DE2321449A1 - THORN FOR THE ASSEMBLY OF BUSHINGS - Google Patents

Description

Patent attorneys

Dr. Ing.Walter Abitz
Dr. Dieter F. Morf
Dr. Hans-A. Browns

8 Munich 86, Pienzenaueistr. 28

April 27, 1973 GT-678-F

THE GENERAL TIRE & RUBBER COMPANY One General Street, Akron, Ohio 44309, V. St. A.

Mandrel for assembling bushes

The invention "relates to an improved device for assembly of sockets and, in particular, an improved mandrel for use in assembling sockets to an annular elastomer insert between two concentric sleeves.

Bushings with an annular insert made of rubber or of a Elastomers between two concentric sleeves are known per se and have been used for many years. In general the bushing is used to mount a second part, for example a motor, on a first cable, for example on a Motor vehicle frame when the two parts need to move with respect to each other is used. The inner sleeve is, for example by means of a pin or bolt, attached to the first part and the outer sleeve to the second part. The relative axial,

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lateral and rotational movement between the "two parts is due." added the annular insert made of an elastomer or rubber.

If the rubber insert is compressed radially between the inner sleeve and the outer sleeve, an increased load capacity can be achieved and achieve service life. In such a bushing, the compression molded rubber insert is vulcanized and in held its position under radial pressure load. The restorative tendencies of the gum help create a relative movement between the insert and the sleeves.

A number of methods and devices exist for the installation of the elastomeric insert with radial pressure load between the inner sleeve and the outer sleeve, for example from U.S. Patents 2,690,001 and 2,660,780. In general, an apparatus for assembling rubber-to-metal bushings has a support on which an open ended guide funnel is carried is arranged. At the narrow end of the funnel there is a clamp in alignment with it for application the outer sleeve arranged. A punch is in axial alignment with and axially into the broad end of the funnel face anticipated. At the opposite end of the beam is a mandrel in axial alignment with the funnel. The mandrel is usually tapered or frustoconical Profile, with its smallest diameter approximately equal to or smaller than the annular opening in the rubber insert is, while its larger diameter is substantially equal to the outer diameter of the inner sleeve. The inner sleeve is behind the larger diameter of the mandrel for insertion into the insert.

The ring-shaped elastomer is used for assembling the bushing Insert between the punch and the wide end of the funnel

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arranged and inserted into the outer sleeve with the aid of the punch, which presses the insert through the wide end of the funnel to compress it into the outer sleeve, the one on the opposite side End of the funnel is arranged. The mandrel is then with the inner sleeve arranged behind it through the annular Pressed opening in the insert to place the inner sleeve in it. The punch and the mandrel are withdrawn around the to release finished aggregate.

An improved apparatus for forming and assembling rubber-to-metal bushings has also been proposed, e.g. in U.S. Patent 3,555,655. In this improved device a mandrel unit and a receiving unit are provided, which are located at a distance from one another and are axially aligned are. The mandrel assembly has an elongated enclosed mandrel cylinder with a piston located in the latter. A first stop surface serves to support one end of the elastomeric insert. Extends through the stop surface a rod, one end of which is connected to the piston, while its other end is formed with a head that is both a tapered tip as well as a frustoconical one Has wedge, the diameter of which decreases towards the opening through which it extends. The transition point between the tip and the frustoconical part forms a shoulder to rest against one end of the inner sleeve. The first stop surface and the mandrel can both move independently to and from the take-up assembly. The receiving unit has an annular stationary holder for the outer sleeve of the socket. A punch is provided which passes through the holder is movable in a direction to the mandrel and away from this and the one insert stop surface and an adjustment pin for has the inner sleeve. In operation, the mandrel with the tip and the conical part passes through the free or not first narrowed inner annular opening of the elastomeric insert

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through, whereupon the stop surface of the dome on the insert comes to rest and presses this into the outer sleeve, which is arranged in the receiving unit. When the first stop surface engages the annular insert and presses it into the outer sleeve, come the tapered tip and shoulder of the frustoconical part to rest on the inner sleeve, which is arranged on the punch of the receiving unit. The Stamp and the mandrel are then pushed back through the annular opening in the insert to insert the inner sleeve therein.

