JP2013170552A - Gear pump and seal member used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gear pump and a seal member used therefor capable of enhancing pressure responsiveness, and capable of restraining an increase in driving torque while restraining liquid leakage in the gear pump.SOLUTION: A gear pump includes: a drive shaft 8 and a driven shaft 9; a pair of gears 2 and 3 which are rotatably supported by the drive shaft and the driven shaft, and whose tooth tips are engaged with each other; a pair of side plates 10 adjacently arranged at both side surfaces 2a, 2a', 3a and 3a' of both of the pair of gears 2 and 3; a housing 18 for storing the drive shaft 8, the driven shaft 9, the gears 2 and 3 and the side plates 10; and endless annular seal members 17 arranged between the housing 18 and the side plates 10 and partitioning a high pressure area and a low pressure area formed between the housing 18 and the side plates 10 by the rotation of the gears 2 and 3. In the seal member 17, a maximum pressing part 67 of a plane P1 abutting on the housing 18 and a maximum pressing part 68 of a plane P3 abutting on the side plate 10 are arranged at different positions in a view in a direction orthogonal to the side surfaces 2a, 2a', 3a and 3a' of the gears 2 and 3.

Description

  The present invention relates to a gear pump and a seal member used therefor, for example, a gear pump used as a hydraulic pressure source for a vehicle brake device and the like, and a seal member that partitions a high-pressure side and a low-pressure side formed therein.

  Conventionally, piston pumps, gear pumps, and the like are known as pumps mounted on vehicles and the like. Although the piston pump is excellent in sealing performance, it has a problem in terms of sound and vibration because of a large discharge flow rate in one operation. On the other hand, the gear pump is an extremely excellent pump in an environment where a quiet operation is required because it is easy to reduce noise and vibration during discharge as compared with, for example, a piston pump.

  As a prior art of the gear pump described above, there are gear pumps disclosed in Patent Documents 1 and 2.

  In the gear pump disclosed in Patent Document 1, a stepped portion and a groove portion are formed on a side plate, and a seal member having a circular cross section is disposed in the stepped portion and the groove portion, so that a high pressure region and a low pressure region formed in the gear pump are provided. The sealing property is ensured.

  Further, the gear pump disclosed in Patent Document 2 has a groove formed in the end face of the side plate, and a pressure partition seal (seal member) having a stepped cross section is disposed in the groove, so that the discharge pressure and the suction port in the rear case are arranged. And the suction pressure of the part.

  According to the gear pump disclosed in Patent Documents 1 and 2, the seal member has elasticity, and has a crushing margin that is sandwiched between the housing and the side plate when assembled to the gear pump. Therefore, a contact pressure can be generated between the sealing member and the side plate or the housing by the crushing margin, the sealing member and the side plate or the housing can be brought into close contact with each other, and high pressure liquid does not leak to the low pressure side. Can be.

JP 2010-59931 A Japanese Patent Laid-Open No. 10-252589

  By the way, in the conventional gear pump, a side plate is disposed adjacent to the side surfaces of a pair of gears that mesh with teeth that are rotatably supported by a drive shaft, and a seal member is compressed between the side plate and the housing. It is arranged in the state.

  When the crushing margin of the seal member is small and the contact pressure between the seal member and the side plate or the housing is small, the seal member cannot be brought into close contact with the side plate or the housing, and the liquid on the high pressure side leaks to the low pressure side and the pump Efficiency can be reduced.

  On the other hand, when the crushing margin of the seal member is large, the repulsive force of the seal member increases when the seal member is assembled, and the side plate disposed adjacent to the side surface of the gear presses the side surface of the gear. Strength increases. As a result, there is a problem that the frictional force between the side plate and the gear side surface is increased, and the pressure responsiveness at the start of the pump is lowered. Furthermore, when the pump is driven, the sealing member is compressed by the high-pressure liquid, and the force with which the side plate presses the side surface of the gear increases, and the frictional force between the side plate and the side surface of the gear further increases, which may reduce the pump efficiency. In some cases, for example, a countermeasure such as increasing the capacity of a pump drive source motor or the like may be required.

  In the gear pump disclosed in Patent Document 2, a space when the seal member is deformed or expanded can be formed by making the cross-section of the seal member stepped, and the pressure on the side surface of the gear by the side plate can be reduced. Although the increase can be suppressed, in order to secure the adhesion between the seal member and the side plate or the housing, a predetermined crushing margin is provided in the seal member, and the seal member is brought into contact with the side plate or the housing in a predetermined area. It is necessary to generate sufficient contact pressure. Therefore, the pressing force in the direction corresponding to the side plate and the housing, that is, the direction orthogonal to the gear side surface cannot be reduced, and the generation of the frictional force between the side plate and the gear side surface cannot be sufficiently suppressed. There are challenges.

  The present invention has been made in view of the above-mentioned problems, and its object is to suppress liquid leakage in the pump, improve pressure response at the time of starting the pump, and drive torque at the time of driving the pump. It is an object of the present invention to provide a gear pump that can suppress an increase in the pressure and a seal member used therefor.

