Self-steering bogies

A self-steering rail bogie, comprising:

• at least two axle structures including axles journalled in axle box bearings;
• and
• an inter-axle shear stiffening apparatus, said inter-axle shear stiffening apparatus comprising:
• an arm rigidly connected or connectable to each of said at least two axle structures of the bogie, said arms extending toward one another from said axle structures;
• a lateral force transmitting connector connected between and acting between the arms to transmit lateral forces between said arms such that, irrespective of the extent of relative movement between said arms, the lateral force transmitting connector transmits lateral forces of limited predetermined magnitude, said transmitted lateral forces being sufficient to provide inter-axle shear stiffness to enhance the hunting stability of the bogie but insufficient to impose excessive force couples on the axle box bearings.

A self-steering motorized rail bogie, comprising:

• at least two axle structures including axles journalled in axle box bearings, wherein said axles carry wheels;
• and
• an inter-axle shear stiffening apparatus, wherein the inter-axle shear stiffening apparatus is located inboard of said wheels, said inter-axle shear stiffening apparatus comprising:
• an arm rigidly connected or connectable to each of said at least two axle structures of the bogie, said arms extending toward one another from said axle structures;
• a lateral force transmitting connector connected between and acting between the arms to transmit lateral forces between said arms such that, irrespective of the extent of relative movement between said arms, the lateral force transmitting connector transmits lateral forces of limited predetermined magnitude, said transmitted lateral forces being sufficient to provide inter-axle shear stiffness to enhance the hunting stability of the bogie but insufficient to impose excessive force couples on the axle box bearings.

An inter-axle shear stiffening apparatus for a self-steering bogie having first and second axle structures including axles that are journalled in axle box bearings, comprising:

• a first arm rigidly connected or connectable to the first axle;
• a second arm rigidly connected or connectable to the second axle, said first and second arms extending toward each other when connected to the first and second axles, respectively;
• a lateral force transmitting connector connected between said first and second arms, said lateral force transmitting connector including a stiffening mechanism that transmits between said arms lateral forces having magnitudes less than a predetermined value for relatively small relative movement between the arms and transmits between said arms little or no lateral forces having magnitudes greater than said predetermined value, even for relatively large relative movement between said arms, wherein said lateral force transmitting connector comprises:
• a cam having a cam surface that includes a recess therein;
• a detent seated in said recess;
• and
• a spring urging said detent and said cam together such that said detent resists relative movement and transmits lateral forces between said arms when seated in said recess as long as the lateral forces are less than said predetermined value and unseats from said recess and transmits substantially no further lateral forces when the lateral forces exceed said predetermined value.