JPH0972284A - Gear pump or motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent early damage and a drop of volumetric efficiency caused by deformation of a seal member. SOLUTION: A cutout part 1A for communicating the gear side with the opposite gear side is formed on the center part on the opposite meshing side end of a side plate 1, and a groove ML including the cutout part 1A and surrounding a gear shaft is formed on the opposite gear surface. A seal member is arranged on the whole groove ML so that the tip 24a may be brought in contact with the inner periphery (m) of a casing H1 in the cutout part 1A, and so that liquid pressure from the gear side through the cutout part 1A may act on the seal member. Therefore, high-pressure oil does not invade the clearance between the seal member and the casing wall surface h1, and the separating action of the seal, member from the wall surface h1, causing the damage of the seal member and a drop of volumetric efficiency is prevented.

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 that can be used in various fluid equipment (hydraulic equipment) fields.

[0002]

2. Description of the Related Art A pump or a motor mainly used in the field of fluid equipment (a fluid machine that functions as a pump when rotational power is applied and functions as a motor when high-pressure liquid is input, but will be described below as an example of a pump). There are piston type and vane type, but the gear type pump that is simplest, easy to process and economical is commonly used. This gear pump, as shown in FIG.
The shafts KS and JS of Nos. 1 and G2 are bearings B2 and have eyeglass holes M.
And a casing H1 on the axial side thereof
2 and the meshing portion is housed in a pump chamber sealed by a casing H1 surrounding the meshing portion. B1 is an oil seal. The gear shaft KS is rotationally driven to form an inlet (not shown) formed in the casing H1.
The liquid (oil) from is discharged to an outlet (not shown). The side plates P1 and P2 are provided to cover the axial side surfaces of the gears G1 and G2 that mesh with each other to prevent liquid leakage.
Sealing materials S1 and S2 for sealing between 1 and P2 and the casings H1 and H2 are held by the side plates P1 and P2. The liquid leaked from the pump chamber (hereinafter, hydraulic gear pump is taken as an example and referred to as oil) flows out through the bearing B2, but flows out from the communication port D to the drain through the guide paths R and N and is guided to the drain. .

In the case of a high-pressure pump, the hydraulic pressure on the high-pressure side is further introduced into the seal members S1 and S2 of the side plates P1 and P2 to urge the side plates P1 and P2 toward the gears G1 and G2 to balance the pressure. It is configured like this. The pressure-balanced side plate P1 and side plate S1 will be described below with reference to FIGS. FIG. 5 is a view showing the side plate P1 taken out from the hydraulic gear pump, and the whole is a spectacle type (gourd-shaped) that substantially covers the entire axial side surfaces of the meshing gears.
And a shaft hole SD through which the gear shafts KS and JS pass is formed. That is, the outer shape of the side plate P1 is the tooth tip peripheral diameter GC.
And has a size to be fitted into the eyeglass hole M. A hatched area in the drawing is a groove ML for holding the seal member formed on the side surface of the side plate P1 opposite to the gear, and has a figure eight shape. That is, the groove ML holds the seal member S1 that prevents oil leakage between the side plate P1 and the casing H1. As shown in FIGS. 6 and 7, the sealing material S1 has protrusions SM formed on both sides of both circular portions of the gourd,
This portion is fitted into the convex portion W of the groove ML of the side plate P1. The high pressure oil is closed by the seal material S1 of the protrusion SM, and the low pressure region and the high pressure region are separated.

By the way, of the side plate P1, the central portion on the non-meshing side, that is, the central portion at both ends of the gourd is formed with an outer diameter SC which is slightly smaller than the tooth tip peripheral diameter GC. Therefore, the tooth tips project at this portion, and the high-pressure oil between the teeth is guided to the outside of the side plate P1 (upper surface of FIG. 5) via the outer diameter SC portion. In the case of FIG. 5, whichever direction the gear rotates, or when the pump and motor are switched, the high pressure side and the low pressure side change,
The high pressure oil generated by that function is introduced from this outer diameter SC. The high pressure oil is introduced to the outside of the side plate P1 in order to guide the high pressure oil to the seal material S1 held in the groove ML and urge the side plate P1 toward the gears G1 and G2. That is, the seal material S1 shown in FIG. 6 is inserted and held in the groove ML, but the surface (upper surface of FIG. 6) of the seal material S1 shown in FIG. 6 is the bottom of the groove ML of the side plate P1 shown in FIG. Inserted and held toward the side. That is, the sealing material S1 of FIG.
5 is inserted and held toward the bottom of the groove ML of the side plate P1 in FIG. 5 (lower side in FIG. 5). In this case, the sealing material S
As shown in FIG. 7, 1 has a special shape composed of a side SH parallel to the side plate P1 and straight sides SN and SL in the axial direction. Therefore, the high-pressure oil introduced through the outer diameter SC portion of the side plate P1 moves from the parallel side SH of the sealing material S1 to the straight side SN,
Guided by PE between SLs. By the introduction of this high-pressure oil, the side plate P1 is urged toward the gear and the pressure balance is ensured.

