Piston pump

Abstract

In a piston pump (1), by lands (81a,81b) moving in accordance with the reciprocation of a pilot piston (8c), piston chamber communication passageways (72a,72b) are switched to a discharge line in communication with oil discharge passageways (82a,82b) and a tank line in communication with connection passageways (83a,83b). Accordingly, at the upward movement of main pistons (8a,8b), the lubricatingoil is fed under pressure via the piston chamber communication passageways and oil discharge passageways to the discharge line. At the downward movement of the main pistons, piston chambers (7a,7b) are brought into communication, via the piston chamber communication passageways and connection passageways, with the tank line. As a result, any abnormally high pressure within the piston chambers canbe prevented.

Description

technical field [0001] The present invention relates to a piston pump for pressure-feeding lubricating oil such as grease. Background technique [0002] Conventionally, there is known a piston pump in which a suction port is provided in a main piston chamber and a discharge port is provided in a sub-piston chamber, and a pilot piston (pilot piston) arranged in the sub-piston chamber and a pilot piston arranged in the main piston chamber are arranged together. The reciprocating motion of the main piston is synchronized with the reciprocating motion, thereby discharging the lubricating oil introduced from the suction port from the discharge port (for example, refer to Patent Document 1). [0003] However, in the piston pump disclosed in the aforementioned Patent Document 1, the discharge is performed only once during one rotation of the rotation shafts of the main piston and the pilot piston. In the lubricating oil discharge step, a predetermined driving force is required to ...

AI Technical Summary

Problems solved by technology

In the pump disclosed in the above-mentioned Patent Document 2, although the above-mentioned abnormal state is avoided by the reverse safety valve etc. installed in the piston chamber, the reverse safety valve etc. , when foreign matter such as dust is mixed into the gap between the check valve and its engaging hole, it is easy to produce a problem that it cannot be pushed away and returned to the original position only by spring force, and the reliability of the pump is significantly reduced.

[0009] (2) In order to pressurize and feed lubricating oil, it is desirable to open the communication path communicating with the discharge port while closing the suction port, but due to the difference in the angle of the eccentric cam that drives each piston with a predetermined phase difference or the It is difficult to process, assemble, and set in such a way that the communication path is opened while closing the suction port due to the deviation of the processing dimensions of each component

Therefore, when using high-viscosity lubricating oil or at low temperature, the discharge volume will be insufficient due to insufficient suction.

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