The purpose of the present invention is to increase the pressure of fuel while reducing an increase in the maximum lift amount of a cam and deterioration of a fuel injection ability. This cam for use in a fuel injection pump that increases the pressure of fuel supplied into a fuel supply chamber by an axial movement of a plunger. The cam includes a first cam surface that causes an increase rate of an axial speed of the plunger when the cam rotates at a constant speed, in a pre-stroke period until the plunger increases the pressure of the fuel in the fuel supply chamber, to be a first increase rate, and a second cam surface that causes the increase rate of the axial speed of the plunger when the cam rotates at the constant speed, in a pressure increasing period that is a period from a start of increasing the pressure of the fuel in the fuel supply chamber by the plunger, to be a second increase rate, wherein the first increase rate is set higher than the second increase rate.

A fuel injection pump pressurizes and injects fuel. A cam rotates about a rotational axis of the cam. A housing includes a cam chamber that houses the cam and a sliding chamber communicated to the cam chamber. A roller rotates while being in contact with a surface of the cam. A shoe reciprocates in the sliding chamber by rotation of the cam and is in contact with and slides on a surface of the roller. A plunger reciprocates with the shoe. A cylinder houses the plunger and includes a pump chamber to pressurize and feed the fuel by reciprocation of the plunger. A deformed section is a groove or a protrusion which extends in a direction of a rotational axis of the cam, on a part of a surface of the cam, and has a shape different from a cam profile of the cam.

A fuel injection pump pressurizes and injects fuel. A cam rotates about a rotational axis of the cam. A housing includes a cam chamber that houses the cam and a sliding chamber communicated to the cam chamber. A roller rotates while being in contact with a surface of the cam. A shoe reciprocates in the sliding chamber by rotation of the cam and is in contact with and slides on a surface of the roller. A plunger reciprocates with the shoe. A cylinder houses the plunger and includes a pump chamber to pressurize and feed the fuel by reciprocation of the plunger. A deformed section is a groove or a protrusion which extends in a direction of a rotational axis of the cam, on a part of a surface of the cam, and has a shape different from a cam profile of the cam.

The purpose of the present invention is to increase the pressure of fuel while reducing an increase in the maximum lift amount of a cam and deterioration of a fuel injection ability. This cam for use in a fuel injection pump that increases the pressure of fuel supplied into a fuel supply chamber by an axial movement of a plunger. The cam includes a first cam surface that causes an increase rate of an axial speed of the plunger when the cam rotates at a constant speed, in a pre-stroke period until the plunger increases the pressure of the fuel in the fuel supply chamber, to be a first increase rate, and a second cam surface that causes the increase rate of the axial speed of the plunger when the cam rotates at the constant speed, in a pressure increasing period that is a period from a start of increasing the pressure of the fuel in the fuel supply chamber by the plunger, to be a second increase rate, wherein the first increase rate is set higher than the second increase rate.