JPS6315596Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to a gear pump or motor that can be used in the field of hydraulic equipment, etc.

(b) Prior art For example, in a general gear pump, a small gap is provided between the tooth tip of the gear and the inner peripheral surface of the casing, and between the tooth side surface and the side plate to ensure smooth operation of the gear. are doing. Therefore, as the discharge pressure increases, there is a disadvantage that leakage from the gap increases, and in particular, leakage from the tooth side portions becomes a problem. Therefore, in recent high-pressure gear pumps, the discharge pressure is guided to the back side of the side plate to statically balance the fluid pressure in the axial direction acting on the side plate, and this side plate is connected to a gasket, etc. It is pressed against the end face of the gear by elastic force. That is, in this device, a groove is provided on the back surface of the side plate at the boundary between the low pressure region and the high pressure region, and the gasket attached to the groove is located in the high pressure region surrounded by the inner circumferential surface of the casing. High-pressure fluid on the discharge side is introduced.

Therefore, in order to properly balance the side plates in such a gear, it is necessary to provide the balance groove at an intermediate dimension position between the shaft diameter of the support shaft of the gear and the tooth bottom diameter. However, in this type of gear pump, there is a demand for the support shaft to be as large in diameter as possible in order to increase rigidity, and a demand for the outer diameter of the gear to be as small as possible in order to achieve compactness. , the outer diameter of the spindle and the tooth bottom diameter of the gear tend to be quite close values. Therefore, conventional systems use a narrow gasket to guide the high pressure fluid on the discharge side to near the intermediate position mentioned above, but if the fluid pressure to be introduced is very high, the gasket There is a problem in that it tends to deform toward the area and cause so-called protrusion. Countermeasures have been taken to deal with this protrusion phenomenon, such as using a backup spring in combination, but such countermeasures have the disadvantage of increasing the number of parts and making assembly difficult. In some cases, a relatively wide gasket is used at some cost to the balance, but with such a gasket, the force with which the side plate is pressed against the tooth side surface varies greatly due to variations in the crushing margin. Therefore, there is a high possibility that the side plate will be pressed against the tooth side surface with an unnecessarily large force, resulting in contamination with products that significantly reduce mechanical efficiency, and this is a particularly big problem for small gear pumps that are sensitive to such situations. Further, in the conventional type, a band-shaped gasket is simply attached to a groove in the side plate. Therefore, if the degree of fitting is set loose so that the inner and outer circumferential surfaces of the gasket do not come into close contact with the inner surface of the groove, the gasket will easily fall from the groove during assembly, making assembly time-consuming. There are problems in that it is difficult to automate the assembly. In addition, if the gasket is loosely fitted, it is difficult to initialize the gasket during assembly, and the gasket tends to move and wear out due to repeated high and low pressures during use. On the other hand, if the degree of fit of the gasket to the groove is set too tightly, it will be difficult to insert and remove the gasket from the groove.
A problem arises in that it adversely affects assemblability and maintainability.

(c) Purpose The present invention was made with attention to the above-mentioned circumstances, and it is possible to effectively improve the volumetric efficiency by optimizing the static pressure balance of the side plate without causing the phenomenon of gasket protrusion. Moreover, it does not cause inconveniences such as an increase in the number of parts or variations in mechanical efficiency, and it also improves ease of assembly and maintenance, and reduces gasket wear. It is an object of the present invention to provide a gear pump or motor that can be effectively suppressed.

(D) Structure In order to achieve the above object, the present invention provides a gear pump or a motor having a movable side plate having a gasket installed in a groove provided on the back surface to partition a high pressure region and a low pressure region. A gasket is provided with a space between a band-shaped part that fits loosely in the groove, a sealing protrusion that is integrally provided on the inner circumferential edge of the band-shaped part and comes into close contact with the bottom surface of the groove, and an outer circumferential surface of the band-shaped part. and a plurality of elastic protrusions that are integrally provided with the gasket and elastically adhere to the inner surface of the groove, and a discharge side is provided in the gap formed between the bottom surface of the groove and the band-shaped portion of the gasket. The device is characterized in that it is configured to be able to introduce high-pressure fluid.

(E) Embodiment Hereinafter, an embodiment in which the present invention is applied to a gear pump will be described with reference to the drawings.

As shown in FIG. 1, the gear pump according to the present invention includes an oil feeding gear 2 housed in a casing 1,
The surface 4 of the movable side plate 4 is attached to the tooth side surfaces 2a and 3a of 3.
a into sliding contact, and the back surface 4b of this side plate 4.
A groove 5 is provided at the boundary between the high pressure region H and the low pressure region L, and a gasket 6 for dividing the region is fitted into the groove 5. The casing 1 is composed of a cup-shaped body 7 and a front cover 8 that is attached to the open end of the body 7, and the gears 2 and 3 are held by the peripheral wall 7a of the body 7. There is. The gears 2 and 3 are spur gears that mesh with each other, and their support shafts 9 and 11 are supported by the body 7 and the front cover 8. Side plate 4
is interposed between the tooth side surfaces 2a, 3a of the gears 2, 3 and the inner surface 7c of the end wall 7b of the body 7, and is slidable in the axial direction.
As shown in the figures and FIG.
1 has shaft holes 14 and 15 into which the shafts 1 are fitted. Further, the groove 5 is provided in a 3-shape so as to partition the high pressure port 12 side and the low pressure port 13 and shaft holes 14, 15 side. On the other hand, the gasket 6 has a band-shaped portion 1 that loosely fits into the groove 5.
6, and the groove 5 integrally provided in this band-shaped portion 16.
It is made of a material such as rubber and has a protrusion 17 for sealing that comes into close contact with the bottom surface 5a of the cover. As shown in an enlarged view in FIG. 4, the strip portion 16 is shaped like a 3 and has a cross section that is one size smaller than the cross section of the groove 5.
A gap 10 communicating with the high pressure port 12 is formed between the tip end surface 16a of the groove 5 and the bottom surface 5a of the groove 5. In addition, the protruding portion 17
has a triangular cross section and is integrally formed along the inner peripheral edge of the tip surface 16a of the band-shaped portion 16. Note that this protruding portion 17 and the strip portion 16
As shown in FIG. When the protrusion 17 is assembled into the groove 5, the protrusion 17 elastically comes into close contact with the bottom surface 5. Further, a plurality of elastic protrusions 18 are integrally provided on the outer circumferential surface 16 of the band-shaped portion 16 at required intervals. and protrusion 18
The width r of the gasket 6 at the protruding portion
is set larger than the opening width s of the groove 5, so that when the gasket 6 is pushed into the groove 5, the protrusion 18 elastically comes into close contact with the inner surface 5b of the groove 5. ing.

