JP7506314B2 - Gear pump or gear motor - Google Patents

Description

This disclosure relates to a gear pump or gear motor.

Conventionally, gear pumps include those equipped with a drive gear, a driven gear, two side plates that slide against both end faces of the drive gear and the driven gear, and two gaskets positioned between each side plate and the housing (see, for example, International Publication No. WO 2014/199489 (Patent Document 1)).

International Publication No. 2014/199489

In the above gear pump, leakage of the working fluid is prevented by pressing a side plate against the end faces of the drive gear and driven gear. If the pressing force of this side plate is too strong, the side plate and the end faces of each gear will seize, but if the pressing force of the side plate is too weak, gaps will form between the side plate and the end faces of each gear, allowing the working fluid to leak, so an appropriate pressing force is required.

The pressing force of the side plate in the above gear pump is obtained by introducing the discharge pressure of the gear pump to the non-sliding surface of the side plate opposite the sliding surface against which the end faces of the gears slide. The pressing force of the side plate is determined by the shape of a 3-shaped sealing member called a gasket, which limits the range over which the discharge pressure acts on the non-sliding surface of the side plate.

The "3"-shaped gasket maintains high pressure by sealing the space enclosed by the non-sliding surface of the side plate, the part facing that non-sliding surface (the housing cover or bearing case), and the housing's gap hole.

The above-mentioned "3"-shaped gasket has the role of limiting the range in which high pressure acts on the non-sliding surface of the side plate and roughly balancing the pressure acting on the sliding surface and non-sliding surface, so its shape resembles the boundary between the high-pressure side and low-pressure side of the sliding surface of the side plate. In a gear pump equipped with a conventional spur gear, the position of the boundary between the high-pressure side and low-pressure side on the outer circumferential circle of the sliding surface of such a side plate is near the suction passage.

In contrast, in a gear pump with a helical gear configuration, the teeth of the drive gear and driven gear are twisted, so at one end of the tooth width of each gear, the change between high and low pressure on the outer circumferential circle of the sliding surface of the side plate occurs near the suction passage, just like in a gear pump with a conventional spur gear, but at the other end of the tooth width, the change between high and low pressure occurs at a position that is phase advanced in the direction of rotation from the suction passage by the amount of twist of the drive gear and driven gear.

In a gear pump, the side plate is pressed against the inner surface of the spectacle hole from the high pressure side to the low pressure side, and the center of the outer circumference of the side plate is shifted from the center of the spectacle hole to the low pressure side. In a gear pump equipped with a helical gear, one of the side plates switches from the low pressure side to the high pressure side at a position where the phase advances in the direction of rotation from the suction passage, but this area is away from the contact area between the inner surface of the spectacle hole and the side plate, and the gap between the side plate and the inner surface of the spectacle hole becomes wider.

This causes the problem that the high-pressure working fluid supplied to the non-sliding surface of the side plate leaks to the low-pressure side (the sliding surface side of the side plate) through the gap between the side plate and the inner circumferential surface of the gap. This reduces the volumetric efficiency of the gear pump.

This disclosure proposes a gear pump or gear motor that can suppress leakage of working fluid from the high pressure side to the low pressure side.

The gear pump or gear motor of the present disclosure comprises:
a driving gear and a driven gear which are helical gears meshing with each other;
a housing having a spectacles hole for accommodating the drive gear and the driven gear, an intake passage communicating with the spectacles hole, and a discharge passage provided on the opposite side of the intake passage and communicating with the spectacles hole;
a first side plate disposed in the gap of the housing, the first side plate having a sliding surface in sliding contact with one end surface of the drive gear and one end surface of the driven gear and a non-sliding surface opposite the sliding surface;
a second side plate disposed in the gap of the housing and having a sliding surface that is in sliding contact with the other end surface of the drive gear and the other end surface of the driven gear and a non-sliding surface opposite the sliding surface;
a first gasket having a 3-shape and contacting the non-sliding surface of the first side plate;
a third-shaped second gasket abutting on the non-sliding surface of the second side plate,
one end of the teeth of the drive gear and the driven gear in sliding contact with the first side plate is advanced in phase in a rotational direction relative to the other end of the teeth of the drive gear and the driven gear in sliding contact with the second side plate,
The first gasket has an end portion facing an inner circumferential surface of the eyeglass hole,
The present invention is characterized in that the circumferential length of the end portion of the first gasket is set to be one pitch or more on the tip circle of the drive gear and the driven gear.

