JPH03213685A - Multiple gear pump - Google Patents

Abstract

PURPOSE:To reduce rate of volume variation in a confining part, and reduce pressure pulsation and vibration/noise generated due to abnormal pressure rise or pressure drop, by providing a communication passage to communication the vicinity of engagement center point of a gear pump to that of another gear pump. CONSTITUTION:A communicating passage 21 to communication the vicnity of an engagement center point of a gear pump A to that of another gear pump B, supplies the fluid in a confinedly compressing part from the beginning of confinement to the center point of confinement of one gear pump A to a confinedly expanding part from the center point of confinement to the end of confinement of the other pump B. Hereby, the pressure in the confined part does not become abnormally high or low. Further, coming in and out of the fluid between the confined part and the suction port or the discharge port due to surplus or shortage of the fluid accompanying confined compression or confined expansion.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a multiple gear pump for pumping fluid, and particularly to a multiple gear pump suitable for reducing pressure pulsations and flow pulsations.

[Conventional technology]

The conventional multiple gear pump is disclosed in Japanese Patent Application Laid-Open No. 57-135288.
Figure 9 shows an outline of one gear pump. Each gear pump consists of a plurality of three-gear pumps, each consisting of three gears 2a, 3a', and 3a' each having two teeth, combined together in the axial direction, and the central gear 2a of each set has a phase difference of one pitch. It was placed. The gear pump transfers the fluid sucked through the suction port 10 and sent to the low pressure chambers 8a, 8b to the high pressure chambers 9a, 9b, and discharges it from the discharge port 11. For example, in the case of a dual gear pump consisting of gear pump A and gear pump B, the relationship between the rotation angle of the central gear 2a and the discharge flow rate is shown in FIG. The discharge flow rate of gear pump A is the average flow rate Q1. It pulsates with a fluctuation amount ΔQ1 period □ with respect to I2π.

On the other hand, the discharge flow rate of gear pump B has the same fluctuation amount and period as that of gear pump A, and pulsates with a - phase difference. Therefore, when gear pump A and gear pump B constitute a dual gear pump, the combined discharge flow rate at that time is as shown in FIG. 11.

The period becomes -.

On the other hand, it was argued that in a dual gear pump where the central gears do not have a phase difference with each other, the average flow rate will be greater.Therefore, if a multiple gear pump is configured with a one-pitch phase difference between the central gears, the discharge flow rate will fluctuate. It is being

Additionally, in a gear pump, a trapped portion generally occurs when the gear rotates. Figure 12 (1) shows the progress of this confinement.
, (2) and (3), and the changes in the confinement volume V at that time are shown in FIG. FIG. 12(1) shows the state at the start of confinement, FIG. 12(2) shows the state at the center of confinement, and FIG. 12(3) shows the state at the end of confinement. During this time, as shown in Fig. 13, the confined volume decreases from the start of confinement to the center of confinement, so the fluid is compressed by volume ΔVl, and from the center of confinement to the end point of confinement, the fluid is compressed by volume ΔV1. Since the confinement volume increases, the volume expands by Δ■2. When the confined volume is reduced and the fluid is compressed in this way, the fluid in the confined area becomes at a very high pressure, and when the confined volume increases, the fluid in the confined area becomes at a very low pressure.

Such confinement causes the discharge pressure to pulsate irregularly, causing vibrations, noise, and a decrease in the discharge amount due to cavitation. There is also a risk of erosion and destruction of pump parts. Conventionally, this problem of confinement has been prevented by providing relief grooves in the casing or side plate on the side surface of the confinement part. This is because while the confinement volume is in the process of decreasing, the confinement part communicates with the high pressure chamber through this escape groove, so the fluid forced out by confinement compression is sent to the high pressure chamber. This prevents the pressure from increasing due to compression. Furthermore, when the confinement volume begins to increase, the confinement portion communicates with the low pressure chamber through another relief groove, so that the insufficient fluid due to confinement expansion is supplied from the low pressure chamber. This prevented the generation of a vacuum.