  In order to solve the above-described problems, a gear pump according to the present invention includes at least two shafts, a pair of gears rotatably supported by the shafts and meshing teeth, and both sides of the pair of gears. A pair of side plates disposed adjacent to a surface, a housing for housing the shaft, the gear, and the side plate, and disposed between the housing and the side plate, and the housing and the side plate by rotation of the gear. An endless annular seal member that divides the high-pressure region and the low-pressure region, and the seal member contacts the maximum pressing portion of the surface that contacts the housing and the side plate. It is characterized in that the maximum pressing portion of the contacting surface is arranged at a different position when viewed in a direction orthogonal to the side surface of the gear.

  The seal member according to the present invention is an endless annular seal member for partitioning a high pressure region and a low pressure region formed in the gear pump, and the seal member is positioned inside the contour of the seal member. A first convex portion, a second convex portion located outside the outline of the seal member with respect to the first convex portion, and a position outside the outline of the seal member with respect to the second convex portion. A third projecting portion and a connection surface that connects the projecting portions, and the second projecting portion and the third projecting portion are each the sealing member with respect to the first projecting portion. It is arrange | positioned on the opposite side of the up-down direction.

  According to the gear pump and the seal member of the present invention, the maximum pressing portion of the surface that comes into contact with the housing and the maximum pressing portion of the surface that comes into contact with the side plate are arranged at different positions as viewed in the direction perpendicular to the side surface of the gear. For this reason, the maximum pressing portion on the housing side of the seal member and the maximum pressing portion on the side plate side are arranged at positions shifted from each other, and the pressing force of the sealing member against the side plate can be reduced, and the direction perpendicular to the gear side surface of the side plate The pressing force can be suppressed. As a result, the frictional force acting on the side surface of the gear can be reduced while ensuring the close contact between the housing and the side plate, the pressure responsiveness at the start of the pump can be improved, and the driving torque at the time of driving the pump can be improved. The increase can be suppressed.

  Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS The cross-sectional view which shows the basic composition of Example 1 of the gear pump based on this invention. AA sectional drawing of the gear pump shown in FIG. BB sectional drawing of the gear pump shown in FIG. CC sectional drawing of the gear pump shown in FIG. DD sectional drawing of the gear pump shown in FIG. It is the E section enlarged view of the gear pump shown in FIG. 3, Comprising: The figure which shows the state before the pump assembly completion of the seal member applied with the gear pump of Example 1. FIG. It is the E section enlarged view of the gear pump shown in FIG. 3, Comprising: The figure which shows the state after the pump assembly completion of the sealing member applied with the gear pump of Example 1. FIG. It is the E section enlarged view of the gear pump shown in FIG. 3, Comprising: The figure at the time of pump drive of the seal member applied with the gear pump of Example 1. FIG. The figure which shows the relationship between the pump discharge pressure at the time of a gear pump drive, and the pressing force with respect to the gear side surface of a side plate. The figure which shows the other example of the sealing member applied with the gear pump of Example 1. FIG. The figure which shows the further another example of the sealing member applied with the gear pump of Example 1. FIG. The figure explaining the manufacturing process of the sealing member applied in Example 2 of the gear pump based on this invention. The bottom view which shows the whole structure of the sealing member applied in Example 3 of the gear pump based on this invention. The figure which shows the state before the pump assembly completion of the sealing member applied with the gear pump of Example 3. FIG. The figure which shows the state after the pump assembly completion of the sealing member applied with the gear pump of Example 3. FIG. The figure which shows the state before the pump assembly completion of the seal member applied in Example 4 of the gear pump based on this invention. The figure which shows the state after the pump assembly completion of the sealing member applied in Example 4 of the gear pump based on this invention.

  Embodiments of a gear pump according to the present invention will be described below with reference to the drawings.

[Example 1]
FIG. 1 shows a basic configuration of Embodiment 1 of a gear pump according to the present invention. 2 is a cross-sectional view taken along line AA of the gear pump shown in FIG. 1, FIG. 3 is a cross-sectional view taken along line BB of the gear pump shown in FIG. 1, and FIG. 4 is a cross-sectional view taken along line CC of the gear pump shown in FIG. FIG. 5 is a cross-sectional view of the gear pump shown in FIG.

  A gear pump 1 shown in FIG. 1 includes a drive shaft 8 and a driven shaft 9 connected to a drive source (not shown), a pair of gears 2 and 3 that are rotatably supported by the gear shafts and meshed with tooth tips. A pair of side plates 10, 10 ′ (see FIG. 2) disposed adjacent to both side surfaces of the gears 2, 3, a drive shaft 8, a driven shaft 9, a pair of gears 2, 3 and a pair of side plates 10, 10. And a housing 18 formed of a rear case 5 and a front cover 4 (see FIG. 2).

  As shown in FIG. 2, the drive shaft 8 is rotatably supported on a housing 18 via bearings 6 and 7 provided on the front cover 4 and the rear case 5, and the gear 2 is integrated with the drive shaft 8. And is supported to rotate.

  Further, the gear 3 is supported by the driven shaft 9, and the tooth tip of the gear 3 meshes with the tooth tip of the gear 2, so that when the gear 2 rotates, the gear 3 rotates integrally with the driven shaft 9. It has become.

