JPH0893656A - Gear pump or motor - Google Patents

Abstract

PURPOSE: To change outflow/inflow timewise according to the gear tooth width direction by constituting a part, where an inlet and an outlet cross with a casing internal circumferential face of both gear tooth width, in such a state as inclined to the gear axial core direction so as to be chamfered. CONSTITUTION: As for a starting point where fluid from an inlet (S) flows into a part (A) enclosed with a casing 1F and both adjoining teeth H of a gear 5, when the rear tooth (H) of both adjoining gear teeth (H) starts to contact with a part where the inlet (S) and the casing internal circumferential face 1F cross with each other, the part (A) to be enclosed and the inlet (S) are not cut off in one part in the gear tooth width in a chamfered part (M), while the part (A) to be enclosed and the inlet (S) are cut off in the other part in the gear tooth width. And the part (A), which is enclosed with the casing internal circumferential face 1F and both adjoining teeth (H) of the gear 5, and the inlet (S) are gradually and then completely cut off by rotation of the gear 5. Namely, inflow of fluid is so set as to change timewise according to the gear width direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear pump or a motor (hereinafter, a gear pump will be described as an example) used in various hydraulic equipment fields.

[0002]

2. Description of the Related Art Generally, a gear pump is provided with both gears that are rotatably engaged with each other about an axis and a casing that accommodates the both gears. One of the meshing points is a fluid suction side and the other is a fluid. Is configured to be on the discharge side. Then, the fluid is sucked from the flow path connected to the suction side and is discharged by applying a constant pressure to the fluid from the flow path connected to the discharge side. In this case, both gears must be in external contact with the casing.Especially on the fluid suction side, the inner circumference of the gear casing is in airtight sliding contact to contain the fluid between the casing and both teeth and transfer it to the discharge side. This is the minimum functional condition of the gear pump.

In this case, the teeth of the gear pump have heretofore been so-called straight gears parallel to the shaft center. Then, on the suction side, the fluid from the suction port flows into the portion surrounded by the two teeth opened in the suction port and is surrounded by the casing and the two teeth when the tooth tip of the direct gear contacts the inner peripheral surface of the casing. The fluid is contained in the part and is transferred to the discharge side as the gear rotates. On the discharge side, the fluid contained in the part surrounded by the casing and both teeth begins to flow out to the discharge port after the tooth tip of the straight tooth gear near the discharge side separates from the inner surface of the casing, and both teeth When the is separated from the inner peripheral surface of the casing, the outflow ends. Each tooth that has finished flowing out meshes with the tooth of the other gear and discharges the fluid to the discharge port.

When such straight tooth gears are engaged with each other to perform a fluid pumping function or a motoring function, when the fluid is completely confined in a portion surrounded by the casing and the teeth, the casing and the teeth are closed. The moment when the fluid contained in the enclosed space begins to flow out is instantaneous. As a result, a small water hammer effect, a so-called water hammering phenomenon occurs, which causes noise. Mechanical noise is generated because the contact between the gear tooth tip and the casing occurs in a line. When it is made helical, it touches at a point. Therefore, in order to gradually start the containment and the outflow of the fluid, the so-called hasbha (helical) gear is used in which the tooth tip is shifted to the left and right of the tooth width (phase angle is different) without making the gear a straight tooth gear. Has been done. Further, there is provided a gear pump in which both hasbha (double helical) gears in which the direction of the hasbha is changed to the left and right are meshed.

[0005]

However, in the case of a gear pump using such a helical gear, it takes time and labor to manufacture the helical gear, and the manufacturing cost is high. In addition, it is necessary to improve the accuracy of the tooth tips of the gears to ensure smooth meshing.If they are not manufactured accurately, the meshing of both gears will not be smooth, and on the contrary, noise will be generated. Become. In any case, the helical gear system has a problem that precision is required because precision is required, productivity is poor and the cost is high. Therefore, the reality is that a gear pump with a straight tooth gear is used while allowing noise. The present invention is intended to provide a gear pump and a gear motor that solve such problems.

[0006]

A gear pump or gear motor provided by the present invention has straight teeth parallel to the gear shaft core, and a casing has a suction side and a discharge side on both sides of both gear meshing portions. Both gears are gear pumps or motors that are in sliding contact with the inner peripheral surface of the casing and flow from the suction side to the discharge side to function as a pump or a motor.
The part where the suction port and the discharge port intersect with the casing inner peripheral surface of both gear tooth widths is configured by inclining with respect to the gear axis direction and chamfered, and the fluid from the suction port is surrounded by the casing and both teeth When the inflow starts and the outflow of the fluid from the portion surrounded by the casing and both teeth to the discharge port starts, the inflow / outflow amount of the fluid changes temporally in the tooth width direction.