[0005]

However, in such a pressure-balance type side plate, the high-pressure oil introduced may damage the sealing material S1 and destroy the sealing function. That is, FIG. 8 is an enlarged view of the portion A of FIG. 4, but high-pressure oil is introduced from the gear G1 and is passed through the outer diameter SC portion of FIG. 5, and particularly for the seal material S1, from the intrusion portion L. It invades and flows in the directions of arrows a and b as shown in FIG. Then, the high-pressure oil flowing in the direction of b enters the gap between the seal material S1 and the casing wall surface h1, and presses and deforms the side SH of the seal material S1 in the direction away from the casing wall surface h1 as indicated by the chain double-dashed line. As the deformation progresses, tension acts on the sealing material S1 in the circumferential direction, and high-pressure oil acts on the sealing material S1 in the radial direction, and finally the sealing material S1 is divided and damaged by the resultant force of these multiple directions. . In addition, the high pressure oil does not damage the seal material S even if it is not damaged.
No. 1 and the casing wall surface h1 and then leaks to the low pressure side, which causes a problem that the performance, particularly the volumetric efficiency is lowered. The above-mentioned problems are exactly the same in the other sealing material S2.

The present invention provides a gear pump or motor that solves the above problems.

[0007]

A gear pump or motor provided by the present invention includes a pair of gears that mesh with each other, and a side plate that is abutted on the axial side faces of both gears and covers the entire area inside the tooth tip. A gear-type pump or motor that is housed in a spectacle hole provided in the side plate and a seal member is interposed between the side plate and the casing wall surface of the pump or motor, and the side plate has a central portion on the non-meshing side or A notch is formed in the vicinity of the notch that communicates the gear side and the counter gear side, and a groove that includes the notch and surrounds the gear shaft is formed on the counter gear side surface. In particular, the notch is arranged so that its tip is in contact with the inner circumference of the eyeglass hole of the casing, and the seal member is configured such that hydraulic pressure from the gear side through the notch acts.

According to the gear pump or motor provided by the present invention, even if the high-pressure liquid from the gear side passes through the notch along the inner circumference of the eyeglass hole and is introduced to the side opposite to the gear of the side plate, the periphery of the notch. In the above, since the end surface of the seal member is in contact with the inner circumference of the eyeglass hole, the high-pressure liquid is prevented from further flowing into the gap between the seal member and the casing wall surface due to the sealing effect of the contact portion. Therefore, in the present invention, a force to separate the seal member from the casing wall surface is not generated, and a situation in which a large amount of liquid leaks to the low pressure side through the gap between the seal member and the casing wall surface is reliably prevented.

As described above, the gear pump or the motor of the present invention can be easily constructed, but is excellent in reliability and durability because the seal member is not damaged early, and a large amount of internal leakage does not occur. The performance such as volume efficiency will be improved.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to the embodiments shown in FIGS. It should be noted that the configuration other than the characteristic part of the present invention is based on the configuration shown in FIGS.

The characteristic configuration of the gear pump or motor provided by this embodiment is as shown in FIGS. FIG. 1 is a view of a side plate 1 applied to a gear pump provided by the present embodiment as viewed from both sides and sides. That is, (A) of FIG. 1 is a view showing a surface of the side plate of the present embodiment which is in contact with the gear, (B) is a view showing the center of FIG. It is the figure which looked at the side plate of this embodiment from the casing side. 2A is a view of the seal member according to the present embodiment as seen from the side plate side, and FIG. 2B is a view showing the center of FIG. Further, FIG. 3 is an enlarged view corresponding to part A of FIG.

