JPH0722078U - Variable displacement pump - Google Patents

Abstract

(57) [Summary] [Purpose] To obtain a variable displacement pump having a large ratio of the maximum discharge amount and the minimum discharge amount. [Structure] The first pump chamber 32 is larger than the second pump chamber 52. The first cam plunger 22 reciprocates at a higher speed than the second cam plunger 42. When the combined discharge amount of the first and second pump devices 20 and 40 is set to a predetermined amount or less, the first pump device 20 does not operate and only the second pump device operates. When the combined discharge amount is equal to or larger than the predetermined amount, both the first and second pump devices 20 and 40 operate.
This increases the ratio of the maximum value and the minimum value of the combined discharge amount.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a variable capacity pump provided for pumping lubricating oil in an internal combustion engine, for example.

[0002]

[Prior art]

 Conventionally, in an oil pump mounted on an engine or the like, the discharge amount of the oil pump needs to change depending on the operating state of the engine and the place where the lubricating oil is supplied. In order to meet such complicated requirements, a variable displacement pump that can change the discharge amount by providing multiple pump chambers in one oil pump and combining the oil discharged from these pump chambers Is proposed.

[0003]

[Problems to be solved by the device]

 However, in recent years, especially in rotary engines and the like, the difference in the amount of lubricating oil required depending on the operating state of the engine is very large, and it cannot be said that the ratio of the maximum discharge amount to the minimum discharge amount is sufficiently large in these oil pumps.

The present invention has been made in view of the above problems, and an object thereof is to obtain a variable displacement pump having a sufficiently large ratio between the maximum discharge amount and the minimum discharge amount.

[0005]

[Means for Solving the Problems]

 The variable displacement pump according to the present invention comprises a first pump means having a relatively large discharge amount, a second pump means having a relatively small discharge amount, a fluid discharged from the first pump means and a second pump means. Means for confluently discharging the fluid discharged from the pump means, and only the second pump means for operating the discharge amount in the combined discharge means to a predetermined amount or less, and for making this discharge amount more than a predetermined amount. And a control means for operating the first and second pump means.

[0006]

【Example】

 The present invention will be described below with reference to illustrated embodiments. FIG. 1 is a sectional view showing the construction of an oil pump according to an embodiment of the present invention. This oil pump has a first pump device 20 and a second pump device 40, and the discharge amount of the first pump device 20 is relatively larger than the discharge amount of the second pump device 40. Here, the first pump device 20 will be described.

In FIG. 1, a sliding hole 21 extending horizontally is formed inside the oil pump body 11, and a first cam plunger 22 and a first main plunger 23 can slide in the sliding hole 21. Has been inserted into. A protrusion 22a is formed at the right end of the first cam plunger 22, and a recess 23a is formed at the left end of the first main plunger 23. The protruding portion 22a is inserted into the recessed portion 23a, whereby the first cam plunger 22 and the first main plunger 23 are integrally connected. That is, the first cam plunger 22 and the first main plunger 23 can rotate integrally within the sliding hole 21 about the axis.

The drive shaft 12 extends in a direction perpendicular to the first cam plunger 22, and the driving worm 13 formed on the outer peripheral surface of the drive shaft 12 is formed on the outer peripheral surface of the first cam plunger 22. It also meshes with the worm gear 25. The drive shaft 12 is driven by an engine (not shown) to rotate, which causes the first cam plunger 22 and the first main plunger 23 to rotate.

A support hole 26 is formed in the first main plunger 23, and a first sub-plunger 27 is slidably inserted in the support hole 26. A spring receiving member 29 is fixed to the tip of the first sub-plunger 27. The spring 28 is provided between the spring receiving member 29 and the first main plunger 23, and always biases the first main plunger 23 to the left and the first sub-plunger 27 to the right. Therefore, the first sub-plunger 27 is always in contact with the lid 17 of the oil pump body 11, and any one of the mountain-shaped projection 22b and the pin-shaped projection 22c described later is engaged with the cam shaft 14.

