Abstract: This plunger pump includes a pressurization chamber that has a tubular inner circumferential wall and a plunger that has a substantially cylindrical outer circumferential surface. The inner circumferential wall has, in a part thereof in a circumferential direction about an axis of the plunger, a suction opening, which communicates with the pressurization chamber and is for introducing a fuel into the pressurization chamber. The inner circumferential wall is formed with an enlarged gap portion having a larger dimension than a dimension, at a position of the suction opening, from the outer circumferential surface of the plunger to an inner circumferential surface of the inner circumferential wall along a radial direction of the plunger, in at least a part of the inner circumferential wall at a position away from the position of the suction opening in the circumferential direction.

Abstract: The present invention provides an inexpensive valve unit fixing structure that enables a valve unit to be easily fixed without the need for unitization in advance, and a fluid pump that enables a discharge valve and a relief valve to be incorporated in a compact manner. The valve unit fixing structure includes a main body (3), a discharge communication passage (9) provided inside the main body (3), a discharge valve unit (10) which is provided in the main body (3) and which opens/closes the discharge communication passage (9), and deformed fixing parts (35) which are formed by plastically deforming the main body (3) and which fix the discharge valve unit (10) to the main body (3).

Abstract: This plunger pump includes a pressurization chamber that has a tubular inner circumferential wall and a plunger that has a substantially cylindrical outer circumferential surface. The inner circumferential wall has, in a part thereof in a circumferential direction about an axis of the plunger, a suction opening, which communicates with the pressurization chamber and is for introducing a fuel into the pressurization chamber. The inner circumferential wall is formed with an enlarged gap portion having a larger dimension than a dimension, at a position of the suction opening, from the outer circumferential surface of the plunger to an inner circumferential surface of the inner circumferential wall along a radial direction of the plunger, in at least a part of the inner circumferential wall at a position away from the position of the suction opening in the circumferential direction.

Abstract: The present invention provides an inexpensive valve unit fixing structure that enables a valve unit to be easily fixed without the need for unitization in advance, and a fluid pump that enables a discharge valve and a relief valve to be incorporated in a compact manner. The valve unit fixing structure includes a main body (3), a discharge communication passage (9) provided inside the main body (3), a discharge valve unit (10) which is provided in the main body (3) and which opens/closes the discharge communication passage (9), and deformed fixing parts (35) which are formed by plastically deforming the main body (3) and which fix the discharge valve unit (10) to the main body (3).