JP3350633B2 - Gear driven oil pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear-driven oil pump used for a lubrication system of an internal combustion engine, and more particularly to an improved technology for driving a gear.

[0002]

2. Description of the Related Art An oil pump used for a lubrication system of an internal combustion engine sucks lubricating oil in an oil pan and pressurizes the oil.
Lubricating oil is pumped to each friction part. As a model of such an oil pump, there is a gear pump that rotates by meshing two gears.

As shown in FIG. 5, the gear pump includes a pump chamber 3 having a lubricating oil inlet 1 and a lubricating oil outlet 2, a drive gear 4, a driven gear 5, and the like. 2 above
The two gears 4 and 5 are meshed with almost no gap in the pump chamber 3, and the suction port 1 of the pump chamber 3 is connected to the oil pan and the discharge port 2 is connected to the main gallery of the cylinder block.

A pump drive gear 6 coaxial with the drive gear 4 meshes with a camshaft of the engine. The drive gear 4 is driven by the rotation of the engine, and the driven gear 5 is driven. Lubricating oil is sucked between the gears 4 and 5 and carried out to the discharge port 2 so that a continuous pressure is applied to the lubricating oil.

[0005]

Incidentally, such a conventional gear-driven oil pump is driven by the driving force of the engine as described above, and the amount of lubricating oil discharged and the hydraulic pressure (pressure) are proportional to the engine speed. (At constant oil temperature). For this reason, when the lubricating oil pressure is low at a low speed of the engine, an appropriate discharge amount and oil pressure are secured, but when the lubricating oil pressure is high at a high speed of the engine, an extra discharge amount is supplied. As a result, the driving load increases, which affects the output of the engine and fuel consumption.

The excess discharge port amount is returned to the oil pan by opening a regulator valve interposed in the lubrication system downstream of the oil pump, and a waste lubricating oil circulation operation is performed. (See FIG. 6). The present invention has been made to solve the conventional problems as described above, and an object of the present invention is to reduce a driving load in a gear-driven oil pump.

[0007]

According to a first aspect of the present invention, there is provided a pump chamber having an oil inlet and an oil outlet, a drive gear and a driven gear disposed in the pump chamber and meshing with each other. , The drive gear and the driven gear are divided into a plurality in the axial direction, and a plurality of drive gears and a plurality of driven gears respectively meshing with the plurality of drive gears are provided. Forming a common rotary drive shaft of the plurality of drive gears separately from a gear portion of the drive gear, supporting the drive gear in an axially slidable manner, and forming the plurality of drive gears in a ring shape, A pump driving means is fixed to one of the plurality of drive gears, a spline tooth is provided on a part of an outer peripheral surface of the rotary drive shaft, and an inner peripheral surface of each of the plurality of drive gears is provided. A spline groove capable of meshing with the spline teeth is provided, and the spline teeth are formed on the outer peripheral surface of the rotary drive shaft in accordance with a sliding position of the rotary drive shaft, with a drive gear to which the pump driving unit is fixed and other pluralities. A first state in which the spline grooves of the entire drive gear mesh with each other, and a second state in which the drive gear to which the pump driving means is fixed and the spline grooves of a drive gear selected from among a plurality of other drive gears mesh with each other. A third state in which the pump driving means is not engaged with a spline groove of the drive gear to which the pump driving means is fixed, while the rotary drive shaft is always in the first state. An elastic member that elastically urges to be located, a pressure chamber communicating with a discharge port forming side space of the pump chamber is provided, and one end of the rotary drive shaft is provided; A piston portion on which the hydraulic pressure guided into the pressure chamber acts, and the piston portion is pressed against the elastic urging force of the elastic member with the increase of the hydraulic pressure guided into the pressure chamber. hand,
The rotary drive shaft is configured to slide from the first state to the third state.

