FR2652141A1 - BALANCING WEIGHT FOR ARTICULATED TRANSMISSION SHAFTS WITH CARDAN JOINTS. - Google Patents

Abstract

This balancing weight for a rotating shaft, in particular an articulated transmission shaft with Cardan joints (1), comprises a sheet metal weight (2) representing the weight, which is assembled to the shaft by two or more zones spaced fasteners (12, 13). To give a long life to the shaft subjected to torsional and bending stresses, the sheet metal flyweight 2 has a relief groove (19, 20) surrounding the fixing zones (12, 13).

Description

The invention relates to a balancing weight

  for balancing the masses of rotating shafts, in particular

  articulated transmission shafts with cardan joints, comprising a weight plate weight representing the weight and which is fixed to the shaft by two zones of

spaced fixing.

  In rotary shafts, including articulated transmission shafts, it is known to fix weights of the kind mentioned above on the surface of the transmission shaft hinged by spot welds or bosses. Fixing balancing weights by

  welding results in a decrease in the mechanical

  that considered elements of the tree in almost all cases in the region of the weld button. Dots

  thus favoring the starting points of rupture

  re possible from the shaft under load and there is therefore the risk of destruction during transmission torque. The destruction occurs by cracking

  at an angle of approximately 45 to the longitudinal axis

  dinal of the tree and is characteristic of

  load of the shaft under torsional stress.

  We already know, by the DE-U 74 17 307, the setting

  in form and the use of a balancing weight

  two spaced fixing points. In this known embodiment of the balancing weights, the attachment zones are constituted by bosses whose balancing weight is provided to ensure the precise fixing at the time of placement in the welding electrode or in the welding device. Flexural torsion stress is not taken into consideration by giving a particular configuration to the sheet or

welding areas.

  Starting from this state of affairs, the invention is

  purpose is to create a balancing weight for

  especially for articulated shafts with cardan joints, which has a high resistance to

  vibration and good long-term resistance under

  twisting and flexing of the shaft, and which

  long life to the latter.

  According to the invention, this problem is solved by the fact that the sheet weight is provided with a groove.

  Discharge around the attachment areas.

  The presence of the common discharge groove around the attachment areas leads to an improvement

  resistance to vibration in the presence of a

  bending and twisting stresses and avoids the crack initiation of the tree. This brings in particular an important advantage in the case of transmission shafts

  articulated with thick-walled cardan joints.

  In one embodiment of the invention, it is provided that the discharge groove is provided in

each fixing area.

  The arrangement of the discharge groove around each fastening zone also leads to the advantages

  already exposed and represents another possibility for

lisation.

  In another embodiment, it is pre-

  since the sheet weight has two or more fastening zones, placed at a mutual spacing

  as large as possible, who are disposed in the di-

  longitudinal and / or circumferential rection of the

ber.

  By using two or more fix points

  tion, we ensure better retention of the weights in

  sheet metal on the shaft, the fixing areas that can be

  in the longitudinal direction or in the direction

  circumferential motion of the shaft, according to the unbalance to compensate. In one embodiment of the invention, it is provided that the attachment zones are constituted

  by welding points on bosses.

  Thanks to the fact that the fixing zones are constituted by zones of welding, the weights in

  sheet metal can be fixed in a welding installation

  on bosses, in a particularly economical way and without preparatory work. The function of the discharge groove here is to receive the weld seam and

  to guarantee an advantageous conformation.

  The conformation of the weld point, which is

  geometrically more advantageous in the case of welds

  on bosses than in the case of

  the free discharge groove reduces the effect of

  size of the welding boss. On the other hand, the discharge groove can better compensate for the geometric deviations from the resulting boss shape and the radii of curvature of the sheet weight and the shaft tube which are contained within the tolerances. This ensures that after welding, the sheet weight is

applied over its entire surface.

  In another embodiment of the invention,

  tion, it is intended that the contact region which is associated

  on the underside of the sheet metal counterweight.

  to the present tree, for the formation of the point of

  welding, a weld boss of a flattened convex shape

  which projects beyond the general plan of the mass

monkfish sheet.

  The presence of the protruding weld boss

  me the point of contact for welding electrodes

  be the tree and the weight of sheet metal.

  In one embodiment of the invention, it is provided that the attachment zones are formed by assemblies made using fastening elements.

mechanical, including screws.

  A fixation made, for example, by a

  seems to be another possibility in

  and allows, thanks to the discharge groove of the sheet weight, to reduce the torsional stress

  and bending which must be transmitted to the piercing practically

  in the tree by the sheet metal weight. In a

  embodiment of the invention, it is expected that the attachment areas are formed by holes and made on the underside facing the shaft, flat on the sheet weight. The fact that the underside of the weight

  sheet metal is flat ensures application by surface area

pletes on the articulated tree.

  In the embodiment of the invention, it is provided that, depending on the shape of the attachment zones, the discharge groove surrounds the attachment zone with a

  oval, annular or elongate shape.