With such a configuration, when the pump operates, high-pressure fluid on the discharge side is formed not only around the outer circumference of the groove 5 but also between the bottom surface 5a of the groove 5 and the band-shaped portion 16 of the gasket 6. It will also invade the gap 10. Therefore, in the same way as when using a narrow gasket having the same width as the protrusion 17 of this gasket 6, the high pressure region H is connected to the support shaft 11.
It becomes possible to expand the diameter to an intermediate dimension between the shaft diameter of the gears 2 and the tooth bottom diameter of the gears 2 and 3, and the static pressure balance of the side plate 4 can be properly ensured. Moreover, the pressure of the high-pressure fluid introduced into the gap 10 presses and fixes the band-shaped portion 16 of the gasket 6 against the inner surface 7c of the end wall 7b of the body 7, so that the high-pressure region H and the low-pressure region L This also effectively prevents the inconvenience of the gasket 6 protruding toward the low pressure region due to the pressure difference between the gasket 6 and the gasket 6, thereby improving the durability of the gasket 6. However, with such a device, there is no need to use a back-up spring, so assembly becomes easy. Moreover, even if there is an error in the depth of the groove 5 of the side plate 6, the crushing margin of the narrow protrusion 17 mainly changes, so the force pressing the side plate 4 against the tooth side surfaces 2a, 3a does not change significantly. Therefore, it is possible to effectively eliminate the inconvenience of reduced mechanical efficiency due to additive errors. Further, if an elastic protrusion 19 is provided on the outer periphery of the band-shaped portion 16 of the gasket 6, the elastic protrusion 1
9 can be used to temporarily hold the gasket 6 in the groove 5 to prevent it from falling. This is convenient when the side plate 4 is assembled into the body 7, and automatic assembly is possible. etc. will also be easier to implement.
Furthermore, since the elastic protrusion 19 also has the function of pressing the gasket 6 inward, it is possible to prevent the inconvenience of the gasket 6 being worn out due to repeated high and low pressure forces. be.

Moreover, since the elastic protrusions 18 are provided intermittently as described above, the elastic protrusions 18 are more difficult to contact with the groove 5 than when the inner and outer circumferential surfaces of the gasket are brought into close contact with the inner surface of the groove. The gasket 6 can be easily installed and removed. Therefore, it is possible to obtain the effect that ease of assembly and maintainability can be improved.

In the illustrated embodiment, only the side plate on the body side has been described, but the same situation applies to the side plate on the cover side.

It goes without saying that the present invention can also be applied to gear motors.

(f) Effects Since the present invention is constructed as described above,
It is possible to effectively improve the volumetric efficiency by optimizing the static pressure balance of the side plate without causing the gasket protrusion phenomenon, but it also has the disadvantages of increasing the number of parts and causing variations in mechanical efficiency. Therefore, it is possible to provide a gear pump or motor that does not cause problems, improves ease of assembly and maintainability, and effectively suppresses gasket wear.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a front view with the interior cut away, FIG. 2 is a side view of the gasket seen from the gear side, FIG. 3 is a perspective view of the main parts, and FIG. The figure is an enlarged view of section A in FIG. 1, and FIG. 5 is a cross-sectional view of the gasket. 1... Casing, 2, 3... Gear, 2a, 3
a...Tooth side surface, 4...Side plate, 4a...Surface, 4b
... Back surface, 5 ... Groove, 5a ... Bottom surface, 6 ... Gasket, 7 ... Body, 7c ... Inner surface, 8 ... Front cover, 10 ... Gap, 16 ... Band-shaped part,
17... Protrusion portion, 18... Elastic protrusion.

Claims (1)

[Scope of utility model registration request] The surface of the movable side plate is brought into sliding contact with the tooth side of the gear housed in the casing, and a groove is provided at the boundary between the high pressure area and the low pressure area on the back side of this side plate, and a gasket for area division is inserted into this groove. A gear pump or motor in which the gasket is fitted loosely into the groove, and a sealing protrusion that is integrally provided on the inner peripheral edge of the band and that is in close contact with the bottom surface of the groove. and a plurality of elastic protrusions that are integrally provided at intervals on the outer circumferential surface of the band-shaped part and elastically come into close contact with the inner surface of the groove, and the bottom surface of the groove and the band-shaped part of the gasket are connected to each other. 1. A gear pump or motor, characterized in that the gear pump or motor is configured such that high-pressure fluid on the discharge side can be introduced into a gap formed between the parts and the parts.