[0007]

The gear pump or the gear motor provided by the present invention is constructed by chamfering the portion where the suction port and the discharge port intersect the casing inner peripheral surface of both gear tooth widths by inclining with respect to the gear axis direction. Therefore, on the suction side, the inflow of fluid into the portion surrounded by the casing and both teeth is not started at once in the entire tooth width direction, but gradually starts. Further, on the discharge side, the fluid in the portion surrounded by the casing and both teeth does not start to flow out to the discharge port all at once in the tooth width direction but gradually starts. That is, the inflow / outflow amount temporally changes in the tooth width direction.

[0008]

Embodiments of the present invention will now be described with reference to the drawings.
The gear pump will be described. FIG. 1 is a perspective view showing a configuration of a gear pump provided by the present invention, in which a left cover is removed. FIG. 2 is a sectional view taken along a plane perpendicular to the gear shaft. In these figures, 1 is a casing for accommodating both gears 4 and 5 that mesh with each other, and covers 2 are integrally attached to both sides by fixing tools (not shown) to form an airtight pump chamber inside. Reference numeral 3 is a hole through which a fixture (bolt) passes. Both gears 4 and 5 have straight teeth H parallel to the gear shaft cores 4P and 5P. 4S and 5S are the respective shafts of the gears 4 and 5,
The gear shaft 4S extends through the cover 2 and is connected to an external rotation drive unit (not shown). The casing 1 has an inner peripheral surface similar to the outer shapes of the gears 4 and 5 that mesh with each other. Therefore, the tooth tops of the gears 4 and 5 are in sliding contact with the inner peripheral surface 1F of the casing 1. Further, as shown in FIG. 2, the casing 1 is provided with a fluid suction port S and a fluid discharge port P on both sides of the meshing portions of the gears 4 and 5. Then, when both gears 4 and 5 rotate in the directions shown by the arrows, the fluid from the suction port S continuously and sequentially flows into the portion A surrounded by the casing inner peripheral surface 1F and the two teeth H, and the discharge port. Transferred to P. Then, the fluid from the portion A surrounded by the casing 1F and the teeth H flows out to the discharge port P. The configuration and operation of these are the same as those of the conventional gear pump, and detailed description thereof will be omitted.

Now, the present invention is characterized in the above-mentioned constitution, particularly in the formation of the inner week surface portion of the casing 1 at the suction port S and the discharge port P. That is,
It is characterized in that the portion where the suction port S and the discharge port P intersect with the casing inner peripheral surface 1F of the tooth width of both gears 4 and 5 is inclined and chamfered with respect to the gear axis direction. In the figure, M is the chamfered portion, and the chamfered portion M is inclined in the tooth width direction. Specifically, as clearly shown in FIG. 1, the chamfered portion M has a large chamfer on the left side. ing.

Therefore, as shown enlarged in FIG.
Looking at the time when the fluid from the suction port S starts to flow into the portion A surrounded by the casing inner peripheral surface 1F and the two teeth H of the adjacent gear 5, the rear teeth H of the two adjacent teeth H are connected to the suction port S. When it starts to contact the portion that intersects with the casing inner peripheral surface 1F, the portion A surrounded by the chamfered portion M and the suction port S are not blocked by one of the tooth widths, but the portion surrounded by the other of the tooth widths. A and the suction port S are cut off. Then, by gradually rotating the gear 5, the portion A surrounded by the casing inner peripheral surface 1F and the two teeth H of the adjacent gear 5 and the suction port S are completely cut off from each other. That is, the inflow amount of the fluid changes with time in the tooth width direction. The same applies to the case where the fluid flows out to the discharge port P. The casing inner peripheral surface 1F
The fluid from the portion A surrounded by both teeth H of the adjacent gear 5 is gradually discharged to the discharge port P, that is, the outflow amount of the fluid changes with time in the tooth width direction. .

FIG. 4 shows the casing 1 of the gear pump shown in FIG. 1 taken out and viewed from another angle.

Although the present invention has been described above, it includes various modified embodiments utilizing the features of the invention. That is, the feature of the present invention is that the portion where the suction port and the discharge port intersect with the casing inner peripheral surface of both gear tooth widths is formed by inclining and chamfering with respect to the gear axis center direction, and a modification that makes use of this point It includes examples. For example, as shown in FIG. 5, two chamfered portions M can be formed by inclining to the both sides from the center of the tooth width.
Although the example of FIG. 5 is a mountain-shaped chamfer, it may be a valley-shaped chamfer. Further, it is possible to make two chevron shapes, and the number may be more than that.
The present invention is applied to a gear pump having straight teeth parallel to the gear axis, but is also applicable to various pumps such as a side plate bearing type gear pump and a gear pump other than that. Of course, as described above, the present invention can be applied to a gear motor, and the present invention includes all of them.

The present invention is as described above, and the summary is as follows.

1) Two gears each having straight teeth parallel to the gear shaft core and rotatable about the gear shaft center and meshing with each other.
The casing is provided with both gears, and both gears are in sliding contact with the inner peripheral surface of the casing on the suction side and the discharge side on both sides of the gear meshing portion, and the fluid flows from the suction side to the discharge side. A gear pump or motor that functions as a flow pump or motor, characterized in that at least the portion where the suction port intersects the casing inner peripheral surface of both gear tooth widths is inclined with respect to the gear axis direction and chamfered. Gear pump or motor.

