JP3919934B2 - Gear pump - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gear pump including external gears that serve as a hydraulic source of hydraulic equipment.
[0002]
[Prior art]
In Japanese Patent Publication No. 43-23361, as shown in FIG. 7, “in the meshing phase when the invalid meshing point located between the two effective meshing points A1 and A2 on the meshing line passes through the pitch point P, two A slight margin is added to the outer side of the figure S including the tooth profile curves of the driving gear 51 and the driven gear 52 and the line segment A connecting the two effective meshing points A1 and A2 separated by the effective meshing points A1 and A2. The groove (recess) 54 connected to the high-pressure port 53 side and the groove (recess) 56 connected to the low-pressure port 55 side are respectively left as the boundary between the high-pressure side and the low-pressure side. 57 ”.
[0003]
[Problems to be solved by the invention]
In the prior art, since the shapes of the grooves (recesses) 54 and 56 are set based on the rotation state where the invalid mesh point A3 passes through the pitch point P as shown in FIG. For example, when further rotating from the state shown in FIG. 8, which is the rotating state slightly before FIG. 7, since the backlash is small, the volume of the portion v in the graphic S (shaded portion) starts to expand while being confined. At this time, since the portion v communicates with the escape groove 54 on the discharge side, there is a problem that the hydraulic efficiency is sucked from the high pressure port 53 and the volumetric efficiency is lowered.
[0004]
The present invention has been made to solve the above-described problems of the prior art, and an object thereof is to provide a gear pump with high volumetric efficiency.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a first invention of a gear pump according to the present application is to communicate a driving gear and a driven gear made of external gears meshing with each other, and a binding volume portion of both gears to a suction port or a discharge port. When a tooth of the driving gear is located on a center line connecting the rotation centers of both gears, the tooth on the discharge port side of the driven gear adjacent to the tooth on the center line Using the original outline as the boundary of the groove communicating with the discharge port, the tooth outline of the driving gear meshing on the discharge side when the ineffective meshing point, which is the middle meshing point of the effective meshing point, passes through the pitch point. The boundary on the discharge side of the gear, and the tooth outline of the driven gear engaged on the suction side when the invalid mesh point passes the pitch point is defined as the boundary on the suction side of the driven gear. The teeth are positioned on the center line connecting the rotation centers of both gears. To time, the dedendum outline of the suction port side of the driving gear adjacent to the teeth of the center line, characterized in that the boundary of the groove which communicates with the intake port.
[0006]
According to the first aspect, when one tooth of the driving gear is further rotated from the engagement position located on the center line connecting the rotational centers of the gears, to the tooth bottom of the tooth tip and a driven gear on the center line of the driving gear The enclosed volume (hereinafter referred to as the binding volume) increases. However, since the binding volume is blocked from the groove communicating with the discharge port, the binding volume does not suck the discharge oil from the discharge port. For this reason, it is possible to prevent a decrease in volumetric efficiency that has been a problem in the prior art. The binding volume decreases up to the meshing position, but since this binding volume is communicated with the discharge port through the groove, the high-pressure oil in the binding volume is not further compressed. For this reason, generation | occurrence | production of a vibration and noise is prevented reliably.
[0007]
When both gears further rotate and both gears further rotate from the meshing state where one tooth of the driven gear is located on the center line connecting the rotation centers of both gears, the binding volume expands. However, since the binding volume communicates with the suction port, oil is replenished from the suction port and does not become negative pressure. Moreover, since the oil is replenished from the suction port, the volumetric efficiency is not lowered.
[0008]
A second invention of the gear pump according to the present application includes a driving gear and a driven gear made of external gears meshing with each other, and a side plate having a groove that communicates the binding volume portion of both gears with the suction port or the discharge port. In a gear pump, when one tooth of a driving gear is located on the center line connecting the rotation centers of both gears, the tooth is in contact with the tooth outline on the discharge port side of the driven gear adjacent to the tooth on the center line and meshed. A tangent line that intersects at a half-pitch length from an intersection with the center line on the line is defined as a boundary of a groove communicating with the discharge port.
[0009]
According to the second invention, the boundary of the groove communicating with the discharge port is in contact with the tooth outline on the discharge port side of the driven gear adjacent to the tooth on the center line of the driving gear, and the center line on the meshing line Since it is a tangent line that intersects at a point of a half pitch length from the intersection point, the shape is substantially the same as in the first invention. For this reason, the same effect as the first invention can be obtained. However, since the boundary of the groove communicating with the discharge port is not the tooth root outline of the driven gear as in the first invention, but the tangent line of the tooth outline of the driven gear, the groove communicating with the discharge port There is a slight dead zone in the cut-off area and communication with the binding volume. Therefore, when the groove communicating with the discharge port and the binding volume are interrupted, the high-pressure oil in the discharge port filling the binding volume is slightly compressed, but the boundary of the groove communicating with the discharge port is a straight line. Therefore, the processing cost is reduced.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of the present invention will be described in detail with reference to FIGS.