According to the present disclosure, by making the circumferential length of the end of the 3-shaped first gasket that contacts the gap longer than one pitch on the tooth tip circle of the drive gear and driven gear, it becomes possible for the first gasket to seal the gap between the first side plate and the gap over the entire area where the pressure switches from low to high, and the high-pressure working fluid supplied to the non-sliding surface of the first side plate (the surface opposite to the surface that slides against the drive gear and driven gear) is prevented from leaking into the high-low pressure switching area on the sliding surface side of the first side plate.

In addition, in a gear pump or a gear motor according to one aspect of the present disclosure,
The second gasket has an end portion facing an inner circumferential surface of the eyeglass hole,
The circumferential length of the end portion of the second gasket is set to be equal to or greater than one pitch on the tip circle of the drive gear and the driven gear.

According to the present disclosure, by making the circumferential length of the end of the 3-shaped second gasket that contacts the gap longer than one pitch on the tooth tip circle of the drive gear and driven gear, it becomes possible for the second gasket to seal the gap between the second side plate and the gap over the entire area where the pressure switches from low to high, and the high-pressure working fluid supplied to the non-sliding surface of the second side plate (the surface opposite to the surface that slides against the drive gear and driven gear) is prevented from leaking into the high-low pressure switching area on the sliding surface side of the second side plate.

In addition, in a gear pump or a gear motor according to one aspect of the present disclosure,
An end of the first gasket extends circumferentially from a first position that is one pitch on the tip circle of the drive gear and the driven gear in the rotational direction from the edge of the opening of the suction passage in the eyeglass hole.

According to the present disclosure, the end of the first gasket extends circumferentially from a first position that is one pitch ahead on the tooth tip circle of the drive gear and driven gear in the direction of rotation from the edge of the opening of the suction passage in the eyeglass hole, so that even if the high-low pressure switching area on the sliding surface side of the first side plate is one pitch ahead on the tooth tip circle in the direction of rotation from the high-low pressure switching area on the sliding surface side of the second side plate, the first gasket can seal the gap between the first side plate and the eyeglass hole.

In addition, in a gear pump or a gear motor according to one aspect of the present disclosure,
An end of the second gasket extends circumferentially in the rotation direction from a second position that is one pitch behind the first position of the end of the first gasket on the tooth tip circle.

According to the present disclosure, the end of the second gasket extends circumferentially in the direction of rotation from a second position that is one pitch behind the first position of the end of the second gasket on the tooth tip circle, so that the gap between the second side plate and the gap hole in the high-low pressure switching area on the sliding surface side of the second side plate can be blocked by the second gasket.

FIG. 1 is an overall perspective view of a gear pump according to a first embodiment of the present disclosure. FIG. 2 is an exploded perspective view of the gear pump of the first embodiment. FIG. 2 is a cross-sectional view taken along line III-III in FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3. 4 is a cross-sectional view taken along line VV in FIG. 3. FIG. 4 is a view of an end face of a drive gear. 7 is a cross-sectional view taken along line VII-VII in FIG. 3. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 3. 1 is a schematic diagram showing a high-low pressure switching region on the inner circumferential surface of a gap of a gear pump of a first embodiment, as viewed from inside the gap. FIG. 1 is a schematic diagram showing a high/low pressure switching region on the inner circumferential surface of a gap of a gear pump of a comparative example, as viewed from inside the gap. FIG. FIG. 2 is a cross-sectional view of a gear pump according to a second embodiment of the present disclosure.

The following describes an embodiment. In the drawings, the same reference numbers indicate the same or corresponding parts. In addition, the dimensions in the drawings, such as length, width, thickness, and depth, have been appropriately changed from the actual scale in order to clarify and simplify the drawings, and do not represent the actual relative dimensions.

