JP2905943B2 - Lubricating device for mechanical supercharger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating device for a mechanical supercharger of an engine.

[0002]

2. Description of the Related Art Conventionally, as a method for increasing the output of an engine, a charging efficiency of an air-fuel mixture is increased by using a supercharger. As this supercharger, a turbocharger that rotates a turbine by exhaust gas and rotationally drives a compressor by the rotation of the turbine is often used. A response delay of rotation increase (a so-called turbo lag) is inevitable. In order to avoid this turbo lag, a mechanical supercharger called a so-called supercharger that obtains the rotational force of a compressor from an engine output shaft is also employed.

[0003] Among such mechanical superchargers, there are types such as a roots type and a Rischholm type in which two-axis rotors arranged in parallel are periodically rotated. In this type, two-axis rotors are arranged in parallel. Gears that mesh with each other are mounted on the shaft end, and the one rotor is driven to rotate so that the other rotor is synchronously driven through the gears. Both ends of the two rotor shafts are supported by bearings, and each bearing is lubricated with oil.
1-83135).

[0004] In the above-mentioned Rischol type supercharger, the rotor shaft is driven at a high speed (20,000 rpm or more) from an engine output shaft via a speed increasing gear, and becomes high temperature due to heat of compression. The oil supplied from the oil pump on the engine side is dripped from the upper side of the gear into the meshing part of the gear to perform lubrication and cooling, and the oil subjected to this lubrication and cooling is returned to the engine side via the return path. Has become.

[0005]

However, the oil after being subjected to lubrication and cooling is agitated with air by the high-speed rotating gears and foams, thereby reducing the return efficiency (oil drainage). In addition to the problem that the oil temperature rises and deteriorates remarkably, there is also a risk that heat is transmitted from the heated gear to the rotor and the rotor thermally expands to lock the rotor.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a lubricating device for a mechanical supercharger in which the return efficiency (oil drainage) of oil is improved and the cooling performance by oil is improved.

[0007]

For this purpose, a lubricating device for a mechanical supercharger according to the present invention comprises two shaft rotors arranged in parallel, and these two shaft rotors are provided at their shaft ends. In a mechanical supercharger of a type driven by an engine output shaft via a speed increasing gear, lubricating oil supply means for supplying lubricating oil to a gear chamber in which the speed increasing gear is accommodated, and A lubricating oil discharging means for discharging the oil from the gear chamber to an oil drain passage of the engine and a negative pressure introducing means for introducing a negative pressure in the oil drain passage into the gear chamber are provided to improve oil drainage. It is characterized by having. Further, in the present invention, the supercharging pressure introducing means for introducing the supercharging pressure into the gear chamber is provided to further improve the oil drainage.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. First, the overall configuration of the Richolm supercharger 1 to which the present invention is applied will be described with reference to FIG.
In this resholl type supercharger 1, a rotor 2 having a thread-shaped concave strip and a rotor 3 having a screw-shaped convex corresponding to the concave strip of the rotor 2 are engaged with each other by a convex strip and a concave strip. The rotors 2 and 3 have shaft portions 2A, 2B and 3A and 3B extending at both ends thereof, respectively, and have side walls 11 and 12 of the rotor housing 4. Are mounted via bearings 21, 31, 22 and 32 and seals 23, 33 and 24 and 34, and are rotatably provided while maintaining airtightness inside and outside the rotor housing 10.

A timing drive gear 25 and a timing driven gear 35 are mounted on a portion of the rotor shaft portions 2A, 3A on the shaft end side with respect to the front side (left side in FIG. 1) of the rotor shaft portions 2A, 3A. 35 are in mesh with each other and the rotor 2
3 rotates synchronously. The rotor shaft 2
A extends forward of the timing drive gear 25,
Here, the speed increasing driven gear 26 is mounted.

