their mutural position and fashioned as a pin retainer spring-loaded in a ra- dial direction. One end of the retainer engages in one of the radial through holes provided in the movable unbalance weight so that movement of the movable unbalance weight will cause a change in the amount of the disturbing force produced by the vibration generator.

A substantial disadvantage of the prior-art vibration generator mentioned above resides in the fact that anism ' f." t he the mecK Lor adjusting the mutual position o:

1 C 4 unbalance weights does not allow the disturbing force to be varied over a wide range, or its smooth adjustment, which prevents vibration treatment of a wide range of products. inconvenience caused by the prior-art vibration generator lies with the sophisticated adjustment of the disturbing force, since the adjustment process involves the use of an additional tool, such as a cylindrical pin or rod, which has to be fittedo in successiont in each of the through holes passing underneath the extensible retainer, thus increasing the total adjustment time.

Furthermore, the vibration generator discussed above features a comparatively high drag coefficient because of the clearance between the movable unbalance weight and the motor housing, which increases noise when the vibration ge15 nerator operates It is therefore an object of the present invention to extend the processing capacities of the vibration generator.

It is also an object of this invention to simplify ' the disturbing force and the adjustment of the amount o.9. to reduce the adjustment time.

It is another object of this invention to reduce noi- -P the vibration generator.

se caused by the operation o.

With the foregoing and other objects in view the.present invention thus resides in the fact that in a vibration generator comprising a drive shaft mounting unba-lance weights, wlic.. are a clearance fit on the shaft and 1 and are turnable with respect to each other, and a mechanism for adjusting their mutual position, according to the invention, the adjusting mechanism is made in the fo= of two coaxially arranged cylinders carrying the unbalance weights and joined together by joining members provided on their engaging surface, one of the cylinders being rigidly mounted on the drive shaft while the other cylinder is mountedso as to be turnable and axiallytraversable. The coaxial arrangement of the cylinders enables the unbalance weights to be put in an enclosed space, which reduces drag, abaies noise and decreases losses of energy. By virtue of engagement between the unbalance weights and the joining members, the mutual position of the unbalance weights can be varied from perfect coincidence to being turned opposite each other, i.e., 1800 out of phase, which makes it possible to change the disturbing force from its greatest to zero (for unbelance weights of a given mass), whereas the movable unbalance weight traversable in an axial direction allows the mutual Do- sition of the unbalance weights to be altered, whereby the disturbing force can be smoothly adjusted over its entire range. The above-described properties of the vibration generator expand the range of products treated, -ies of the vibration genera- hence the processing capacit t or.

According to the preferred embodLmenu of the present invention, the movable cylinder is spring-loaded in an 1 C 6 axial direction, and the cylinders have on the grooved portions thereof annular grooves whose width is greater than the distance between the adjacent grooves. The grooves enable the joining members to be brought out of engage- ment and provide for smooth adjustment of the disturbing force, Spring- loading of the movable unbalance weight makes it possible to positively lock the unbalance weights in their working position.

According to another embodiment of the invention, the movable cylinder has an annular groove thereof provided at the point where it engages with the drive shaft, while the drive shaft has an axial hole therethrough ending in a radial slot whose length is greater than the clearance between the unbalance weights, the axial hole of the dri- ve shaft being adapted to receive a spring-loaded rod provided with a radial hole therethrough disposed closs to the annular groove, and a retainer being fitted in the radial hole provided in the drive shaft and rod. Such an ion allows the drive shaft to be embodiment of the invent installed on two supports, which, in turn, permits use of unbalance weights of greater mass, thus sharply inc reasing the disturbing force, whereby components of far greater mass.can be treated, which extends the processing capacities of the vibration generator.

According to still another embodiment of the inven tion, the movable cylinder has an annular groove provided at the point where it engages with the drive shaft, while 7 the drive shaft has an axial hole having at its end a radial hole engageable with the annular groove adapted to receive a retainer, the axial hole accommodating an adjustIng rod adapted to interact with holes arranged under the retainer. The balls permit the retainer to be positively looked (without backlash) in the groove. This embodiment is preferable for high-speed vibration generators because positive locking of the movable parts prevents backlash and extends service life of the vibration generator.

In what follows the present Invention will now be disclosed in a detailed description of an illustrative embodiment thereof with reference to the accompanying drawings. wherein:

FIG. 1 is a general longitudinal sectional view of a -or. according to the invention; vibration generat FIG. 2 is a view as seen facing an arrow A in Pig.1 (partly cut away). according to the invention; FIG. 3 is a scaled-up view of unit B in FIG. 1 (partly cut away), according to the invention; FIG. 4 is a general longitudinal sectional view of an embodiment of a vibration generator. according to the invention; FIG. 5 is a cross-sectional view taker. along the line V-V in FIG. 4, according to the invention; - FIG. 6 Is a longitudinal sectional view of an embodi ment of a vibration generator according to the inven tion.

