Bearing assembly

Abstract

A bearing assembly is disclosed which addresses the problem of axially retaining a bearing journaled onto a shaft within a casing in an axially compact and technically economic and reliable way by first mounting a retaining plate ( 6 ) onto an outer race of the bearing ( 1 ). The mounting can be achieved by press fining onto a shoulder so that the retaining plate can rotate relative to the outer race. The bearing is then journaled onto a shaft ( 4 ) and inserted into a compact casing ( 3 ) so that the outer race is guided into a housing ( 2 ) formed in an end wall of the casing ( 3 ). The retaining plate can then be rotated as required to align fastening bosses ( 7 ) with holes ( 8 ) to be engaged by screws ( 9 ) so that the retaining plate us urged axially against the outer race.

1 . A bearing assembly comprising:
 a bearing ( 1 ) having an outer race for reception in a bearing housing ( 2 ) formed in a casing ( 3 ) and an inner race to be journaled onto a shaft ( 4 ), characterised in that   a retaining plate ( 6 ) is mounted onto the outer race before assembly into the bearing housing ( 2 ) and provided with fastening means ( 7 ) to cooperate with fastening means ( 9 ) provided in or on a wall of the casing ( 3 ) opposing the retaining plate ( 6 ).   
     
     
         2 . An assembly according to  claim 1  wherein the retaining plate ( 6 ) is mounted for relative rotation with respect to the outer race. 
     
     
         3 . An assembly according to  claim 1  wherein the retaining plate ( 6 ) is mounted by means of a press action loose fitting clinching lip ( 17 ) ( 17 ) formed on a circular inside edge of the retaining plate ( 6 ) which deforms plastically to engage in a circular groove ( 21 ) formed in a circular shoulder ( 20 ) in the outer race of the bearing ( 1 ). 
     
     
         4 . An assembly according to  claim 3  wherein the clinching lip ( 17 ) is formed only on spaced parts of the circular inside edge of the retaining plate ( 6 ). 
     
     
         5 . An assembly according to  claim 4  wherein the total circumferential length of the spaced parts is between 10% and 30% of the circumference of the inside edge. 
     
     
         6 . An assembly according to  claim 1  in combination with a shaft ( 4 ) on which are mounted components in such close proximity to the retaining plate ( 6 ) that a fastening tool cannot be operated between the components and the retaining plate ( 6 ). 
     
     
         7 . An assembly according to  claim 1  in combination with a bearing housing ( 2 ) formed in a casing ( 3 ) wherein once the bearing ( 1 ) is received into the housing, the casing ( 3 ) and components prevent a fastening tool from acting on the retaining plate ( 6 ). 
     
     
         8 . An assembly according to  claim 1  wherein the fastening means ( 9 ) comprises a screw received into a boss in the retaining plate ( 6 ) via a through hole formed in the casing ( 3 ). 
     
     
         9 . An assembly according to  claim 8  wherein the fastening means ( 9 ) act together to angularly align the retaining plate ( 6 ) to a predetermined orientation. 
     
     
         10 . An assembly according to  claim 1  wherein the retaining plate ( 6 ) includes further locating or retaining elements to locate or retain other components of the assembly. 
     
     
         11 . An assembly according to  claim 10  in combination with a gear box. 
     
     
         12 . An assembly according to  claim 11  wherein at least one further locating element is a hole or recess which receives an end of a gear change support rod. 
     
     
         13 . A method of forming a bearing assembly comprising the steps of:
 first mounting a retaining plate ( 6 ) on an outer race of a bearing ( 1 ) whereby, when the bearing ( 1 ) is subsequently seated in a bearing housing ( 2 ) it is axially retained by the retaining plate ( 6 ) which is secured by fastening means ( 9 ) acting between a casing ( 3 ) in which the bearing housing ( 2 ) is formed and the retaining plate ( 6 ).   
     
     
         14 . A method according to  claim 13  wherein the retaining plate ( 6 ) is mounted onto the outer race to rotate relative to the outer race. 
     
     
         15 . A method according to  claim 13  comprising the steps of:
 forming a shoulder on an outer edge of an outer race of the bearing ( 1 ), 
 forming a groove in the shoulder, 
 forming the retaining plate ( 6 ) by punching a hole in strip material, 
 punching a sizing nose onto the retaining plate ( 6 ) in an arc around the hole, 
 locating the hole of the retaining plate ( 6 ) over the shoulder and 
 pressing the retaining plate ( 6 ) axially against the side of the outer race to upset the clinching lip ( 17 ) so that a reshaped lip ( 17 ) is formed engaging in the groove. 
 
     
     
         16 . A method of forming a bearing assembly according to  claim 15  comprising the steps of forming a plurality of circumferentially spaced clinching lip ( 17 )s around parts of the circumference of the hole. 
     
     
         17 . A method according to  claim 15  wherein the clinching lip ( 17 )s are formed around arcs extending in total between 10% and 30% around the hole. 
     
     
         18 . A method according to  claim 13  wherein fastening means ( 9 ) is formed into the retaining plate ( 6 ). 
     
     
         19 . A method according to  claim 18  wherein the fastening means ( 9 ) is formed by punching a plurality of bosses through the plate around the hole. 
     
     
         20 . A method according to  claim 19  wherein the radius of curvature formed between the body of the plate and the boss complies with the formula:
   radius=plate thickness× A  
 
 
       where “A” has a value between 0.3 and 0.7 and the material from which the retaining plate ( 6 ) is formed has high strain hardening coefficient exceeding 0.35 such that the arcuate portion of the boss work hardens under load to produce a region having a high local tensile strength. 
     
     
         21 . A method according to  claim 13  wherein the material from which the plate is formed is selected from Austentitic stainless steel grade 304. 
     
     
         22 . A method according to  claim 13  comprising the steps of journaling the assembled bearing ( 1 ) and retaining plate ( 6 ) onto a shaft ( 4 ) in such close proximity to other components mounted on the shaft ( 4 ) that a fastening tool cannot operate between the components and the retaining plate ( 6 ). 
     
     
         23 . A method according to  claim 13  wherein
 the bearing ( 1 ) is journaled onto a shaft ( 4 ) and inserted into a bearing housing ( 2 ) formed in a casing ( 3 ), and 
 fastenings are driven through the casing ( 3 ) to engage the fastening means ( 9 ) formed in the retaining plate ( 6 ). 
 
     
     
         24 . A method according to  claim 23  wherein the fastenings are screws. 
     
     
         25 . A method of forming a boss in a plate to be subject to cyclic fatigue loads in use comprising,
 selecting the material of the plate to have a high strain hardening coefficient in excess of 0.35, and   press forming the boss against a die such that the radius of curvature of the region between the original plate and the wall of the boss complies with the formula:
   radius=plate thickness× A  
 
   where “A” has a value between 0.3 and 0.7 such that the arcuate portion of the boss work hardens under load to produce a region having a high local tensile strength.   
     
     
         26 . A method according to  claim 25  wherein the material of the plate is Austentitic stainless steel grade 304.