First Embodiment
1 is an overall perspective view of a gear pump 1 according to a first embodiment of the present disclosure. The gear pump 1 of the first embodiment draws in and pressurizes a working fluid (hydraulic oil in this embodiment), and discharges the pressure-increasing fluid to a hydraulic device (e.g., a hydraulic device).

As shown in FIG. 1, the gear pump 1 of the first embodiment has a housing 20 consisting of a body 21, a cover 22 fixed to the body 21, and a mounting 23 fixed to the body 21. In FIG. 1, 11a is a drive shaft extending axially from the drive gear 11, and 26 is a discharge passage.

Figure 2 is an exploded perspective view of the gear pump 1 of the first embodiment, and Figure 3 is a cross-sectional view taken along line III-III in Figure 1.

As shown in Figures 2 and 3, the gear pump 1 of the first embodiment includes a pair of meshing drive gears 11 and driven gears 12, a housing 20 that houses the drive gear 11 and driven gear 12, and bearing cases 71, 72, 73, and 74 arranged within the housing 20. A gap 24 is provided in the body 21 of the housing 20 to house the drive gear 11, driven gear 12, etc.

The gear pump 1 has a first side plate 30 that slides against one end face of the drive gear 11 and the driven gear 12 on one axial side (the right side in FIG. 3), and a second side plate 40 that slides against the other end face of the drive gear 11 and the driven gear 12 on the other axial side (the left side in FIG. 3).

The drive gear 11 and the driven gear 12 are helical gears. The teeth of the drive gear 11 and the teeth of the driven gear 12 are configured to mesh with each other. The twist angle of the teeth of the drive gear 11 is the same as the twist angle of the teeth of the driven gear 12, and the twist direction of the teeth of the drive gear 11 is opposite to the twist direction of the teeth of the driven gear 12. The amount of twist of the drive gear 11 and the driven gear 12 is one pitch.

One end of the teeth of the drive gear 11 and the driven gear 12 that slides against the first side plate 30 is ahead of the other end of the teeth of the drive gear 11 and the driven gear 12 that slides against the second side plate 40 in the direction of rotation by a phase (equivalent to one pitch).

The drive gear 11 has a drive shaft 11a that extends in the axial direction of the drive gear 11 from both sides of the drive gear 11 in the axial direction. A drive source (not shown), such as a motor, is mechanically connected to the other end of the drive shaft 11a (the left side in FIG. 3). The driven gear 12 has a driven shaft 12a that extends in the axial direction of the driven gear 12 from both sides of the drive gear 12 in the axial direction of the driven gear 12.

The bearing case 71 has a bearing 71a that supports the drive shaft 11a. The bearing case 72 has a bearing 72a that supports the driven shaft 12a. A first gasket 50 shaped like a number 3 is provided on the surface of the bearing cases 71 and 72 that faces the first side plate 30. The first gasket 50 shaped like a number 3 is intended to limit the range in which the pressure of the high-pressure hydraulic oil that has flowed between the first side plate 30 and the bearing cases 71 and 72 acts. The first side plate 30 is pressed against the drive gear 11 and the driven gear 12 by the pressure of the high-pressure hydraulic oil that has flowed into a portion between the first side plate 30 and the bearing cases 71 and 72.

The bearing case 73 has a bearing 73a that supports the drive shaft 11a. The bearing case 74 has a bearing 74a that supports the driven shaft 12a. A second gasket 60 is provided on the surface of the bearing cases 73, 74 that faces the second side plate 40. The second gasket 60 is intended to limit the range in which the pressure of the high-pressure hydraulic oil that has flowed between the second side plate 40 and the bearing cases 73, 74 acts. The second side plate 40 is pressed against the drive gear 11 and the driven gear 12 by the pressure of the high-pressure hydraulic oil that has flowed into a portion between the second side plate 40 and the bearing cases 73, 74.