1 8 A vibration generator comprises two unbalance weights 19 2 (FIG. 1) and a m'echanism for adjusting their mutual position made in the form of a drive shaft 3 mounting two coaxillay arranged cylinders 4. 5, said unbalance weigtLts 19 2 being secured to or cast integral with annular opposite chambers provided in the cylinders. The cylinder 4 secured to the driveshaft 3 by means of a retainer 8 has an extended hub 9 thereof carrying the cylinder 5 which is mounted slidable and turnable with respect to the hub. The cylinder 5 is enclosed along its periphery in a casing 10 rigidly secured to or cast integral with the cylinder.

The cylinder 5 is spring-loaded in an axial direction through the agency of a spring 11 fitted between the cylinder 5 and the cylinder 4 rigidly secured to the drive shaft 3. On the outer side, movement of the cylinder 5 is restricted by a flange 12 held to the drive shaft 3 by bolts 13. Torque transmission is affected by a joining member 14 (FIG. 2) provided on the inside sutface of the protruding portion of the casing 10. The joining member 14 can be made in the form of fine-module teetho splines, keying, etc. The joining member 14 engages with its mating joining member 15 provided along the Periphery of the cylinder 5. To allow the cylinder 5 to be brought out of engagement and return relative to the cylinder 4, thus adjusting the disturbing force, said joining members 14, 15 are provided with annular grooves 14a, 14b, 15c (FIG-3) S C1 9 made in such a way that their width 11111 and 'Is" is some- what greater than the width Ilk" of the protruding portions of the joining members 14, 15. These parameters are so selected that, when the cylinder 5 is moved to rest against the cylinder 4, it is possible for the spline crests of the joining member 15 of the cylinder 5 to engage in the grooves 14a, and 14b of the casing 10. The width 111" of the groove 14a, which determines the elastic travel of the cylinder 5 before it rests against the cylinder 4. For easy maintenance of the vibration generator, a mark 16 (FIG. 2) is provided at the periphery of the end of the cas4Lng 10, while a dial 16a graduated in per cent with respect to the maximum disturbing force, is provided at the periphery of the and face of the cylinder 5.

The drive motor comprises a housing 17 (FIG. 1) installed on a base 18, The housing 17 accommodates the drive shaft 3 which is journalled in bearings 19, 20 and extends on one side so as to receive the joined cylinders 4, 5 with enclosed unbalance weights 1, 2, and on the other side, so as to connect to a fixed electric mo tor 21 aligned axially with respect to the shaft. The diameter of the drive shaft 3 decreases, in steps, toward he hous' the electric motor 21. T Lng 17 is closed at its working end by a cover 22, while its top surface of-If 'ers a handling clip 23 -11"or carrying the vibration generator.

1 The vibration generator operates as follows.

In the initial positions the cylinder 5 engages, by its joining member 15, with its mating joining member 14 of the casing 10 so as to form an enclosed space, viz., a rotor with eccentric unbalance mass. Axial movement of the cylinder 5 is prevented by springs 11 and the flange 12. The disturbing force generated with the operation of the electric motor 21 is transmitted, via the unbalance weights 1, 2, to the drive shaft 3 and the housing 17, the amount of the disturbing force being dependent on the mutual position of the unbalance weights I and 2. For changing the amount of the disturbing force, the vibration generator must be stopped and the cylinder has to be moved, overcoming the tension of the spring 11, until it rests against the cylinder 4. At this, the protruded portiong of the joining member 15 will be in the grooves 14a, 14b. To set a required amount of the disturbing force, the cylinder 5 should be turned, while checking the amount of turn against the dial 10a, and released. The spring 11 will return the cylinder 5 in its initialposition where the joining member 15 engages with the joining member 14 of the casing 10 so as to form an operable rotor. Next, the drive motor 21 is started to continue treatment.

