JPH0742445U - Variable displacement oil pump - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a variable displacement oil pump which has a simple structure of an oil capacity adjusting mechanism including a hydraulic pressure adjusting valve, is excellent in function, and is inexpensive. [Structure] A pump operating portion (1) in which oil pressurized by first and second pump means (12, 13) is discharged through first and second discharge passages (3, 4), and Second to the moving part
A hydraulic pressure adjusting section (2) including a plunger chamber having an opening for communicating the discharge passage 4 with the first discharge passage and an opening for the return passage, and a hydraulic pressure adjusting portion (2) having a spool valve is provided. The spool valve has four oil amount / hydraulic pressure adjustment positions.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a variable displacement oil pump, and more particularly, to a variable displacement oil pump with a hydraulic pressure adjusting valve, which is used for lubrication of an engine for an automobile, and whose discharge pressure is appropriately adjusted according to the engine speed. Regarding the oil pump.

[0002]

[Prior art]

 As such a conventional variable displacement oil pump, for example, the one disclosed in Motor Fan Magazine, September 1991, page 182 is known. In this conventional example, two large and small external gear pumps are arranged in parallel, and the adjusting valves arranged on the discharge side adjust the discharge pressure in three stages at low speed, medium speed and high speed. By adjusting the amount of oil and oil pressure from the two pumps appropriately by adjusting valves, the engine horsepower is not consumed unnecessarily and the driving friction at high speed is reduced. There is.

[0003]

[Problems to be solved by the device]

 However, in such a conventional variable displacement oil pump, the manufacturing cost is high because the structure of the adjusting valve is complicated. In addition, since the oil return passage at a low speed intersects in a loop shape, the return passage portion cannot be integrally formed by die casting, which is bulky and requires a large number of parts, resulting in an increase in cost.

The object of the present invention is, in order to solve such a conventional problem, a structure of an oil capacity adjusting mechanism including a hydraulic pressure adjusting valve is simple and excellent in function, and a variable capacity type which is obtained at a low price. To provide an oil pump.

[0005]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention provides a pump operation part in which oil pressurized by the first and second pump means is discharged through the first and second discharge passages, respectively, and the pump operation part is provided at the top. A pressure chamber into which hydraulic pressure is introduced from the first discharge passage, a plunger chamber having an opening for communicating the second discharge passage with the first discharge passage and an opening of an oil return passage in the sliding portion, and the pressure chamber A spool valve that slides along the sliding portion in accordance with the guided hydraulic pressure, and a hydraulic pressure adjusting portion capable of adjusting the amount of oil discharged from the pump operating portion and the hydraulic pressure. A first position for communicating the second discharge passage with the first discharge passage via a communication space provided in the spool valve by hydraulic pressure of the spool valve guided to the pressure chamber; and a second discharge passage. From the oil A second position to cut off, a third position to guide the oil from the second discharge passage to the oil return passage, and at least a part of the oil from the first and second discharge passages to the oil return passage. It is characterized in that it is made to slide sequentially to the fourth position which leads to.

[0006]

[Action]

 According to the present invention, the spool valve is located at the first position in the oil pressure adjusting portion in the low speed rotation region of the oil pump where the oil pressure in the first discharge passage is sufficiently low, so that the second discharge passage communicates with the spool valve. Since it communicates with the first discharge passage through the space, oil is discharged from both the first and second discharge passages. Further, when the hydraulic pressure in the first discharge passage rises as the rotation increases, the spool valve slides from the first position to the second position, the second discharge passage is blocked, and only the first discharge passage is cut off. The oil is discharged, and the amount of the discharged oil is gradually increased. Then, when the oil pressure in the first discharge passage further rises due to the high rotation, the spool valve slides from the second position to the third position, and the oil discharged from the second discharge passage is returned to the oil return passage. When returning to a higher rotation speed, it slides from the 3rd position to the 4th position to return a part of the oil from both discharge passages to the oil return passage, so that unnecessary load is not always applied to the pump operating part. The amount of oil is controlled as follows.

