JPH0467598B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a circumscribed gear pump or motor that can be used in the field of hydraulic equipment and the like.

(b) Prior art As this type of gear pump or motor, the first
As shown in the figure, gears a and b are housed in a body c, and tooth sides d,
It is known that a side plate f is attached to e. However, in the conventional type, the side plate f is fitted to the inner periphery of the body c, and the high pressure fluid on the discharge side is guided to the back surface g side of the side plate f to reduce the fluid pressure in the axial direction acting on the side plate f. At the same time, the surface i of the side plate f is pressed against the tooth surfaces d and e of the gears a and b by the elastic repulsion force of the packing b, etc., and the high pressure fluid on the discharge side is pushed against the tooth surfaces d and e of the gears a and b. This is to prevent leakage to the suction side through section e. Therefore, high precision is required for the perpendicularity between the outer circumferential surface j of the side plate f and the surface i, and the fitting gap between the outer circumferential surface j of the side plate f and the inner circumferential surface k of the body c. There's a problem. Moreover, in the conventional one, as shown in FIG.
A groove m is provided at a position that separates a high pressure region H and a low pressure region L, and the gasket h is fitted into this groove m, so that the high pressure on the discharge side is applied only to the high pressure region H formed on one side of the glass ket h. I am trying to introduce fluid. Therefore, the side plate f receives a biasing force in the direction of arrow X due to the difference between the fluid pressure in the high pressure region H and the fluid pressure on the low pressure region L side, and the outer circumferential surface j of the side plate f on the low pressure region f side is pressed against the body c. It will be strongly pressed against the inner circumferential surface k of. As a result, the outer peripheral edge of the side plate f on the low pressure region L side is deformed in the thickness direction as shown by the imaginary line in FIG. A gap is created in between. Therefore, there is a problem in that it is difficult to sufficiently improve the volumetric efficiency even though it is processed with high precision.

(C) Purpose The present invention has been made in view of the above circumstances, and is easy to manufacture without requiring high processing accuracy, and moreover, prevents leakage of high-pressure fluid from the discharge side to the suction side. It is an object of the present invention to provide a gear pump or motor that can effectively prevent this and achieve high volumetric efficiency.

(D) Structure In order to achieve the above object, the present invention provides a cover that is attached to the open end of a cylindrical body housing a gear, and a side plate is provided between the inner surface of the cover and the tooth side of the gear. In a circumscribed gear pump or motor, the width of the body is set substantially equal to the tooth width of the gear so that the tooth side of the gear is substantially flush with the opening end surface of the body, The present invention is characterized in that the outer peripheral edge of the front surface of the side plate is attached to the opening end surface of the body so that high-pressure fluid on the discharge side can be guided to the entire outer peripheral edge of the back surface of the side plate.

(E) Embodiment An embodiment of the present invention will be described below with reference to FIGS. 4 and 5.

FIG. 4 is a front sectional view of an example of a gear pump according to the present invention. This gear pump has a rear cover 4 and a front cover 5 each attached to the open end of a body 3 housing gears 1 and 2 for oil feeding, and inner surfaces 4a and 5a of each of these covers 4 and 5.
Side plates 6 and 7 are interposed between and the tooth side surfaces 1a and 2a of the gears 1 and 2, respectively. gears 1, 2
are spur gears that mesh with each other, and the support shafts 8 and 9 of each of these gears 1 and 2 are supported by the covers 4 and 5. The body 3 is cylindrical, and its width w1 is set to be equal to the face width w2 of the gears 1 and 2. That is, the tooth surfaces 1a and 2a of the gears 1 and 2 are the open end surface 3a of the body 3.
The settings are made so that they are flush with each other. On the other hand, side plate 6
is a disc-shaped member having a diameter larger than the opening width of the body 3, and its surface 6a has an outer peripheral edge 6c attached to the opening end surface 3a of the body 3. The side plate 6 includes a high-pressure port 11 communicating with a discharge port (not shown), a low-pressure port 12 communicating with a suction port (not shown), and a shaft hole 13 into which the support shafts 8 and 9 fit.
14 is bored. The low pressure port 12 and shaft holes 13 and 1 are provided on the back surface 6b of this side plate 6.
4 are provided with annular grooves 15, 16, 17 surrounding the annular packing 1.
Attach 8, 19, 20 and pack these 1
The outside of 8, 19, and 20 is a high pressure region H, and the inside is a low pressure region L. That is, the high-pressure fluid on the discharge side is introduced throughout the outer peripheral edge 6d of the back surface 6b of the side plate 6. Note that the side plate 7 has a substantially symmetrical shape to the side plate 6.