2) Two gears each having straight teeth parallel to the gear shaft center and rotatable about the gear shaft center and meshing with each other.
A casing for accommodating both gears is provided, and both gears are in sliding contact with the casing on the suction side and the discharge side on both sides of the gear engagement portion, and the fluid flows from the suction side to the discharge side by a pump or a motor. A gear pump or a motor that functions as a suction port, the suction port and the discharge port are formed by inclining the portion of the gear tooth width that intersects the casing inner peripheral surface with respect to the gear shaft center direction and chamfering it. When the fluid starts to flow into the part surrounded by the casing and both teeth and when the fluid from the part surrounded by the casing and both teeth starts to flow out to the discharge port, the amount of inflow and outflow is the time in the tooth width direction. A gear pump or motor characterized in that the gear pump or the motor changes.

3) Two gears each having straight teeth parallel to the gear shaft center and rotatable about the gear shaft center and meshing with each other.
A casing for accommodating both gears is provided, and both gears are in sliding contact with the casing on the suction side and the discharge side on both sides of the gear meshing portion, and the fluid flows from the suction side to the discharge side by a pump or a motor. A gear pump or motor that functions as a structure in which the portion where the suction port and the discharge port intersect the casing inner peripheral surface of both gear tooth widths is inclined from the center of the tooth width toward both sides in the direction of the gear axis and chamfered in a chevron shape. However, when the fluid from the suction port starts to flow into the part surrounded by the casing and both teeth and when the fluid from the part surrounded by the casing and both teeth starts to flow out to the discharge port, the amount of inflow and outflow The gear pump or the motor is characterized in that it changes with time in the tooth width direction.

4) Two gears each having straight teeth parallel to the gear shaft center and rotatable about the gear shaft center and meshing with each other.
A casing for accommodating both gears is provided, and both gears are in sliding contact with the casing on the suction side and the discharge side on both sides of the gear engagement portion, and the fluid flows from the suction side to the discharge side by a pump or a motor. A gear pump or motor that functions as a chamfer in a valley shape by inclining the portion where the suction port and the discharge port intersect the casing inner peripheral surface of both gear tooth widths from the tooth width sides toward the center in the gear axis direction. When the fluid from the suction port starts to flow into the part surrounded by the casing and both teeth and the fluid from the part surrounded by the casing and both teeth starts to flow out to the discharge port, A gear pump or motor characterized in that the amount thereof is changed with time in the tooth width direction.

5) Two gears each having straight teeth parallel to the gear shaft core and rotatable about the gear shaft center and meshing with each other.
A casing for accommodating both gears is provided, and both gears are in sliding contact with the casing on the suction side and the discharge side on both sides of the gear engagement portion, and the fluid flows from the suction side to the discharge side by a pump or a motor. A gear pump or motor that functions as a suction pump, the suction port and the discharge port intersecting the casing inner peripheral surface of both gear tooth widths to form a plurality of angle-shaped or valley-shaped chamfered portions in the axial direction of the gear. When the fluid from the mouth starts to flow into the part surrounded by the casing and both teeth, and when the fluid from the part surrounded by the casing and both teeth starts to flow out to the discharge port, the amount of inflow and outflow is the tooth width. A gear pump or motor characterized in that it is made to change with time in direction.

[0019]

Since the gear pump or motor provided by the present invention is as described above, there is no noise in a gear pump having straight teeth parallel to the gear axis, and the gear pump is inexpensive and has high productivity. Alternatively, a motor is provided.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing the configuration of a gear pump or a motor according to the present invention.

FIG. 2 is a diagram showing a configuration of a gear pump or a motor according to the present invention.

FIG. 3 is an enlarged view showing a configuration of a gear pump or a motor according to the present invention.

FIG. 4 is a diagram showing a configuration of a gear pump or a motor according to the present invention.

FIG. 5 is a diagram showing a modification of the gear pump or the motor according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Casing 1F ... Inner peripheral surface of casing 2 ... Covers 4, 5 ... Gears 4S, 5S ... Gear shafts 4P, 5P ... Gear shaft cores M ... Chamfered portions A ... A portion surrounded by both teeth S ... Suction port P ... Discharge Outlet H ... Gear teeth

Claims (1)

[Claims] 1. Gears each having straight teeth parallel to a gear shaft center, rotatable about the gear shaft center and engaged with each other, and a casing for housing the both gears. A gear pump or motor that functions as a pump or motor, with both gears slidingly contacting the inner peripheral surface of the casing on the suction side and the discharge side on both sides of the gear meshing part, and the fluid flows from the suction side to the discharge side. A gear pump or a motor, characterized in that a portion of the tooth width of each gear that intersects with the inner peripheral surface of the casing is chamfered by inclining with respect to the gear axis direction.