JPH01104991A - Variable displacement gear pump - Google Patents

Abstract

PURPOSE:To eliminate waste of power of a pump so as to reduce an operation cost by providing, in an inside gear pump, an eccentric ring or a disc which changes the track of an outer rotor, or a sealing piece which changes the terminal position of an intake port etc. CONSTITUTION:An eccentric ring 2, an outer rotor 3 and an inner rotor 4 are assembled in a pump housing 1. The eccentric ring 2 has its inner circumference concentric with the circle of the outer rotor 3, its diameter nearly equal to the outer diameter of the rotor 3 and placed on the concentric circle of the outer circumference of the inner rotor 4 with its diameter nearly equal to the diameter of the inner circumference of the housing which is concentric with the circle of the rotor 3. The suction volume of an pump is changed by the rotation of the eccentric ring 2. Thus, waste of power of the pump is eliminated so as to reduce an operation cost.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is applicable to pumps that require variable suction and discharge amounts to avoid wasting power, such as pumps for automatic transmissions. This invention relates to a variable displacement gear pump using an internal gear suitable for

[Conventional technology]

A typical variable displacement pump is a vane type pump, but variable discharge vane pumps have a large number of parts, are expensive, require a large amount of power at low speeds, and have low volumetric efficiency. I have a problem.

Therefore, this invention has developed a gear pump known for its simple structure, especially an internal gear pump with a trochoidal tooth profile that has excellent power requirements and volumetric efficiency at low speeds, and made the pump's discharge volume variable. This is what I am trying to do.

All well-known internal gear pumps are constant discharge pumps in which the positional relationship between the gear center, which consists of an internal gear (inner rotor) and an external gear (outer rotor), and the suction port and discharge port is fixed, and the rotation speed is fixed. As the number increases, the amount of inhalation increases,
Operating power increases. If you want to reduce the amount of liquid supplied to the hydraulic circuit as necessary using such a constant discharge pump, you will have to install an unload circuit using a relief valve etc. to return the unnecessary liquid to the tank. However, in this case, the pump power does not change, so the gear pump requires less power.

Even if it is small, unless the suction liquid is unloaded and the discharge amount is made variable, the pump will be forced to do unnecessary work and the driving energy of the power source will be wasted.

The pump of the present invention also takes this point into consideration.

[Means for solving problems]

The pump of the present invention has an internal gear set in which an internal gear and an external gear with a difference in the number of teeth of one tooth are assembled eccentrically by a predetermined amount, and are mounted on the housing body, the cover plate thereof, or both at the suction port and the discharge port. A gear pump built into a pump housing whose outlets are sealed to each other,
The relative positional relationship between the gear set and the suction and discharge ports is made variable.

The following three methods can be considered as specific measures to change the positional relationship.

One is to interpose an eccentric ring whose inner diameter is approximately the same as the outer diameter of the external gear between the outer periphery of the external gear and the pump housing, and to hold this ring rotatably concentrically with the internal gear. This method changes the trajectory of the external gear (thereby changing the position of the gear set) by rotating this ring within a predetermined angle range.

Another method is to interpose a disk having substantial openings for the suction port and the discharge port between the end face of the gear and the pump housing, and place this disk concentrically with either the inner or outer gear. This is a method in which the position of the suction port or discharge port is changed with respect to a gear set whose position is constant by rotating the plate by a predetermined angle.

Furthermore, the other one is to provide an arcuate groove with a constant width and depth connecting the suction port and the discharge port on at least one of the pumping chamber seal surfaces on the housing side in the positions where the pumping chambers with the maximum and minimum volumes exist. This is a method in which a seal piece is inserted without any gaps, and the piece is moved in the circumferential direction to change the end positions of the suction port and discharge port relative to the fixed gear set.

Note that rotation of the ring or disk and movement of the seal piece may be accomplished by providing an operating mechanism that can be operated from the outside.

[Effect]

In the graph of changes in inhalation and exhalation amounts shown in Fig. 8, now the 9th
As shown in the figure, the terminal end position 6a of the suction port 6 is placed above the OA cotton wire passing through the contact point of the inner rotor 4 and the outer rotor 5 at the position where the pumping chamber is at its maximum, and the starting end position 6b of the suction port 6 is If it is taken on B1BJI that crosses the pumping chamber that has started to open, then one pumping chamber can obtain an intake amount equivalent to the volume of the pumping chamber indicated by the diagonal line. If this amount is v6, the suction amount per revolution of the inner rotor is "Jogv
, xn (number of inner teeth).

Here, if the eccentric ring or disk described above is rotated or the seal piece is moved in the circumferential direction and the position of the inlet port is rotated by an angle of θ relative to the gear set, one pumping chamber The amount of inhalation obtained by
This is the difference between a and b in the θ diagram. If this is V, then v
ma-bmf (θ, θ') x v・The suction amount per revolution of the inner rotor at this time is VmvXn
becomes.