As shown in FIG. 1, the gear pump is formed by an involute curve, and side plates 3 (3a, 3b) for sealing are installed at both end portions of a driving gear 1 and a driven gear 2 made of external gears meshing with each other. ing. The side plate 3 has a groove 5 that communicates the portion of the figure S (shown by hatching) closed by the meshing points A1 and A2 with the discharge port 4 or a groove 7 that communicates the portion of the figure S to the suction port 6. Is formed. The boundaries between the grooves 5 and 7 are set as follows. The depth of the groove 5 is also substantially the same as the depth h of the groove 7 shown in FIG. Further, the tooth bottom of the gear is formed by a trochoid curve.
[0013]
(1) When one tooth 1a of the driving gear 1 is located on the center line connecting the rotation centers G1, G2 of the two gears 1, 2, the tooth on the discharge port side of the driven gear 2 adjacent to the tooth 1a on the center line The original outline 2b is defined as a boundary of the groove 5 communicating with the discharge port 4 of the driven gear 2.
(2) As shown in FIG. 2, the tooth root outline 1e of the driving gear 1d during meshing on the discharge side when the invalid meshing point (meshing point between the effective meshing points A1 and A2) passes through the pitch point P A boundary on the discharge side of the driving gear 1 is used. Further, the tooth outline 2e of the driven gear 2d that is engaged on the suction side when the invalid meshing point passes the pitch point P is defined as a boundary on the suction side of the driven gear 2. Further, a boundary is formed by a part of each tooth bottom of the driving gear 1 and the driven gear 2 continuously from the boundary.
(3) As shown in FIG. 3, when one tooth 2c of the driven gear 2 is located on the center line connecting the rotation centers G1, G2 of the two gears 1, 2, the driving gear adjacent to the tooth 2c on the center line The tooth outline 1c on the suction port 6 side of 1b is defined as the boundary of the groove 7 communicating with the suction port 6 of the driving gear 1b.
(4) Furthermore, a groove 5 communicating with the discharge port 4 and a groove 7 communicating with the suction port 6 are formed by the root circles 1f, 1g and 2f, 2g continuous at the boundaries of the above (1) to (3). is doing.
[0014]
The operational effects of the configuration of the first embodiment will be described.
In FIG. 1, when one tooth 1a of the driving gear 1 meshes with the driven gear 2 at the meshing point B1, and further rotates from the meshing position located on the center line connecting the rotation centers G1, G2 of the two gears 1, 2 , The volume surrounded by the tooth tip of the driving gear 1a on the center line and the tooth bottom of the driven gear 2 (hereinafter referred to as the binding volume v) increases. However, since the binding volume v is blocked from the groove 5 communicating with the discharge port 4, the binding volume v does not suck the discharge oil from the discharge port 4. For this reason, it is possible to prevent a decrease in volumetric efficiency that has been a problem in the prior art. Although the binding volume v decreases up to the meshing position, the binding volume v is communicated with the discharge port 4 through the groove 5, so that the high pressure oil in the binding volume v is not further compressed. . For this reason, generation | occurrence | production of a vibration and noise is prevented reliably.
[0015]
In FIG. 2, the groove 5 communicating with the discharge port 4 and the groove 7 communicating with the suction port 6 are the boundary on the discharge side of the driving gear 1 or the boundary on the suction side of the driven gear 2 with the meshing position in FIG. It is blocked by either. Accordingly, since the groove 5 communicating with the discharge port 4 and the groove 7 communicating with the suction port 6 do not communicate with each other via the binding volumes u and v, a decrease in volume efficiency is prevented.
[0016]
In FIG. 3, when one tooth 2c of the driven gear 2 is meshed with the driving gear 1 at the meshing point B3 from the meshing position located on the center line connecting the rotation centers G1 and G2 of the two gears 1 and 2, the binding volume is increased. u expands. However, since the binding volume u communicates with the suction port 6, oil is not replenished from the suction port 6 and does not become negative pressure. In addition, since the oil is replenished from the suction port 6 instead of the discharge port 4, the volumetric efficiency is not lowered. Until the meshing position, the binding volume u decreases, so that further compression will cause the high pressure oil of the penetration volume u to be partially discharged to the suction port 6 through the gap B4, and the other notches as in the prior art. Or it discharges | emits from the escape groove | channel (illustration omitted) to the groove | channel 5, and generation | occurrence | production of a vibration and noise is prevented. In addition, the boundary which continues to each boundary of the said groove | channel 5 and the groove | channel 7 is formed by the root circle 1f, 1g and 2f, 2g, the groove | channel 5 and the groove | channel 7 are enlarged, and the oil leak from the discharge side to the suction side It is preventing.
[0017]
A second embodiment of the present invention will be described in detail with reference to FIGS.
