JP4120066B2 - Gear pump or motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a circumscribed gear pump or motor mainly used in the field of hydraulic related industries.
[0002]
[Prior art]
In this type of gear pump or motor, a case in which a pair of gears are accommodated in a meshed state is made up of a body, and a front cover and a rear cover disposed before and after the body. As schematically shown in FIG. 6, the body 102 is provided with a through hole 121 for receiving the gear in the axial direction, and the front cover 103 and the rear cover 104 extend from the gear. Bearing holes 13a and 14a for pivotally supporting the rotation shaft are provided. The front cover 103 and the rear cover 104 are provided with protrusions 131 and 141 that fit into the eyeglass holes 121. When the front cover 103 and the rear cover 104 are attached to the body 102, the protrusions 131 and 141 are provided. The body 102 and the covers 103 and 104 are positioned and assembled by in-row fitting with the eyeglass hole 121.
[0003]
Therefore, in view of the performance of the pump or the motor, it is necessary to make the fitting gap at the in-row fitting portion as small as possible, and to accurately set it to 0 if possible. If the fitting gap at this part is large and there is rattling between the body 102 and the covers 103, 104, when both are finally fixed with a mounting bolt or the like, the side surface of the eyeglass hole 102 and the gear for each product. This is because the gap between the tooth tip and the tip of the tooth is different, and with respect to those having a large gap, there is a problem that the predetermined performance is not exhibited due to internal oil leakage.
[0004]
[Problems to be solved by the invention]
However, due to processing errors, it is impossible to reduce the fitting gap to zero, and it is unavoidable that the fitting gap that is inevitably generated causes some problems that the performance is not stable due to the reasons described above. I want. Therefore, in the past, it was necessary to repeat the work of loosening the mounting bolts and adjusting the positional relationship between the body and the cover and performing the test again for those that did not exhibit the specified performance during the pre-shipment test such as running-in. . Such work is extremely complicated and time-consuming, and finally, there is a problem that this process is reflected in the product price.
[0005]
On the other hand, it is easy to deal with by reducing the fitting gap, but in practice, the manufacturing accuracy must be increased and the smaller the fitting gap, the more the protrusion fits into the eyeglass hole. The problem that it becomes difficult to assemble and the assembly becomes difficult may occur, and it does not lead to a radical solution.
Therefore, according to the present invention, when the pump or motor action is performed, a force toward the low pressure side acts on the cover via the gear to the cover, and therefore even the low pressure side inlay fitting portion can be brought into close contact. This is the first time to focus on the fact that the cover can be accurately positioned with respect to the body and is stable in strength. The main purpose is to improve and stabilize the performance by setting the positioning error to zero.
[0006]
[Means for Solving the Problems]
In order to achieve this object, the present invention employs the following configuration.
That is, the gear pump or motor according to the present invention includes a pair of gears that mesh with each other and a case that accommodates these gears and supports them rotatably, and this case has a glasses hole that accommodates the gears. A body and a cover that pivotally supports a rotation shaft extending from each gear, and this cover includes a protrusion that fits into the eyeglass hole to form an in-row fitting portion. A tapered surface is provided on each side surface of the projecting portion and the side surface of the eyeglass hole on the side where the high pressure is generated, and the projecting portion is fitted into the eyeglass hole so as to attach a cover to the body. By doing so, the tapered surfaces are engaged with each other to form a tapered engaging portion.
[0007]
If this is the case, when the protrusion is fitted into the eyeglass hole to attach the cover to the body, the taper engagement portion exerts a component force perpendicular to the attachment direction toward the low pressure side. Therefore, it is possible to easily position and attach the cover to the body with the low-pressure side of the in-row fitting portion securely in close contact. As a result, it is possible not only to prevent variations in performance among products due to manufacturing errors, but also to improve the performance itself. In addition, when the pump or motor action is operated, a force to move the cover to the low pressure side acts on the cover due to the generated high / low pressure difference, but the low pressure side in the in-row fitting portion has the above-mentioned force. Since the surfaces perpendicular to the direction are in close contact with each other, sufficient strength can be obtained and positional displacement does not occur.