[Problem to be solved by the invention]

The above conventional technology takes into consideration the reduction of pulsation in the discharge flow rate in multiple gear pumps, but does not take into account confinement, which causes the problem of pressure pulsation.Furthermore, the conventional technology provides relief grooves. is a confinement part and a discharge port, or
No consideration was given to the flow of fluid into and out of the suction port.
There was a problem with flow pulsation.

An object of the present invention is to provide a multiple gear pump that reduces both pressure pulsations and flow pulsations.

[Means to solve the problem]

To achieve the above object, the present invention provides a multiple gear pump in which at least one of the plurality of gear pumps has a drive gear in a phase different from the phase of the drive gear in the other gear pumps. , a communication path is provided that communicates the vicinity of the meshing center point of the gear pump with the meshing center point of the other gear pump.

[Effect]

A communication path that connects the vicinity of the meshing center point of one gear pump with the meshing center point of the other gear pump is used to connect the fluid in the confinement compression section from the start of confinement to the center of confinement to the confinement of the other gear pump. Since the pressure is supplied from the center to the confinement expansion section until the end of confinement, the pressure in the confinement section will not become abnormally high or low. In addition, there is no possibility of fluid flowing in and out between the confining portion and the suction port or the discharge port due to excess or deficiency of fluid due to confinement compression or confinement expansion.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

FIG. 1 is an embodiment of the present invention, FIG. 2 is a section I-1 in FIG. 1, FIG.
The figure shows the IV-IV cross section in FIG.

1 is a multiple gear pump, which is composed of gear pumps A and B. 2a and 2b are drive gears, 3a and 3b are driven gears, and 4a, 4b, 4c, and 4d are casings. The drive gear 2a and the driven gear 3a are in mesh with each other. Similarly, the driving gear 2b and the driven gear 3b are in mesh with each other. The driving gear 2a and the driven gear 3a are connected to the casing 4.
a.

4b to form a gear pump A, and drive gear 2
b and the driven gear 3b are housed in casings 4c, 4d to form a gear pump B. The drive gears 2a and 2b each have a drive shaft 6a.

6b, and a driven gear 3a.

3b are formed integrally with the driven shafts 7a and 7b, respectively. The drive gear 2a and the drive gear 2b are coupled by a coupling 5 via a drive shaft 6a and a drive shaft 6b with a tooth phase difference between them. The low pressure chamber 8 and the high pressure chamber 9 are located in the casings 4b, 4c, and 4d, respectively.
They are formed in a non-communicating state and communicate with the suction port 1o and the discharge port 11, respectively. An oil groove 21a is formed in the casing 4b near the meshing center point of the gear pump A. Similarly, an oil groove 21b is formed in the casing 4c near the meshing center point of the gear pump B. Oil groove 21a
and 21b communicate with each other through communication passages 21 formed within the casings 4b and 4c.

With this configuration, the drive shaft 6a is rotated by an electric motor (not shown). Accordingly, the drive gear 2a integrally formed on the drive shaft 6a and the drive gear 2b coupled by the coupling 5 rotate. Drive gears 2a and 2b
When the driven gears 3a mesh with each other,
, 3b also rotate. Now, in the case of the gear pump A, when the drive gear 2a and the driven gear 3a rotate in the direction of the arrow in FIG. The fluid is further transferred to the high pressure chamber 9 while filling the fluid transfer space surrounded by the driving gear 2a or the driven gear 3a and the casings 4a and 4b, and is led to the discharge port 11. Similarly, for the gear pump B, the fluid flows between the driving gear 2b or the driven gear 3b and the casings 4c and 4.
The fluid is guided from the suction port 1° to the discharge port 11 while filling the fluid transfer space surrounded by d. For example, the number of teeth of the driving gear 2a and the driven gear 3a of the gear pump A is two, and the number of teeth of the driving gear 2b and the driven gear 3b of the gear pump B are also two. Further, the angle θ1 is set to 2π/Z, and the phase angle of the teeth of the drive gears 2a and 2b is set to 02. Now, θ2=
If θ1/4, 6 gear pump A and gear pump B
The change in the confinement volume is shown in Figure 5. In other words,
The change in the confined volume of gear pump A and gear pump B is
The average volume VM, the amount of variation ΔV, and the tooth phase angle θ2 vary. After the gear pump A starts confining, the confinement part opens into the oil groove 21a, and if this is communicated with the oil groove 21b through the communication passage 21, the confinement volume changes as shown in FIG. 6, Average volume 2VM,
The volume change rate becomes - with the amount of variation ΔV. Therefore, pressure pulsations within the confinement are also reduced accordingly.

