JPH05332348A - Friction loss reducing structure for crankshaft seal part and oil pump - Google Patents

Abstract

PURPOSE:To provide friction loss reducing structures for a crankshaft seal part and for an oil pump wherein a friction loss can be reduced as small as possible. CONSTITUTION:In the case of sealing between an end part 5a of a crankshaft 5 and a case for a generator 7 fixed to a crankcase 2, a magnetic fluid seal formed by suspension of magnetic particles in lubricating oil is arranged between the end part 5a and a boss part 7f of a case bottom 7c. A cooling means formed of a water-cooling jacket is arranged in the periphery of this magnetic fluid seal. In this way, a friction loss is reduced in the case of sealing, and further a temperature rise of the magnetic fluid seal is suppressed, to ensure durability of the magnetic fluid seal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction loss reducing structure for a crankshaft seal portion of an engine and a friction loss reducing structure for an oil pump.

[0002]

2. Description of the Related Art For example, in an engine for a motorcycle, it is general that an end portion of a crank shaft is projected from a side wall of a crank case and a generator is mounted on the projected portion. When such a structure is adopted, it is necessary to seal between the crankshaft end and the crankcase side wall in order to prevent the lubricating oil from entering the generator side. As this seal structure, conventionally, an ordinary rubber oil seal is generally arranged between the crankshaft end and the crankcase side wall.

In the trochoidal oil pump, an outer rotor is rotatably arranged in a casing, and an inner rotor is eccentrically arranged in the outer rotor so as to be rotatably arranged. As a bearing structure of the outer rotor in such an oil pump, a structure in which an outer peripheral surface of the outer rotor and an inner peripheral surface of the casing are slid is generally used.

[0004]

The conventional crankshaft seal structure and the conventional trochoidal oil pump described above have a large frictional resistance, which causes an output loss of the engine, and a structure capable of reducing these frictional losses. Has been requested.

The present invention has been made in view of the above problems of the prior art, and provides a structure for reducing the friction loss of a crankshaft seal portion and a structure for reducing the friction loss of an oil pump in which the friction loss can be reduced as much as possible. The purpose is to

[0006]

According to a first aspect of the present invention, in a friction loss reducing structure of a seal portion between an end portion of a crankshaft and a crankcase, a lubricating oil is provided between the end portion and the crankcase. It is characterized in that a magnetic fluid seal formed by suspending magnetic particles is provided, and a cooling means for cooling the peripheral portion of the magnetic fluid seal is provided.

According to a second aspect of the present invention, there is provided a friction loss reducing structure for a trochoidal oil pump comprising an outer rotor rotatably arranged in a casing and an inner rotor rotatably and eccentrically arranged in the outer rotor. A rolling bearing is provided between the outer rotor and the casing.

According to a third aspect of the present invention, in the friction loss reduction structure for the trochoidal oil pump, an annular groove is formed on the outer peripheral surface of the outer rotor or the inner peripheral surface of the casing to reduce the contact area between the two. It has a feature.

[0009]

According to the friction loss reducing structure of the crankshaft seal portion according to the first aspect of the invention, a magnetic fluid seal formed by suspending magnetic particles in lubricating oil between the end portion of the crankshaft and the crankcase. The friction loss can be reduced as compared with the conventional structure using the ordinary rubber oil seal.

On the other hand, the temperature of the seal portion of the crankshaft rises due to the heat from the engine, and if the magnetic fluid seal is used as it is, there is a concern that the sealing performance will be deteriorated at an early stage. Therefore, in the present invention, the peripheral portion of the magnetic fluid seal is positively cooled by the cooling means, so that the temperature rise of the magnetic fluid seal can be suppressed and the deterioration of the sealing performance due to the temperature rise can be avoided.

According to the invention of claim 2, since the rolling bearing is arranged between the outer rotor and the casing, the friction loss is reduced as compared with the conventional structure in which the outer rotor and the casing are slid directly. it can. Further, in the invention of claim 3, since the sliding area between the outer rotor and the casing is reduced by providing the annular groove, the friction loss can be reduced as compared with the conventional structure in which the entire surface slides.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a sectional view for explaining a friction loss reducing structure of a crankshaft seal portion according to a first embodiment of the invention.