The first side plate 30 and the second side plate 40 are arranged in the housing 20 so as to sandwich the drive gear 11 and the driven gear 12. The first side plate 30 is provided between the drive gear 11 and the driven gear 12 and the bearing cases 71 and 72. The second side plate 40 is provided between the drive gear 11 and the driven gear 12 and the bearing cases 73 and 74.

The first side plate 30 has a sliding surface 30a that slides against the drive gear 11 and driven gear 12, and a non-sliding surface 30b located on the opposite side. The first gasket 50 abuts against the non-sliding surface 30b of the first side plate 30. The pressure of the hydraulic oil acts on the sliding surface 30a of the first side plate 30, pressing the first side plate 30 in a direction away from the drive gear 11 and driven gear 12. On the other hand, the pressure of the high-pressure hydraulic oil introduced between the first side plate 30 and the bearing cases 71, 72 acts on the non-sliding surface 30b, pressing the first side plate 30 in a direction toward the drive gear 11 and driven gear 12.

The shape of the first gasket 50 is set so that the force acting on the non-sliding surface 30b of the first side plate 30 is slightly greater than the force acting on the sliding surface 30a of the first side plate 30. As a result, the first side plate 30 is pressed against one end face of the driving gear 11 and one end face of the driven gear 12 with an appropriate force so that the gap between the first side plate 30 and one end faces of the driving gear 11 and driven gear 12 is small.

The second side plate 40 has a sliding surface 40a that slides against the drive gear 11 and the driven gear 12, and a non-sliding surface 40b located on the opposite side. The second gasket 60 abuts against the non-sliding surface 40b of the second side plate 40. The pressure of the hydraulic oil acts on the sliding surface 40a of the second side plate 40, so that the second side plate 40 is pressed in a direction away from the drive gear 11 and the driven gear 12. On the other hand, the pressure of the high-pressure hydraulic oil introduced between the second side plate 40 and the bearing cases 73, 74 acts on the non-sliding surface 40b of the second side plate 40, so that the second side plate 40 is pressed in a direction toward the drive gear 11 and the driven gear 12.

The shape of the second gasket 60 is set so that the force acting on the non-sliding surface 40b of the second side plate 40 is slightly greater than the force acting on the sliding surface 40a of the second side plate 40. As a result, the second side plate 40 is pressed against the other end surface of the driving gear 11 and the other end surface of the driven gear 12 with an appropriate force so that the gap between the other end surfaces of the driving gear 11 and the driven gear 12 and the second side plate 40 is small.

Figure 4 is a cross-sectional view taken along line IV-IV in Figure 3.

As shown in Figure 4, the gap 24 of the body 21 has a cross-sectional shape consisting of two overlapping circles. The gap 24 of the body 21 is divided into a low pressure space 24a and a high pressure space 24b by the drive gear 11, the driven gear 12, the first side plate 30 (shown in Figures 2 and 3), the second side plate 40 (shown in Figures 2 and 3), the first gasket 50 (shown in Figures 2 and 3), the second gasket 60 (shown in Figures 2 and 3), and the bearing cases 71, 72, 73, and 74 (shown in Figures 2 and 3).

The body 21 has an intake passage 25 that communicates with the low pressure space 24a of the aperture 24, and an exhaust passage 26 that communicates with the high pressure space 24b of the aperture 24.

When the drive gear 11 rotates around the axis C1 (see arrow R1 in the figure) by a drive source (not shown) mechanically connected to the drive shaft 11a, the driven gear 12 meshing with the drive gear 11 rotates around the axis C2 (see arrow R2). As a result, the hydraulic oil sucked in from the suction passage 25 is discharged from the discharge passage 26 via the gap 24.

Figure 5 is a cross-sectional view taken along line V-V in Figure 3. As shown in Figure 5, the first gasket 50 is formed in a 3-shape and has ends 50a and 50b that face the inner peripheral surface of the eyeglass hole 24. The first gasket 50 is attached to the mounting portion 71b provided on the bearing case 71 and the mounting portion 72b provided on the bearing case 72.

