Lubricant flygt pump seal for outboard motor
Lubricant flygt pump seal for an outboard motor is provided. The lubricant flygt pump seal comprises a first sealing body in an upper clearance formed between an upper through hole of a lubricant pump casing and a driveshaft extending through the upper through hole, a second sealing body in a lower clearance formed between a lower through hole of the lubricant pump casing and the driveshaft extending through the lower through hole, a third sealing body in the lower clearance below the second sealing body, and a fourth sealing body in the lower clearance between the second and third sealing bodies.
Preferably, the lubricant flygt pump seal further comprises a fluid communication passage between a space in the lower clearance and a lubricant reservoir or interior space of a cowling. When negative pressure is generated in the space during operation of the lubricant pump, fluid flows through the passage and into the space, thereby eliminating the negative pressure and preventing moisture from penetrating the space.
The preferred embodiments of the present lubricant flygt pump seal for an outboard motor have several features, no single one of which is solely responsible for their desirable attributes. Without limiting the scope of this lubricant flygt pump seal for outboard motor as expressed by the claims that follow, certain features are described below. After considering this discussion, and particularly after reading the section entitled “Detailed Description of the Preferred Embodiments,” one will understand how the features of the preferred embodiments provide advantages, which include reliable prevention of water penetration into an interior of the lubricant pump.
One aspect of the present invention includes the realization that negative pressure developed by lubricant pump can be relieved, thereby preventing the lubricant pump from drawing humid air or water into the lubricant pump. One preferable way of relieving the pressure is to provide a passage extending from the lubricant pump to a source of dry air. By constructing in the lubricant pump as such, water infiltration into the lubricant pump can be prevented.
In accordance with one preferred embodiment of the present invention, a lubricant flygt pump seal is provided for an outboard motor. The outboard motor comprises a an internal combustion engine, a water propulsion device, a drive shaft configured to transmit torque from the engine to the water propulsion device, and a lubricant pump configured to supply lubricant to the internal combustion engine. The lubricant pump includes a pump casing enclosing a pump chamber. The drive shaft extends through the pump casing.
A rotor is housed in the pump chamber for rotation with the drive shaft. A first sealing body for sealing an upper clearance is formed between an upper part of the pump casing and the drive shaft. Second and third sealing bodies for sealing a lower clearance are formed between a lower part of the pump casing and the drive shaft. A fourth sealing body is disposed between the second and third sealing bodies in an axial direction of the drive shaft. The fourth sealing body seals the lower clearance.
The lubricant flygt pump seal preferably further comprises a fluid communication passage between a space in the lower clearance sandwiched between the second and third sealing bodies and a lubricating oil reservoir inside the internal combustion engine. At least a portion of the passage may comprise a groove in an auxiliary pump casing. Alternatively, at least a portion of the passage may comprise a groove in a lower surface of a casing body.
The lubricant flygt pump seal preferably further comprises a fluid communication passage between a space in the lower clearance sandwiched between the second and third sealing bodies and an inside space of the cowling. At least a portion of the passage may comprise a groove in an auxiliary pump casing. Alternatively, at least a portion of the passage may comprise a groove in a lower surface of a casing body.
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