Abstract: A friction test apparatus includes a base structure and a receptacle secured to the base structure. At least three lower test balls are positioned in the receptacle. The friction test apparatus includes a motor having a rotatable shaft providing powered rotation of the shaft. An upper test ball is positioned on the shaft in a chuck, and contracts the at least three test balls in the receptacle in use. The chuck may include tapered inner surfaces that frictionally engage the upper test ball along a substantially continuous ring of contact to prevent rotation of the upper test ball relative to the chuck during operation. The receptacle may include a fluid inlet and a fluid outlet to permit fluid in the receptacle to be changed.

Abstract: A friction test apparatus includes a base structure and a receptacle secured to the base structure. At least three lower test balls are positioned in the receptacle. The friction test apparatus includes a motor having a rotatable shaft providing powered rotation of the shaft. An upper test ball is positioned on the shaft in a chuck, and contracts the at least three test balls in the receptacle in use. The chuck may include tapered inner surfaces that frictionally engage the upper test ball along a substantially continuous ring of contact to prevent rotation of the upper test ball relative to the chuck during operation. The receptacle may include a fluid inlet and a fluid outlet to permit fluid in the receptacle to be changed.

Abstract: A friction test apparatus includes a base structure and a receptacle secured to the base structure. At least three lower friction surfaces are positioned in the receptacle. The friction test apparatus includes a motor having a rotatable shaft providing powered rotation of the shaft. An upper friction surface is positioned on the shaft in contact with the at least three friction surfaces in the receptacle. The receptacle includes a fluid inlet and a fluid outlet to permit a fluid in the receptacle to be changed.

Abstract: A friction test apparatus includes a base structure and a receptacle secured to the base structure. At least three lower friction surfaces are positioned in the receptacle. The friction test apparatus includes a motor having a rotatable shaft providing powered rotation of the shaft. An upper friction surface is positioned on the shaft in contact with the at least three friction surfaces in the receptacle. The receptacle includes a fluid inlet and a fluid outlet to permit a fluid in the receptacle to be changed.

Abstract: A four-ball test apparatus for evaluation of friction and wear characteristics of lubricants is disclosed. The test apparatus includes a motor and adjustable weight assembly that is supported by the upper test ball on the lower test balls positioned in a test cup. All of the weight of the motor/weight assembly is supported by the test ball itself, and thrust bearings or the like are not required for support of the test cup. The four-ball test apparatus eliminates numerous sources of error found in prior four-ball testers, and permits various instruments or fluid lines to be connected to the test cup without introducing errors into the test measurements.

Abstract: A four-ball test apparatus for evaluation of friction and wear characteristics of lubricants is disclosed. The test apparatus includes a motor and adjustable weight assembly that is supported by the upper test ball on the lower test balls positioned in a test cup. All of the weight of the motor/weight assembly is supported by the test ball itself, and thrust bearings or the like are not required for support of the test cup. The four-ball test apparatus eliminates numerous sources of error found in prior four-ball testers, and permits various instruments or fluid lines to be connected to the test cup without introducing errors into the test measurements.