The end 50a of the first gasket 50 extends circumferentially from a first position P1, which is one pitch on the tooth tip circle of the drive gear 11 (range A2 in FIG. 5), in the rotational direction of the drive gear 11 (clockwise in FIG. 5) from a second position P2 on the edge EG1 of the opening of the suction passage 25 in the eyeglass hole 24. The circumferential length of the end 50a of the first gasket 50 is set to be one pitch or more on the tooth tip circle of the drive gear 11 (range A1 in FIG. 5).

Here, the circumferential length of the end 50a of the first gasket 50 is the length of the arc on the outer periphery of the end 50a. The circumferential length of the end 50a of the first gasket 50 is equal to or greater than one pitch on the tooth tip circle of the drive gear 11, meaning that the central angle of the arc is equal to or greater than the angle range equivalent to one pitch on the tooth tip circle of the drive gear 11. One pitch on the tooth tip circle of the drive gear 11 is shown in Figure 6.

Similarly, the end 50b of the first gasket 50 also extends circumferentially from a first position P1 that is one pitch on the tooth tip circle of the driven gear 12 (the same as one pitch on the tooth tip circle of the drive gear 11) from the edge EG2 of the opening of the suction passage 25 in the hole 24 in the rotational direction of the driven gear 12 (counterclockwise in FIG. 5). The circumferential length of the end 50a of the first gasket 50 is set to be one pitch or more on the tooth tip circle of the driven gear 12.

Figure 7 is a cross-sectional view taken along line VII-VII in Figure 3. As shown in Figure 7, the second gasket 60 is formed in a 3-shape and has ends 60a and 60b that face the inner peripheral surface of the eyeglass hole 24. The second gasket 60 is attached to the mounting portion 73b provided on the bearing case 73 and the mounting portion 74b provided on the bearing case 74.

The end 60a of the second gasket 60 extends circumferentially in the rotational direction (clockwise in FIG. 7) from the edge EG1 of the opening of the suction passage 25 in the eyeglass hole 24. In other words, the end 60a of the second gasket 60 extends circumferentially in the rotational direction from a second position P2 that is one pitch behind the first position P1 on the tooth tip circle. The circumferential length of the end 60a of the second gasket 60 is set to be one pitch or more on the tooth tip circle of the drive gear 11, as shown by B1 in FIG. 7.

Similarly, the end 60b of the second gasket 60 also extends circumferentially from the edge EG2 of the opening of the suction passage 25 in the hole 24 in the direction of rotation (counterclockwise in FIG. 7). The circumferential length of the end 60a of the second gasket 60 is set to be equal to or longer than one pitch on the tooth tip circle of the driven gear 12 (the same as one pitch on the tooth tip circle of the drive gear 11).

Figure 8 is a cross-sectional view taken along line VIII-VIII in Figure 3.

As shown in FIG. 8, the center of the arc on the high-pressure side (discharge passage 26 side) of the first side plate 30 is the same as the center of the arc on the low-pressure side (suction passage 25 side). In addition, to ensure clearance between the spectacle hole 24 and the first side plate 30, the radius of curvature of the arc on the low-pressure side and high-pressure side of the first side plate 30 is made smaller than the radius of curvature of the arc on the inner surface of the spectacle hole 24.

For this reason, when the first side plate 30 is pressed toward the low pressure side of the eyeglass hole 24 by the discharge pressure during operation, the gap between the inner circumferential surface of the eyeglass hole 24 and the low pressure side of the first side plate 30 becomes small in region S2 shown in FIG. 8, while the gap between the inner circumferential surface of the eyeglass hole 24 and the low pressure side of the first side plate 30 becomes large in region S1 shown in FIG. 8. The same is true on the driven gear 12 side.

In FIG. 8, region S2 is the region from second position P2 of edge EG1 of the opening of suction passage 25 in hole 24 shown in FIG. 5 and FIG. 7 to first position P1 whose circumferential length in the rotation direction is one pitch on the tooth tip circle. Region S1 is the region from first position P1 shown in FIG. 5 and FIG. 7 to whose circumferential length in the rotation direction is one pitch on the tooth tip circle.