With such a configuration, the high pressure fluid on the discharge side is transferred to the outer peripheral edge 6 of the back surfaces 6b and 7b of the side plates 6 and 7.
Since the fluid is guided throughout the areas d and 7d, no biasing force in the direction perpendicular to the axis due to the pressure difference between the high pressure fluid and the low pressure fluid acts on the side plates 6 and 7. Therefore, there is no inconvenience such as the outer peripheral edge of the side plate being pressed against the inner peripheral surface of the body and deforming. Therefore, it is possible to effectively prevent fluid on the high pressure side from leaking to the low pressure side through the tooth surfaces 1a and 2a of the gears 1 and 2, and high volumetric efficiency can be achieved. In addition, since it is not necessary to fit the side plates 6 and 7 to the inner circumference of the body 3, the perpendicularity between the surface of the side plates and the outer circumference, the fitting gap between the outer circumference and the inner circumference of the body, etc. It is easy to manufacture without the inconvenience of requiring high precision. Moreover,
If this is the case, by changing the width of the body 3, the side plates 6, 7 and the tooth side surface 1 can be
It is possible to precisely adjust the minute distance between a and 2a, and the volumetric efficiency can be set to a desired value.

It should be noted that the shape of the high-pressure region into which the high-pressure fluid is introduced on the discharge side is of course not limited to the above-described shape.
For example, it may be as shown in FIG. That is, in the one shown in FIG.
The high pressure area H is surrounded by a common packing 22 that is fitted into the area, and the outer peripheral surface of this packing 22 is a high pressure area H.

Further, in the above embodiment, a case was explained in which a groove for attaching packing was provided to the side plate, but for example, as shown in FIG. 7, the side plate 6',
Grooves 16', 17' are provided in the inner surfaces 4a', 5a' of the covers 4', 5' instead of the grooves 16', 17', and packing 19' is provided in the grooves 16', 17' to separate a high pressure area and a low pressure area. , 20' can be fitted in various ways.

Further, the present invention can be implemented as a gear motor that outputs torque by introducing pressure oil or the like.

(f) Effects Since the present invention has the above-described configuration, it is easy to manufacture without requiring high processing accuracy, and moreover, it effectively prevents leakage of high-pressure fluid from the discharge side to the suction side. Therefore, it is possible to provide a gear pump or motor that can achieve high volumetric efficiency.

[Brief explanation of the drawing]

Figure 1 is a front sectional view showing a conventional example, and Figure 2 is a front sectional view showing a conventional example.
3 is an enlarged sectional view taken along the - line in FIG. 2, FIG. 4 is a front sectional view showing an embodiment of the present invention, and FIG. 5 is a sectional view taken along the - line in FIG. 4. 6 is a sectional view corresponding to FIG. 5 showing another embodiment of the invention, and FIG. 7 is a front sectional view showing still another embodiment of the invention. 1, 2...Gear, 3...Body, 4, 4', 5,
5'...Cover, 6, 6', 7, 7'...Side plate, 6a,
7a...front surface, 6b, 7b...back surface, 6c, 7c...outer peripheral edge of front surface, 6d, 7d...outer peripheral edge of back surface.

Claims (1)

[Claims] 1. A circumscribed gear pump or motor in which a cover is attached to the open end of a cylindrical body housing a gear, and a side plate is interposed between the inner surface of the cover and the tooth side of the gear, The width of the body is set substantially equal to the tooth width of the gear so that the tooth side surface of the gear is substantially flush with the opening end surface of the body, and the outer peripheral edge of the surface of the side plate is aligned with the opening end surface of the body. A gear pump or motor characterized in that the gear pump or motor is configured so that high pressure fluid on the discharge side can be introduced to the entire outer peripheral edge of the back surface of the side plate.