JP2598994Y2 - Variable displacement 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 variable displacement oil pump, and more particularly, to a hydraulic pump for lubricating an automobile engine, wherein a discharge pressure is appropriately adjusted according to an engine speed. The present invention relates to a variable displacement oil pump with a valve.

[0002]

2. Description of the Related Art As such a conventional variable displacement oil pump, one disclosed in, for example, Motor Fan Magazine, September 1991, page 182, is known. In this conventional example, two large and small circumscribed gear pumps are arranged in parallel, and an adjusting valve arranged on the discharge side adjusts the discharge pressure in almost three stages according to low speed, medium speed and high speed. By appropriately switching and adjusting the oil amount and the oil pressure from the two pumps, the engine horsepower is not unnecessarily consumed and the driving friction at high speed is reduced.

[0003]

However, in such a conventional variable displacement oil pump, since the structure of the regulating valve is complicated, the manufacturing cost is high. Also, since the oil return passage at low speed is shaped to intersect in a loop, the return passage cannot be integrally formed by die casting,
In addition to being bulky, the number of parts is increased, resulting in an increase in cost.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems by providing a variable displacement oil pump in which the structure of an oil displacement adjusting mechanism including a hydraulic pressure regulating valve is simple, has excellent functions, and is inexpensive. Is to provide.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is directed to an oil pump, wherein oil pressurized by first and second pump means is discharged through first and second discharge passages, respectively. A pump operating section, a pressure chamber in which oil pressure is guided from the first discharge passage at the top, and an opening for connecting the second discharge passage to the first discharge passage and an opening for an oil return passage in the sliding portion. A hydraulic pressure that has a plunger chamber and a spool valve that slides along the sliding portion in accordance with the hydraulic pressure guided to the pressure chamber, and that can adjust the amount of oil discharged from the pump operating portion and the hydraulic pressure. And an adjustment unit,
The spool valve is driven by the hydraulic pressure guided to the pressure chamber through the communication space provided in the spool valve.
A first position in which a discharge passage communicates with the first discharge passage;
A second for interrupting oil discharge from the second discharge passage;
A third position for guiding oil from the second discharge passage to the oil return passage, and a fourth position for guiding at least a portion of the oil from the first and second discharge passages to the oil return passage. It is characterized by sliding sequentially.

[0006]

According to the present invention, the spool valve is located at the first position in the oil pressure adjusting section in the low speed rotation range of the oil pump where the oil pressure in the first discharge passage is sufficiently low.
Since the discharge passage communicates with the first discharge passage via the communication space of the spool valve, oil is discharged from both the first and second discharge passages. Further, when the hydraulic pressure in the first discharge passage increases with an increase in rotation, the spool valve slides from the first position to the second position, the second discharge passage is shut off, and oil flows only from the first discharge passage. The oil is discharged, thereby increasing the amount of oil that is slowly discharged. Then, when the oil pressure in the first discharge passage further rises with high rotation, the spool valve slides further from the second position to the third position to return the oil discharged from the second discharge passage to the oil return passage. When the rotation speed is further increased, a part of the oil from both the discharge passages is returned to the oil return passage by sliding from the third position to the fourth position so that an unnecessary load is not always applied to the pump operating portion. The amount of oil is controlled.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

FIG. 1 shows a configuration according to an embodiment of the present invention.

Here, reference numerals 1 and 2 denote a pump operating portion and a hydraulic pressure adjusting portion, respectively, of the variable displacement oil pump 10 of the present invention. The pump operating section 1 is driven by an engine, and has a main pump section 12 and a sub-pump section 13 that generate a different hydraulic pressure from one suction port 11.
And FIG. 2 shows the pump operating unit 1 according to the present invention.
This shows an example of the configuration of an internal pump that can be applied as an example, where 14 is an inner rotor, and 15 is an outer rotor. The oil guided from the suction port 11 to the volume chamber 16 formed between the two tooth forms is first discharged from the first discharge port 18 through the first closing portion 17A. Then, the first discharge port 19 is discharged from the second discharge port 19 through the second closing portion 17B, and the first discharge port is discharged from the second discharge port 19 through the two-stage closing portions 17A and 17B. Higher oil pressure can be obtained from the discharge port 18.