Figure 9 is a schematic diagram of the high-low pressure switching region on the inner circumferential surface of the gap 24 of the gear pump 1 of the first embodiment, as viewed from inside the gap 24. In Figure 9, 11b is the tooth tip seal portion of the drive gear 11, and 12b is the tooth tip seal portion of the driven gear 12.

As shown in FIG. 9, by making the circumferential length of the ends 50a, 50b of the first gasket 50 that come into contact with the gap 24 longer than one pitch on the tooth tip circle of the drive gear 11 and driven gear 12, it becomes possible for the first gasket 50 to seal the gap between the first side plate 30 and the gap 24 over the entire area where the pressure changes from low to high, and the high-pressure hydraulic oil supplied to the non-sliding surface 30b of the first side plate 30 (the surface opposite to the surface that slides against the drive gear 11 and driven gear 12) is prevented from leaking into the high-low pressure switching area on the sliding surface side of the first side plate 30.

In addition, by making the circumferential length of the ends 60a, 60b of the second gasket 60 that come into contact with the gap 24 longer than one pitch on the tooth tip circle of the drive gear 11 and driven gear 12, it becomes possible for the second gasket 60 to seal the gap between the second side plate 40 and the gap 24 over the entire area where the pressure switches from low to high, and the high-pressure hydraulic oil supplied to the non-sliding surface 40b of the second side plate 40 (the surface opposite to the surface that slides against the drive gear 11 and driven gear 12) is prevented from leaking into the high-low pressure switching area on the sliding surface side of the second side plate 40.

In addition, since the gap between the first and second side plates 30, 40 and the eyeglass hole 24 is filled by the first and second gaskets 50, 60 throughout the entire region where the pressure switches from the low pressure side to the high pressure side, the gap between the first and second side plates 30, 40 and the eyeglass hole 24 can be slightly wider. This allows the dimensional tolerance to be relaxed, and also makes it easier to install the first and second side plates 30, 40 into the eyeglass hole 24. Furthermore, when the temperature of the first and second side plates 30, 40 rises, the first and second side plates 30, 40 can be prevented from becoming stuck due to the loss of the gap between them and the eyeglass hole 24 caused by thermal expansion.

As shown in FIG. 5, the ends 50a, 50b of the first gasket 50 extend circumferentially from a first position P1 that is one pitch ahead on the tooth tip circle of the drive gear and driven gear in the direction of rotation from the edges EG1, EG2 of the opening of the suction passage 25 in the eyelet hole 24. This allows the first gasket 50 to close the gap between the first side plate 30 and the eyelet hole 24 even if the high-low pressure switching region on the sliding surface side of the first side plate 30 is one pitch ahead on the tooth tip circle in the direction of rotation from the high-low pressure switching region on the sliding surface side of the second side plate 40.

As shown in FIG. 7, the ends 60a, 60b of the second gasket 60 extend circumferentially in the rotational direction from a second position P2 that is one pitch behind the first position P1 of the ends 50a, 50b of the second gasket 60 on the tooth tip circle. This allows the second gasket 60 to close the gap between the second side plate 40 and the gap hole 24 in the high/low pressure switching region on the sliding surface side of the second side plate 40.

Comparative Example
10 is a schematic diagram of the high-low pressure switching region on the inner circumferential surface of the gap 24 of a gear pump of a comparative example, as viewed from inside the gap 24. This gear pump of the comparative example has a similar configuration to that of the first embodiment, except for the first and second gaskets 150, 160, and Figures 1 to 3 are incorporated herein.

In FIG. 10, a first gasket 150 is provided on the surfaces of the bearing cases 71 and 72 that face the first side plate 30. Also, a second gasket 160 is provided on the surfaces of the bearing cases 73 and 74 that face the second side plate 40.

The ends 150a, 150b of the first gasket 150 in this comparative example extend circumferentially in the direction of rotation from a first position P1 (shown in FIG. 5) like the ends 50a, 50b of the first gasket 50 in the first embodiment, but are shorter in circumferential length than in the first embodiment. The ends 160a, 160b of the second gasket 160 extend circumferentially in the direction of rotation from a second position P2 (shown in FIG. 7) like the ends 60a, 60b of the second gasket 60 in the first embodiment, but are shorter in circumferential length than in the first embodiment.

