GB1585733A

GB1585733A - Manufacture of arcuate articles

Info

Publication number: GB1585733A
Application number: GB240278A
Authority: GB
Original assignee: Daido Metal Co Ltd
Current assignee: Daido Metal Co Ltd
Priority date: 1977-01-24
Filing date: 1978-01-20
Publication date: 1981-03-11
Also published as: JPS5391063A; JPS5625896B2

Description

(54) MANUFACTURE OF ARCUATE ARTICLES (71) We, DAIDO METAL COMPANY LTD., a corporation organised under the laws of Japan, of 2, Sanage-cho, Kita-ku, Nagoya, Japan, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement : - The present invention relates to a method of manufacturing an arcuate article with a projection.

The conventional method of manufacturing an arcuate article with a projection us to punch out blanks of the desired articles successively from a sheet material by a press machine. The conventional method, however, is expensive because of its very poor yield of articles in relation to the sheet material; it requires about four times as much raw material as that portion of the material that actually becomes the articles, wasting about three-fourths of the raw material as scrap.

It is an object of this invention to increase the yield and reduce the wastage.

According to this invention a method of manufacturing an arcuate article with a projection comprises: cutting out from a strip polygonal work pieces each having a rectangular base portion and a projection, the work pieces being arranged with respect to the strip material with their base portions in overlapping relationship lengthwise of the strip and with their projections directed alternately in opposite lateral directions; and performing the following steps on each work piece: a step of positioning and clamping the work piece between an end surface of a fixed shaft, which shaft comprises a forming portion having a diameter equal to or slightly smaller than the inner diameter of the arcuate article, and an axially movable clamp member for defining together with the said end surface a predetermined clearance therebetween: a step of compressing the projection of the clamped work piece by exerting radial pressure on the projection towards the axis of the forming portion of the shaft; and a step of carrying out compressive bending of the base portion of the clamped work piece into an arcuate shape around the forming portion of the shaft by a pair of pressing means each comprising a roll provided with notched portions and actuated to move along a circular orbit concentric with the axis of the said forming portion of the shaft while rotating freely on its own axis, and a pressure cylinder for pressing the respective roll against the clamped work piece; firstly radially compressing the base portion of the clamped work piece adjacent both sides of the projection with the rolls towards the axis of the forming portion; and secondly effecting progressive compressive bending of the clamped work piece radially towards the axis of the forming portion by moving the pair of rotatable rolls about that axis from adjacent the sides of the projection towards the ends of the work piece.

An exemplary embodiment of the invention, and the conventional method for comparison, will now be described with reference to the accompanying drawings, in which : - FIGURE 1 is a schematic view showing the conventional method of manufacturing an arcuate article with a projection; FIGURE 2 is a schematic representation of a method of manufacturing an arcuate article with a projection in accordance with the present invention; FIGURE 3 and FIGURE 4 are perspective views of a cut out blank and a finished arcuate article made by the method of the invention; FIGURE 5 is a view showing the principle of a roll forming machine used in performing the method of the invention; FIGURE 6 is a cross-section taken along the line A-A of Figure 5; FIGURE 7 is a schematic view showing the movements of the rolls of the roll forming machine; FIGURE 8 is a schematic view showing the rotating mechanism of the roll forming machine; FIGURE 9 is a cross-section taken along the line B-B of Figure 8; FIGURE 10 is a fragmentary view showing how a cut-out work piece blank is bent in the roll forming machine; and FIGURE 11 is a cross-section taken along the line C-C of Figure 10.

For convenience of explanation, Figures 5, 8 and 10 show in the left-hand half the condition before the bending operation and in the right-hand half the condition during or after the bending operation. In fact the operations are conducted symmetrically on both sides.

Referring to Figure 1, there is illustrated a conventional method of manufacturing an arcuate article with a projection.

Arcuate blanks 2, each having a projection are punched out successively from a sheet 1 of the raw material using a press machine.

In that method a large proportion of the raw material is wasted as punched scrap, so the method has a very poor yield rate.