θ' is a variable determined by the tooth profile of the rotor, the rotation angle θ, and the H dimension in FIG. 9, and can be expressed as v=r<gear element, H5α, θ). Based on this functional relationship, the suction amount V (=discharge amount) can be made variable by controlling the angle θ.

〔Example〕

The present invention will be explained in detail based on FIGS. 1 to 7.

1 to 3 show the most desirable form of the pump of the present invention, that is, a pump in which the relative positions of the gear set and the suction/discharge ports are changed using an eccentric ring.

Reference numeral 1 in the figure indicates the housing main body 1a and the cover plate Nb.
A pump housing consisting of a pump housing with an eccentric ring 2 inside it.
, an outer rotor 3, and an inner rotor 4 are incorporated. 5 is a drive shaft of the inner rotor. Further, 6 in FIGS. 1 and 3 is an inlet port, and 7 is a discharge port, which are provided in the housing body 1a. The difference in the number of teeth is 1
The outer rotor 3 and inner rotor 4 are assembled with a certain amount of eccentricity (C in FIG. 2). In addition, the eccentric ring 2 has an inner circumferential surface concentric with the outer rotor 3 and a diameter that is approximately equal to the outer diameter of the rotor 3, and an outer circumferential surface of the eccentric ring 2 that is concentric with the inner rotor and has a diameter that is equal to the outer diameter of the rotor 3. The diameter of the inner circumferential surface of the concentric housing is equal to 1', and the inner rotor 4 can rotate within the housing around an axis concentric with the inner rotor 4.

The eccentric ring 2 has a boss concentric with the inner rotor 4 on its end surface, and a recess into which the boss is fitted is provided in the pump housing, so that the eccentric ring 2 is concentric with the inner rotor by engaging the two. In this case, the outer peripheral surface of the ring 2 and the inner peripheral surface of the housing may not be concentric with the inner rotor, but the inner peripheral surface of the housing may be used to hold the ring 2 concentrically with the inner rotor. The exemplary ring rotatably held on the pump facilitates construction of the pump.

In the pump of the first embodiment configured in this way, when the eccentric ring 2 is rotated clockwise by an angle θ in FIG. The orbit of the
The centers of the maximum and minimum volume pumping chambers, which were on line C in the figure, are now on line C'. Therefore, a state is created in which the suction port 6 and the discharge lower rotate by an angle θ counterclockwise with respect to the gear center, and the suction amount decreases due to the above-mentioned effect.

4 and 5 are specific examples of a mechanism for rotating the eccentric ring 2 within a predetermined angle range.

FIG. 4 shows the operating mechanism adopted in the pump of FIG. 1, which is composed of an input lever 8 fixed to the eccentric ring 2 and a circumferential elongated hole 9 that allows one end of this lever to protrude outside the housing. be done.

On the other hand, the mechanism shown in Fig. 5 has a circumferentially long slit 10 in the housing body, a keyway 1) exposed in the slit 10 in the eccentric ring 2, and a rank 12 that is locked in the keyway 1). The ring 2 is rotated by linear movement. There are various other operating mechanisms for the eccentric ring.For example, if a magnet in an attraction relationship is used, the ring 2 can be rotated without making a power transmission hole in the housing.

6 and 7 show a second embodiment of the pump employing a disc. This pump, as shown in Figure 6,
Between the end face of the internal gear set consisting of the outer and inner rotors and the housing body 1a, there is a substantial opening 6' on the gear set side of the suction port 6 and the discharge lower. A disc 13 having a diameter of
This pump is not much different from the pump of the first embodiment except that the disc 13 is held concentrically with the input lever 8 and the slit 1.
0) to change the position of the openings 6' and 7' relative to the positioned gear set. This change in position changes the amount of suction based on the same principle as above.

FIGS. 12 and 13 show a third embodiment of the pump using a seal piece. There are two pumping chamber sealing surfaces in the housing body 1a facing the end faces of the gear set. That is, what exists between the terminal end 6a of the suction port and the starting end 7a of the discharge port is the pumping chamber sealing surface having the maximum volume at the end face facing the gear of the seal portion between the suction port 6 and the discharge lower, and The end face of the seal between the suction port 6 and the discharge lower is the minimum volume pumping chamber sealing surface between the starting end 6b of the suction port and the terminal end 7b of the discharge port. An arcuate groove 14 having a constant depth and a width in the radial direction that coincides with that of the suction port 6 and the discharge lower portion is constant over the entire length is formed on the sealing surface of the suction port from the terminal end 6a of the suction port to the beginning end 7a of the discharge port. A seal piece 15 is provided in the seal piece 15, which seals the opening of the pumping chamber with three surfaces excluding both side surfaces in the circumferential direction in close contact with the groove surface and the other surface in contact with the end surface of the gear set, which is movable in the circumferential direction. It is inserted into.