In the gear pump of the comparative example, the circumferential length of the ends 150a, 150b of the first gasket 150 is short, so the area where the low pressure side switches to the high pressure side does not close the gap between the first side plate 30 and the inner surface of the eyeglass hole 24 at a position away from the contact area between the inner surface of the eyeglass hole 24 and the first side plate 30. As a result, the high pressure side hydraulic oil supplied to the non-sliding surface 30b of the first side plate 30 leaks to the low pressure side (the sliding surface 30a side of the first side plate 30) through the wide gap between the first side plate 30 and the inner surface of the eyeglass hole 24 (thick arrow in Figure 10).

In contrast, in the gear pump 1 of the first embodiment, as shown in FIG. 9, the gap between the first and second side plates 30, 40 and the gap hole 24 can be blocked by the first and second gaskets 50, 60 throughout the entire region where the pressure switches from the low pressure side to the high pressure side, and the high pressure hydraulic oil supplied to the non-sliding surfaces 30b, 40b of the first and second side plates 30, 40 can be prevented from leaking to the low pressure side.

Second Embodiment
Fig. 11 is a cross-sectional view of a gear pump 101 according to a second embodiment of the present disclosure, taken along line VV in Fig. 3. The gear pump 101 according to the second embodiment has the same configuration as the gear pump 1 according to the first embodiment, except for a reinforcing member 251 for preventing the first gasket 250 from being pushed by the high pressure of the hydraulic oil and protruding into the gap, and Figs. 1 to 3 are incorporated herein.

As shown in FIG. 11, in the gear pump 101 of the second embodiment, the first gasket 250 is formed in a 3-shape as shown in FIG. 5, and has ends 250a and 250b that face the inner circumferential surface of the gap 24. The first gasket 250 is attached to the mounting portion 71b provided on the bearing case 71 and the mounting portion 72b provided on the bearing case 72.

Furthermore, a reinforcing member 251 is attached to the mounting portion 71b of the bearing case 71 and the mounting portion 72b of the bearing case 72 together with the first gasket 250. The reinforcing member 251 surrounds the drive shaft 11a and driven shaft 12a side of the first gasket 250, and the portions of the ends 250a and 250b of the first gasket 250 that face the eyeglass holes 24. This is also the case with the second gasket (not shown).

The gear pump 101 of the second embodiment has the same effect as the gear pump 1 of the first embodiment.

In the above first and second embodiments, the gear pumps 1 and 101 are described, but the present disclosure may also be applied to a gear motor configured similarly to a gear pump.

In addition, in the above first and second embodiments, a description has been given of a case in which hydraulic oil is used as the working fluid, but the present disclosure may also be applied to gear pumps or gear motors that use other fluids as the working fluid.

Specific embodiments of the present disclosure have been described above, but the present disclosure is not limited to the first and second embodiments described above, and various modifications can be made within the scope of the present disclosure.

LIST OF SYMBOLS 1,101...Gear pump 11...Drive gear 11a...Drive shaft 11b...Tooth seal portion 12...Driven gear 12a...Driven shaft 12b...Tooth seal portion 20...Housing 21...Body 22...Cover 23...Mounting 24...Spectral hole 24a...Low pressure space 24b...High pressure space 25...Suction passage 26...Discharge passage 30...First side plate 30a...Sliding surface 30b...Non-sliding surface 40...Second side plate 40a...Sliding surface 40b...Non-sliding surface 50...First gasket 50a,50b...End portion 60...Second gasket 60a,60b...End portion 71,72,73,74...Bearing case 71a,72a,73a,74a...Bearing 150...First gasket 150a, 150b...ends 160...second gasket 160a, 160b...ends 250...first gasket 250a, 250b...ends 251...reinforcing member EG1, EG2...edges P1...first position P2...second position

Claims (4)