Both types of devices require a mandrel to be radial Expansion of the opening ... in the compressed elastomeric insert for inserting the inner sleeve. Both devices for Insertion of the inner sleeve require a large axial force not only because of the large radial forces of the compressed insert, but also because of the material-related high axial Frictional forces of the elastomer or rubber insert. Except the required high axial forces arise when assembling the bush, especially when inserting the inner sleeve, high noise levels, what unsatisfactory i

The invention avoids those present in the known devices Disadvantages due to the fact that a new type of mandrel is used in the device, which regulates the flow or the piling speed of the elastomeric insert during assembly. The mandrel according to the invention gives a uniform Ren contact of the elastomeric insert and the inner sleeve to more evenly tension and stretch across the sleeve do. Furthermore, the invention reduces the power expenditure and the noise during assembly achieved.

309846/0452

The General Tire & Rubber Co.

May 9, 1973

S ^0Τ - ⁶⁷ _Λ ⁸ ΐ321449

received on._JLiJ-l_.

The invention therefore creates an improved mandrel, which is suitable for use in both new and existing jack assembly devices. According to the invention is the tapering or frustoconical part of the dome or its segments of an η-th derivative of the displacement profile adapted and preferably either a constant acceleration or a constant speed profile.

In general, the smallest diameter of the dome is at the end or at the tip, which is first in the radially compressed one Use occurs. The diameter increases along its length to the rear part, which serves as a shoulder against which the front peripheral edge of the inner sleeve rests. Preferably the tip has a diameter smaller than that of the Insert opening is when it is radially compressed by the outer sleeve is. The diameter of the shoulder is preferably slightly larger than the outer diameter of the inner sleeve. The summit can be either oblong or blunt-nosed and the shoulder can either have an oblong or blunt-nosed attachment be for the axial support of the inner sleeve. The radial profile (xA) at each point (t) (where t is numerically equal to the axial Is the distance from the front point of the fir-tree profile to the point from which χΛ is to be determined) along the axial profile length t .. of the mandrel part according to the invention changes according to the following relationship:

= 1/2

4 -

1/2

S «s

whereby

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ORIGINAL INSPECTED

and where Q is a constant determined by the diameter and length values of the female insert, and further η is a positive integer equal to 1, 2, 3 ... η. A constant Velocity profile is obtained when η = 1 while a constant acceleration profile is obtained when η = 2.

A better understanding of the essence of the present invention and the profile relationships result from the following Description of a presently preferred embodiment in conjunction with the accompanying drawings, namely:

Pig. 1 is a view in elevation and partly in section of FIG Main parts of a device for assembling rubber-metal bushings;

Pig ·. Figure 2 is a sectional view of the elastomeric insert with various Relation parameters;

Pig. 3 is a sectional view of the elastomeric insert assembled with the sleeves as well as the relation parameters;

Pig. 4 is a partial view in section of a mandrel and an inner sleeve; which rests against the shoulder of the mandrel, and

Pig. 5 is an elevational view showing the diameter relationship between the constant acceleration mandrel and the Constant speed mandrel.

To facilitate understanding of the invention, Pig. 1 the main parts a conventional device 10 for the assembly of rubber-to-metal bushings is shown. The device 10 has two vertical support guides 11 arranged on a base 12. On the support guides 11 is an upper cross piece 13 as well a lower crosspiece 14 slidable. These cross pieces are provided with bearings 15 which slide against the guides.

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The upper cross piece 13 is provided with a cylindrical pneumatic ram 16 provided, which has an annular end face 17 of has such a cross section that it can act on the elastomeric insert A. The punch 16 is with a pneumatic Cylinder and a power source (not shown) connected.

The upper cross piece 13 is at its inner end with two connecting rods 18 connected, which in turn are connected to pistons (pneumatically or hydraulically operated), not shown, to move the crosspiece 13 along the guides 11. The crosspiece 13 also contains a funnel support 19 on which a Funnel 21 is attached in axial alignment with the punch 16. In the distance between the funnel 21 and the punch 16 and A cylindrical insert holder 22 is axially aligned with them. The holder 22 is attached to the upper crosspiece 13 and preferably has a diameter substantially equal to the outer diameter of the insert A.

At the outer ends of the crosspiece 13 there are two pneumatic ones or hydraulic working cylinder 23. Each cylinder is -preferably arranged on the top of the crosspiece 13 and with a cylindrical rod 24 which extends downwardly from the cylinder and is guided through an opening 26 in the crosspiece 13 is. The ends of the cylinder rods 24 are connected to the outer ends of the lower crosspiece 14. The cylinders 23 and the cylinder rods 24 serve to move the upper and lower crosspieces 13 and 14 with respect to one another.