[0007]

【Example】

 Embodiments of the present invention will be specifically described below with reference to the drawings.

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

Here, 1 and 2 are a pump operating portion and a hydraulic pressure adjusting portion of the variable displacement oil pump 10 of the present invention, respectively. The pump operating unit 1 is driven by an engine, and has one intake port 11 and a main pump unit 12 and a sub-pump unit 13 that generate different hydraulic pressures. FIG. 2 shows an example of the structure of an inscribed pump applicable as the pump operating section 1 according to the present invention, in which 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 both tooth molds is discharged from the first discharge port 18 via the first closing portion 17A. Then, it is discharged from the second discharge port 19 through the second closing portion 17B, and is discharged from the second discharge port 19 after being discharged through the two-stage closing portions 17A and 17B. A higher hydraulic pressure can be obtained from the first discharge port 18.

That is, in the case of the pump operating unit 1 shown in FIG. 2, the discharge from the second discharge port 19 can function as the main pump unit 12, and the discharge from the first discharge port 17 can function as the sub pump 13. it can.

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

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

In FIG. 3, 21 is a cylindrical valve chamber, 22 is a sliding valve body that slides in the valve chamber 21, and switches the sub discharge passage 4 as described later, and 23 is the valve chamber 21. A pressure chamber provided at the top of the main discharge passage 3 for guiding the oil pressure of the main discharge passage 3, a spring 24 for biasing the sliding valve body 22 toward the pressure chamber 23 side, and a spring 25 for attaching to the end of the valve chamber 21. It is a plug body that holds the spring 24 between it and the sliding valve body 22. The sliding valve body 22 has a first valve body 22A, a second valve body 22B, and a shaft body 22C that connects 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 hydraulic pressure in the main discharge passage 3 is sufficiently low at a low speed, as shown in FIG. By virtue of the spring force overcoming the hydraulic 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. Therefore, in the pump operating unit 1, oil is delivered from both sides of the main pump unit 12 and the sub pump unit 13, and the hydraulic pressure corresponding to the low speed rotation from the discharge port 28 of the oil pump 10 is shown as a curve C _{L in} FIG. Is sent out.

Next, when the rotation speed slightly increases from the low speed state shown in FIG. 3A, the oil pressure in the pressure chamber 23 overcomes the spring force of the spring 24 as the oil discharge pressure rises. As shown in FIG. 3B, the sliding valve body 22 descends. Then, the first valve body 22A closes the first port 27A, and the second valve body 22B closes the second port 27B, whereby the communication of the sub discharge passage 4 to the main discharge passage 3 is interrupted, and the main pump is closed. By discharging the oil only from the portion 12, the discharge flow rate is suppressed, and therefore, the hydraulic pressure is suppressed from abruptly rising, and the oil is discharged with the tendency shown by the curve C _{M in} FIG.

Then, when the rotation in the pump operating portion 1 is further increased from the rotational state shown in FIG. 3B, the hydraulic pressure adjusting portion 2 further increases the hydraulic pressure in the pressure chamber 23, thereby sliding The valve body 22 descends, and as shown in FIG. 5 (A), the sub discharge passage 4 communicates with the relief passage 6 through the communication space 26. As shown in FIG. The oil discharged from 13 is returned to the oil suction passage 5 side by the relief passage 6. Therefore, the amount of oil discharged is only from the main pump portion 12 through the main discharge passage 3, and the increase in discharge pressure with the increase in pump rotation speed follows the tendency shown as curve C _{H in} FIG.