The front side of the side wall 11 of the rotor housing 10
1 (left side in FIG. 1), the timing drive gear 25 and the timing driven gear 35 are provided with a gear chamber 40 for accommodating the speed-up driven gear 26 and the speed-up driving gear 41 meshed with the speed-driven driven gear 26. The speed increasing gear housing 4 is integrally connected. A drive shaft 42 rotatably supported through bearings 43 and 44 and a seal 45 is disposed through the speed-increasing gear housing 4, and the speed-increasing drive gear 41 is provided at the rear end of the drive shaft 42. It is installed. The drive shaft 42 is disposed in front of the rotor shaft 3A and on the same axis as the rotor shaft 3A. The pulley 5 is mounted on a shaft end protruding from the front end of the drive shaft 42. The pulley 5 is connected to an engine output shaft (both not shown) via a belt, so that the drive shaft 42 is driven to rotate by the engine output shaft, and the speed-up drive gear 41 meshes with this. By driving the speed-up driven gear 26, the rotor 2 rotates, and the timing drive gear 25 mounted on the rotor 2 drives the timing driven gear 35 meshing therewith, so that the rotor 3
, And rotates at a higher speed than the rotor 2.

On the other hand, on the wall surface of the speed increasing gear housing 4,
An oil discharge port 6 for discharging oil lubricating the respective gears 25, 26, 35, 41 in the gear chamber 40 from the gear chamber 40 is provided. Further, bearings 22, 3 for rotatably supporting the rear (rightward in FIG. 1) rotor shaft portions 2B, 3B are provided.
An oil chamber 8 covered with a rear cover 7 is formed on a side wall 12 of the rotor housing provided with the oil chamber 2.
Oil lubricating the bearings 22 and 32 facing the oil chamber 8
The oil discharge port 9 for draining from inside is provided with the rotor housing 10.
Is provided on the wall.

FIG. 2 is a view showing a lubricating system of a first embodiment in a mechanical supercharger having the above-described configuration. FIGS. 3 and 4 are lines III-III and IV- of FIG. 2, respectively. FIG. 4 is a schematic sectional view taken along a line IV. Oil supply port 13 for this lubrication system
2 and 3 are provided on a plane including the seals 23 and 33 on the side wall of the rotor housing 10, and the oil passage 1 leading from the oil supply port 13 to the seal 23 is provided.
4 and an oil passage 15 leading to the seal 33 are formed in the side wall 11. Oil passages 16, 17 extending back and forth in the direction of extension of the rotor shaft extend from the middle of the oil passage 15 over substantially the entire length of the speed increasing gear housing 4 and the rotor housing 10. The oil passage 17 reaches the seal 45 at the front end of the gear housing 4 and the rear oil passage 17 reaches the seals 24 and 34 at the rear end of the rotor housing 11. Further, in the middle of the front oil passage 16, as is apparent from FIG. 4, an oil injection port 18 that injects oil toward a meshing portion between the speed increasing drive gear 41 and the speed increasing driven gear 26 is provided. . The oil discharge port 6 of the gear chamber 40 is connected to an oil discharge passage 19 of the engine as shown in FIG. 2, and further, a negative pressure introduction passage 20 communicating the oil discharge passage 19 with the gear chamber 40.
Is provided. The oil drain passage 19 is suitable for a blow-by chamber or the like provided between both banks of the V-type engine, for example, which has a negative pressure during operation of the engine.

Next, the lubricating action of the lubrication system will be described. The oil pumped from the oil pump (not shown) of the engine to the oil supply port 13 is supplied to the oil passages 14 and 15.
Through the seals 23 and 33 and then the bearing 2
After lubricating the first and the third gears 31, respectively, the gears enter the gear chamber 40, lubricate the engagement between the two timing gears 25 and 35,
Is discharged from Further, the oil supplied to the oil passage 16 extending forward has the seal 45, the bearings 44 and 43.
After being lubricated, the oil enters the gear chamber 40, is discharged from the oil discharge port 6, and the oil injected from the oil injection port 18 in the middle of the oil passage 16 is supplied with the speed-up driving gear 41 and the speed-up driven gear 26.
Is lubricated and discharged from the oil discharge port 6. In this case, since the gear chamber 40 communicates with the oil discharge passage 19 (having a negative pressure) via the negative pressure introduction passage 20,
The oil drainage (return efficiency) in the gear chamber 40 is improved, and therefore, the cooling performance by oil is improved. The oil supplied to the oil passage 17 extending rearward is sealed by the seals 24 and 34.
And the bearings 22, 32 are lubricated into the oil chamber 8,
The oil is discharged from the oil discharge port 9.