The lower cross piece 14 contains an annular receiving element 27 for the outer sleeve, through which the outer sleeve B securely in an axially aligned position to the funnel 21 to the punch 16 and to the insert A is held. The receiving element 27 has a first inner annular shoulder 28 through which one

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axial movement of the outer sleeve B is prevented. A second inner shoulder 29 serves to stop a cylindrical insert 31 to keep. J) he stop 31 is with a splash 32 formed, the to the plant of the second shoulder 29 and to axial alignment of the stop 31 within) the receiving element 27 serves. The cylindrical opening 33 in the stop 31 has a diameter which is slightly larger than the outer diameter the inner sleeve C. The cross-sectional area of the flange 32 and the stop 31 can be of a size sufficient to to prevent the insert A from axial movement when inserting beyond the stop.

A mandrel spacer holder 34 is arranged on the base 12. A mandrel intermediate piece 36 is located within the holder 34. Both the intermediate piece 36 and the holder 34 are axially aligned within the receiving element 27 and the funnel 21. The intermediate piece 36 has a cavity 37 for securely holding and adjusting the dome 38. The mandrel 38 has an end portion 40 with a ratio according to the invention and explained in more detail below between diameter and length. First of all, be mentions that the tip of portion 40 has a diameter equal to, but preferably less than, diameter the annular opening through the insert A when it is fully inserted into the outer sleeve B. The rear end or the shoulder of portion 40 has a diameter equal to, but preferably greater than, the outer diameter of the inner sleeve C is. The mandrel 38 has an elongated cylindrical portion 41 which enters the cavity 37. The diameter of the cylindrical part 41 is slightly smaller than the inner diameter of the inner sleeve C.

In the operation of the door direction 10, the cross pieces 13 and 14 initially fully extended and spaced from each other. The punch 16 is fully withdrawn.

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An annular elastomeric insert A is inserted into the holder 22, brought an outer sleeve B into the receiving element 27 and arranged an inner sleeve C on the part 41 of the dome 38, the is then placed in the holder 34. The upper cross piece 13 is lowered so that the narrow end face of the funnel 21 is in contact and in alignment with the circumference send part of the sleeve B. is located. Then the punch 16 is actuated, whereby its surface 17 comes to rest on the end of the insert A and this is pressed through the large opening of the funnel 21 and then into the sleeve B through the small opening. The movement of the punch is brought to a standstill by suitable limit switches or the like when the insert .. A comes to rest against the stop 31. Then v / ground both the upper and the lower cross piece 13, 14 lowered by the connecting rods 18 so that the The mandrel 38, and in particular the part 40, passes through the opening 33 of the stop 31 and adjoins it through the compressed annular opening in insert A passes and this opens. The part 40 of the dome emerges from the insert A into the Opening 42 of the stamp 16 from. After the part 40 of the mandrel 38 has fully emerged from the insert A, the inner sleeve C is properly inserted and aligned within the assembly. The punch 16 and the cross pieces 13 and 14 are now withdrawn, whereupon the assembled socket is removed.

In 3 ig. 2 and 3 indicate the various reference values that are used to calculate the radial profile (the radius of the mandrel at each point (t) over the length t .. of the axial profile of the Part 40) of the mandrel 38, which are defined below:

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Xq = the inside diameter of the compressed insert A after, the insertion into the outer sleeve and before the insertion into the inner sleeve;

X ^ = the effective length of the insert A;

Xp = the effective length of the beveled end portions d * es Insert A (Pig. 2);

χ-, = the outside diameter of the insert A in its not compressed state;

x. = the diameter of the front edge of the insert A in Pig. 2;

Xr = the inside diameter of the uncompressed Insert A;

/
Xg = the inside diameter of the outer sleeve B;

x "= the outer diameter of the inner sleeve C;

t = numerically equal to the axial distance from the front one Point of the fir tree to the point from which χΛ is determined shall be;

ι .. is the axial length of the mandrel profile 40.

If the chamfered parts of the insert A (Pig. 2) are only extensions of the same and do not contribute to the elongation of the insert, Xp and x. both assumed equal to zero. It should also be mentioned that for the purposes of calculating the maximum radius χΛ of the dome it is preferable _{to take X 7} slightly larger than the actual outer diameter of the inner sleeve (see Pig. 4), for example x ^ = outer diameter

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of C + 0.7620 mm (0.030 ") for a smooth end and x _? = outside diameter of C + 1.270 mm (0.050") for a fluted end.