As is apparent from these figures, the side plate 1 has a gourd shape similar to that shown in the prior art (FIG. 5), but the difference from the conventional one is that both the gourd-shaped circles have the gear meshing side end portions. Except for this, it is formed in a perfect circle. That is, as shown in FIG. 5, the side plate 1 covers the entire inner circumference of the addendum around the axial side surfaces of the gears that mesh with each other without forming a notched outer diameter portion SC. A notch 1A for connecting the gear side and the counter gear side is provided at the center of the end of the side plate 1 on the non-meshing side. The specific shape of the cutout portion 1A is substantially rectangular. In the case of the cutout portion 1A, as compared with the case of forming a crescent-shaped through hole in the side plate 1, for example, the processing is simple and the point that the hydraulic pressure from the gear side can be smoothly introduced is also secured. A recess 1K is formed on the side surface 1G of the gear around the portion where the cutout 1A is formed so that high-pressure oil between the teeth can be smoothly guided by the cutout 1A. On the other hand, on the opposite gear surface, that is, the surface 1H joined to the casing H1, a groove ML including the cutout portion 1A and surrounding the gear shafts KS and JS is formed. Specifically, the groove ML is a groove portion ML corresponding to a mountain-shaped region in which the high pressure is always high even if the high pressure and the low pressure are reversed.
1 and the groove portion ML2 corresponding to the other "V" shaped areas
And a groove portion ML3 corresponding to the high / low pressure partition position and a groove portion ML4 corresponding to the non-meshing side end portion. Groove ML3,
The ML 4 has a tip extending in the radial direction and opened to the outer peripheral edge of the side plate 1. Then, the seal member 2 shown in FIG. 2 is fitted into the groove ML. This seal member 2 has a groove portion ML1 corresponding to a mountain region in the groove ML of the side plate 2.
, A seal portion 21 having a U-shaped cross section, a seal portion 22 having a rectangular cross-section fitted in the groove portion ML2 corresponding to the "V" shape region, and a groove portion ML corresponding to a high / low pressure partition position.
A wide cross section rectangular seal portion 23 fitted into
The seal portion 24 has an L-shaped cross section and is fitted into the groove portion ML4 corresponding to the end portion on the non-meshing side. In particular, the seal part 2
4, the L-shaped bottom wall tip 24a is in contact with the inner periphery m of the eyeglass hole M toward the end of the non-meshing side, as shown in FIG. It is extended so that a desired sealing effect is exerted between the tip 24a and the inner circumference m.

In the case of the gear pump or the motor having such a structure, the high pressure oil from the gear side passes through the notch 1A from the gear side of the side plate 1 along the inner circumference m of the eyeglass hole as shown by the arrow in FIG. Even if it is introduced to the counter gear side, the tip 24a of the bottom wall of the seal portion 24 of the seal member 2 is in contact with the inner circumference m of the eyeglass hole around the cutout portion 1A, as in the conventional case (see FIG. 8). Since the tip of the bottom wall is not lifted, the high pressure oil is prevented from further wrapping around the gap between the seal portion 24 and the casing wall surface h1 due to the sealing effect of the contact portion. Therefore, in the present embodiment, a force that separates the seal portion 24 from the casing wall surface h is not generated, and a situation in which a large amount of liquid leaks to the low pressure side through the gap between the seal portion 24 and the casing wall surface h1 is reliably prevented. To be done. The above operation has the casing H2.
The same is true on the side.

For this reason, this gear pump or motor can be easily constructed, yet it is possible to effectively prevent early damage of the seal member 2 and to have excellent reliability and durability. Since a large amount of internal leakage does not occur, performance such as volumetric efficiency can be surely improved.

The present invention is not limited to the above embodiment. For example, in the above description, a hydraulic device is taken as an example of the fluid device, but a special water other than oil may be used as the fluid to be used, and the fluid is not limited to oil. Further, it is obvious that the invention can be applied not only to a pump but also to a motor that obtains a rotational force by supplying a pressurized liquid. Further, the shape of the notch is not limited to the above, and the place where the notch is formed is not particularly limited as long as it is a region where the high pressure is always high even when the high and low pressures are reversed. Good. Other configurations can be variously modified without departing from the spirit of the present invention.

[Brief description of drawings]

FIG. 1 is a diagram showing a side plate that constitutes an embodiment of the present invention.

FIG. 2 is a view showing a seal member which constitutes the same embodiment.

FIG. 3 is an enlarged cross-sectional view showing a main part of the same embodiment.

FIG. 4 is a cross-sectional view showing a conventional gear pump or motor.

FIG. 5 is a view showing a side plate which constitutes the conventional example.

FIG. 6 is a view showing a seal member constituting the conventional example.

FIG. 7 is a perspective view showing the seal member.

8 is an enlarged view showing a portion A in FIG.

[Explanation of symbols]

 1 ... Side plate 2 ... Seal member 24a ... Tip A1 ... Notch G1, G2 ... Gears H1, H2 ... Casing h1 ... Casing wall surface M ... Glasses hole m ... Glasses hole inner circumference ML ... Groove

Claims (1)

[Claims] 1. A pair of gears meshing with each other, and a side plate abutting on the axial side surfaces of both gears and covering the entire area around the addendum of teeth are housed in a spectacle hole provided in a casing, and a side plate and a pump or a motor are provided. A gear-type pump or motor having a seal member interposed between the casing wall surface and a notch for communicating the gear side and the non-gear side with the side plate at or near the center of the end of the non-meshing side. And a groove that includes the cutout portion and surrounds the gear shaft is formed on the surface on the side opposite to the gear, and the sealing member is formed in the entire groove, particularly at the cutout portion, the tip of which is the inner circumference of the eyeglass hole of the casing. A gear pump or a motor which is arranged so as to come into contact with, and is configured such that hydraulic pressure from the gear side that passes through the cutout portion acts on the seal member.