  Further, side plates 10, 10 'are arranged on both side surfaces of the gears 2, 3 so as to be adjacent to both side surfaces (upper and lower surfaces in the figure) 2a, 2a', 3a, 3a 'of the gears 2, 3, respectively. The side surfaces 2a, 2a ', 3a and 3a' of the gears 2 and 3 are sealed. When the gears 2 and 3 are rotated when the gear pump 1 is driven, the side surfaces 2a, 2a ', 3a and 3a' of the gears 2 and 3 are brought into sliding contact with the side plates 10 and 10 ', and the side surfaces 2a, 2a' and 3a of the gears 2 and 3 are contacted. 3a 'is sealed. Each of the side plates 10 and 10 'has a through hole through which the drive shaft 8 and the driven shaft 9 are passed. By driving the drive shaft 8 and the driven shaft 9 through the through holes of the side plates 10 and 10', the side plates 10 and 10 'are driven. Both shafts 8 and driven shafts 9 are supported in parallel and at a predetermined interval.

  Further, the rear case 5 of the housing 18 has a concave portion 5a having a substantially circular cross section (see FIG. 1), and the front cover 4 is attached to the open end portion thereof to seal the pump fluid. A space is formed. Here, when the front cover 4 is attached to the rear case 5, endless annular seal members 17, 17 ′ are arranged between the front cover 4 and the rear case 5 and the side plates 10, 10 ′. The rear case 5 sandwiches the gears 2 and 3, the side plates 10 and 10, and the seal members 17 and 17 ′.

  The front cover 4 has a groove 19 between the front cover 4 and the front cover 4 is attached to the rear case 5 in a state where the housing seal 11 is disposed in the groove 19. Thus, the housing seal 11 is in close contact with the wall surface of the groove 19 of the rear case 5 and the front cover 4, and seals a gap that may be generated between the front cover 4 and the rear case 5 when assembled. The liquid inside is prevented from leaking outside.

  In addition, a recess 20 is provided on the surface (the lower surface in the drawing) of the front cover 4 opposite to the rear case 5, and an oil seal 12 is disposed inside and around the drive shaft 8. The outer peripheral surface of the oil seal 12 is in close contact with the wall surface of the concave portion 20 by being press-fitted into the concave portion 20 of the front cover 4, and the inner surface of the oil seal 12 slides on the outer peripheral surface of the drive shaft 8 when the pump is driven. By contacting, the gap between the drive shaft 8 and the bearing 6 of the front cover 4 is sealed, so that the liquid inside does not leak outside through the gap.

  Here, the side plates 10 and 10 ′ have substantially the same shape, and also have a suction port 13 serving as a suction hole as shown in FIGS. Further, the outer edges of the side plates 10, 10 ′ in the vicinity of the suction port 13 have a shape substantially equal to the outer shape of the addendum circles of the gears 2, 3.

  A seal block 14 is disposed around the gears 2 and 3 adjacent to the gears 2 and 3 in order to seal the tooth tips of the gears 2 and 3 in the vicinity of the suction port 13. The contact surfaces of the seal block 14 with the side plates 10 and 10 'have substantially the same shape as the arc portions of the side plates 10 and 10', and the seal block 14 and the side plates 10 and 10 'are in contact with each other. The surface 15 is in close contact. The seal block 14 is a separate member from the front cover 4 and the rear case 5.

  Thus, the suction port 13 is formed by the side plates 10, 10 ', the seal block 14, and the rear case 5, and the discharge port 16 is a flow path formed in the rear case 5, as shown in FIG. 21 and communicates with the internal space of the rear case 5.

  Next, the seal between the high pressure region and the low pressure flow region formed in the internal space of the rear case 5 when the gear pump 1 is driven will be described.

  When the gear pump 1 is driven and a pressure difference occurs between the discharge pressure near the discharge port 16 (high pressure side) and the suction pressure near the suction port 13 (low pressure side) inside the rear case 5, the side plates 10, 10 ' Sealing is performed while being in sliding contact with the side surfaces 2a, 2a ′, 3a, 3a ′ of the gears 2 and 3, and the liquid inside the rear case 5 is transferred to the side surfaces 2a, 2a ′, 3a, 3a ′ of the gears 2 and 3 and the side plates 10, Do not communicate through a gap with 10 '.

  Further, as shown in FIG. 5, the endless annular seal members 17 and 17 ′ are outer peripheral surfaces of shoulder portions 10 a, 10 a ′, 14 a and 14 a ′ formed on both end surfaces of the side plates 10, 10 ′ and the seal block 14. Are arranged between the front cover 4, the rear case 5, the side plates 10, 10 ′ and the seal block 14 so that the inner side surfaces of the seal members 17, 17 ′ come into contact with each other. A high pressure region and a low pressure region formed between the front cover 4, the rear case 5, the side plates 10, 10 ′ and the seal block 14 are partitioned. In other words, the seal members 17 and 17 ′ are in close contact with the side plates 10, 10 ′ or the seal block 14 and the wall surface of the front cover 4 or the rear case 5, and the liquid inside the rear case 5 is filled with the side plates 10, 10. The communication between the front cover 4 and the rear case 5 is prevented from communicating with each other.

  A tank (not shown) for supplying liquid to the gear pump 1 is connected upstream of the suction port 13, and a valve, a cylinder (not shown) or the like is connected downstream of the discharge port 16. The discharge pressure can be adjusted. The drive shaft 8 is connected to a drive source (not shown) such as a motor.

  Next, the operation of the gear pump 1 of the first embodiment will be described. Here, the drive shaft 8 is driven by a drive source such as a motor (not shown) as described above, and the gear 2 supported integrally with the drive shaft 8 rotates in the direction of the arrow R1 shown in FIG. The gear 3 in which the tooth tips mesh with each other rotates together with the driven shaft 9 in the direction of the arrow R2.