In Pig. 4 shows a mandrel with a constant acceleration profile, in which the value of X _{7 is increased} compared to the actual outer diameter of the sleeve C. FIG. X ₇ therefore refers in this case to the preferred diameter at the shoulder of the mandrel part 40. Furthermore, the diameter of the leading edge or the tip of the mandrel part 40, x _Q , should be slightly larger than the inner diameter of the compressed insert A, to only the To facilitate entry into this, for example 0.7620 mm (O.O3O ").

Fig. 5 shows the profile ratio between a mandrel for constant Acceleration and for constant speed. The thorn for constant speed is shown with solid lines, while the mandrel for constant acceleration is shown in dashed lines is shown.

The radial profile of the mandrels according to the invention from the η-th Ab-

t
line, where the radius (x ₇ ) of the mandrel at each point t over its length t ^ of 40 is:

1/2

1/2

T) _

(4th

4)

JO-

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Ui-

(x ² - χ ² '

^ x ₄ X ₅₁

and

η = 1, 2, 3 ... η.

The profile can change over its length so that there is more contains as a first derivative; for example η = 1 for one Part of the length, η = 2 for a part and the like »

I ¹ Ur a mandrel for constant acceleration is η = 2. Pur the radial profile:
speed is η = 1:

Pur the radial profile, χΛ, of a dome for constant geometry

= 1/2

t _y R

1/2

whereby

R =

(4 -

and

Q =

■ * ■ X ₂ / ν X ^ ~ X ₅ 4

Table 1 shows a comparison of the diameter of the mandrels for constant acceleration and for constant speed according to Pig. 5 given. The length of the mandrel portion 40, t, is 142.875 mm (5.625 "), x _Q was 47.752 mm (1.88") and X ₇ was 71.882 mm (2.836 ").

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A. 2321449 Table I. t in mm 2 * xX = diameter 2 - χΛ = diameter (in inches) for constant acceleration
inclination
in mm
(in inches)
(η = 2) for constant speed
age
in mm
(in inches)
(n = D 12.70 48.02124 51.62296 (0.5) (1.8946) (2.0324) 25.40 49.20488 54.89956 (1.0) (1.9372) (2.1614) 38.10 50.9016 57.72912 (1.5) (2,004) (2.2728) 50.80 53.06568 60.20308 (2.0) (2.0892) (2.3702) 63.50 55.56504 62.39256 (2.5) (2.1876) (2.4564) 76.20 58.24728 64.34836 (3.0) (2.2932) (2.5334) 88.90 61.01080 66.10604 (3.5) (2.4020) . (2.6026) 101.60 63.76416 67.69608 (4.0) (2.5104) (2.6652) 114.30 66.43624 69.09300 (4.5) (2.6156) (2.7222) 127.00 68.90680 70.56468 (5.0) (2,716) (2.7742)

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Different mandrel lengths both with a constant acceleration profile as well as having a constant velocity profile have become more "familiar" with conventional tapered mandrels per se Kind of compared. The conventional mandrels used for comparison had a value for t ^ of 50.80 mm (2 "), one straight taper (P) and a straight taper (t ..) of 50.80 mm (2 ") with a blunt nose (B). The mandrel profiles according to the invention used for comparison were:

mandrel

profile

mm

customs

2.5 A. '63.50 2.5 " 2.5V 63.50 2.5 " 1.75 A. 44.45 1.75 " 1.75V 44.45 1.75 " 1.00 A 25.40 1.00 " 1.00 V 25.40 1 .00 "

Constant acceleration Constant speed Constant acceleration Constant speed Constant acceleration Constant speed

Table II compares the assembly forces required to insert the inner sleeve C into the radially compressed insert A required for the conventional mandrels P and B and for the mandrels profiled in the manner indicated above are.

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Table II Inner sleeve installation forces "for various mandrel designs

Average value of the force on the metallic inner sleeve of three assemblies, per test in kp (l "bs.)