  This conformation of the discharge groove makes it possible to manufacture sheet metal weights mechanically.

  with low manufacturing costs and gives an aptitude for

  deformation particularly advantageous when

  the weights are loaded by torsional constraints

  sion and bending. At the same time, the discharge groove

  ge can receive excess material from the solder lens. In addition, the reduction of the thickness of

  wall in the area of the welding lens is

  by a concentrated heat input in the solder lens and in the thermal influence zone during annealing. Thanks to the reduction of the thickness of the wall in the region of the boss, one can be satisfied

  lower welding power and, consequently,

  a smaller amount of heat to bring

  for welding and thus avoids deformation of the

  during the welding operation.

  According to another characteristic of the invention,

  it is expected that the sheet weight is to conform

  rectangle and curved and that its curvature is

adapted to the tree.

  The curved shape of the sheet metal weight

  re an application on the tree by all its surface,

  with simplification of the execution of the welded joint.

  In a device used for forming the welded joint using a boss welding machine and electrodes belonging to this machine, and for

  to mount a sheet weight on a rotor, in particular

  bind on an articulated shaft with gimbal joints, it is expected that the second electrode is supported only on

  limited contact areas in the region of the

  this upper part of the sheet metal weight, which is at the oppo-

se welding lenses.

  The conformation of the electrodes on the machine to

  welding on bosses has the effect, on the one hand, of trans-

  put the necessary application pressure on the shaft and, on the other hand, establish the welding contact with the shaft and with the sheet weight. Here we obtain a particularly uniform welded joint, having two spaced fixing points when, as obtained in the device, a distribution is established.

  Uniform current on the soldering points. The electro-

  associated with the sheet weights therefore has a

  circular me of radius inferior to the radius of the masselot-

  You are in sheet metal. The electrode is thus supported on the masselot-

  sheet metal by two contact surfaces which are

  in the immediate vicinity of the weld points.

  Other features and advantages of the

  will be better understood when reading the description of

  The following is a description of several exemplary embodiments and with reference to the accompanying drawings, in which: FIG. 1 is a view partly in section of an articulated transmission shaft with cardan joints; Figures 2a and 2b show a flyweight having two attachment points, a top view and a side view in section; Figure 3 is a sectional side view of two attachment points before and after attachment to the shaft by welding;

  Figure 4 shows two other forms of reali-

  fixing areas; Figure 5 shows an attachment zone for a mechanical assembly;

  FIG. 6 represents a schematic layout

  only a welding machine on bosses; FIG. 7 represents an electrode in the form of the machine for welding on bosses, with the flyweight

in sheet metal set up.

  FIG. 1 shows a cardan joint articulated transmission shaft 1 which is provided with

  of sheet weights 2 according to the invention. The artificial tree

  1 is composed of two Cardan joints 3 which are joined together in rotation, but with relative freedom of movement, by a connecting shaft 4. The articulated joints 1 comprise an inner fork 5

  and an outer fork 6 which are joined by a cross

  groove 7 so as to oscillate relative to each other in two planes. The outer fork 6 has

  a flange 8 which serves for connection to an element of ma-

  China or vehicle that is engine or receiver. The two inner forks 5 of the joints are joined to each other by the connecting shaft 4. The connecting shaft 4 comprises a sliding inner portion 9 and an outer sliding portion 10, the latter having a groove profile in his bore and the

  sliding inner part 9 being fitted into this

  the outer part by a complementary groove

  provided on its outer surface, so as to be

  bound integrally in rotation and free in axial translation. The inner sliding portion 9 is joined to the other inner seal fork 5 by a connecting tube 11 which, in general, serves to adapt the length

  articulated driveshaft 1 in case of application

considered.

  The articulated shaft 1 is balanced after its

  to achieve the necessary balancing quality

  which is required for the particular application case

  flabbergasted. To balance the tree, we use pre-

  felt in the form of sheet metal weights 2

  mounts preferably one or more on the connecting tube

  11 or on the outer sliding portion 9. The fixing of the sheet weights 2 is carried out either by welding on bosses, by means of a boss welding machine, or by a screw connection on the connecting tube 11 The sheet feeder 2 shown in FIG. 1 is welded to the connecting tube 11 by

  example by two attachment zones 12, 13.

  We can see in Figure 2 that the weight

  rectangular sheet 2 is fixed by two fixing

  12, 13 and is adapted to the connecting tube 11 by its

  14. The two attachment zones 12, 13 present

  tent on the upper face 15 of the sheet metal weight

  2 two deepening rounds 16, 17 which are of a

  imposed me by the technique of manufacture. On one side

  18, are arranged around the fixing zones

  12, 13, two annular discharge grooves 19, 20 which receive the excess material after the boss welding. In the discharge grooves 19, 20,

  find the welding lenses 21, 22 which are

  The welding lenses 21, 22 project beyond the lower face 18 and come into contact with the connecting tube 11 and represent at the same time

  the point of contact for the bossing machine

  between the articulated shaft 1 and the sheet weight 2.

  In FIG. 2b, there is furthermore shown a

  plate weight 2 with its lower face 18, which pre-

  in addition to the two discharge grooves 19,

  , a discharge groove 34 which connects the first.