In the partial throttle region, although the amount of refueling may be small, it is not shown in the drawing. A valve may be provided.

FIG. 5 is a diagram showing a configuration of a second embodiment of the present invention. Since the lubrication system of FIG. 5 is the same as that shown in FIG. 2, the corresponding parts are denoted by the same reference numerals and redundant description will be omitted, but in FIG.
A three-way solenoid valve 50 is provided in the middle of the negative pressure introduction passage 20 that connects the gear chamber 40 and the gear chamber 40. A port of the three-way solenoid valve 50 is connected to a supercharge pressure discharge passage 51 of the rotor housing 10 through a supercharge pressure introduction passage 51. It differs from that of FIG. 2 in that a supercharging pressure is supplied. Normally, the three-way solenoid valve 50 closes the supercharging pressure introduction passage 51 and opens the negative pressure introduction passage 20, so that the negative pressure in the oil discharge passage 19 is introduced into the gear chamber 40 to improve the oil discharge property. However, when the oil temperature rises due to insufficient oil drainage, the three-way solenoid valve 50 is operated in response to the detection of the oil temperature, the negative pressure introduction passage 20 is closed, and the supercharging is performed. When the pressure introduction passage 51 is opened, the supercharging pressure is introduced from the rotor housing 10 into the gear chamber 40, and the oil discharge performance is further enhanced.

In place of the three-way solenoid valve 50, the pressure in the intake manifold is changed from negative pressure to positive pressure by the supercharging by the mechanical supercharger, and the supercharging pressure introduction passage 51 is opened. A diaphragm type actuator may be provided in the supercharging pressure introduction passage 51. In this case, both the negative pressure and the supercharging pressure can be introduced into the gear chamber 40 to further improve the oil drainage.

[0017]

According to the present invention, by introducing a negative pressure or a supercharging pressure into the gear chamber, the oil drainage (return efficiency) in the gear chamber is improved. Since the temperature rise of the oil due to the stirring action can be suppressed, the amount of heat conduction from the gear chamber to the rotor is reduced, so that the occurrence of lock due to the thermal expansion of the rotor can be prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a Richolm supercharger to which the present invention is applied.

FIG. 2 is a sectional view showing the configuration of the first embodiment of the present invention.

FIG. 3 is a sectional view taken along the line III-III in FIG. 2;

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 2;

FIG. 5 is a sectional view showing a configuration of a second exemplary embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Resholm-type supercharger 2, 3 Rotor 4 Speed-increase gear housing 5 Pulley 6, 9 Oil discharge port 10 Rotor housing 11, 12 Side wall of rotor housing 13 Oil supply port 14-17 Oil passage 18 Oil injection port 21, 22, 31 , 32 Bearing 23, 24, 33, 34 Seal 25 Timing drive gear 26 Speed-driven driven gear 35 Timing driven gear 40 Gear chamber 41 Speed-driven drive gear 42 Drive shaft

Claims (2)

(57) [Claims] 1. A mechanical supercharger comprising two shaft rotors arranged in parallel, wherein the two shaft rotors are driven by an engine output shaft via a speed increasing gear provided at their shaft ends. A lubricating oil supply means for supplying lubricating oil into a gear chamber in which the speed increasing gear is housed; a lubricating oil discharging means for discharging the lubricating oil from the gear chamber to a drain passage of an engine; A lubricating device for a mechanical supercharger, comprising: negative pressure introducing means for introducing a negative pressure in an oil passage into the gear chamber. 2. The lubricating device for a mechanical supercharger according to claim 1, further comprising a supercharging pressure introducing means for introducing a supercharging pressure into said gear chamber.