  First, the liquid that has flowed into the rear case 5 through the suction port 13 is accommodated in the tooth spaces of the gears 2 and 3 along with the rotation of the gears 2 and 3 and is conveyed in the rotation direction of the gears 2 and 3. .

  Next, when the gears 2 and 3 are engaged again on the discharge port 16 side, the liquid is pushed out from the tooth spaces of the gears 2 and 3. When the gears 2 and 3 are completely meshed with each other, the liquid is not flown into the suction port 13 because the meshed portion is sealed.

  Thus, the gear pump 1 continuously conveys the liquid to the discharge port 16 side by the rotation of the gears 2 and 3, and the liquid is discharged from the discharge port 16 when the pressure on the discharge port 16 side increases. At this time, since the tooth tips of the gears 2 and 3 are sealed by the seal block 14, only the inside of the seal members 17 and 17 ′ around the suction port 13 becomes low pressure inside the gear pump 1, and the other parts Becomes high pressure.

  As described above, the gear pump 1 of the first embodiment is of a movable side plate type in which the side plates 10 and 10 ′ are not fixed to the housing 18. This type of gear pump 1 includes a pressure distribution on the back surface of the side plates 10 and 10 '(a surface facing the front cover 4 or the rear case 5 of the side plates 10 and 10') and an inner surface (side plates 10 and 10 'of the side plates 10 and 10'. The pressure distribution of the surface (slidably contacting the gears 2 and 3) can be adjusted by the shape and dimensions of each surface. That is, the forces generated in the axial direction of the drive shaft 8 and the driven shaft 9 can be balanced by the shape and size of each surface, the configuration of the seal member, etc., and the side surfaces 2a, 2a ', 3a, The design is such that the pressing force in the direction perpendicular to 3a ′ (Z direction in the figure) is reduced, and the side surfaces 2a, 2a ′, 3a of the gears 2, 3 using the pressure generated by driving the gear pump 1 A design in which a force in a direction of pressing the side plates 10 and 10 ′ against 3 a ′ is generated and the adhesion is enhanced at a high pressure is possible.

  Therefore, the seal member 17 disposed between the side plate 10 and the rear case 5 of the gear pump 1 according to the first embodiment will be described in more detail with reference to FIGS.

  FIG. 6 is an enlarged view of a portion E of the gear pump shown in FIG. 3, and shows a state before the pump assembly of the seal member 17 applied in the gear pump of the first embodiment, and FIG. 7 shows the completion of the pump assembly. FIG. 8 shows a later state, and shows a state when the pump is driven. 6 to 8, the shoulder 10a of the side plate 10 is formed by a shoulder upper portion 10e, a shoulder wall portion 10b, a shoulder bottom R portion 10c, and a shoulder bottom portion 10d.

  As shown in FIG. 6, the seal member 17 includes a convex portion 63 positioned inside the contour of the seal member 17, a convex portion 61 positioned outside the contour of the seal member 17 relative to the convex portion 63, The convex portion 62 is located outside the contour of the seal member 17 relative to the convex portion 61, and a connection surface that connects the convex portions. The convex portion 61 and the convex portion 62 are respectively formed on the convex portion 63. In contrast, the seal member 17 is disposed on the opposite side in the vertical direction. In addition, the surface P1 (surface that contacts the rear case 5) that connects the convex portion 63 and the convex portion 62 is substantially flat and has a convex shape toward the convex portion 61 (toward the side plate 10). . More specifically, when the seal member 17 is disposed on the shoulder 10a of the side plate 10 in a cross section orthogonal to the axis of the seal member 17, the seal member 17 first contacts the shoulder bottom 10d of the shoulder 10a of the side plate 10. The convex portion 61 has a convex portion 62 that first contacts the rear case 5, and a convex portion 63 that is positioned between the shoulder upper portion 10e and the rear case 5 toward the shoulder wall portion 10b. And the convex part 62 are connected by a curved part 64, the convex part 62 and the convex part 63 are connected by a substantially straight line part 66, and the convex part 63 and the convex part 61 are connected by a curved part 65. Here, the convex portion 61 is disposed so as to be positioned on the inner side of the contour of the endless annular seal member 17 than the convex portion 62, that is, on the inner side when viewed in the direction (Z direction) in which the side plate 10 and the rear case 5 face each other. Has been.

  Next, when the rear case 5 is pressed toward the side plate 10 and the seal member 17 is crushed by the rear case 5 and the side plate 10 and the gear pump 1 is assembled, the seal member 17 is in a state as shown in FIG. Become. More specifically, when the rear case 5 is pressed toward the side plate 10 and the convex portion 62 comes into contact with the rear case 5, the vicinity of the convex portion 62 is pressed down toward the side plate 10 while being compressed. At this time, as described above, the convex portion 61 is disposed so as to be positioned on the inner side when viewed from the side in which the side plate 10 and the rear case 5 face each other than the convex portion 62. A rotational force is generated (clockwise in the figure), and the convex portion 61 moves on the shoulder bottom portion 10d toward the inner side of the outline of the seal member 17. That is, the seal member 17 rotates between the rear case 5 and the side plate 10.