In the figure, 1 is a water-cooled 4-cycle 4-cylinder engine adopting the structure of this embodiment, 2 is a crankcase, 3 is a cylinder block, and 4 is a cylinder head. A piston 9 arranged in the cylinder block 3 is connected to a crankshaft 5 arranged in the crankcase 2 via a connecting rod 10.

Journal parts and both ends of the crankshaft 5 between the cylinders are pivotally supported by sliding bearings 6. The illustrated right end of the crankshaft 5 projects outward from the right wall 2a of the crankcase 2, and the rotor 7a of the generator 7 is bolted to the projecting portion 5a. The casing 7b of the generator 7 is of a two-part type having a case bottom 7c and a case lid 7d, and the case bottom 7c is bolted and fixed to the right wall 2a of the crankcase 2.

A magnetic fluid seal 8 is provided between the protrusion 5a of the crankshaft 5 and the case bottom 7c to prevent the lubricating oil in the crankcase 2 from entering the generator 7. is doing.

The magnetic fluid seal 8 has a housing filled with a magnetic fluid obtained by suspending magnetic particles in lubricating oil. This housing has a ring-shaped housing body 8a, a base member 8b for fixing the housing body 8a to the boss portion 7f of the case bottom 7c, and the protruding portion 5 of the crankshaft 5.
The collar 8c is fixed to the side a, and the collar 8c
And the housing body 8a face each other with a slight gap therebetween, and sealing is performed by forming a thin film of the magnetic fluid in the gap.

A labyrinth wall 7 is provided on the case bottom 7c.
e is integrally formed. The labyrinth wall 7e covers the right wall 2a side of the magnetic seal 8 and faces the collar 8c, and an oil seal is interposed between the two.

A water cooling jacket 11 is formed at the portion where the case bottom 7c and the right wall 2a face each other. The water cooling jacket 11 has an annular shape surrounding the magnetic fluid seal 8 and is connected to a cooling water pump (not shown).

Next, the function and effect of this embodiment will be described. In the present embodiment, since the magnetic fluid seal 8 is provided between the case bottom 7c of the generator 7 and the protrusion 5a of the crankshaft 5, the friction loss due to the seal between the two is the case when an ordinary oil seal is used. Significantly reduced compared to.

Since the water cooling jacket 11 is formed around the magnetic fluid seal 8 and cooling water is supplied to the water cooling jacket 11, the temperature rise of the magnetic fluid seal 8 can be avoided.
It is possible to suppress the deterioration of the sealing performance. The end face of the magnetic fluid seal 8 on the crankcase side is attached to the labyrinth wall 7e.
Since it is covered with, it is possible to avoid direct contact of the high temperature lubricating oil with the magnetic fluid seal 8, and from this point also the temperature rise can be suppressed. Furthermore, the housing body 8a of the magnetic fluid seal 8 is separate from the crankcase and the like, and the heat insulation collar 8c attached to the crankshaft 5 is used for sealing. The temperature rise can be suppressed.

FIG. 2 shows a modification of the first embodiment. In this modification, the cooling fins 12 are provided around the magnetic fluid seal 8.
Are formed and are cooled by the running wind to suppress the temperature rise of the magnetic fluid seal 8. It is more effective to forcibly cool with a cooling fan.

3 and 4 show the second aspect of the invention of claim 2.
It is a figure for demonstrating the frictional resistance reduction structure of the oil pump by an Example. In the figure, 13 is a trochoidal oil pump bolted to the left wall 2c of the crankcase, and 14 is the left wall 2c so as to cover the pump 13.
It is a cooling water pump that is bolted and fixed to. The cooling water pump 14 has a structure in which a rotary blade 16 is arranged in a casing 15, and the rotary blade 16 is fixed to a rotary shaft 17 pivotally supported by the casing 15. The rotary shaft 17 is connected to a drive shaft 19 via a rotary shaft 18 of the oil pump 13, and the drive shaft 19 is rotationally driven by an engine output via a drive gear 20.