FIG. 4 shows an embodiment of the vibration generator whic.h. dif L ers from that describ ed above in that it- f or the drive shaft 3 and provides two supports 24 ard C_ 1 11 an appropriately changed mechanism for adjusting the mutual position of the unbalance weights 1, 2. Provision of two supports 24, 25 makes it possible to increase the mass of the unbalance weights 1.2, which sharply increases the disturbing force, thus extending the processing capacities of the vibration generator. The cylinder 5 is slidable in an axial direction until the joining member 15 is brought out of engagement with the joining member 14, since the clearance 11111 between the unbalance weight 1., 2 is similar in application to the groove 14a of the first embodiment described above and is somewhat greater than the width of projection of the joining portion Ilk", its movement being restriced by the end face of the cylinder 4. The cylinder 5 is provided with the hub 26. The cylinder 5 can be locked in the working position as follows. An axial hole 27 is provided lengthwise the axis of the drive shaft 3, on the opposite side of the drive motor 21. The axial hole receives a rod 28 whose one end terminates in a head 29, while its other end has a radial hole 30 adapted to take a radial retainer 31 extending also within a through radial slot 32 and interacting with an annular groove 33 provided in that surface of the hub 26 of the cylinder 5 which surface mates with the drive shaft 3.. The rod 26 is spring-loaded by means of the spring 11 fitted in a groove 34 of the drive shaft 3. The pararieters off the components described above are so selected as to enable the protruding portion of the jo:LTiing 1 12 member 15 to be brought out of engagement with the Joining member 14, and the cylinder 5 to be turnable adjustable.

The length of the hole 25 Is so selected as to allow for accommodation of the radial slot 32 effecting the inter action between the retainer 31 and the shoulders of the an nular groove 33. i.e., the cylinder 5. The width of'the slot 32 is so selected as to enable unhindered radial mo vement of the retainer 31. and Its length "all Is chosen to provide for a required length 11111 of travel of the cy linder 5. The length of the retainer 31 is so selected as to enable it to be freely fitted in the diametrically op posite portions of the annular groove 33. The width of the groove 33 is so selected as to allow for free accom modation of the retainer 31, and its depth Is so chosen as to be sufficient to ensure interaction between the shoulders of the groove 33 and the retainer 31.

f the rod 28 with the retainer 31, For the assembly o.

i.e., In order to fit the retainer 31 into the hole 30 of the rod 28, the hub 26 has a manufacturing hole 35 (FIG. 5) aligned with the annular groove 33. whileAts diameter is so selected as to allow for free passage of the retainer 31. After assembly, the manufacturing hole is closed by a Plug 36. For ease oil rotation of the cylinder 5, a serration 37 (FIG. 4) is provided on its protruding portion.

by The bearings 19 of the journal 38 are closed cover 38, and the bearing 20 of the journal 25 are closed 3 13 by a shoulder 39 of the drive shaft 3. which prevents the bearings from ingress of dust or leakage (ejection) of lubricant.

The vibration generator operates in the following manner. In the initial position, the joining member 14 engages with the joining member 15, the cylinder 5 being looked in position by the retainer 31 which is held in the annular groove 33 by means of the rod 28 and the spring 11. Upon starting the drive motor 21, the disturbing force generated by rotation of the unbalance weights 1, 2 is transmitted to the drive shaft 3. the supports 24, 25 and the housing 17.

For changing the amount of the disturbing force, the electric motor 21, hence the vibration generator has to be stopped. To readjust the amount of the vibrational force, the head 29 has to be depressed and the rod 28 has to be moved, overcoming the tension of the spring 11, so that the retainer 31 engaged in its hole 30 and interacting -he oylinder.

with the groove in the hub 26, should move IU 5 as to bring the joining member 15 out of engagement with the joining member 14 of the casing 10 until it should rest against the end face of the cylinder 4, where- by the protruding portion of the joining member 15 enters the clearance Ill", thus allowing the cylinder 5 to be turned. By tui-ning the head 29 of the rod 28 or the protruding portion of the cylinder 5 in the zone of the serrations 37, the cylinder 5 can be turned, while checking C 14 X the amount of turn against the dial 16a, to readjust the vibrational force for the required amount. After the head 29 has been released, the spring 11 will return the rod 28 to its initial position, thus entraining the retainer 319 and the cylinder 5, whose joining member 15 is brought into engagement with the joining member 14 of the casing 10 whereby an operable rotor is formed.

Another embodiment of the vibration generator is illustrated in FIG. 6. It differes from that described above in the construction of the mechanism for adjusting the initial position of the unbalance weights 1, 2. Pitted in the axial hole 27 of the drive shaft 3, under the retainer 31, are balls 40 adapted to interact with the rod 28. For this, the hole 27 is provided with a threaded portion 41, while the rod 28 has a threaded portion 42. A radial hole having a diameter sufficient to allow free movement of the retainer 31 and communicating with the axial hole 27, is provided in the drive shaft 3 to receive the retainer 31.

Parameters of the components of the vibration gene rator are selected on the base of the same principle, that is provision of a capability for the joining mem bers 14, 15 to disengage from each other. The length of axial movement of the cylinder 1.5 is selected to be sone what greater then the width of the joining member 14.