That is, in the case of the pump operating section 1 shown in FIG. 2, the discharge from the second discharge port 19 is controlled by the main pump section 1.
2 and the discharge from the first discharge port 17 can function as the sub-pump 13.

Returning to FIG. 1, reference numeral 3 denotes a main pump unit 12
4 is a sub-discharge passage from the sub-pump unit 13, 5 is an oil suction passage, and 6 is a relief passage from the hydraulic pressure adjustment unit 2 to the oil suction passage 5. A bypass passage 7 is provided between the main discharge passage 3 and the sub discharge passage 4 to allow oil to flow only from the sub discharge passage 4 to the main discharge passage 3. Reference numeral 8 denotes a check valve provided in the bypass passage 7.

Next, the configuration of the hydraulic adjustment unit 2 according to the present invention will be described with reference to FIG.

In FIG. 3, reference numeral 21 denotes a cylindrical valve chamber;
Reference numeral 2 denotes a sliding valve body which slides in the valve chamber 21 and switches the sub discharge passage 4 as described later. Reference numeral 23 denotes a pressure provided at the top of the valve chamber 21 to guide the hydraulic pressure of the main discharge passage 3. A chamber 24 is a spring for biasing the sliding valve body 22 toward the pressure chamber 23, and a stopper 25 is mounted on an end of the valve chamber 21 and holds the spring 24 between the sliding valve body 22 and the valve chamber 21. Body. The sliding valve body 22 includes a first valve body 22A and a second valve body 22B.
And a shaft 22C connecting the two valve bodies so that a communication space 26 is formed therebetween.

Therefore, in the oil pump 10 shown in FIG. 1, when the oil pressure in the main discharge passage 3 is sufficiently low at a low speed, as shown in FIG. When the force overcomes the oil pressure in the pressure chamber 23, the sub-discharge passage 4 is opened via the communication space 26 provided in the sliding valve body 22 and the first port 27A. Accordingly, sent oil from both the pump operation portion 1 in the main pump unit 12 and the sub pump 13, the hydraulic pressure commensurate from the discharge port 28 of the oil pump 10 to the low-speed rotation as shown in FIG. 4 as curve C _L Sent out.

Next, when the rotation speed slightly increases from the low speed state shown in FIG. 3A, the oil discharge pressure increases,
When the oil pressure in the pressure chamber 23 overcomes the spring force of the spring 24, the sliding valve body 22 descends as shown in FIG. When the first valve 27A closes the first port 27A and the second valve 22B closes the second port 27B, the communication of the sub discharge passage 4 with the main discharge passage 3 is interrupted, and the main pump by oil discharge from only part 12 is performed, the discharge flow rate is suppressed, therefore, a sharp rise as the hydraulic pressure is suppressed, the discharge of the oil is carried out in a tendency shown in FIG. 4 as curve C _M.

When the rotation of the pump operating unit 1 is further increased from the rotational state shown in FIG. 3B, the hydraulic pressure adjusting unit 2 further increases the oil pressure in the pressure chamber 23, thereby causing sliding. The valve body 22 is lowered, and as shown in FIG. 5A, the sub-discharge passage 4 communicates with the relief passage 6 through the communication space 26, and as shown in FIG. Is discharged to the oil suction passage 5 by the relief passage 6. Accordingly, the oil discharge quantity is only the one passing through the main discharge passage 3 from the main pump unit 12, increases the discharge pressure with increasing pump speed follows the trend shown as curve C _H in FIG.

Subsequently, when the rotation of the pump operating section 1 continues to rise, the sliding valve element 22 further lowers in the hydraulic pressure adjusting section 2 as shown in FIG. Communicates with the relief passage 6 through the communication space 26, and a part of the discharge oil from the main discharge passage 3
It is guided to the relief passage 6 via the port 27B and the communication space 26. FIG. 6B shows such a state of the oil pump 10, whereby the oil discharge pressure is no longer rapidly increased, and the curve C _{HL is} shown in FIG.
As a result, the discharge is performed with the tendency as shown, and it is possible to suppress the unnecessary discharge of the oil,
The friction can be reduced as a variable displacement oil pump. In this case, in the hydraulic adjustment unit 2,
When the sliding valve body 22 descends more than shown in FIG. 5B, the main discharge passage 3 and the sub discharge passage 4 are separated from each other by the pressure chamber 2.
There is a possibility that the communication may be made directly via the communication line 3. Therefore, a stopper (not shown here) that regulates the lowering of the sliding valve body 22 is provided to prevent such a situation, or the thickness of the first valve body 22A is set so as not to cause the above-mentioned danger. Any of the above measures may be taken.