The cam shaft 14 is installed perpendicularly to the first cam plunger 22 and the first main plunger 23, and has a column portion 14 a, a first cam 31 and a second cam 51, and a cam chamber 61. It is housed inside. A lever 15 is fixed to a portion of the cam shaft 14 protruding from the oil pump body 11, and the lever 15 is rotationally displaced according to a motion state of the engine, whereby the cam shaft 14 rotates. The seal ring 16 is inserted between the cam shaft 14 and the oil pump main body 11 to prevent the oil inside the cam chamber 61 from leaking to the outside.

At the left end of the first cam plunger 22, as shown in FIG. 2, two mountain-shaped protrusions 22b and a pin-shaped protrusion 22c are formed. The mountain-shaped projection 22b and the pin-shaped projection 22c project at the same height in the axial direction of the first cam plunger 22. The mountain-shaped protrusion 22b can be engaged with the columnar portion 14a, and the pin-shaped protrusion 22c can be engaged with the first cam 31.

When the mountain-shaped protrusion 22b is located on the first cam 31 of the cam shaft 14 (the state of FIG. 1), the mountain-shaped protrusion 22b does not engage with the columnar portion 14a, and the pin-shaped protrusion 22c does not move. The tip is engaged with the first cam 31. Therefore, the first cam plunger 22 and the first main plunger 23 are located on the leftmost side. When the first cam plunger 22 and the first main plunger 23 rotate 90 ° from this state, the mountain-shaped protrusion 22b engages with the column 14a. As a result, the first cam plunger 22 and the first main plunger 23 are located on the rightmost side. When the first cam plunger 22 and the first main plunger 23 are further rotated by 90 °, the pin-shaped protrusions 22c are again engaged with the first cam 31, and are located on the leftmost side. In this way, the first cam plunger 22 and the first main plunger 23 make one reciprocation every 180 ° rotation.

Inside the support hole 26, a first pump chamber 32 is formed between the first main plunger 23 and the first sub-plunger 27. The volume of the first pump chamber 32 changes according to the reciprocating movement of the first main plunger 23, and increases when the first main plunger 23 moves to the left and decreases when it moves to the right. A suction passage 33 and a discharge passage 34 are formed in the first main plunger 23, one end of each of which opens to the first pump chamber 32 and the other end of which opens to the outer peripheral surface of the first main plunger 23.

The second pump device 40 has the same configuration as the first pump device 20. That is, a sliding hole 41 extending horizontally is formed inside the oil pump body 11. A second cam plunger 42 and a second main plunger 43 are slidably inserted in the sliding hole 41, and a second sub-plunger 47 is provided in a supporting hole 46 formed in the second main plunger 43. It is slidably inserted. Inside the support hole 46, a second pump chamber 52 is formed between the second main plunger 43 and the second sub-plunger 47. Thus, the reference numerals of the components of the second pump device 40 are shown by adding 20 to the reference numerals of the corresponding members of the first pump device 20, and the description of the other components is omitted.

Oil passages 62, 64 and an oil chamber 63 are formed in the oil pump body 11. One end of the suction hole 55a is opened in the oil passage 62, and the other end of the suction hole 55a is opened in the sliding hole 41. One ends of the suction holes 35 and 55 b are opened in the oil passage 64, the other end of the suction hole 35 is opened in the sliding hole 21, and the other end of the suction hole 55 b is opened in the sliding hole 41. . The suction hole 35 can be closed by the first main plunger 23 and can communicate with the suction passage 33. The suction holes 55a and 55b can be closed by the second main plunger 43 and can communicate with the suction passage 53.