Subsequently, when the rotation of the pump operating portion 1 continues to increase, the sliding valve body 22 further lowers in the hydraulic pressure adjusting portion 2 as shown in FIG. Communicates with the relief passage 6 via the communication space 26, and part of the discharge oil from the main discharge passage 3 is guided to the relief passage 6 via the second port 27B and the communication space 26. FIG. 6 (B) shows such a state in the oil pump 10, and as a result, the oil discharge pressure is no longer suddenly increased, and the tendency shown by the curve C _{HL in} FIG. 4 is shown. Therefore, it is possible to suppress unnecessary discharge of oil, and it is possible to achieve low friction as a variable displacement oil pump. In this case, in the hydraulic pressure adjusting unit 2, when the sliding valve body 22 is lowered further than that shown in FIG. 5B, the main discharge passage 3 and the sub discharge passage 4 communicate directly with each other via the pressure chamber 23. There is a risk of Therefore, a stopper (not shown here) for restricting the lowering of the sliding valve body 22 is provided to prevent this, or the thickness of the first valve body 22A is set so as to avoid the above-mentioned fear. You should be prepared to take any of these measures.

Although the mechanism of the internal oil pump is used as the pump unit in the embodiments described above, the application of the present invention is not limited to such an internal oil pump, and the present invention is not limited to this. It goes without saying that the invention can also be applied to a pump unit including two pumps such as a tandem type in which the suction port side is common by combining with the hydraulic pressure adjusting unit according to the invention.

[0019]

[Effect of device]

 As described above, according to the present invention, a pump actuating 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 hydraulic pressure is introduced 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 and an opening for an oil return passage in the sliding portion. A hydraulic pressure adjusting unit capable of adjusting the amount of oil discharged from the pump operating unit and the hydraulic pressure, and a spool valve that slides along the sliding unit corresponding to the hydraulic pressure guided to the pressure chamber. A first position for communicating the second discharge passage with the first discharge passage via a communication space provided in the spool valve by hydraulic pressure of the spool valve guided to the pressure chamber; Discharge of oil from the discharge passage A second position for shutting off, a third position for guiding the oil from the second discharge passage to the oil return passage, and a third position for guiding at least a part of the oil from the first and second discharge passages to the oil return passage. Since it slides sequentially to the four positions, the hydraulic pressure adjustment mechanism can be simplified, and the hydraulic pressure and oil amount can be controlled appropriately according to the rotation speed at a low price without using a complicated control mechanism. This makes it possible to provide a variable displacement oil pump that contributes to effective wear prevention of pump constituent elements by suppressing unnecessary hydraulic pressure and oil amount discharge especially at high rotation speeds.

[0020]

[Brief description of 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 portion to which the present invention can be applied.

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

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

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

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pump operating part 2 Oil pressure adjusting 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 portion 13 Sub pump portion 14 Inner rotor 15 Outer rotor 17A, 17B Closing portion 18, 19 Discharge Port 21 Valve chamber 22 Sliding valve body 22A, 22B Valve body 22C Shaft body 23 Pressure chamber 24 Spring 26 Communication space 27A, 27B Port 28 Discharge port

Claims (1)

[Scope of utility model registration request] 1. A pump operating portion in which oil pressurized by the first and second pump means is discharged through the first and second discharge passages, respectively, and a hydraulic pressure is introduced to the top from the first discharge passage. Pressure chamber,
A plunger chamber having an opening for communicating the second discharge passage with the first discharge passage and an opening for an oil return passage in the sliding portion, and the sliding portion corresponding to the hydraulic pressure introduced to the pressure chamber. A spool valve that slides along the spool valve, and a hydraulic pressure adjusting unit that can adjust the amount of oil discharged from the pump operating unit and the hydraulic pressure, wherein the spool valve is driven by the hydraulic pressure introduced into the pressure chamber. The second through the communication space provided in the valve
A first position for communicating the discharge passage with the first discharge passage;
Second for blocking the discharge of oil from the second discharge passage
A position, a third position for guiding the oil from the second discharge passage to the oil return passage, and a fourth position for guiding at least a part of the oil from the first and second discharge passages to the oil return passage. A variable displacement oil pump characterized by sliding in sequence.