Oil filter unit with drain valve device

An oil filter unit comprising:

• a filter housing comprising a housing proper and a lid member;
• a filter element received in the filter housing;
• a drain passage defined by the filter housing and connected with an interior of the filter housing;
• and
• a drain valve device that opens and closes the drain passage in response to detachment and attachment of the lid member from and to the housing proper,
• the drain valve device comprising:
• a valve seat provided in the drain passage and having a drain bore formed therethrough;
• a retainer installed in the drain passage and axially movable in the same, the retainer having an oil flow passage formed therethrough;
• a valve member installed in the retainer, the valve member being movable to contact with the valve seat to close the drain bore;
• a first biasing member that biases the retainer away from the valve seat;
• a second biasing member that biases the valve member toward the valve seat;
• and
• a structure that causes, upon attachment of the lid member to the housing proper, the retainer to move toward the valve seat thereby to induce a contact of the valve member with the valve seat due to an input force applied from the lid member against the biasing force of the first biasing member and causes, upon detachment of the lid member from the housing proper, the retainer to move away from the valve seat thereby to induce a separation of the valve member from the valve seat due to the biasing force of the first biasing member.

An oil filter unit comprising:

• a filter housing comprising a housing proper and a lid member;
• a filter element received in the filter housing;
• a drain passage defined by the filter housing and connected with an interior of the filter housing;
• and
• a drain valve device that opens and closes the drain passage in response to detachment and attachment of the lid member from and to the housing proper,
• the drain valve device comprising:
• a valve seat provided in the drain passage and having a drain bore formed therethrough;
• a retainer installed in the drain passage and axially movable in the same, the retainer having an oil flow passage formed therethrough;
• a valve member installed in the retainer, the valve member being movable to contact with the valve seat to close the drain bore;
• a first biasing member that biases the retainer away from the valve seat;
• and
• a structure that causes, upon attachment of the lid member to the housing proper, the retainer to move toward the valve seat thereby to induce a contact of the valve member with the valve seat due to an input force applied from the lid member against the biasing force of the first biasing member and causes, upon detachment of the lid member from the housing proper, the retainer to move away from the valve seat thereby to induce a separation of the valve member from the valve seat due to the biasing force of the first biasing member,
• wherein the retainer is formed with a tool inserting through bore through which a press rod is insertable for pushing the valve member toward the valve seat.