[0008]
Furthermore, when the projecting portion is fitted into the eyeglass hole, the mating opening is wide open, which makes assembly very easy.
[0009]
【Example】
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
As shown in the longitudinal sectional view of FIG. 1, this gear pump or motor is a spectacle-shaped eyeglass made of a case 1 comprising a body 2, a front cover 3 and a rear cover 4, which is penetrated through the body 2 in the axial direction. The drive gear 5 and the driven gear 6 are accommodated in the hole 21 in an engaged state, and both ends of the body 2 are closed by the front cover 3 and the rear cover 4. The front cover 3 and the rear cover 4 have bearing holes 3a and 4a at positions where they abut against the body 2, and bushes 3b and 4b as bearings are fitted into these bearing holes 3a and 4a, and gears 5 and 6 are attached. The rotary shafts 7 and 8 are supported respectively. In the body 2, suction ports IN and discharge ports OUT are opened at positions facing the meshing portions of both gears 5 and 6. The suction ports IN and discharge ports OUT are respectively provided on the outer surface of the case 1. The suction port and the discharge port are not connected. From the body-side end faces 3c and 4c of the front cover 3 and the rear cover 4, projecting portions 31 that fit into the eyeglass holes 21 are projected. When assembling, the protrusions 31 and 41 are fitted in the eyeglass holes 21 by in-row fitting, the front cover 3 and the rear cover 4 are positioned with respect to the body 2, and the mounting bolts BLT are attached along the axial direction. It is fixed by tightening.
[0010]
Side plates 11 are respectively disposed between the side surfaces of the gears 5 and 6 and the front cover 3 and the rear cover 4. This side plate 11 guides high-pressure fluid generated on the gears 5 and 6 side to the surface on the counter-gear side, and uses pressure balance to contact both side surfaces of the gears 5 and 6 to seal the volume space. Thus, the entire contour substantially coincides with the shape projected from the axial direction of a pair of gears meshing with each other, and two shaft holes (not shown) are punched in the center. Further, a pressure introducing groove (not shown) is provided on the outer peripheral edge of the side plate 11 in order to reduce the bearing load.
[0011]
Then, by applying a driving force from the outside to the rotating shaft 7 of the driving-side gear 5 having one end extended to the outside, both the gears 5 and 6 are synchronously rotated in reverse and the liquid sucked from the suction port IN is discharged. A well-known pumping action is performed in which the space between the teeth of the gears 5 and 6, the side plate 11, and the eyeglass hole 21 is confined in a volume space, which is guided to the discharge port OUT and discharged. Further, when operating the motor, high-pressure hydraulic oil is introduced from the discharge port OUT, torque is applied to the rotating shaft 7 of the drive gear 5 to drive the external load, and low-pressure hydraulic oil is supplied from the suction port IN. Discharge.
[0012]
At this time, the high-pressure hydraulic oil generated at the discharge port OUT is guided to the pressure introduction groove and reaches the gears 5 and 6 and the substantially half portion HA of the side surface 21a of the glasses hole. The substantially half LA on the opposite side is filled with low-pressure hydraulic oil. Due to the difference between the high and low pressures, the gears 5 and 6 and the rotation shafts 7 and 8 are pressed against the low pressure side to rotate.
[0013]
Thus, in this embodiment, as shown in FIGS. 2 to 5 (the front cover 3 is representatively shown in FIG. 2), the protruding portion 31 (41) is formed by fitting into the eyeglass hole 21. Tapered surfaces 31b (41b) and 21b are provided on the side surface 31a (41a) of the protruding portion 31 (41) and the side surface 21a of the eyeglass hole 21, respectively, over the side HA where the high pressure is generated in the in-row fitting portion IR. By fitting the projection 31 (41) into the eyeglass hole 21, the tapered surface 31b (41b) and the tapered surface 21b are engaged with each other to form a tapered engagement portion TP. .
