JPH0433994B2 - - Google Patents

Description

[Detailed Description of the Invention] [Conventional Field of Application] The present invention relates to a variable oil pump for pumping lubricating oil for an internal combustion engine, and in particular to a variable oil pump that automatically maintains the pressure on the discharge side at a substantially constant level. Regarding oil pumps.

[Description of Prior Art] Trochoid pumps are mainly used as pumps for pumping lubricating oil for conventional internal combustion engines.
This conventional trochoid pump, for example,
-159984, etc., which includes an outer rotor with internal teeth formed inside a body forming an inlet and a discharge port, and external teeth for engaging with the internal teeth inside the outer rotor. The formed inner rotor is rotatably attached. The rotation center of the inner rotor and the rotation center of the outer rotor are eccentric, and the number of internal teeth of the outer rotor is different from the number of external teeth of the outer rotor. That is, the inner rotor and the outer rotor rotate in proportion to the number of teeth. The outer rotor is rotated by the rotation of the inner rotor, and oil is held and moved between the inner rotor and the outer rotor, which rotate at different speeds, thereby performing a pumping action.

In this conventional trochoid pump, the amount of lubricating oil discharged is proportional to the rotational speed of a rotating shaft connected to an engine that rotates the inner rotor. That is, as the rotational speed of this rotating shaft increases, the pressure on the discharge port side increases, and more lubricating oil than necessary is pumped, increasing power loss and shortening the life of the pump.

In order to overcome this drawback, a patent application filed in 1983 was developed in which the discharge pressure did not increase beyond a predetermined value even if the rotational speed of the inner rotor increased.
No. 7241. A cross-sectional view of this trochoid pump is shown in FIG. 7, and a cross-sectional view taken along the line X--X in FIG. 7 is shown in FIG. First body 10
has a cylindrical shape, and an annular outer rotor 12 that fits therein is rotatably mounted inside the cylinder. Five equal-angled internal teeth 14 are formed on the inner wall surface of this annular outer rotor 12.
An inner rotor 18 is provided on the annular inner side of the outer rotor 12 and has four equiangular outer teeth 16 that engage with the inner teeth 14 thereof. This inner rotor 18 is fixed to a rotating shaft 20 that is directly connected to a drive means (not shown). The center of the rotation axis 20 of this inner rotor 18 is located at a point P in FIG.
The center of rotation of the inner teeth 14 of the outer rotor 12 is indicated by a point Q. The rotational center point P of the inner rotor 18 and the rotational center Q of the outer rotor 12 are eccentric by a length e.

A disk-shaped plate 22 is disposed on one side of the inner rotor 18 and the outer rotor 12, and the plate 22 connects the first body 10 and a second body 27 forming an inlet 24 and an outlet 26. It is rotatably held by.

Here, the sectional view taken along the Y-Y line in FIG.
As shown in the figure. The position of the plate 22 shown in FIG. 9 is the normal position. The rotating shaft 20 is inserted through the center of the plate 22, and the plate 22 rotates concentrically with the rotation center P of the inner rotor 18, but rotates independently of the inner rotor 18. Involume teeth 28 are formed on the outer periphery of this plate 22. This plate 22 has a semi-circular suction window 32 and a semi-circular discharge window 34 defined by a partition wall 30.
is formed.

Here, when the plate 22 is in the normal position shown in FIG. The discharge area formed by the rotor 12 is also set so that almost the entire area communicates with the discharge side window 34.

A plunger 36 is slidably mounted within the second body 44, and a rack 38 that engages with the involute teeth 28 of the plate 22 is fixed to the tip of the plunger 36. This plunger 36 is always pressed in a fixed direction by a spring 40, and normally holds the plate 22 in a predetermined position (the position shown in FIG. 9). A flange 42 is formed on the plunger 36, and a space 44 is formed between the flange 42 and the second body 44 on the opposite side of the spring 40. This space 44 communicates with the discharge port 26 via a passage 46. That is, the pressure of the lubricating oil from the discharge port 26 is applied to the space 44 .

With the above configuration, when the pressure of the lubricating oil applied to the discharge port 26 and the space 44 increases beyond a predetermined level, the high pressure moves the plunger 36 upward in FIG. 9 against the spring 40. , the plate 22 is rotated counterclockwise around the rotating shaft 52. By rotating this plate 22, the suction side window 32 and the discharge side window 34 of the plate 22 are rotated.
move, and the communication cross section where they coincide with the suction area and the discharge area formed by the inner rotor 18 and the outer rotor 12 becomes narrower. This reduces the suction amount and discharge amount, making it possible to adjust the pressure of lubricating oil discharged from the discharge port so that it does not exceed a predetermined value, reducing the pump's driving force and increasing the durability of the pump. I was able to improve it.