According to a second aspect of the present invention, a lock means for locking the rotary drive shaft is provided when the pump drive means is in the third state in which the pump drive means is not engaged with the spline groove of the fixed drive gear. The invention according to claim 3 is characterized in that the oil pump is interposed in a lubrication system of an internal combustion engine to pump lubricating oil to each part of the engine.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the attached drawings. FIG. 1 shows an oil pump interposed in a lubrication system of an internal combustion engine as an embodiment of a gear drive type oil pump according to the present invention, which includes a lubricating oil inlet 11 and a lubricating oil outlet 12. And a drive gear 16 and a driven gear 17 provided in the pump chamber 13 and meshing with each other.

Here, the drive gear 16 and the driven gear 17 are each divided into two parts in the axial direction, whereby the first and second drive gears 16A and 16B,
First and second driven gears 17A and 17B meshing with the first and second drive gears 16A and 16B, respectively;
Is formed. First and second drive gears 16A, 1
6B, the common rotary drive shaft 18
A and 16B are formed separately from the gear portions, and are slidably supported in the axial direction.

The structure for supporting the rotary drive shaft 18 will be described later. Further, the first and second drive gears 16A, 1
6B are each formed in a ring shape. A spline tooth 18A is provided on a part of the outer peripheral surface of the rotary drive shaft 18, and the first and second drive gears 16A and 16B are provided.
Are provided with spline grooves 16a and 16b which can be engaged with the spline teeth 18A.

In this case, the spline groove 16a of the first drive gear 16A is formed on the inner peripheral surface of the end of the first drive gear 16A on the side close to the second drive gear 16B. 16B spline groove 16
b is formed on the entire inner peripheral surface. Spline teeth 18
A is the rotation driving shaft 1 on the outer peripheral surface of the rotation driving shaft 18.
In accordance with the slide position of No. 8, a state where the first drive gear 16A to which a pump drive gear 19 as a pump drive unit to be described later is fixed and the spline grooves 16a and 16b of the second drive gear 16B are engaged (state 1). And a state where it does not mesh with the spline groove 16a of the first drive gear 16A (state 2).

A spring 20 is provided as an elastic member for elastically biasing the rotary drive shaft 18 so as to always be located at the slide position where the state 1 is established. Pressure chamber 2 communicating with space
1 is provided, and a piston portion 22 is formed at one end of the rotary drive shaft 18 on which hydraulic pressure guided into the pressure chamber 21 acts.

Here, one end of the rotary drive shaft 18 is
The pump drive gear 19 is projected outward from an opening 15A formed in the cover 15 and is rotatably fitted to the outer peripheral surface of the end on the projected side. In this case, the shaft 19A of the pump drive gear 19 protrudes into the cover 15 from the opening 15A, and is fixed to the end of the first drive gear 16A.

A part of the other end of the rotary drive shaft 18 is supported by a support wall 14A formed on an end wall of the housing 14.
Of the rotary drive shaft 18 is rotatably and slidably supported by a support hole 14b formed in an end wall of the housing 14. It is supported. The support wall 14A
A recess 23 is formed in the through-hole 14a forming portion of the through-hole 14a, and a spline groove 23 which can
a is formed.

The pressure chamber 21 is formed on the outer periphery of the rotary drive shaft 18 between the support wall 14A at the end wall of the housing 14 and the support hole 14b forming portion. The space on the discharge port 12 forming side is the housing 14
Are communicated through the communication holes 24 formed in the holes. The piston portion 22 is integrally formed in a cylindrical shape having one end opened at the outer peripheral portion of the rotary drive shaft 18, and the spring 20 is interposed between the inner end surface of the piston portion 22 and the inner end surface of the pressure chamber 21. It has become.

Then, as the hydraulic pressure guided into the pressure chamber 21 from the space on the side of the discharge port 12 rises, the piston portion 22 is pressed against the elastic urging force of the spring 20, and
The rotary drive shaft 18 is configured to slide from the state 1 to the state 2. The common rotation drive shaft 25 of the first and second driven gears 17A, 17B is rotatably supported by the housing 14 and the cover 15, respectively.