FIG. 3 is a sectional view of the oil pump body 11 taken along the line III-III in FIG. Two merging passages 65 are bored inside the oil pump body 11. The merging passage 65 is located on both sides of the first main plunger 23 and the second main plunger 43 in FIG. 3, and extends in the vertical direction. A tubular member 66 is provided inside each of the merging passages 65, and the tubular member 66 is fixed to a predetermined portion. An annular sheet member 69 is provided at one end of the tubular member 66, and a hole 66a is formed at the other end of the tubular member 66. A spring 67 and a check valve 68 are provided in the tubular member 66, and the check valve 68 can open and close a valve hole 69 a formed in the seat member 69. The check valve 68 is biased by a spring 67 in a direction to close the valve hole 69a.

An opening 36 a of the discharge hole 36 and an opening 56 a of the discharge hole 56 are formed on the wall surface forming each merging passage 65. The opening 36a is provided below the sheet member 69 in FIG. 3, and the opening 56a is provided above the tubular member 66. The discharge hole 36 and the discharge hole 56 are formed inside the oil pump body 11, and open at the other end into the sliding holes 21 and 41, respectively. The discharge hole 36 is closed by the first main plunger 23 and can communicate with the discharge passage 34. The discharge hole 56 is closed by the second main plunger 43 and can communicate with the discharge passage 54. The oil inside the confluence passage 65 is pressure-fed to the lubricating portion of the engine (not shown) via the outlet 70.

The operation of the apparatus of this embodiment will be described. Oil is sucked into the cam chamber 61 from an oil inlet (not shown). The oil in the cam chamber 61 passes through the oil passage 62 and the oil chamber 63 and is guided to the oil passage 64.

When the first main plunger 23 is moving to the left, the suction stroke is performed because the volume of the first pump chamber 32 increases. That is, the suction passage 33 and the suction hole 35 communicate with each other, and the oil is sucked into the first pump chamber 32 from the oil passage 64. At this time, the discharge passage 34 is blocked from the discharge hole 36. On the other hand, when the first main plunger 23 is moving to the right, the volume of the first pump chamber 32 decreases, so that the discharge stroke is performed. That is, the discharge passage 34 communicates with the discharge hole 36, and the oil in the discharge passage 34 is compressed and discharged to the discharge hole 36. At this time, the suction passage 33 is blocked from the suction hole 35. Such suction and discharge strokes are similarly performed in the second pump device 40.

The oil discharged from the discharge holes 36, 56 passes through the respective openings 36 a, 56 a and is guided to the merging passage 65. The oil discharged from the opening 36a pushes the check valve 68 open to flow in the merging passage 65, passes through the hole 66a formed in the tubular member 66, and merges with the oil discharged from the discharge hole 56. , Is discharged from the outlet 70. The amount of oil discharged from the openings 36a and 56a is proportional to the strokes of the first main plunger 23 and the second main plunger 43, respectively, and these strokes correspond to the shapes of the first cam 31 and the second cam 51, respectively. It is controlled by the rotation angle of the cam 14.

FIG. 4 is a graph showing the discharge characteristics of the apparatus of this embodiment, and FIG. 5 is a sectional view of the first cam 31 and the second cam 51. The control of the discharge amount will be described with reference to these drawings. In FIG. 4, the vertical axis represents the discharge amount, and the horizontal axis represents the rotation angle of the cam shaft 14. Reference symbols Q1 and Q2 show the discharge characteristics of the first pump device 20 and the second pump device 40, respectively, and reference symbol Q3 shows the combined discharge characteristics of the discharge from the outlet 70.

When the rotational angular position of the camshaft 14 is in the state represented by reference sign A or B, the pressure of the oil discharged from the first pump device 20 is higher than the pressure of the spring 67 pressing the check valve 68. large. Therefore, the oil discharged from the first pump device 20 opens the check valve 68 and flows in the merging passage 65, merges with the oil discharged from the second pump device 40, and is discharged from the outlet 70. That is, the amount of oil discharged from the oil pump is the sum of the discharge amounts of the first pump device 20 and the second pump device 40. In particular, when the rotational angular position of the cam shaft 14 is represented by the symbol A, the strokes of the first main plunger 23 and the second main plunger 43 are maximum. Therefore, the discharge amount by this oil pump becomes maximum.