[Problems to be solved by the invention] In this way, by interposing a plate having a suction side window and a discharge side window between the suction port or the discharge port and the inner rotor or the outer rotor, it is possible to increase the pressure on the discharge side. In the case where the plate is rotated to change the suction area with respect to the suction port and the discharge area with respect to the discharge port, the outer rotor rotates once (the inner rotor rotates 450 degrees), as shown in Fig. 10 A. In between, when the discharge port is closed and the suction port is open, a port cut (the port is closed during the suction process) occurs. This port cut occurs because the S point at the end of exhalation and the T point at the beginning of suction move. When this port was cut, there were problems such as cavitation noise and an unnecessary increase in torque.

[Object of the Invention] The present invention has been made in view of the above points, and is intended to improve the durability of the pump by always preventing the pressure on the discharge side from rising above a certain level even when the rotational speed increases. Another object of the present invention is to provide a variable oil pump that eliminates the occurrence of port cuts and prevents cavitation noise and unnecessary torque increases.

[Means for Solving the Problems] In order to achieve the above object, the present invention forms a suction port and a discharge port in a pump body, rotatably holds a rotating shaft in the pump body, and attaches an inner wall to the rotating shaft. A rotor is fixed, and a cylindrical outer rotor that engages with the inner rotor is rotatably held within the pump body, and the outer rotor is rotated as the inner rotor rotates, and the rotation of the outer rotor causes suction area and discharge In the variable oil pump, the fluid is transferred from the suction port to the discharge port via between the external teeth of the inner rotor and the internal teeth of the outer rotor. A movable boat body is rotatably provided on a surface opposite to the discharge port, and a suction-side recess is formed in the movable port body to form a regular suction port with the suction port, and rotation of the movable port body is provided. The rotating tip of the indentation on the suction side extends to the discharge area, and the rear end of the rotation of the indentation on the suction side remains in the suction area. The starting position is set to remain unchanged, an oil reservoir chamber communicating with the discharge port is formed, and biasing means for resisting the hydraulic pressure of the oil reservoir chamber is provided, and the oil is slid by the biasing means. and means for rotating the movable port body when the pressure in the reservoir chamber increases above a predetermined pressure.

[Function] When the pressure at the discharge port increases above a predetermined pressure, the rack slides against the spring due to the pressure.
As the rack slides, the movable port body is rotated. By rotating this movable port body,
The rotating tip of the recess on the suction side enters the discharge area.
As a result, the lubricating oil in the discharge area is returned to the suction area through the suction side recess, and the pressure on the discharge port side is reduced.

Due to this movement of the movable port body, the length of the regular suction port consisting of the suction port and the suction side recess is extended, and the end of suction is delayed. In this way, by delaying the end of opening of the regular suction port, the discharge amount can be reduced.

Furthermore, even if the movable port body moves, the suction start position in the regular suction port consisting of the suction port and the suction side dent, and the discharge end position in the regular discharge port consisting of the discharge port and the discharge side dent will change. This will prevent port cuts.

[Example] Next, the present invention will be explained based on the drawings.

FIG. 1 is a sectional view of essential parts of a variable oil pump according to the present invention, FIG. 2 is a sectional view taken along line A-A in FIG. 1,
3 is a sectional view of the movable port body taken along the line B--B in FIG. 1, and FIG. 4 is a rear view of the movable port body taken along the line C--C in FIG. 1.

As shown in FIG. 1, a space is formed by a cylindrical first body 50 with one end closed and a cylindrical second body 56 having an inlet 52 and an outlet 54 formed on its end face. An inner rotor 58 is provided within the space.
The outer rotor 60 and the movable port body 62 are rotatably held. This inner rotor 58 is fixed to a rotating shaft 59 that is directly connected to a drive means (not shown). The inner rotor 58 and the outer rotor 60 are arranged such that one side surface contacts the suction port 52 and the discharge port 54 of the second body 56, and the other side surface contacts the movable port body 62. Inner rotor 58 in this movable port body 62
A suction side recess 64 and a discharge side recess 66 are formed on the contact surface with the outer rotor 60.

As shown in FIG. 2, the shape of the suction port 52 formed in the second body 56 is approximately a semicircular arc shape (shorter than half of the arc), and the shape of the discharge port 52 is approximately semicircular (shorter than half of the arc).
The shape of No. 4 is approximately a quarter arc (longer than a quarter of an arc). The suction start point of this suction port 52 is a1, and the suction end point is b1.
On the other hand, the discharge start point of the discharge port 54 is c1, and the suction end point is d1.