Next, the operation of the gear-driven oil pump having such a configuration will be described. Rotational driving force from a gear train (not shown) is transmitted to the pump drive gear 19, and when the pump drive gear 19 is driven to rotate, the first drive gear 16A fixed thereto is driven to rotate. When the engine rotation speed is low and the hydraulic pressure in the discharge port side space is low, the rotation drive shaft 18 is positioned at the slide position where the state 1 is established as shown in FIG. The spline teeth 18A of the shaft 18
Of the drive gear 16A and the spline grooves 16a, 16b of the second drive gear 16B are in mesh with each other.

Therefore, the rotation of the first drive gear 16A rotates the rotation drive shaft 18, and this rotation is also transmitted to the second drive gear 16B. As a result,
First drive gear 16A and second drive gear 16B
Rotate together, and the first driven gear 17A and the second driven gear 17B also rotate integrally.

Thus, when the engine is running at low speed and low oil pressure, both drive gears 16A, 16B and both driven gears 17A, 16B are driven.
The rotation of A and 17B causes the lubricating oil discharged from the discharge port 12 to have an appropriate oil pressure and discharge amount as shown in FIG. On the other hand, when the oil pressure rises as the engine speed rises and the oil pressure in the space on the discharge port 12 side reaches a predetermined high pressure, the piston portion 22 receives the elastic urging force of the spring 20 due to the high pressure as shown in FIG. The rotary drive shaft 18 is moved in the state 2
The spline teeth 18A of the rotary drive shaft 18 are separated from the spline grooves 16a of the first drive gear 16A, and the support wall 1
4A engages with the spline groove 23a on the inner peripheral surface of the concave portion 23.

Therefore, the rotational drive of the first drive gear 17A is not transmitted to the rotational drive shaft 18, and the second drive gear 17B is not rotationally driven. Also, the rotation drive shaft 18
The spline teeth 18A are engaged with the spline grooves 23a on the inner peripheral surface of the concave portion 23 of the support wall 14A, so that the rotation drive shaft 18 is locked in a non-rotatable state. This configuration corresponds to a lock unit.

As a result, only the first drive gear 16A and the first driven gear 17A rotate. in this way,
When only the first drive gear 16A and the first driven gear 17A rotate at the time of high speed and high oil pressure of the engine, the lubricating oil discharged from the discharge port 12 has an appropriate oil pressure and discharge amount as shown in FIG. Become.

That is, by changing the drive gear and driven gear that are driven to rotate between when the engine is at low speed and low oil pressure and when the engine is at high speed and high oil pressure, the required oil pressure and discharge amount are obtained when the engine is at low speed and low oil pressure. On the other hand, when the engine is running at high speed and high oil pressure, the hydraulic pressure and discharge rate are set to an appropriate value without waste, and when the engine is running at high speed and the lubricating oil pressure is high, the drive load can be reduced. Output and fuel efficiency can be improved.

Further, since the load increase due to the high oil pressure at the time of the low temperature start can be suppressed, the low temperature startability can be improved. In the above embodiment, the drive gear 16 and the driven gear 17 are divided into two in the axial direction, and the two drive gears 16A and 16B and the two driven gears 17 meshing with the two drive gears 16A and 16B, respectively.
A and 17B have been described, but the drive gear and the driven gear are divided into a plurality of three, four,... In the axial direction, and a plurality of drive gears and the plurality of drive gears are respectively provided. A plurality of meshed driven gears may be provided.