Figure 2 illustrates a method embodying the invention for manufacturing a semicircular thrust washer with a locking lip for use as a thrust bearing. A sheet 4 of raw material is divided by longitudinal slits 5 into several strips 3. Each strip 3 is then cut into polygonal blanks or work pieces 7 each having rectangular base portion and a projection 6. The work pieces 7 are arranged with respect to the strip 3 with their base portions in overlapping relationship lengthwise of the strip and with their projections 6 directed alternately in opposite lateral directions, as shown. The polygonal work pieces 7 are fed, one at a time, to a predetermined position on a roll forming machine 8 which is actuated successively to compress and bend each work piece 7 into a finished product 9, namely a semicircular thrust washer with a locking lip.

Figure 3 is a perspective view showing the shape, dimensions and structure of a work piece 7 prior to bending. It comprises a steel backing 10 lined with a layer 11 of a bearing alloy with which said backing is lined. The work piece has a base portion 12 and projection 6. The dimensions a and b are widths and c is the thickness of the bimetal material consisting of the steel backing 10 and the bearing alloy lining 11.

The widths a and lb of the work piece 7 are larger than the widths d and e of the finished product 9 shown in Figure 4, and the thickness c of the blank 7 is smaller than the thickness f of the finished product 9.

The work piece 7 shown in Figure 3 is formed into the shape shown in Figure 4 by means of a roll forming machine illustrated in Figures 5 to 11. The work piece 7 is bent by the roll forming machine into a semi-circular product having arc angle of 1800 and is reduced in width while being increased in thickness by a compressive force applied by the roll forming machine.

The compression accompanying the bending operation serves to prevent radial cracks occuring in the outer circumferential surface being bent, and further has the effect of making the widths and the thickness uniform.

The roll forming machine will now be described in more detail.

Clamping Mechanism First, a thickness-wise clamping mechanism 13 will be described with reference to Figure 9. This mechanism is used for setting the clearance between an end surface 17 of a thickness-wise clamp member 16 and an end surface 20 of a fixed shaft 18. It comprises a forming portion (a reduced diameter portion) 19 having an outer diameter equal to or slightly smaller than the inner diameter of the finished product 9 and an axial dimension equal to the desired thickness , of the finished product.

The clamp member 16 has a rod 22 passing through a bore 21 in the fixed shaft 18 and is axially movable therein by means of a clamp cylinder 23 ;so that the clamp member 16 can be caused to clamp and release successive work pieces 7. The end surface 17 of the clamp member 16 engages with the end surface 24 of the forming portion 19 of the fixed shaft 18, thus setting the clearance between the end surface 17 and the end surface 20 to the dimension f. An alternative form of clamping (not illustrated) would be to provide a separate clamp mechanism that would, for instance, hold a clamp member against the end surface 24 of the forming portion 19 of the fixed shaft 18 by a compressive force.

Compressing Mechanism A mechanism 25 for exerting compressive force on the projection 6 of the work piece 7 will be explained with reference to Figure 5 and Figure 6. This mechanism 25 is for pushing the projection 6 of the work piece 7 by a compressive force in a radial (vertical) direction relative to the forming portion 19 of the fixed shaft 18 until the width s is reduced to the width ',d of the finished product. The projection 6 is held and compressed by a cylinder 26 via a rod 27.

Roll Pressing Mechanism A roll pressing mechanism 28 will be explained with reference to Figures 5, 8 and 9. This is a mechanism for reducing the width b of the work piece 7 to the width e of the finished product 9 by means of a compressive bending force. A cylinder 29 acts via a slide 30 and a pin 31, 34 to advance a roll 33 radially towards the axis of the forming portion 19 of the fixed shaft 18. The roll 33 is provided with cut-away portions 32. The roll 33 is freely rotatable about its own axis by a frictional force applied at its periphery. Upon completion of the compression bending of the piece 7 in a width-wise direction (described below), the roll 33 comes out of the frictional contact with the work piece 7 and so becomes freely rotatable in the opposite direction by means of a spring (not shown) until it returns to the original position where a stop 35 is provided.