The configuration of the second embodiment is in contact with the tooth outline 2b on the discharge port 4 side of the driven gear 2a adjacent to the tooth 1a on the center line, and the center on the meshing line as compared with the configuration of the first embodiment. A groove communicating with the discharge port 4 by a tangent line T intersecting at a point Q having a length half the normal pitch (tn / 2) from the intersection point P with the line and a radial line N of the driving gear 1a passing through the point Q The configuration is the same as that of the first embodiment except that the boundary of 5 is used.
[0018]
The operational effects of the configuration of the second embodiment will be described.
The boundary of the groove 5 communicating with the discharge port 4 is in contact with the tooth outline of the driven gear 2a adjacent to the tooth 1a on the center line of the driving gear 1 on the discharge port 4 side, and on the meshing line with the center line. Since the tangent line T intersects at a point having a length of half normal pitch (tn / 2) from the intersection point P, the shape is substantially the same as that of the first embodiment. For this reason, the same effect as the first embodiment can be obtained. However, the boundary of the groove 5 communicating with the discharge port 4 is not the tooth outline 2b of the driven gear 2a as in the first embodiment, but the tangent T of the tooth outline 2b of the driven gear 2a. Therefore, there is a slight dead zone in the communication between the groove 5 communicating with the discharge port 4 and the binding volume v, and in the blocking area. Therefore, when the groove 5 communicating with the discharge port 4 and the binding volume v are blocked, the high-pressure oil at the discharge port filling the binding volume v is slightly compressed, but the groove 5 communicating with the discharge port 4 Since the boundary is a straight line, the processing cost is reduced.
[Brief description of the drawings]
1A and 1B are views showing a reference meshing state of a first embodiment of a gear pump according to the present invention, wherein FIG. 1A is a front view, and FIG. 1B is a side view.
FIG. 2 is a diagram showing a meshing state after the meshing state of FIG. 1;
FIG. 3 is a diagram showing a meshing state after the meshing state of FIG. 2;
4A and 4B are diagrams showing a reference meshing state of a second embodiment of the gear pump according to the present invention, wherein FIG. 4A is a front view, and FIG. 4B is a side view.
FIG. 5 is a diagram showing a meshing state after the meshing state of FIG. 4;
6 is a view showing a meshing state after the meshing state of FIG. 5; FIG.
FIGS. 7A and 7B are diagrams showing a reference meshing state of a gear pump according to the related art, where FIG. 7A is a front view and FIG. 7B is a side view.
FIG. 8 is a diagram showing a meshing state before the meshing state of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Drive gear 1a Tooth 1b on the center line of the drive gear 1b, 1e of the drive gear adjacent to the tooth on the center line of the drive gear 1f, 1g Tooth root line 1f, 1g of the drive gear The tooth 2b, 2e of the driven gear adjacent to the tooth on the center line of the gear The tooth outline 2c of the driven gear The tooth 2f, 2g on the center line of the driven gear 3 The bottom circle 3 of the driven gear 4 The side plate 4 The discharge port 5 The communication with the discharge port Groove 6 Suction port 7 Groove communicating with the suction port G1 Rotation center G2 of driven gear T2 Rotation center T of driven gear T Tan tangent Q Contact R Arc B1, B3 Engagement point B2, B4 Gap

Claims (2)

The driving gear (1) and driven gear (2) consisting of external gears meshing with each other, and a groove (5) that connects the binding volume of both gears (1, 2) to the discharge port (4) or the suction port (6). , 7) and a side plate (3) formed with a gear pump,
When one tooth (1a) of the driving gear (1) is located on the center line connecting the rotation centers (G1, G2) of both gears (1, 2), the driven gear adjacent to the tooth (1a) on this center line The root outline (2b) on the discharge port (4) side of (2a) is defined as the boundary of the groove (5) communicating with the discharge port (4).
When the invalid mesh point, which is an intermediate mesh point between the effective mesh points (A1, A2), passes through the pitch point (P), the tooth outline (1e) of the primed gear (1d) during meshing on the discharge side is represented by the prime gear. The boundary on the discharge side of (1) and the tooth outline (2e) of the meshing driven gear (2d) on the suction side when the invalid meshing point passes through the pitch point (P) are the driven gear (2 )
When one tooth (2c) of the driven gear (2) is located on the center line connecting the rotation centers (G1, G2) of the two gears (1, 2), the driving gear adjacent to the tooth (2c) on this center line A gear pump characterized in that the tooth outline (1c) on the inlet (6) side of (1b) is a boundary of a groove (7) communicating with the inlet (6). The driving gear (1) and driven gear (2) consisting of external gears meshing with each other, and a groove (5) that connects the binding volume of both gears (1, 2) to the discharge port (4) or the suction port (6). , 7) and a side plate (3) formed with a gear pump,
When one tooth (1a) of the driving gear (1) is located on the center line connecting the rotation centers (G1, G2) of both gears (1, 2), the driven gear adjacent to the tooth (1a) on this center line A tangent line that touches the tooth outline (2b) on the discharge port (4) side of (2a) and intersects at a half-pitch length point (Q) from the intersection (P) with the center line on the meshing line Is a boundary of the groove (5) communicating with the discharge port (4).

Images