In the above embodiments, a dual pump was shown.

The present invention can be realized even with two or more pumps. Alternatively, one pump may be a multiple pump composed of pumps with three or more gears. It can also be realized by using internal gears shown in FIGS. 7 and 8 instead of the external gears. Furthermore, although the number of teeth of each driving gear and driven gear was set to be the same in the example, it is not necessarily limited to the same number, and when a multi-gear pump is configured, it may be selected to reduce pressure pulsation. No problem. Furthermore, the phase angle θ2 may also be determined depending on the number of gear pumps installed in parallel and the number of teeth.

Furthermore, although this embodiment has been described with respect to a pump, a multiple gear motor may be used instead of the pump.

〔Effect of the invention〕

According to the present invention, in a multiple gear pump arranged such that the phase of the teeth of the drive gear of each gear pump is different from the phase of the teeth of the other drive gears, an oil groove is provided near the meshing center point of each gear pump. Since each oil groove is connected through a communication path, the rate of change in volume within the confined part is reduced, resulting in the effect of reducing pressure pulsations, vibrations, and noise caused by abnormal pressure rises or pressure drops. There is. Furthermore, since it is possible to eliminate fluid inflow and outflow associated with confinement compression or confinement expansion, there is an effect of reducing flow rate pulsation.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view of a multiple gear pump according to an embodiment of the present invention, Fig. 2 is a sectional view taken along the line 1-1 in Fig. 1, and Fig. 3 is a sectional view taken along the line ■-■ in Fig. 1. 4 is a sectional view taken along line IV-IV of FIG. 2, FIG. 5 is an explanatory diagram showing changes in confined volume of each gear pump, and FIG. An explanatory diagram showing changes in confinement volume of a gear pump, FIG. 7 is a vertical cross-sectional view of a multiple gear pump of another embodiment, and FIG. 8 is a cross-sectional view taken along the ■-V line and VI-VI cross-section of FIG. 7. 9 is an explanatory diagram of a conventional multiple gear pump, FIG. 10 is an explanatory diagram showing the discharge flow rate of a conventional gear pump, and FIG. 11 is an explanatory diagram showing the discharge flow rate of a conventional multiple gear pump. Figure, Figure 12 (1)
, (2) and (3) are explanatory diagrams showing the state of confinement, and FIG. 13 is an explanatory diagram showing changes in the confinement volume. 1... Multiple gear pump, 2a, 2b... Drive gear,
3a, 3b...Driver gear, 8...Low pressure chamber, 9...High pressure chamber, Kishi＼CL Car 3 Prison diagram Fig. 5 Canter @ Gear rotation square Plate 6 Fig. 11 *ml可斡斡字 ``I Concave■ 7-cho high 8 figure 3 hole CL z1α 1 10th ward 11 figure Hi-convex;

Claims (1)

[Claims] 1. A plurality of gears forming a fluid transfer space for sucking and discharging fluid are provided in the pump casing, and the fluid in the fluid suction portion is enclosed in the fluid transfer space to rotate the gears around the drive rotation axis. Therefore, a plurality of gear pumps are arranged in the axial direction to transfer and discharge the fluid to the fluid discharge section, and at least one of the gear pumps has a phase in which the gears are arranged in the rotation direction of the gears of the other gear pumps. A multiple gear pump having different phases, characterized in that a communication path is provided for interlocking the vicinity of the meshing center point of the gear pump with the meshing center point of the other gear pump. .