  Here, since the seal member 17 has an annularly closed structure, the curved portion 65 of the seal member 17 is deformed so as to protrude toward the shoulder wall portion 10b of the side plate 10. Further, the convex portion 61 slides on the shoulder bottom portion 10d and the shoulder bottom R portion 10c of the side plate 10 and comes close to the shoulder wall portion 10b side, and the curved portion 65 is in close contact with the shoulder wall portion 10b. That is, the side surface P2 on the low pressure region side of the seal member 17 contacts the outer peripheral surface of the shoulder wall portion 10b of the shoulder portion 10a and the shoulder bottom R portion 10c provided on the low pressure region side of the side plate 10. Further, the straight portion 66 is in close contact with the rear case 5. In the first embodiment, the surface that contacts the side surface P2 on the low pressure region side of the seal member 17 is formed by the shoulder portion 10a of the side plate 10. For example, the housing 18 is provided with a seal accommodating portion such as a shoulder portion or a groove portion. It is also possible to form a surface that contacts the side surface P2 on the low pressure region side of the seal member 17 on an appropriate side surface of the seal housing portion such as the shoulder portion or the groove portion.

  In the state shown in FIG. 7, the maximum pressing portion 67 of the surface P1 that contacts the housing 18 (rear case 5) of the seal member 17 and the maximum pressing portion 68 of the surface P3 that contacts the side plate 10 are the side plate 10 and the rear case. 5 are arranged at different positions when viewed in the direction (Z direction) facing the side 5, the repulsive force of the seal member 17 in the direction in which the side plate 10 and the rear case 5 face each other can be suppressed. Therefore, the pressing force of the seal member 17 in the direction (Z direction) orthogonal to the side surfaces 2a, 2a ′, 3a, 3a ′ of the gears 2 and 3 can be effectively reduced. Generation of frictional force that hinders rotation and movement can be effectively suppressed.

  Further, by providing the shoulder portion 10a of the side plate 10 on the side surface P2 side of the seal member 17 on the low pressure region side, further sliding on the shoulder bottom portion 10d and the shoulder bottom R portion 10c of the side plate 10 of the convex portion 61 is suppressed. The side wall P2 on the low pressure region side of the seal member 17 and the shoulder wall portion 10b of the shoulder portion 10a of the side plate 10 can be brought into close contact with each other.

  As a result, the torque at the start of the pump can be reduced, and the time until the tooth tips of the gears 2 and 3 are brought into close contact with the tooth tip seal portion of the seal block 14 due to the pressure difference can be shortened. The pressure responsiveness with respect to the drive command of the gear pump 1 can be remarkably improved.

  Further, the rear case 5 and the seal member 17 can be brought into contact with each other at the straight portion 66, and the side plate 10 and the seal member 17 can be brought into contact in a planar manner with the shoulder wall portion 10 b of the shoulder portion 10 a of the side plate 10. The contact pressure between the seal member 17 and the rear case 5 and the side plate 10 can be ensured, and the seal member 17, the rear case 5 and the side plate 10 can be sufficiently adhered. Therefore, even when the gear pump 1 is driven and a high pressure region and a low pressure region are formed, the leakage of liquid from the high pressure side to the low pressure side can be effectively suppressed.

  As shown in the figure, the convex portions 61 and the convex portions 62 are connected by the curved portions 64, that is, the side surfaces P2 and P4 that connect the surface P1 that contacts the housing 18 of the seal member 17 and the surface P3 that contacts the side plate 10. Of these, by forming the side surface P4 on the high pressure side as a curved surface, the stress concentration at the curved portion 64 is suppressed, and the force generated at the curved portion 64 is efficiently transferred to the shoulder wall portion 10b side of the shoulder portion 10a of the side plate 10. Can communicate. That is, even when the high pressure region and the low pressure region are formed by driving the gear pump 1, the pressing force to the curved portion 64 of the seal member 17 by the liquid in the high pressure region is the shoulder portion of the rear case 5 and the side plate 10. 10a is oriented toward the shoulder wall portion 10b, and the seal member 17 is pressed toward the gap between the rear case 5 and the shoulder upper portion 10e of the side plate 10, thus effectively improving the adhesion when the gear pump 1 is driven. be able to. In addition, as shown in the figure, the straight portion 66 may not be linear before the assembly is completed, but the convex portion 62 and the convex portion 63 may be connected with a curve that is convex toward the rear case 5, for example.

  Further, when the gear pump 1 is driven and the pressure difference between the low pressure region and the high pressure region becomes large, the seal member 17 is in a state as shown in FIG. That is, since the seal member 17 is pressed toward the rear case 5, the high-pressure side liquid tends to enter the low-pressure region side from the side plate 10 side rather than the rear case 5 side of the seal member 17.

  Even in such a state, the seal member 17 has a fan shape centered on the convex portion 63 disposed in the vicinity of the gap between the rear case 5 and the upper shoulder portion 10e, and the contour of the seal member 17 is Since the inner side surface P2 is in contact with the shoulder wall portion 10b side of the shoulder portion 10a of the side plate 10, it is possible to ensure the sealing performance in the high pressure region and the low pressure region, and the seal repulsion force due to the compression of the seal member 17 An increase in the pressing force of the side plate 10 toward the gears 2 and 3 due to the increase can be suppressed. That is, even when the pressure difference between the low pressure region and the high pressure region is large, the frictional force on the side surfaces of the gears 2 and 3 can be effectively reduced, and an increase in driving torque during driving of the pump can be suppressed. Therefore, for example, a small motor can be used for driving the pump, and the entire gear pump 1 can be downsized.