When the rotational angular position of the cam shaft 14 is in the state represented by the symbol C or D, the pin-shaped protrusion 22c of the first pump device 20 and the first cam 31 of the cam shaft 14 are always engaged. Therefore, the first cam plunger 22 and the first main plunger 23 do not reciprocate. On the other hand, in the second pump device 40, the pin-shaped protrusion 42c and the second cam 51, or the mountain-shaped protrusion 42b and the columnar portion 14a are alternately engaged, so that the second cam plunger 42 and the second main plunger 42 are engaged. 43 makes a reciprocating motion. Therefore, the amount of oil discharged from the outlet 70 is only the amount discharged by the second pump device 40. Particularly, when the rotational angle position of the cam shaft 14 is represented by the symbol D, the stroke of the second main plunger 43 is minimized. Therefore, the amount discharged by this oil pump is minimized.

In the second pump chamber 52, the maximum discharge amount is 20 times the minimum discharge amount. The maximum discharge amount of the first pump chamber 32 is 6 times the maximum discharge amount of the second pump chamber 52. Further, in the pump device 20 and the pump device 40, the worm gears 25 and 45 are formed with different gear ratios, and the rotation speed of the first cam plunger 22 is about 2.5 times the rotation speed of the second cam plunger 42. Is. Therefore, the first cam plunger 22 reciprocates about 2.5 times faster than the second cam plunger 42, so that the discharge amount of the first pump device 20 is about 2.5 times the discharge amount of the second pump device 40. Becomes With the above, in the oil discharged from the confluent passage 65, the maximum discharge amount is about 300 times the minimum discharge amount (20 × 6 × 2.5).

Further, in the case of the symbols C or D in FIGS. 4 and 5, it is not always the case that the discharge amount from the first pump device 20 is not always present at all, and a very small amount of back-and-forth due to an error in manufacturing accuracy or the like. Due to the movement, unstable discharge may be performed, or the pressure fluctuation of the first pump chamber 20 may adversely affect the discharge of oil from the second pump chamber. Even in such a case, the check valve 68 in the merging passage 65 closes the valve hole 69a with the spring 67, so that the oil discharged from the first pump device 20 flows into the outlet 70 side of the merging passage 65. Is prevented, and the pressure fluctuation of the first pump chamber 32 is prevented from affecting the oil discharged from the second pump chamber 52 having a small capacity.

The structure of the check valve 68 is not limited to the ball valve as in the illustrated embodiment, and may have any structure.

[0027]

[Effect of device]

 As described above, according to the present invention, it is possible to obtain a variable displacement pump having a sufficiently large ratio of the maximum discharge amount and the minimum discharge amount.

[Brief description of drawings]

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

FIG. 2 is a detailed view of an engagement portion between a cam shaft 14 and a first cam plunger 22.

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

FIG. 4 is a diagram showing a relationship between a cam shaft rotation angle and a discharge amount.

FIG. 5 is a sectional view of a first cam 31 and a second cam 51.

[Explanation of symbols]

 11 oil pump main body 20 first pump device 40 second pump device 65 confluence passage 68 check valve

Claims (3)

[Scope of utility model registration request] 1. A first pump means having a relatively large discharge amount, a second pump means having a relatively small discharge amount, a fluid discharged from the first pump means and a second pump means. Means for merging and discharging the fluid to be discharged, and only the second pump means for operating the discharge amount in the merging and discharging means to be less than or equal to a predetermined amount, and the first and And a control means for operating the second pump means. 2. The variable valve according to claim 1, wherein the combined discharge means has a check valve for preventing a pressure fluctuation of the first pump means from affecting the second pump means. Capacity pump. 3. The variable displacement pump according to claim 1, further comprising means for controlling the first pump means to drive at a higher speed than the second pump means.