Rotating Mechanism A rotating mechanism 37 for the roll pressing mechanism 28 will be explained with reference to Figure 8 and Figure 9.

This mechanism is provided for progressively bending the work piece 7 in the circumferential direction (indicated by a downward arrow) into a semi-circle while the work piece 7 is being radially compressed by the above mentioned roll pressing mechanism 28. The axis of rotation of the roll pressing mechanism is concentric with the axis 0 (Figure 8) of the fixed shaft 18. This rotating mechanism 37 also causes the roll pressing mechanism 28 to rotate upwards in the direction indicated by upward arrow upon completion of the compressive bending of the work piece 7 so as to return the rolls to their original positions. Cylinders 38 push a rack 39 to rotate a pinion 40 which also meshes with gear teeth on a rotatable support 36 for the roll pressing mechanism 28 whereby the mechanism 28 is moved upwards or downwards in the directions indicated by arrows depending on the direction in which the rack 39 is pushed by the cylinders 38. The support 36 is rotatably mounted on a base plate 41 by a main bearing 42 and an auxiliary bearing 43.

The method of carrying out the invention by the apparatus described above will now be described. The work piece 7 is positioned by a transportation device (not shown) between the end surface 17 of the clamp member 16 of the clamping mechanism 13 and the end surface 20 of the fixed shaft 18 and is clamped by the clamp cylinder 23 through the tie-rod 22. At this time the! surface 17 of the clamp member 16 engages with the surface 24 of the forming portion 19 provided on the fixed shaft 18, as shown in Figure 6.

When the work piece 7 has been thus clamped, the compressing machine 25 compresses the projection 6 of the work piece 7 by means of the rod 27 until the projection is reduced in width to the desired dimension d of the final product 9 and holds the work piece against the forming portion 19 of the fixed shaft (see Figures 5 and 6).

Subsequent to the above-mentioned operation, each recessed roll 33 is pressed tightly against the base portion of the work piece 7 in the region 12 adjacent the sides of the projection 6, by means of the roll pressing mechanism 28, until the width b is reduced to the width e of the final product 9 (see, arrows (1) in Figure 7). Then, the rotating mechanism 37 comprising the cylinders 38, the rack 39, the pinion 40 and the toothed support 36 causes the whole roll pressing mechanism 28 to rotate in the downward direction, indicated by arrows concentric with the axis of the fixed shaft 18, while maintaining the compressive force and allowing each roll 33 to rotate around its pin 31, 34. When the roll pressing mechanism 28 has rotated through approximately 90 , the bending work is completed and the work piece 7 is formed into a semicircular shape (see Figures 5, 6 and 8 and arrows (2) in Figure 7).

Upon completion of the bending, each roll 33 comes out of frictional contact with the outer periphery of the work piece 7, and is rotated in the opposite direction by means of the said spring until it returns to its original position determined by the stop 35 (see Figures 5 and 8, and arrows (3) in Figure 7). Then, the rotating mechanism 37 is actuated to cause the entire roll pressing mechanism 28 to rotate concentrically about the axis of the fixed shaft 18 in the opposite (upward) direction through about 90 degrees until it returns to the original position prior to the bending operation (see Figure 8 and arrows (4) in Figure 7). Thereafter, the operations described above are repeated.

In this way, the whole forming operation, from the feeding of the work piece 7 which has been obtained through the cutting process to the roll forming machine 8 until the completion of the work for forming the final product 9, is carried out automatically and continuously. As illustrated in Figure 7, all forming operations, i.e., (1) compressing the projections 6, (2) compression bending, (3) disengagement from the workpiece upon completion of (2), and (4) return to the original position, of both the rolls 33, are carried out concurrently and symmetrically on both sides of the work piece with respect to the centre of the projection 6.

The forming portion 19 of the fixed shaft 18 is made either equal to or slightly smaller than the internal diameter of the finished product 9, depending on the characteristics of the raw material, for instance, with respect to its plastic deformation properties.