  In addition, as shown in FIG. 8, if the sealing member 17 is deformed so as to fill a gap between the rear case 5 and the shoulder upper portion 10e of the side plate 10, it is considered that the sealing performance between the low pressure region and the high pressure region can be further improved. It is done. Further, as shown in FIG. 6, the convex portion 61 and the convex portion 63 of the seal member 17 are connected by a curved portion 65, and the curved surface of the seal member 17 is opposed to the shoulder wall portion 10 b of the shoulder portion 10 a of the side plate 10. Thus, the deformation amount of the seal member 17 can be suppressed when the pressure difference between the low pressure region and the high pressure region becomes large while the curved portion 65 is securely adhered to the shoulder wall portion 10b in a state before the pump is driven. . Therefore, even when the gear pump 1 is frequently switched from a low pressure to a high pressure, the deformation amount of the seal member 17 can be suppressed, and the durability can be effectively improved.

  FIG. 9 shows the relationship between the pump discharge pressure when the gear pump is driven and the pressing force against the gear side surface of the side plate. The solid line L1 in the figure shows the pump discharge when the seal member 17 in the first embodiment is used. The relationship between the pressure and the pressing force on the side surface of the gear of the side plate, the broken line L1 ′ shows the relationship between the pump discharge pressure and the pressing force on the side surface of the gear when the conventional circular cross-section seal member is used. .

  As is apparent from FIG. 9, by applying the seal member 17 to the gear pump 1, the pressing force of the side plate 10 against the side surfaces 2a, 2a ', 3a, 3a' of the gears 2, 3 is reduced at both low pressure and high pressure. It can be remarkably reduced.

  Next, FIG. 10 shows another example of the seal member applied in the gear pump 1 of the first embodiment, and FIG. 11 shows still another example of the seal member applied in the gear pump 1 of the first embodiment. It is shown.

  A seal member 107 shown in FIG. 10 has a protrusion 101 at a part thereof, and the protrusion 101 is close to the rear case 5 and first contacts the rear case 5 when the gear pump 1 is assembled. However, since the protrusion 101 is extremely small, no large pressing force is generated.

  Therefore, in the cross section orthogonal to the axial center of the endless annular seal member 107, for example, even if the projection 101 exists inside the convex portion 102 that contacts the side plate 10, the pressing force of the projection 101 when the gear pump 1 is assembled is Since it is smaller than the pressing force in the vicinity of the convex portion 103, the maximum pressing portion 105 of the contact surface P <b> 1 of the seal member 107 with the rear case 5 is disposed outside the maximum pressing portion 104 of the contact surface P <b> 3 with the side plate 10. Thus, the same effect as that of the sealing member 17 described above can be obtained.

  Further, as shown in FIG. 11, even when the convex portion 111 and the convex portion 112 of the seal member 117 are connected by the straight portion 114 and the convex portion 111 and the convex portion 113 are connected by the straight portion 115, the seal member 117 is sealed when the pump is assembled. The member 117 can be rotated in the direction of arrow R4, and among the side surfaces P2 and P4 that connect the contact surface P1 of the seal member 117 with the rear case 5 and the contact surface P3 of the side plate 10, the side surface P2 on the low pressure region side. Can be brought into intimate contact with the shoulder wall portion 10b, and the pressing force of the side plate 1 against the side surfaces 2a, 2a ', 3a, 3a' of the gears 2, 3 can be reduced, and the side surfaces 2a of the gears 2, 3 can be reduced. The frictional force acting on 2a ′, 3a, 3a ′ can be effectively suppressed.

[Example 2]
FIG. 12 illustrates the manufacturing process of the seal member applied in the second embodiment of the gear pump according to the present invention. The seal member applied in the gear pump 1 of the first embodiment described above can be manufactured using, for example, a single mold. On the other hand, the seal member 17A applied in the gear pump of the second embodiment is manufactured by using two molds including an upper mold and a lower mold. Since the other configuration is the same as that of the first embodiment, the same reference numerals are given to the same configuration as that of the first embodiment, and the detailed description thereof is omitted.

  As shown in FIG. 12A, the seal member 17A includes an upper mold K1 that defines a cavity corresponding to the upper portion of the seal member 17A, and a lower mold K2 that defines a cavity corresponding to the upper portion of the seal member 17A. Is manufactured using a molding die. When manufacturing a molded product using such separation molds K1 and K2, the parting line 123A is formed at a position corresponding to the boundary of the separation mold.

  Therefore, when molding the seal member 17A, the upper mold K1 and the lower mold K2 are divided at positions where they do not contact the rear case 5 or the side plate 10 when the seal member 17A is disposed in the gear pump. Specifically, for example, as shown in FIG. 12B, the curved portion 64A and the curved portion 65A are arranged near the convex portion 63A.

  As a result, it is possible to suppress a decrease in adhesion between the seal member 17A and the rear case 5 or the side plate 10 due to the parting line (burr) 123A that can be formed at the time of molding the seal member 17A. Leakage to the low pressure side can be easily suppressed.

[Example 3]
FIG. 13 shows the overall configuration of the seal member applied in the third embodiment of the gear pump according to the present invention, and FIG. 14 shows the state before the pump assembly of the seal member applied in the gear pump of the third embodiment is completed. FIG. 15 shows a state after the completion of the pump assembly.