Next, as shown in FIG. 3, the movable port body 62
The shape of the suction side recess 64 is the same as the shape of the suction port 52. On the other hand, the discharge side recess 66 is
The length is shorter than the discharge port 54, and the discharge side recess 66 is located at a position where a portion thereof overlaps with the discharge port 54 when viewed from the direction of arrow D in FIG. The suction start point of this suction side recess 64 is designated as a2, and the suction end point thereof is designated as b2. The discharge start point of the discharge side recess 66 is defined as c2, and the suction end point thereof is defined as d2.

Here, the intake port 5 seen from the direction of arrow D in FIG.
FIG. 5 shows the normal overlapping state of the suction side recess 64 and the suction side recess 64, and the overlapping state of the discharge port 54 and the discharge side recess 66. There is. That is, the respective suction start points a1 and a2 are at the same position, and the respective suction end points b1 and b2 are at the same position. The length of the regular suction port in this state is from a1, a2 to b1, b2. On the other hand, the discharge port 54 and the discharge side recess 66 are set so that they partially overlap. That is, when viewed from the direction of arrow D in FIG. 1, the discharge start point d2 of the discharge side recess 66 is located between the discharge start point c1 of the discharge port 54 and the suction end point d1. The length of the regular discharge port in this state is the maximum length of the discharge port 54 and the discharge side recess 66, that is, c2
This is the length from point to point d1.

In the movable port body 62, a support shaft 68 is integrally formed on the side opposite to the suction side recess 64 and the discharge side recess 66, and the tip of this support shaft 68 is held by the first body 50 via a bearing 70. .
The movable port body 62 also has annular involute teeth 72 integrally formed around the support shaft 68 .

As shown in FIG. 4, a rack 74 is slidably provided in the first body 50 and engages with the involume tooth 72. As shown in FIG. A large-diameter intermediate plate 76 is fixed to one end of the rack 74, and the intermediate plate 76 and the rack 74 are always urged in one direction by a spring 78. Rack 7 of this intermediate plate 76
An oil reservoir chamber 80 is formed on the 4 side, and this oil reservoir chamber 80
and the discharge port 54 are communicated through a passage 82.

Next, the operation will be explained.

Under normal conditions, the left side of the E-E line in FIG. 5 is the suction area due to the action of the inner rotor 58 and the outer rotor 60, and the right side of the E-E line is the discharge area. The suction-side recess 64 is located in the suction region, and the discharge-side recess 66 is located in the discharge region. In the state shown in FIG. 5, the amount of lubricating oil discharged from the discharge port 54 increases in accordance with the rotation speed of the rotating shaft of the inner rotor 58, and the discharge pressure increases.

Here, when the pressure at the discharge port 54 becomes higher than a predetermined value, the high pressure reaches the oil reservoir chamber 80, and the high pressure pushes the intermediate plate 76 and the spring 78, causing the rack 74 to move to the left in FIG. 4, and rotate the movable port body 62 counterclockwise as shown in FIG. That is, this rotates the movable port body 62 clockwise in FIG. 5. However, the maximum rotation angle of the movable port body 62 is 90 degrees.

FIG. 6 shows a state in which the movable port body 62 has been rotated to the maximum clockwise from the state shown in FIG. 5. In this state, the suction end point b2 of the suction side recess 64
protrudes to the ejection area on the right side of the E-E line. The higher the pressure at the discharge port 54 is, the more the movable port body 62 is rotated, and the suction side recess 64 enters the discharge area. In this way, the suction side recess 64 straddles the suction region and the discharge region, so the lubricating oil with increased pressure in the discharge region flows to the suction region via the suction side recess 64.
Thereby, it is possible to reduce the discharge amount and prevent lubricating oil with a pressure higher than a predetermined level from being discharged from the discharge port 54.

Thereafter, when the pressure in the discharge region decreases, the pressure acting on the oil reservoir chamber 80 decreases, causing the spring 78 to push the rack 74 to the right in FIG. It rotates clockwise from the state shown in FIG. 5. This causes the suction side recess 64 to return to the suction area.

Also, from the state shown in FIG. 5, the movable port body 62
When rotated to the state shown in FIG. 6, the normal suction port consisting of the suction port 52 and the suction side depression 64 is
The inhalation start point is a1, and the inhalation end point is b2. Point a1, which is the position at the beginning of suction, does not change, but point b2, which is the position at the end of suction, is changed so that the normal suction port becomes longer. On the other hand, in the regular discharge port consisting of the discharge port 54 and the discharge side recess 66, the discharge start point is c1 and the discharge end point is d1. In this case, the discharge start point is from c2 to c
1, and the discharge end point d2, which is the rotating tip of the discharge side recess 66, does not reach the discharge end point d1 of the discharge port 54, and the discharge end point d1 does not change. That is, the regular discharge port has a shorter overall length.

