Patent GB-118640-A (GB)
Title: Improvements in and relating to the Manufacture of Track-rings for Ball and Roller-bearings.
IPC: B21K1/04
Filed: 1918-08-29
Abstract: 118,640. Aktiebolaget Svenska Kullagerfabriken. Aug, 31, 1917, [Convention. date]. Bearings and bearing surfaces.-Track rings for ball and roller bearings are made by cutting tubular blanks to suitable lengths, and giving each blank its desired cross-section by upsetting it in the longitudinal direction while the blank is fixed between a mandrel inserted therein and a die surrounding the blank. In the machines described, the mandrel is grooved when it is desired to form an inner shoulder en the ring, or the die is grooved when projections are to be formed on the outside of the ring, the die in the latter case being formed of a number of separate jaws movable in relation to each other. A tubular blank 6, Figs. 1 and 2, is placed so as to rest on a counter die 4 with its exterior in contact with a die 3 secured by screws to a holder 21 screwed to a block 23 which is placed on a machine table. A holder 9 connected with a movable member of the press is then depressed to bring into action an upsetting ring 1 which is so mounted relatively to the holder 9 that its motion is arrested momentarily when it engages the upper surface of the blank 6, Fig. 2. For this purpose, the ring 1 is mounted in a socket 10 screwed to a socket 11, which is normally held raised by the engagement of a flange 13 en the holder with a flange 12 on a socket 11. While the ring 1 is arrested a mandrel 2, which is mounted on a slidable rod 15 secured to a nut 16 guided by the engagement of a screw 17 with a groove 18, continues to move with the holder 9 owing to the action of a spring 19, and is brought into engagement with the head of a corresponding grooved mandrel 5 which is mounted in the spring-raised counter-die 4. The mandrels 2, 5 are depressed until the counter die 4 meets the head of a socket 24 in which the spring 25 is mounted, and at this time the Range 13 meets the socket 8, and the upsetting die 1 is positively depressed to upset the metal in a longitudinal direction and to form an inner shoulder on the ring by pressing it against the grooves ' in the mandrels 2, 5, Fig. 2. On the return of the holder 9, the finished ring adheres to the mandrel 2, and it is stripped therefrom by the arresting of the die 1 by a stripper 27 which acts on the flange 12 as the holder 9 ascends. The ring may be treated to form a second internal shoulder grinding out a groove near the internal shoulder formed as described. In a modification, for pressing inner track rings, a die is used composed of three separate jaws 29, Fig. 3, movable radially in relation to each other, and forming, when joined, an inner cylindrical surface having two annular recesses situated one each side of an annular rib of curved cross-section, said recesses and rib corresponding to the two shoulders of the ball track repectively of the finished track ring 30, Fig. 6. The jaws 29 have a conical outer surface and are movable endways in a conical recess formed in a die 31 and each end of them is guided by a wedge 32 fixed to the die. The jaws are held between a disk 33 and a ring 41 secured respectively by bolts 34, 40 to a plate 35, which is depressed against the action of springs 36 by the action of the mandrel 2 on a rod 42 attached to the plate 35 and passing through the counter-die 43 which in this case is formed with a groove at its upper end adapted to receive the mandrel 2 and is secured rigidly to the die holder 38. The movement of the plate 35 and its associated parts relatively to the die 31 causes the jaws 29 to move inwards and to bear against the blank 30. The upsetting ring 1 is arrested by the engagement of the lower face 4S thereof with the jaws 29 after the top part of the ring has been upset, and the operation is completed by depressing the die 31 relatively to its holder 38 against the action of springs 44 which normally press the die 31 against a ring 46 secured to the holder 38. The effect of the depression of the die 31 is to raise the counter-die 43 relatively to the mandrel 2, and the upsetting operation is thus completed from the bottom of the ring. In modifications, the jaws may be formed with more than two annular recesses, or the mandrel may be formed in several movable parts provided with several annular recesses for pressing, the outer track rings of ball bearings having track faces for several rows of balls.