[0014]
More specifically, the tapered surface 31b (41b) formed on the protrusion side surface 31a (41a) is inclined so that the cross-sectional area of the protrusion 31 (41) gradually decreases in the protrusion direction. . Further, the tapered surface 21b formed on the side surface 21a of the eyeglass hole is inclined so as to correspond to the tapered surface 31b (41b) so that the cross-sectional area of the eyeglass hole 21 decreases toward the back.
[0015]
Thus, when the protrusion 31 (41) is fitted into the eyeglass hole 21 and the mounting bolt BLT is tightened, the cover 3 (4) is lowered with respect to the body 2 by the action of the taper engagement portion TP. Thus, the low-pressure side of the in-law fitting portion IR can be reliably brought into close contact with the side surface 21a of the low-pressure side and the protrusion side surface 31a (41a).
As a result, it is possible to accurately position the cover 3 (4) with respect to the body 2, and to prevent variations in performance from product to product. Therefore, not only the work for adjusting the mounting position of the body 2 and the cover 3 (4), which has been performed during the conventional running-in operation, can be omitted, but various ripple effects such as the performance itself can be improved. . Further, when the pump or motor action is operated, a force to move to the low pressure side acts on the body 2 via the gear 5 (6) due to the generated high and low pressure difference. However, since the surfaces 21a and 31a (41a) perpendicular to the direction of the force are in close contact with each other on the low pressure side in the in-row fitting portion IR, sufficient strength can be obtained and no positional deviation occurs.
[0016]
Further, when the projecting portion 31 (41) is fitted into the eyeglass hole 21, the fitting opening is wide open, so that the assembly becomes very easy.
The present invention can be variously modified in addition to the above embodiments. For example, the tapered surface does not need to be provided over the entire side where the high pressure is generated in the in-wax fitting portion, and may be provided only in a part in order to simplify the manufacture.
[0017]
In addition, the specific configuration of each part is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.
[0018]
【The invention's effect】
According to the present invention described in detail above, when the protrusion is fitted into the eyeglass hole in order to attach the cover to the body, the taper engaging part causes the component to move toward the low pressure side perpendicular to the attachment direction. Therefore, the low pressure side of the in-row fitting portion can be securely adhered, and the cover can be accurately positioned and attached to the body. As a result, not only the performance of each product can be kept constant, but also the performance itself can be improved.
[0019]
Also, when the protrusion is fitted into the eyeglass hole, the mating opening is wide open, so that the assembly becomes very easy.
[Brief description of the drawings]
FIG. 1 is a schematic longitudinal sectional view showing an embodiment of the present invention.
FIG. 2 is a front view showing the body of the embodiment.
FIG. 3 is a rear view showing the front cover of the embodiment.
FIG. 4 is a longitudinal sectional view showing the front cover of the embodiment.
FIG. 5 is a schematic cross-sectional view particularly showing an in-flaw fitting portion of the present embodiment.
FIG. 6 is a schematic cross-sectional view specifically showing a conventional in-row fitting portion.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Case 2 ... Body 21 ... Glass hole 21b ... Tapered surface 3 ... Front cover 31 ... Protrusion part 4 ... Rear cover 41 ... Protrusion part 41b ... Tapered surface 5 ... Gear (drive side)
6 ... Gear (driven side)
7 ... Rotating shaft (drive side)
8 ... Rotating shaft (driven side)
IR ... In-row fitting part TP ... Taper engaging part

Claims (1)

A pair of gears meshing with each other and a case that accommodates these gears and rotatably supports them, the case having a body having a spectacle hole that accommodates the gears, and a rotating shaft extending from each gear A cover that pivotally supports the projection, and the cover includes a protruding portion that fits into the eyeglass hole to form an in-row fitting portion,
By providing tapered surfaces on the side surface of the projection and the side surface of the eyeglass hole on the side where the high pressure is generated in the in-row fitting part, and fitting the projection to the eyeglass hole to attach the cover to the body. A gear pump or a motor characterized in that the tapered surfaces engage with each other to form a tapered engaging portion.

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