  FIG. 3 shows the attachment of the sheet weights 2 to the connecting tube 11, the sheet weights 2 being shown before the boss welding on the left side of the figure and after

  Embossed welding on the right side of Figure 1.

  The sheet weight 2 is in contact with the tube of

  connection 11 by the welding lens 21 before the operation

  welding, and after welding, it relies almost all of its lower face 18 on the connecting tube 11, the welding lens 22 then filling

  partially the annular groove 20 and being partially

  inserted into the material of the connecting tube 11. The

  annular groove 19 which still remains allows the mas-

  selects the absorption of flexural stress and

  torsion when the connecting tube 11 undergoes a constraint

te of couple.

  In FIG. 4, two other zones

  welding nes which are respectively of configuration

oval and elongated.

  Figure 5 shows a reciprocating sheet weight.

  tangular 2 which has a hole 33, with an

  preinte 16 to form the attachment zone 12, and

  an annular discharge groove 19 on its underside

  18. The lower face 18 of the counter weight

  the 2 is here planar configuration to better apply

quer on the tree.

  FIG. 6 schematically shows the arrangement for a boss welding machine which comprises a lower electrode 24 and an upper electrode 25,

  the lower electrode 24 serving to receive the masselot-

  2 and the upper electrode 25 is fixed to the upper pressure cylinder 27 of the boss welding machine by two fixing screws 26. The sheet weight 2 is arranged in the lower electrode 24 before the operation of welding and is pressed against the articulated shaft 1 which has been placed in the desired angular position. The required welding pressure is

  produced by the compression cylinder 27 during the operation

  welding. The supply of current to the bosses of sou-

  21, 22 takes place through the two elec-

  trodes 24, 25 and focuses in touch points

  between the shaft 1 and the sheet weight 2 which are

  driven by the welding bosses 21, 22.

  Figure 7 shows an internal welding electrode

  bottom 24 of the boss welding machine, which pre-

  a fixing groove 23 and a contact surface

  round tact 28, which serves to support the weight

  sheet 2. The contact surface 28 is shaped

  to have a radius 29 which is smaller than the radius 30 of the sheet metal weight 2. This

  way a support of the weight plate 2 on the electro

  24 in two contact surfaces 31, 32, and this is

  by a concentration of the welding current in

  the welding bosses 21, 22, with a uniform distribution

  shape on the two welding bosses 21, 22 present.

  Of course, various modifications may be made by those skilled in the art to the device which has just been described by way of non-limiting example without

depart from the scope of the invention.

R E V E N D I C AT ION S

  1. Balancing weight for the balancing of rotary shaft masses, in particular

  articulated gimbal transmission (1), comprising

  a sheet weight (2) representing the balancing weight, which is fixed to the shaft by two zones of

  spaced apart fastenings (12, 13), characterized in that the mas-

  sheet salt (2) is provided with a discharge groove

  (19, 20, 34) in the area surrounding the fixing points

tion (12, 13).

  Balance weight according to Claim 1, characterized in that the discharge groove (19, 20) is arranged around each of the fastening zones.

(12, 13).

  3. Balance weight according to the claim

  1, characterized in that the sheet weight (2) pre-

  two or more attachment areas (12, 13) with as wide a distance as possible, which are arranged in the longitudinal direction and / or the

  circumferential direction of the tree.

  Balance weight according to Claim 1, characterized in that the fastening regions (12, 13)

  are constituted by weld points on bosses.

  5. Balance weight according to claim 4, characterized in that the contact region associated with the underside (18) of the sheet weight (2) which is directed towards the shaft has, to form the weld (12, 13), a weld boss (21, 22) of a flattened dished shape which protrudes beyond

the sheet weight (2).

  Balancing weight according to Claim 1, characterized in that the fixing regions (12, 13) consist of an assembly executed using

  mechanical fasteners, in particular screws.

  Balancing weight according to Claim 6, characterized in that the fastening zones (12, 13) consist of bores (33, 34) and are formed on the lower face (18) directed towards the shaft, in

  the plane of the main surface of the counterweight

the 2).

  Balance weight according to Claim 2, characterized in that the discharge groove (19, 20)

  surrounds the attachment area (12, 13) with an oval shape

  the, annular or elongated, according to the shape of the zone of

fixation.

  Balance weight according to Claim 1, characterized in that the sheet weight (2) is

  of rectangular and curved shape and that the cour-

bure is adapted to the shaft (1).

  10. Device for forming a gasket

  with the aid of a boss welding machine and electrodes (24, 25) belonging to this machine, for fixing a sheet weight (2) to a rotor, particularly to

  an articulated transmission shaft (1) with

  dan according to one or more of claims 1 to 7,

  wherein one of the electrodes (25) is provided with a trough

  of receiving the tree, characterized in that the second

  electrode (24) is applied only by

  these limited contacts (31, 32) in the region of the

  this upper (15) of the sheet weight (2) which is

  opposite to the welding lenses (21, 22).

  11. Device according to claim 10, characterized

  characterized in that the second electrode (24) has a semicircular trough having a lower radius (29)

  to that of the sheet weight (2).