In this case, a spline tooth provided on a part of the outer peripheral surface of the rotary drive shaft is connected to a drive gear on which the pump drive gear is fixed in accordance with the sliding position of the rotary drive shaft on the outer peripheral surface of the rotary drive shaft. A first state in which the spline grooves of the other plurality of drive gears are engaged with each other, and a second state in which the drive gear to which the pump drive gear is fixed and the spline grooves of the drive gear selected from the other plurality of drive gears are engaged. And a third state in which the pump drive gear is not engaged with a spline groove of a drive gear to which the pump drive gear is fixed. The portion may be configured to be pressed against the elastic biasing force of the spring, and the rotary drive shaft may be slid from the first state to the third state.

With this configuration, it is possible to control the capacity of the oil pump in a plurality of stages according to the engine speed.

[0027]

As described above, according to the first aspect of the present invention, it is possible to variably control the capacity of the oil pump in a plurality of stages. According to the second aspect of the invention, the rotary drive shaft can be locked in the third state in which the pump drive means is not engaged with the spline groove of the drive gear to be fixed, so that only the drive gear and the drive gear to be driven can be locked. It can be driven reliably.

According to the third aspect of the present invention, it is possible to improve the output and fuel efficiency of the engine and to improve the low temperature startability.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a gear-driven oil pump according to the present invention.

FIG. 2 is a sectional view of the same.

FIG. 3 is a characteristic diagram of the oil pump according to the embodiment;

FIG. 4 is a characteristic diagram of the oil pump according to the embodiment.

FIG. 5 is a sectional view showing an example of a conventional gear-driven oil pump.

FIG. 6 is a characteristic diagram of an oil pump according to the related art.

[Explanation of symbols]

 Reference Signs List 11 suction port 12 discharge port 13 pump chamber 14 housing 15 cover 16 drive gear 17 driven gear 16A first drive gear 16B second drive gear 17A first driven gear 17B second driven gear 18 rotation drive shaft 18A spline teeth 16a, 16b Spline groove 19 Pump drive gear 20 Spring 21 Pressure chamber 22 Piston part

Claims (3)

(57) [Claims] 1. A gear-driven oil pump comprising: a pump chamber having an oil suction port and an oil discharge port; and a drive gear and a driven gear disposed in the pump chamber and meshing with each other. The drive gear and the driven gear are divided into a plurality in the axial direction, and a plurality of drive gears and a plurality of driven gears meshing with the plurality of drive gears are provided, and a common rotary drive shaft of the plurality of drive gears is provided. It is formed separately from the gear portion of the drive gear, is slidably supported in the axial direction, and is formed with a plurality of drive gears each in a ring shape, and the pump driving means is fixed to one of the plurality of drive gears. A spline groove provided on a part of an outer peripheral surface of the rotary drive shaft and meshable with the spline tooth on an inner peripheral surface of each of a plurality of drive gears; The spline teeth are provided on the outer peripheral surface of the rotary drive shaft in accordance with the sliding position of the rotary drive shaft, in which the drive gear to which the pump drive means is fixed is engaged with the entire spline grooves of the other plurality of drive gears. (1), a second state in which the drive gear to which the pump driving means is fixed and a spline groove of a drive gear selected from a plurality of other drive gears, and a drive gear to which the pump driving means is fixed And a third state in which the spline groove does not mesh with the spline groove, and an elastic member that elastically urges the rotary drive shaft so as to be always in the first state. A pressure chamber communicating with a discharge port forming side space of the pump chamber is provided, and a hydraulic pressure introduced into the pressure chamber acts on one end of the rotary drive shaft. Forming a ton portion, the piston portion is pressed against the elastic urging force of the elastic member with an increase in hydraulic pressure guided into the pressure chamber, and the rotary drive shaft is moved from the first state. A gear-driven oil pump configured to slide in a third state. 2. A lock means for locking a rotary drive shaft when the pump drive means is in a third state in which the pump drive means is not engaged with a spline groove of a fixed drive gear. Gear driven oil pump. 3. A gear-driven oil pump according to claim 1, wherein said oil pump is interposed in a lubrication system of an internal combustion engine to pump lubricating oil to each part of the engine.