  The seal member applied in the gear pump of the third embodiment shown in FIGS. 13 to 15 is different from the seal member 17 applied in the gear pump of the first embodiment in that an overhang portion (seal reversal prevention portion) is provided. Since the other configurations are the same as those of the first embodiment, the same reference numerals are given to the same configurations as those of the first embodiment, and the detailed description thereof is omitted.

  FIG. 13 is a bottom view of the seal member 17B viewed from the side plate 10, and the seal member 17B extends outwardly to a part of the endless annular seal member 17B in the annular direction (seal reversal prevention unit). 131B is provided. In the third embodiment, the overhang 131B is provided at a plurality of locations in the annular direction of the seal member 17B. However, it can be formed over the entire circumference of the seal member 17B in the annular direction, for example.

  As shown in FIGS. 14 and 15, the overhang 131B of the seal member 17B is assembled to the gear pump. It has a height h that does not contact the bottom 10d. Thereby, when the seal member 17B is assembled, the seal member 17B can be prevented from being reversed, and the rear case 5 is pressed toward the side plate 10 to sandwich the seal member 17B between the rear case 5 and the side plate 10. When doing so, the curved portion 65B of the seal member 17B can be securely adhered to the shoulder wall portion 10b of the shoulder portion 10a of the side plate 10 without hindering the rotation of the seal member 17B in the direction of the arrow R5. .

  If the height h of the overhang 131B is set so as not to contact at least one of the rear case 5 and the side plate 10, when the seal member 17B is disposed between the rear case 5 and the side plate 10, the seal member 17B can be smoothly rotated.

[Example 4]
FIG. 16 shows a state before completion of pump assembly of the seal member applied in Embodiment 4 of the gear pump according to the present invention, and FIG. 17 shows a state after completion of the pump assembly. .

  The seal member applied in the gear pump of the fourth embodiment shown in FIGS. 16 and 17 is different in the cross-sectional shape of the seal member and the rear case from the seal member 17 and the rear case 5 applied in the gear pump of the first embodiment. Since the other configurations are the same as those of the first embodiment, the same reference numerals are given to the same configurations as those of the first embodiment, and the detailed description thereof is omitted.

  As shown in FIG. 16, the seal member 17C applied in the gear pump of the fourth embodiment has a substantially circular cross section before being sandwiched between the side plate 10 and the rear case 5C. Further, the surface of the rear case 5C that faces the side plate 10 has an inclined surface 151C that faces the side plate 10 side.

  As shown in the drawing, even when the seal member 17C has a substantially circular cross section, the surface facing the side plate 10 of the rear case 5C has the inclined surface 151C directed toward the side plate 10 so that the first embodiment can be realized. Similar to the gear pump, the first contact portion 171C of the seal member 17 with the rear case 5 and the first contact portion 172C of the side plate 10 at the time of assembling the pump are different positions when viewed in the direction in which the rear case 5C and the side plate 10 face each other. Can be arranged. Specifically, the first contact portion 171C of the seal member 17 with the rear case 5 can be disposed outside the contour of the endless annular seal member 17C, rather than the first contact portion 172C with the side plate 10.

  Thus, the maximum pressing portion (contact portion) 171C of the contact surface P3 of the contact surface P3 of the side plate 10 with the maximum pressing portion (contact portion) 171C of the contact surface P1 of the seal member 17C with the rear case 5C is changed. It can be arranged at different positions as viewed in the direction orthogonal to the side surfaces 2a, 2a ′, 3a, 3a ′, and the pressing force toward the side surfaces 2a, 2a ′, 3a, 3a ′ of the gears 2, 3 can be reduced. it can.

  Further, since the surface facing the side plate 10 of the rear case 5C has the inclined surface 151C, as shown in FIG. 17, the pressing force against the seal member 17C of the rear case 5C at the time of pump assembly is applied to the shoulder of the side plate 10. Since it can be directed in the direction of the shoulder wall portion 10b of the portion 10a (the direction of the arrow Q1), the low pressure of the side surfaces P2 and P4 connecting the surface P1 that contacts the rear case 5C and the surface P3 that contacts the side plate 10 of the seal member 17C The region side surface P2 can be brought into intimate contact with the surface of the shoulder wall portion 10b of the shoulder portion 10a of the side plate 10 and the low pressure region and the high pressure region formed between the rear case 5C and the side plate 10 The sealing property can be ensured.

  Therefore, similarly to the gear pump of the first embodiment, the pressing force on the side surfaces 2a, 2a ', 3a, 3a' of the gears 2, 3 can be reduced, the pressure responsiveness at the time of starting the pump can be improved, and the pump A decrease in driving torque during driving can be suppressed. Moreover, since the adhesiveness with respect to the shoulder wall part 10b of the shoulder part 10a of the rear case 5C and the side plate 10 can be ensured, the leakage of the liquid from a high voltage | pressure area | region to a low voltage | pressure area | region can be suppressed effectively.

  In the fourth embodiment, the first contact portion 171C of the seal member 17 with the rear case 5 is disposed outside the contour of the endless annular seal member 17C rather than the first contact portion 172C with the side plate 10. However, for example, the shape of the contact surface of the side plate 10 is changed so that the first contact portion 171C of the seal member 17 with the rear case 5 is more endless than the first contact portion 172C with the side plate 10. You may arrange | position inside the outline of 17C.