In the state shown in FIG. 6, the end of suction at the regular suction port is delayed, and at the same time, the start of discharge at the regular discharge port is delayed. This means that the variable point R from the normal suction port open to the normal discharge port open in FIG. 10B is moved to the right in the figure, and the discharge flow rate is reduced.

Furthermore, from the state shown in FIG. 5, the movable port body 62
Even when rotated to the state shown in FIG. 6, the start of suction at the regular suction port is the same point a1 as in FIG. 5, and the end of discharge at the regular discharge port is at the same point d1 as in FIG. In this way, even if the length of the regular suction port or the regular discharge port changes due to the rotation of the movable port body, the positions of the start of suction and the end of discharge do not change. Thereby, as shown in FIG. 10B, it is possible to prevent the occurrence of a port cut between the suction process and the discharge process as shown in FIG. 10A.

In the present invention, almost the same result can be obtained without providing the discharge side recess 66, but by providing the discharge side recess 66 and delaying the discharge start point of the regular discharge port, the discharge control effect can be improved. can be raised.

[Effects of the Invention] As described above, according to the variable oil pump according to the present invention, the movable port body having the suction side recess and the discharge side recess is connected between the suction port and the discharge port by sandwiching the inner rotor and the outer rotor. Place it oppositely;
When the pressure on the discharge side increases, the movable port body is rotated so that the suction end position of the suction side recess enters the discharge area, and the suction area and the discharge area are communicated through the suction side recess. . Therefore, when the rotational speed of the rotating shaft increases, the discharge pressure of the pump can be kept below a certain level, and the durability of the pump can be improved.

In addition, even if the length of the regular suction port or regular discharge port changes due to the rotation of the movable port body, the suction start of the regular suction port and the discharge end of the regular discharge port do not change, so it is not necessary to use the conventional port cut. The occurrence of cavitation noise and unnecessary torque increase can be prevented.

[Brief explanation of drawings]

FIG. 1 is a sectional view of essential parts of a variable oil pump according to the present invention, FIG. 2 is a sectional view taken along line A-A in FIG. 1,
Figure 3 is a sectional view of the movable port body taken along line B-B in Figure 1, Figure 4 is a rear view of the movable port body taken along line C-C in Figure 1, and Figure 5 shows the inlet and suction ports. A diagram showing the overlapping state of the side dent and the discharge port and the discharge side dent in normal times. Figure 6 is a diagram showing the state in which the movable port body has been rotated from the state in Figure 5. Figure 7 is a diagram showing the conventional variable oil type. A sectional view showing the pump, FIG. 8 is a sectional view taken along line X-X in FIG. 7,
Figure 9 is a sectional view taken along the line Y-Y in Figure 7, and
The figure is a relationship diagram showing the open positions of the suction port and the discharge port with respect to the rotation angle of the inner rotor. 50...first body, 52...intake port, 56...
... Second body, 54 ... Discharge port, 58 ... Inner rotor, 60 ... Outer rotor, 62 ... Movable port body, 64 ... Suction side dent, 66 ... Discharge side dent, 72 ... Involute tooth, 74...
...Rack, 78...Spring, 80...Oil sump chamber, a
1, a2...Inhalation start point, b1, b2...Inhalation end point, c1, c2...Exhalation start point, d1, d2...
...Discharge end point.

Claims (1)

[Claims] 1. A pump body is provided with an inlet port and a discharge port,
The rotating shaft is rotatably held in the pump body,
An inner rotor is fixed to the rotating shaft, a cylindrical outer rotor that meshes with the inner rotor is rotatably held within the pump body, and the outer rotor is rotated as the inner rotor rotates. In a variable oil pump that forms a suction region and a discharge region, and transfers fluid from the suction port to the discharge port via between the external teeth of the inner rotor and the internal teeth of the outer rotor, A movable port body is rotatably provided on a surface opposite to the suction port and the discharge port, and a suction side recess is formed in the movable port body to configure a regular suction port with the suction port, As the movable port rotates, the rotating tip of the suction side recess extends to the discharge area, and the rotational rear end of the suction side recess remains in the suction area. The suction port is set so that the suction start position does not change, and an oil reservoir chamber communicating with the discharge port is formed;
and a means for rotating the movable port body when the pressure in the oil reservoir chamber increases above a predetermined pressure by being slid by the urging means. A variable oil pump with the following features: 2. A discharge side recess is formed in the movable port body, and the discharge port constitutes a regular discharge port, and as the movable port body rotates, the rotating tip of the discharge side recess moves to the discharge end position of the regular discharge port. The variable oil pump according to claim 1, characterized in that the variable oil pump does not shift.