Dornbau test 1 test 2 test 3 test 4 Average value form of 4 tests

mm (inches) mm (inches) mm (inches) mm (inches) mm (inches)

2.5 A. 1 A. 53.070 58.513 45.359 48.988 51,483 (117) (129) (100) (108) (113.5) 2.5 V V 73.028 48,534 61.235 42.184 56.245 (161) (107) (135) (93) (124.0) P. A. 30.181 80.740 105.687 101.151 104.440 (287) (178) (233) (223) (230.25) B. V 84.822 77.111 76.204 64.864 75.750 (187) (170) (168) (143) (167.0) 1.75 KLonstantent 57.153 55.792 54.885 51.256 54.771 (126) (123) (121) (113) (120.75) 1.75 71.214 48,081 62,596 69,400 62.823 (157) (106) (138) (153) (138.5) 1.00 72.575 81.193 71.668 92.079 79.379 (160) (179) (158) (203) (175.0) 1.00 71.214 63,049 88.904 80.740 75.977 (157) (139) (196) (178) (167.5)

A ...: welding machine settings

1. Main ram - 4.90 kp (70 psi)

2. Stamp TrnlTjen - 3.15 kp (45 psi)

B «. . GircDlite Oil

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Table III comparatively shows the mean value of the force required for the onset of those provided with a thick phosphate layer metallic inner sleeve in the conventional mandrel and in the inventive Thorns is required.

Table III

Heavily phosphate- coated metals mandrel Average force in kp (lbs.)

2.5 A. 2.5 Y P. B. 1.75 A. 1.75 Y 1.00 A.

in mm in inches (Heavy fuel oil
necessary) 73.028 161 86.183 190 204.117 450 192.777 425 (Heavy oil he
conducive) 101.151. 223 107.048 236 177.355 391 136.985 302

1.00 V
Note: Sun 2150 was used as the heavy fuel oil.

As can be seen from Tables II and III, is the force required to insert the inner sleeve into the compressed elastomer Insertion is required through thorns of the n — th derivative and especially with thorns that have either a constant acceleration profile or a constant speed have profile according to the invention. At the same time, the mandrels according to the invention also reduce the noise during assembly achieved.

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Although it is preferable that the profile follow the foregoing at each point t specified ratios over the length of the dome Of course, rectilinear approximations can produce essentially the same results with reduced machining costs of the thorn profile can be achieved.

Furthermore, the tip of the mandrel part 40 can of course be rounded (Pig. 1) or blunt (Pig. 5) or elongated, as in Pig. shown. For example, in the Palle is in Pig. 4, the elongation of the tip is approximately 12.70 mm (1/2 "). At each point along the tip the diameter is equal to x _Q. An elongation of the tip would be required if the inventive mandrel were to be used in the device U.S. Patent 3,555,655 is used.

Although the foregoing has described in detail the presently preferred embodiments of the invention, the invention can experience various other refinements within their framework.

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Claims (9)

Claims ^x o ³ V = ^X 5 ^X 6 X ₇ = the inner diameter of the compressed annular insert; ■ = effective length of the annular insert; = Length of any reduction in the insert that contributes to its elongation; Xp = 0 does not contribute to elongation; = Outside diameter of the undeserved stake; = front diameter of part x ₉ ; x i = 0 when X ₂ = 0; ■ = inside diameter of the uncompressed Use; = Inner diameter of the outer sleeve; = Outer diameter of the inner sleeve; = an integer 1, 2, 3 ... n. - 18 - 309846/0452 GT-678-F 2. mandrel according to claim 1, characterized in that Xq is slightly is smaller than the diameter of the opening of the compressed insert. 3. Mandrel according to claim 2, characterized in that X _{7 is} slightly larger than the outer diameter of the inner sleeve. 4. mandrel according to claim 3, characterized in that x '' is the same the outer diameter of the inner sleeve plus between 0.7620 mm. and 1.270 mm (0.030 "and 0.050») 5. mandrel according to claim 1, characterized in that η at least is an integer selected from the group of positive integers. 6. mandrel according to claim 1, characterized in that η is a whole Number is selected from the group of integers 1,2 and 3 is. 7. mandrel according to claim 6, characterized in that Xq is slightly is larger than the diameter of the compressed insert. 8. mandrel according to claim 7, characterized in that x "slightly is larger than the outer diameter of the inner sleeve. 9. Mandrel according to claim 6, characterized in that x "equals the outer diameter of the inner sleeve plus is between 0.7620 mm and 1.270 mm (0.030 »and 0.050"). - 19 - 309846/0452