The oil pump 13 has a casing 21.
The outer rotor 22 is rotatably arranged therein, and the inner rotor 23 inside the outer rotor 22 is rotatably arranged eccentrically. Further, the inner rotor 23 is driven by the rotary shaft 18 and thereby pumps the lubricating oil.

A rolling bearing 24 is provided between the outer rotor 22 and the casing 21. The rolling bearing 24 includes a large number of rollers 26 and the rollers 26.
The holding member 27 for holding the casing in place and the casing 21.
And an outer race 25 fixed to the inner surface of the.

An annular groove 21b is formed in the casing 21 so as to surround the rolling bearing 24, and the annular groove 21b is formed at the lowest position in the return holes 21a and 2b.
Through the inside of the crankcase.

In the oil pump 13 of this embodiment, since the rolling bearing 24 is arranged between the outer rotor 22 and the casing 21, the friction loss is reduced as compared with the conventional structure in which the outer rotor and the casing are slid. It can be reduced. Further, metal powder and the like generated by the rotation of the outer rotor 22 and the like are returned to the crankcase together with the lubricating oil through the return holes 21a and 2b and filtered by the oil filter.

FIG. 5 is a view for explaining a friction loss reducing structure of an oil pump of a third embodiment according to the invention of claim 3, and the same reference numerals as those in FIG. 3 indicate the same or corresponding portions. In the third embodiment, the outer peripheral surface of the outer rotor 22 is formed with an annular groove 22a, whereby the outer rotor 22 is formed.
The sliding area with the casing 21 is reduced, and the friction loss is reduced accordingly.

[0028]

As described above, according to the structure for reducing the friction loss of the crankshaft seal portion according to the invention of claim 1, a magnetic fluid seal is used for the seal portion between the crankshaft and the crankcase, and Since the cooling means for cooling the periphery of the magnetic fluid seal is provided, there is an effect that the temperature rise of the magnetic fluid seal can be suppressed and the life can be secured while reducing the friction loss.

According to the friction loss reducing structure for the oil pump of the second aspect of the present invention, the rolling bearing is interposed between the outer rotor and the case.
Since the outer rotor or the casing is provided with the annular groove for reducing the sliding area, the friction loss can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional side view for explaining a friction loss reducing structure of a crankshaft seal portion of a first embodiment according to the invention of claim 1.

FIG. 2 is a sectional side view showing a modified example of the first embodiment.

FIG. 3 is a sectional side view for explaining a friction loss reduction structure of an oil pump according to a second embodiment of the invention.

4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is a sectional side view of a third embodiment according to the invention of claim 3;

[Explanation of symbols]

 2 Crankcase 5 Crankshaft 5a Projection (End) 8 Magnetic Fluid Seal 11 Cooling Jacket (Cooling Means) 12 Cooling Fins (Cooling Means) 13 Oil Pump 21 Casing 22 Outer Rotor 22a Groove 23 Inner Rotor 24 Rolling Bearing

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location F16C 3/16 9242-3J F16J 15/40 A 7197-3J

Claims (3)

[Claims] 1. A structure for reducing friction loss between a crankshaft end and a crankcase, wherein a magnetic fluid seal formed by suspending magnetic particles in lubricating oil is provided between the end and the crankcase. A structure for reducing friction loss in a crankshaft seal portion, wherein cooling means is provided for cooling a peripheral portion of the magnetic fluid seal. 2. A friction loss reduction structure for a trochoidal oil pump, comprising: an outer rotor rotatably arranged in a casing; and an inner rotor rotatably and eccentrically arranged in the outer rotor. A friction loss reducing structure for an oil pump, characterized in that a rolling bearing is interposed between the oil pump and the bearing. 3. A friction loss reduction structure for a trochoidal oil pump, comprising: an outer rotor rotatably arranged in a casing; and an inner rotor rotatably and eccentrically arranged in the outer rotor. A friction loss reduction structure for an oil pump, wherein an annular groove is formed on the surface or the inner peripheral surface of the casing to reduce the contact area between the two.