The type and construction of the material to be bent is not limited to bimetals comprising a steel backing lined with a bearing alloy as used in the described embodiment of the invention. Other bimetals of various combinations, single metals, trimetals and multilayer metals can also be used.

WHAT WE MAIM IS: 1. A method of manuafcturing an arcuate article with a projection comprising: cutting out from a strip polygonal work pieces each having a rectangular base portion and a projection, the work pieces being arranged with respect to the strip material with their base portions in overlapping relationship lengthwise of the strip ad with their projections directed alternately in opposite lateral directions; and performing the following steps on each work piece: a step of positioning and clamping the work piece between an end surface of a fixed shaft, which shaft comprises a forming portion having a diameter equal to or slightly smaller than the inner diameter of the arcuate article, and an axially movable clamp member for defining together with the said end surface a predetermined clear- ance therebetween: a step of compressing the projection of the clamped work piece by exerting radial pressure on the projection towards the axis of the forming portion of the shaft; and a step of carrying out compressive bending of the base portion of the clamped work piece into an arcuate shape around the forming portion of the shaft by a pair of pressing means each comprising a roll provided with notched portions and actuated to move along a circular orbit concentric with the axis of the said forming portion of the shaft while rotating freely on its own axis, and a pressure cylinder for pressing the respective roll against the clamped work piece; firstly radially compressing the base portion of the clamped work piece adjacent both sides of the projection with the rolls towards the axis of the forming portion; and secondly effecting progressive compressive bending of the clamped work piece radially towards the axis of the forming portion by moving the pair of rotatable rolls about that axis from adjacent the sides of the projection towards the ends of the work piece.

2. A method as claimed in Claim 1 wherein the rolls are returned automatically to their original positions ready for the next forming operation when they have passed the ends of the arcuate article on completion of the compressive bending.

3. A method as claimed in Claim 1 or Claim 2 wherein the axially movable clamp member has a rod passing through a bore in the fixed shaft, and clamping and releasing of the work piece is effected by moving the rod axially relative to the fixed shaft.

4. A method as claimed in any one of the preceding Claims wherein the rolls and pressure cylinders of the pressing means are caused to rotate about the axis of the forming portion of the fixed shaft concurrently and in opposite directions.

5. A method of manufacturing an arcuate article with a projection, substantially as described with reference to Figures 2 to 11 of the accompanying drawings.

6. An arcuate article with a projection, which has been manufactured by a method as claimed in any of the preceding Claims.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. combinations, single metals, trimetals and multilayer metals can also be used. WHAT WE MAIM IS:

1. A method of manuafcturing an arcuate article with a projection comprising: cutting out from a strip polygonal work pieces each having a rectangular base portion and a projection, the work pieces being arranged with respect to the strip material with their base portions in overlapping relationship lengthwise of the strip ad with their projections directed alternately in opposite lateral directions; and performing the following steps on each work piece: a step of positioning and clamping the work piece between an end surface of a fixed shaft, which shaft comprises a forming portion having a diameter equal to or slightly smaller than the inner diameter of the arcuate article, and an axially movable clamp member for defining together with the said end surface a predetermined clear- ance therebetween: a step of compressing the projection of the clamped work piece by exerting radial pressure on the projection towards the axis of the forming portion of the shaft; and a step of carrying out compressive bending of the base portion of the clamped work piece into an arcuate shape around the forming portion of the shaft by a pair of pressing means each comprising a roll provided with notched portions and actuated to move along a circular orbit concentric with the axis of the said forming portion of the shaft while rotating freely on its own axis, and a pressure cylinder for pressing the respective roll against the clamped work piece; firstly radially compressing the base portion of the clamped work piece adjacent both sides of the projection with the rolls towards the axis of the forming portion; and secondly effecting progressive compressive bending of the clamped work piece radially towards the axis of the forming portion by moving the pair of rotatable rolls about that axis from adjacent the sides of the projection towards the ends of the work piece.