The length of the retainer 31 is chosen so as to enable interaction with the shoulders of the annular groove 33, 1 C for example, equal to the surn of the radius of the drive shaft 3 and the length of the groove 33- The end face of the retainer 31 adapted to interact with the balls 40, can be made in the form of a taper or hemisphere. The length of the rod 28, the number and diameter of the balls 40 and the diameter of the hole 27 are so selected as to allow interaction between the balls 40 and the retainer 31. The diameter of the balls 40 is selected so as to suit the condition of their positive moveability, i.e. 4 to 5 times less than that of the hole 27 the diameter of the retainer 31 being approximately equal to that of the hole 27. For easy maintenance and identification of the the retainer 31, a mark 44 is D-ro- vertical position o:L vided on the shaft 3. The outer end face of the cylindrical portion of the cylinder 5 has a flanged projecting member 45, which facilitates handling of the movable cylinder 55, The embodiment now under consideration differs in the operations involved in readjusting the disturbing force.

For changing the amount of the disturbing force, the electric motor 221 is to be stopped. To readjust vibrational force, the drive shaft 3 has to be placed so that the mark 44 is directed upward, which is indicative that the retainer 31 is in its uppermost, vertical position. Turning the head 29 releases the rod 28 which moves to increase the volLmqe of the space of the hole 27 tinF t Ils 40. The balls are caused to accommodat - Uhe ba- 1 Ck 16 spread over the hole 27 and the retainer 31 is brought down from the annular groove 33 to release the cylinder 5. The cylinder 5 is then moved lengthwise the axis of the drive shaft 3. through the agency of the'projecting member 45, until the joining member 15 is brought out of E' the casing 10, engagement with the joining member 14 of so that the cylinder 5 can be turned. The amount of turn is checked as against the dial 16a and the mark 16, until a required reading is obtained. The joining member 15 is again brought into engagement with the joining member 14 by reversing the axial movement. To retain the preset position, the head 29 is rotated to turn in the rod 28 which first presses the balls 40 together so as to urge the retainer 31 to move into the annular groove 33, and holding it therein, which prevents axial displacement of the-cylincler 5.

-arting the e] Upon st Lectric =otor 21, the unbalance weights 1, 2 transmit the disturbing force to the drive shaft 3, the support 24 and the housing 17.

I

Claims

CLAIMS:

1. A vibration generator comprising a drive shaft carrying unbalancing weights accommodated in two coaxial cylindrical housings having means engageable to couple the housings to rotate together, one housing being fast for rotation with the shaft, and the housings being relatively axially displaceable for disengaging the coupling means to permit relative rotation of the housings for adjusting the relative positions of the unbalancing weights about the drive shaft.

2. A vibration generator Comprising a drive shaft mounting unbalance weights, which are a clearance fit on the shaft and are turnable with respect to each other, and a mechanism for adjusting their mutual position, the adjusting mechanism being made in the form of two coaxial ly axrari6ed cylinder carrying the unbalance weights and joined 'together by joining menbers provided on their en gaging surfaGest one of the cylinders being rigidly mount ed on the drive shaft, while the other cylinder is mount ed so as to be turnable and axially traversable.

3. A vibration generator as claimed in Claiml where in the movable cylinder is spring-loaded in an axial direc tion, whereas the portions of the cylinders having joinin ing memIjers are provided with grooves whose width is greater trian the distance between the adjacent grooves.

1 C - 18 A

4. A vibration generator as claimed in Claim 2 wherein the movable cylinder has an annular groove provided at the point where it engages with the drive shaft, while the drive shaft has an axial hole terminating in a radial slot whose length is greater than the clearance between the unbalance weights, the axial hole in the drive shaft being adapted to receive a spring-loaded rod provided with a radial hol! disposed close to the annular groove, and a retainer being provided in the radial holes of the drive shaft and the rod.

5. A vibration generator as claimed in Claim 2 wherein the movable cylinder has an annular groove provided at the point where it engages with the drive shaft, while the drive shaft is provided with an axial hole having at its end a radial hole engageable with the annular groove adapted to receive the retainer, the axial hole accommodating the adjusting rod adapted to interact with balls arranged under the retainer.

6. A vibration generator as claimed in any of the Claims and made substantially as described above with reference to the accompanying drawings.

Published 1990 at The Patent Office. State House. 66 71 High H0100M. London WClA4TP.FurLher copies maybe obtained from The Patent Office Sa2es Branch. St, Mary Cray. Orpmgtor.. Kent BRS 3RD- Printed by Mu:t-;,i,_., . techniques Itd. St Mary Cray. Kent- Con I s7 T