  In the first to fourth embodiments described above, the seal member for partitioning the low pressure region and the high pressure region formed between the rear case 5 and the side plate 10 constituting the housing 18 has been described. If the seal member is applied between the low pressure region and the high pressure region formed between the members, the seal member is generated between the members via the seal member while ensuring the sealability between the low pressure region and the high pressure region. It is possible to effectively reduce the pressing force.

  In addition, this invention is not limited to above-described Examples 1-4, Various modifications are included. For example, the first to fourth embodiments described above are described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configurations of the first to fourth embodiments.

DESCRIPTION OF SYMBOLS 1 Gear pump 2, 3 Gear 2a, 2a ', 3a, 3a' Gear side surface 4 Front cover 5 Rear case 5a Rear case recessed part 6, 7 Bearing 8 Drive shaft (shaft)
9 Driven shaft
10, 10 'side plate (second member)
10a, 10a 'Side plate shoulder 10b Shoulder wall 10c Shoulder bottom R 10d Shoulder bottom 10e Shoulder top 11 Housing seal 12 Oil seal 13 Suction port 14 Seal block 14a, 14a' Seal block shoulder 15 Contact surface of side plate 16 Discharge port 17, 17 ′ Seal member 18 Housing 19 Front cover groove 20 Front cover recess 21 Rear case channel 61, 62, 63 Seal member protrusion 64, 65 Seal member curve 66 Seal member straight line Portion 67 Maximum pressing portion 68 of the surface abutting against the housing (rear case) Maximum pressing portion 101 of the surface abutting the side plate Projection 102 of the sealing member 103, convex portion 104 of the sealing member Maximum pressing portion 105 of the surface abutting the side plate Housing Maximum pressing portion 107 on the surface in contact with the (rear case) seal members 111, 112, 1 3 straight portion 117 seal protrusions 114, 115 and 116 seal member of the seal member member 123A parting line (Bari)
131B Overhang (Seal reversal prevention part)
131Bb Overhang bottom K1 Upper mold K2 Lower mold P1 Contact surface P2 of the seal member with the housing (rear case) Side surface P3 of the seal member on the low pressure region side Contact surface P4 with the side plate of the seal member P4 of the seal member on the high pressure region side side

Claims (15)

At least two axes;
A pair of gears that are rotatably supported by the shafts and in which the tooth tips mesh with each other;
A pair of side plates disposed adjacent to both side surfaces of the pair of gears;
A housing that houses the shaft, the gear, and the side plate;
An endless annular seal member disposed between the housing and the side plate and defining a high pressure region and a low pressure region formed between the housing and the side plate by rotation of the gear. And
In the sealing member, the maximum pressing portion of the surface that contacts the housing and the maximum pressing portion of the surface that contacts the side plate are arranged at different positions as viewed in a direction orthogonal to the side surface of the gear. And a gear pump.   The said side plate and / or the said housing have the contact surface contact | abutted with the side surface which connects the surface contact | abutted with the said housing of the said sealing member, and the surface contact | abutted with the said side plate. Gear pump.   The gear pump according to claim 2, wherein the contact surface is in contact with a side surface on the low-pressure region side of a side surface connecting a surface of the seal member that contacts the housing and a surface that contacts the side plate.   The gear pump according to claim 1, wherein a surface of the seal member that contacts the housing is larger than a surface that contacts the side plate.   The gear pump according to claim 4, wherein the seal member has a shape that protrudes toward the side plate.   2. The gear pump according to claim 1, wherein a side surface connecting a surface of the seal member that contacts the housing and a surface that contacts the side plate is a curved surface.   The seal member is provided with a seal reversal prevention portion on an entire circumference or a part of an annular direction of a side surface connecting a surface of the seal member that contacts the housing and a surface that contacts the side plate. Item 10. The gear pump according to Item 1.   The gear pump according to claim 7, wherein the seal inversion preventing portion does not contact the housing and / or the side plate.   The seal member is formed using a split mold, and the seal member has a parting line at a position corresponding to the boundary of the split mold, and the parting line includes a surface in contact with the housing, The gear pump according to claim 1, wherein the gear pump is provided on a side surface that connects surfaces that contact the side plate. An endless annular seal member for partitioning a high pressure region and a low pressure region formed in the gear pump,
The seal member includes a first convex portion located inside the contour of the seal member, a second convex portion located outside the contour of the seal member relative to the first convex portion, and the second A third projection located outside the contour of the seal member with respect to the projection of the sealing member, and a connection surface connecting the projections, and the second projection and the third projection. Are respectively arranged on the opposite side of the seal member in the vertical direction with respect to the first convex portion.   The sealing member has a shape in which a connecting surface connecting the first convex portion and the third convex portion is a flat surface and is convex toward the second convex portion. The sealing member according to claim 10.   The seal member according to claim 10, wherein a connection surface connecting the first convex portion and the second convex portion of the seal member is a curved surface.   11. The seal member is provided with a seal inversion preventing portion on an entire circumference or a part of an annular direction of a connection surface connecting the second convex portion and the third convex portion. The seal member according to 1.   The seal member is disposed between the first member and the second member accommodated in the gear pump, and is formed between the first member and the second member. The maximum pressing portion of the surface in contact with the first member and the maximum pressing portion of the surface in contact with the second member sandwich the seal member. The seal member according to claim 10, wherein the member and the second member are disposed at different positions when viewed in a facing direction.   The seal member according to claim 14, wherein a surface of the seal member that contacts the first member is larger than a surface that contacts the second member.

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