Further, as an example of the operating mechanism of this seal piece 15,
The housing body 1a is provided with a circumferential slit 10, and the piece 15 is provided with an input lever 8 whose one end passes through the slit 10 and faces the outside.

This pump can displace the terminal end 6a of the suction port by operating the input lever 8 and sliding the piece 15 in the circumferential direction at a certain angle within the flexible range that exists between the slit 10 and the lever 8. The position of the gear set does not change for this displacement, so that the pumping chamber is closed off before reaching its maximum volume point and the suction volume changes.

Furthermore, if the seal piece 15 is provided at the seal part on the starting end side of the suction port 6 and the end position of the discharge port is changed, an amount of liquid corresponding to the change is left in the pumping chamber at the end point of the discharge and is discharged. The amount changes.

Therefore, in the pump of this third embodiment, the seal piece 15
It is sufficient if it is provided in either of the two seal parts,
By providing the pieces in both seals, a larger pump can be realized during capacity change than in the previous two examples.

〔effect〕

As mentioned above, this invention applies to internal gear pumps. An eccentric ring that changes the orbit of the rotor or a disk with substantial openings for the suction and discharge ports, or a seal piece that changes the end position of the suction port, etc., is provided, and the eccentric ring or disk is rotated or the seal piece is displaced. Since the relative position of the gear set and the suction port/discharge port is changed to change the suction amount of the pump, waste of pump power can be eliminated and operating costs can be reduced. That is, in Fig. 1), when a liquid amount of Ql is required, if the pump is a constant discharge pump, the amount exceeding Q is unloaded.
The pump does unnecessary work, which increases the energy consumption of the power source, but with a variable pump, the suction volume can be adjusted to match the required liquid volume and the power can be lowered, eliminating unnecessary work. Enables energy-saving operation that does not cause

Additionally, general-purpose variable discharge vane pumps have a large number of parts.
Whereas the pump of this invention is expensive and has a complicated mechanism, the pump of this invention is based on an internal gear pump, has a small number of parts, and has a simple mechanism, so it is inexpensive and highly reliable (and therefore has low fuel consumption). A particularly great effect can be expected when used as a pump installed in automobiles, etc., which require high reliability.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a pump according to the present invention;
Figure 2 is a front view of the pump with the cover plate removed, and Figure 3 shows the housing, eccentric ring, suction port,
4 and 5 are front views showing an example of the operating mechanism of the eccentric ring. FIG. 6 is a sectional view of another embodiment of the pump. FIG. 7 is the pump. Figure 8 is a front view showing the positional relationship between the housing, the eccentric ring, and the suction and discharge ports. A graph showing the changes. Figure 9 is a diagram for explaining the principle of the pump of this invention. Figure 10 shows the change in suction amount when the position of the suction port is changed using a rotor under the same conditions as in Figure 8. Figure 1) is a graph comparing the flow rate and required power of a constant discharge pump and a variable discharge pump, Figure 12 is a sectional view of the pump of the third embodiment, and Figure 13 is a diagram of the housing and seal of the pump. It is a front view showing the positional relationship of a piece, an inlet, and an outlet. 1...Pump housing, 1a...Housing body, 1b...Cover plate, 2...
... Eccentric ring, 3 ... Outer rotor, 4 ... Inner rotor, 5 ... Drive shaft, 6 ... Suction port, 7 ... ...Discharge port, 8
...Input lever, 9...Long hole, 10.
...Slit, 1) ...Keyway, 12.
...Rank, 13...Disc, 6', 7'
...Opening, 14...Circular groove, 15...
...Seal piece. Patent issuer: Sumitomo Electric Industries, Ltd. Agent: Kama 1) Text 2C) U)

Claims (2)

[Claims] (1) An internal gear set, in which an internal gear and an external gear with a difference in the number of teeth of one tooth are assembled eccentrically by a predetermined amount, is installed in the housing body, its cover plate, or both, so that the inlet and outlet are mutually connected. In a gear pump built into a sealed pump housing, there is an eccentric ring interposed between the outer periphery of the external gear and the pump housing, the inner diameter of which is approximately the same as the outer diameter of the external gear, and the end face of the gear and the pump housing. A disk having substantial openings for the suction port and the discharge port interposed therebetween, or a pumping chamber sealing surface on at least one of the housing side at the position where the pumping chamber of maximum and minimum volume exists. The eccentric ring is concentric with the internal gear, and the disc is located between the inner and outer gears. The seal piece is configured to be movable in the circumferential direction by being guided by the arcuate groove, and the ring, disk, or seal piece can be rotated concentrically with either of the two, and the ring, disc, or seal piece can be moved within a predetermined angle from the outside of the pump housing. A variable capacity gear pump characterized by being provided with an operating mechanism for rotation. (2) The eccentric ring is a ring whose outer diameter is approximately equal to the inner diameter of the pump housing, and whose outer peripheral surface is concentric with the internal gear (
The variable displacement gear pump described in item 1).