In the embodiment described above, the mechanism of the inscribed oil pump is used as the pump portion. However, the application of the present invention is not limited to such an inscribed oil pump. It goes without saying that the present invention can be applied to a pump unit including two pumps, such as a tandem type having a common suction port side, in combination with the hydraulic pressure adjusting unit according to the present invention.

[0019]

As described above, according to the present invention, a pump operating section in which oil pressurized by the first and second pump means is discharged through the first and second discharge passages, respectively. A pressure chamber in which a hydraulic pressure is guided from the first discharge passage at the top, and a plunger chamber having an opening for communicating the second discharge passage with the first discharge passage in a sliding portion and an opening for an oil return passage. A spool valve that slides along the sliding portion in accordance with the hydraulic pressure guided to the pressure chamber, and a hydraulic adjustment portion capable of adjusting the amount of oil discharged from the pump operating portion and the hydraulic pressure; A first position in which the spool valve communicates with the first discharge passage through a communication space provided in the spool valve by hydraulic pressure guided to the pressure chamber; and Oy from the discharge passage And a third position for guiding oil from the second discharge passage to the oil return passage, and at least a part of oil from the first and second discharge passages to the oil return passage. To the fourth position to guide the hydraulic pressure and oil amount appropriately in accordance with the rotational speed without using a complicated and low-cost control mechanism. And it is possible to provide a variable displacement oil pump that contributes to effectively preventing the wear of the pump components by suppressing unnecessary discharge of hydraulic pressure and oil amount at high rotation speed.

[0020]

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration example of a variable displacement oil pump according to the present invention.

FIG. 2 is a front view showing a configuration example of a pump operating unit to which the present invention can be applied;

FIG. 3 is an explanatory diagram showing the configuration of the hydraulic pressure adjusting unit according to the present invention in a state of low rotation (A) and a state of middle speed rotation (B).

FIG. 4 is a characteristic diagram of a pump rotation speed-discharge pressure according to the present invention.

FIG. 5 is an explanatory view showing the operation of the hydraulic pressure adjustment unit according to the present invention in a state of high-speed transition rotation (A) and a high rotation state (B).

FIG. 6 is an explanatory diagram showing the operation according to the present invention in a state of high-speed transition rotation (A) and a state of high rotation (B).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pump operation part 2 Hydraulic pressure adjustment part 3 Main discharge passage 4 Sub discharge passage 5 Oil suction passage 6 Relief passage 7 Bypass passage 11 Suction port 12 Main pump part 13 Sub pump part 14 Inner rotor 15 Outer rotor 17A, 17B Closing part 18, 19 Discharge Port 21 Valve chamber 22 Sliding valve element 22A, 22B Valve element 22C Shaft element 23 Pressure chamber 24 Spring 26 Communication space 27A, 27B Port 28 Discharge port

Claims (1)

(57) [Scope of request for utility model registration] 1. A pump operating portion in which oil pressurized by first and second pump means is discharged through first and second discharge passages, respectively, and a hydraulic pressure is guided from the first discharge passage to a top portion. Pressure chamber
A plunger chamber having an opening for communicating the second discharge passage with the first discharge passage to the sliding portion and an opening for an oil return passage; and a sliding portion corresponding to the hydraulic pressure guided to the pressure chamber. And a hydraulic pressure adjusting unit capable of adjusting the amount of oil discharged from the pump operating unit and the hydraulic pressure. The spool valve is provided with a hydraulic pressure guided to the pressure chamber. Each of the second through the communication space provided in the valve
A first position in which a discharge passage communicates with the first discharge passage;
A second for interrupting oil discharge from the second discharge passage;
A third position for guiding oil from the second discharge passage to the oil return passage, and a fourth position for guiding at least a portion of the oil from the first and second discharge passages to the oil return passage. A variable displacement oil pump characterized by sliding sequentially.