A driving gear (11) and a driven gear (12) which are helical gears meshing with each other;
a housing (20) having a spectacle hole (24) for accommodating the drive gear (11) and the driven gear (12), a suction passage (25) communicating with the spectacle hole (24), and a discharge passage (26) provided on the opposite side of the suction passage (25) and communicating with the spectacle hole (24);
a first side plate (30) disposed in the eyeglass hole (24) of the housing (20), the first side plate having a sliding surface (30a) in sliding contact with one end surface of the drive gear (11) and one end surface of the driven gear (12) and a non-sliding surface (30b) opposite the sliding surface (30a);
a second side plate (40) disposed in the gap (24) of the housing (20) and having a sliding surface (40a) in sliding contact with the other end surface of the drive gear (11) and the other end surface of the driven gear (12) and a non-sliding surface ( 40b ) opposite the sliding surface (40a);
a first gasket (50) in a 3-shape that abuts against the non-sliding surface (30b) of the first side plate (30);
a third-shaped second gasket (60) that contacts the non-sliding surface (40b) of the second side plate (40);
one end of the teeth of the drive gear (11) and the driven gear (12) in sliding contact with the first side plate (30) is advanced in phase in the rotation direction from the other end of the teeth of the drive gear (11) and the driven gear (12) in sliding contact with the second side plate (40);
The first gasket (50) has ends (50a, 50b) facing the inner circumferential surface of the eyeglass hole (24),
A gear pump or gear motor, characterized in that the circumferential length of the ends (50a, 50b) of the first gasket (50) is set to one pitch or more on the tip circles of the drive gear (11) and the driven gear (12). 2. The gear pump or gear motor according to claim 1,
The second gasket (60) has ends (60a, 60b) facing the inner circumferential surface of the eyeglass hole (24),
A gear pump or gear motor, characterized in that the circumferential length of the ends (60a, 60b) of the second gasket is set to one pitch or more on the tip circles of the drive gear (11) and the driven gear (12). A driving gear (11) and a driven gear (12) which are helical gears meshing with each other;
a housing (20) having a spectacle hole (24) for accommodating the drive gear (11) and the driven gear (12), a suction passage (25) communicating with the spectacle hole (24), and a discharge passage (26) provided on the opposite side of the suction passage (25) and communicating with the spectacle hole (24);
a first side plate (30) disposed in the eyeglass hole (24) of the housing (20), the first side plate having a sliding surface (30a) in sliding contact with one end surface of the drive gear (11) and one end surface of the driven gear (12) and a non-sliding surface (30b) opposite the sliding surface (30a);
a second side plate (40) disposed in the gap (24) of the housing (20) and having a sliding surface (40a) in sliding contact with the other end surface of the drive gear (11) and the other end surface of the driven gear (12) and a non-sliding surface (40b) opposite the sliding surface (40a);
a first gasket (50) in a 3-shape that abuts against the non-sliding surface (30b) of the first side plate (30);
a third-shaped second gasket (60) that abuts against the non-sliding surface (40b) of the second side plate (40);
Equipped with
one end of the teeth of the drive gear (11) and the driven gear (12) in sliding contact with the first side plate (30) is advanced in phase in the rotation direction from the other end of the teeth of the drive gear (11) and the driven gear (12) in sliding contact with the second side plate (40);
The first gasket (50) has ends (50a, 50b) facing the inner circumferential surface of the eyeglass hole (24),
the circumferential length of the ends (50a, 50b) of the first gasket (50) is set to be one pitch or more on the tip circles of the drive gear (11) and the driven gear (12);
A gear pump or gear motor characterized in that the ends (50a, 50b) of the first gasket (50) extend circumferentially from a first position (P1) that is one pitch on the tip circles of the drive gear (11) and the driven gear (12) in the direction of rotation from the edge (EG1) of the opening of the suction passage (25) in the gap (24). A gear pump or gear motor according to claim 3,
a gear pump or a gear motor, characterized in that the ends (60a, 60b) of the second gasket (60) extend circumferentially in the direction of rotation from a second position (P2) that is one pitch behind the first position (P1) of the ends (50a, 50b) of the first gasket (50).

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