JPH041354Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an internal gear type pump such as an internal gear pump or a trochoid pump in which the outer rotor has more teeth or the equivalent of teeth than the inner rotor. It is.

Prior Art In order to supply lubricating oil to the lubricated parts of an engine, an internal gear type pump is often used because it can be easily driven directly by a crankshaft and has a small number of parts.

This internal gear type pump was filed by the present applicant as Utility Application No. 145155 (Sho 62-145155) dated September 22, 1985 (see Figure 1). The suction port 0 is on one side with the line X-X connecting the center lines of 02 as the border.
3 is disposed on the other side, and a discharge port 04 is disposed on the other side, and the suction port 03 and the discharge port 04
The suction passage 05 and the discharge passage 06, which communicate with each other, are oriented perpendicularly to the line XX connecting the rotor center.

However, due to the rotational direction of the engine and the intake passage
Depending on the arrangement of the strainer connected to 5 and the lubricating oil equipment connected to the discharge passage 06, the second
As shown in the figure, the pump may be configured such that the discharge passage 06 is oriented from the longitudinal center of the discharge port 04 in a direction opposite to the rotation tangential direction A of the rotors 01 and 02.

Problems to be Solved In the trochoid pump shown in FIG. 2, when the rotors 01 and 02 rotate at high speed, the lubricating oil adjacent to the side surfaces of the rotors 01 and 02 in the discharge port 04 is affected by its viscosity. Rotor 01,0
2, and is pushed into the vicinity of the discharge end 04a of the discharge port 04, and this portion 04
The oil pressure at a is abnormally increased, and this pressure increase presses the side surfaces of the rotors 01 and 02 strongly against the pump casing, increasing the frictional force.

The above-mentioned phenomenon also occurs when the lubricating oil temperature is low and its viscosity is high.

Note that a relief passage 07 is communicated with the discharge passage 06, and a relief valve 0 is connected to this relief passage 07.
8 is interposed.

Means and Effects for Solving the Problems The present invention relates to an improvement of an internal gear type pump that eliminates such inconveniences, and the pump outlet is disposed farther from the discharge end of the discharge port and closer to the discharge start end. The internal gear type pump is characterized in that a bypass passage communicating with the pump outlet is provided near the discharge end of the discharge port.

Since the present invention is configured as described above,
Even if the pump rotates at high speed or the viscosity of the fluid pumped by the pump becomes extremely high, and the fluid is pushed into the discharge port near the discharge end adjacent to the side surface of the rotor, the fluid is forced into the pump outlet via the bypass passage. The fluid can flow through the discharge port, and an abnormal increase in fluid pressure near the discharge end within the discharge port can be prevented.

Embodiment An embodiment of the present invention illustrated in FIGS. 3 to 5 will be described below.

A crankshaft 1 of an automobile engine is rotatably supported by a crankcase 4 via a journal bearing 3, and a small diameter shaft portion 2 integral with the crankshaft 1 projects outward from the crankcase 4. A trochoid type oil pump 5 is disposed outside the crankcase 4 surrounding the portion 2.

The oil pump 5 also includes an inner rotor 6 that is integrally fitted to the small diameter shaft portion 2 of the crankshaft 1, an outer rotor 7 that is eccentrically inscribed around the inner rotor 6, and , a pump housing 8 that rotatably accommodates the outer rotor 7, and this pump housing 8.
The pump cover 9 is formed with a suction port 10, a discharge port 11, a suction passage 12, a discharge passage 13, and a relief passage 14.
A relief valve 15 is interposed in the suction passage 1.
2 and the discharge passage 13 are respectively connected to the suction port 1
0, are communicated with the discharge port 11 and are mutually connected via the relief passage 14.

Therefore, the discharge passage 13 is oriented in the tangential direction and opened near the discharge start end 11a of the discharge port 11, and the relief passage 14 is located on the outer circumferential side of the discharge port 11 and is curved concentrically with the discharge port 11. The discharge end 11b of the discharge port 11 and the relief passage 14 are also communicated through a bypass passage 16.

The embodiment shown in FIGS. 3 to 5 is constructed as described above, so that the crankshaft 1 is
When the oil pump 5 rotates clockwise in the figure, the inner rotor 6 and outer rotor 7 of the oil pump 5 are also rotated in the same direction 7, and lubricating oil flows into the suction port 10 from the suction passage 12 and the inner rotor 6 and outer rotor 7 are rotated clockwise. After being sucked into the gap, it is sent from the discharge port 11 to the discharge passage 13, and is supplied to the lubricated parts of the engine and the oil cooler (not shown).

When the engine is not rotating at high speed or the oil temperature is not low, the lubricating oil discharged into the discharge port 11 flows toward the discharge passage 13 as shown by the solid arrow, and lubricates especially the vicinity of the discharge end 11b. Oil also flows toward the discharge passage 13 against the rotation direction of the inner rotor 6 and outer rotor 7.

However, when the engine rotates at high speed or the oil temperature is low, the influence of the viscosity of the lubricating oil becomes strong, and the lubricating oil near the discharge end 11b is dragged to the side surfaces of the inner rotor 6 and outer rotor 7, and the broken line Even if it flows in the direction of the arrow and is pushed into the discharge end 11b, it can pass through the bypass passage 16 and flow into the discharge passage 13 via the relief passage 14, so the pressure at the discharge end 11b becomes abnormally high. As a result, no large frictional force acts on the inner rotor 6, outer rotor 7, and pump housing 8, allowing the inner rotor 6 and outer rotor 7 to rotate easily, and the oil Loss of power for driving the pump 5 is small, wear of the inner rotor 6 and outer rotor 7 is reduced, and durability is improved.

Further, if the pressure in the discharge passage 13 increases for some reason, the pressure acts on the relief valve 15 via the relief passage 14, and the relief valve 15
is opened, the pressure oil in the discharge passage 13 is returned to the suction passage 12 via the relief passage 14 and the relief valve 15, and abnormal pressure rise in the discharge passage 13 is prevented.

Effects of the invention As described above, the present invention can prevent an abnormal increase in the fluid pressure near the discharge end in the discharge port, so the pressing force of the rotor side surface against the pump casing is minimized to prevent an increase in frictional force. by minimizing power loss to drive the pump,
Efficiency can be improved.

[Brief explanation of the drawing]

FIGS. 1 and 2 are partially cutaway side views of a conventional trochoid pump, FIG. 3 is a side view of a pump cover showing an embodiment of the internal gear type pump according to the present invention, and FIG. 3 is a longitudinal sectional front view taken along the - line in FIG. 3, and FIG. 5 is a transverse side view taken along the - line in FIG. 4. 1... Crankshaft, 2... Small diameter shaft portion, 3... Journal bearing, 4... Crank case, 5... Oil pump, 6... Inner rotor, 7... Outer rotor, 8... Pump housing, 9 ... pump cover, 10 ... suction port, 11 ... discharge port, 12 ... suction passage, 13 ... discharge passage,
14... Relief passage, 15... Relief valve, 16... Bypass passage.

Claims (1)

[Scope of utility model registration request] In an internal gear type pump in which the pump outlet is disposed farther from the discharge end of the discharge port and closer to the discharge start end, a bypass passage leading to the pump outlet is provided near the discharge end of the discharge port. Features an internal gear type pump.