JP2018119476A - Gear pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gear pump which suppresses the deterioration of flow rate efficiency.SOLUTION: A side plate 13 having a pair of supporting holes includes a first end surface 31 on a gear side; a second end surface 32 on the opposite side to the first end surface 31; and a peripheral side surface 33. A plane including a center axis of the pair is made to be a first plane P1. A plane orthogonal to the first plane P1 while having the center axis C4 of the supporting holes 35 as a first intersection 61 is made to be a second plane P2. A low-pressure chamber side part 33L on the peripheral side surface 33 intersects the second plane P2 at a second intersection 62. Concerning projecting amount from an orthogonal plane PV passing through an intersection point 62A between the second intersection 62 and the first end surface 31 and orthogonal to the second intersection 62 to a gear side, the maximum projecting amount TH of a high-pressure chamber side part 31H of the first end surface 31 is larger than the maximum projecting amount TL of the low-pressure chamber side part 31L of the first end surface 31.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a gear pump.

In a general gear pump structure, a pair of gears that mesh with each other is accommodated in a housing, and a gear chamber is defined in the accommodation hole by a pair of side plates that are disposed so as to sandwich the pair of gears in the axial direction. The gear support shaft is rotatably supported by a support hole formed in each side plate.
In the gear pump of Patent Document 1, as shown in FIG. 13A, the side plate 90 is a gear-side end surface 93 that faces the side surface 92 of the gear 91 and a surface opposite to the gear-side end surface 93. 94 and a back surface 95 opposite to 94. A seal 98 that divides the low pressure chamber 96 and the high pressure chamber 97 is interposed between the back surface 95 and the cover member 94. The seal 98 elastically presses and biases the high pressure chamber side portion 95H of the back surface 95 of the side plate 90 toward the gear 91 side.

JP 2000-64967 A

  When the gear pump is not operated, the gear side end surface 93 of the side plate 90 is inclined with respect to the side surface 92 of the gear 91 by the biasing force of the seal 98 as shown in FIG. For this reason, the high pressure chamber side minimum clearance HS, which is the minimum clearance between the high pressure chamber side portion 93H of the gear side end surface 93 and the side surface 92 of the gear 91, is the side surface of the low pressure chamber side portion 93L of the gear side end surface 93 and the side surface of the gear 91. 92 is smaller than the low-pressure chamber-side minimum clearance LS, which is the minimum clearance with 92.

  On the other hand, when the gear pump is operated, as shown in FIG. 13 (b), the internal pressure on the high pressure chamber 97 side biases the high pressure chamber side portion 93H of the gear side end surface 93 of the side plate 90 (with white arrows). Is larger than the biasing force of the seal 98, the high-pressure chamber-side minimum clearance HS is expanded to be equal to the low-pressure chamber-side minimum clearance LS. For this reason, the working fluid leaks from the high-pressure chamber 97 side to the low-pressure chamber 96 side through the expanded high-pressure chamber-side minimum gap HS, and the flow efficiency is lowered.

  The objective of this invention is providing the gear pump which suppresses the fall of flow efficiency.

  According to the first aspect of the present invention, the pump housing (2) in which the accommodation hole (21) is formed, and the gear chamber (50) are opposed to each other so that the gear chamber (50) is defined therebetween, and are parallel to each other. And a pair of side plates (12, 13; 13K; 13KF) each having a pair of cylindrical holes having a pair of central axes (C3, C4) and formed with support holes (34, 35). A pair of gears (8, 9) disposed in the gear chamber and rotatably supported by the side plate via gear support shafts (10, 11) inserted into the pair of support holes, When viewed from the axial direction (X) of the gear support shaft during rotation of the pair of gears, the low pressure chamber (51) and the low pressure chamber have a higher pressure than the low pressure chamber with the meshing position of the pair of gears inside the gear chamber. A high pressure chamber (52) of Each of the side plates includes a first end surface (31; 31K) on the gear side, a second end surface (32) opposite to the first end surface, and an inner peripheral surface of the accommodation hole. A low pressure chamber side portion (33L; 33KL) of the peripheral side surface of each side plate with respect to a first plane (P1) including the pair of central axes. Crossing each of the central axes as a first intersecting line (61) at a second plane (P2) perpendicular to the second intersecting line (62; 62K), and when the gear pump is operated, A high pressure chamber side minimum gap (HS), which is a minimum gap between the high pressure chamber side portion (31H; 31KH) of the first end face and the pair of gears, is connected to the low pressure chamber side portion (31L; 31KL) of the first end face. Low pressure chamber side minimum clearance (LS) that is the minimum clearance between the pair of gears Projecting from the orthogonal plane (PV; PKV) perpendicular to the second intersection line through the intersection (62A; 62KA) between the second intersection line and the first end surface to the gear side A gear pump in which the maximum protrusion amount (TH; TKH) of the high pressure chamber side portion of the first end face is larger than the maximum protrusion amount (TL; TKL) of the low pressure chamber side portion of the first end face. provide.

In addition, although the alphanumeric character in a parenthesis represents the corresponding component etc. in embodiment mentioned later, this does not mean that this invention should be limited to those embodiment as a matter of course. The same applies hereinafter.
As in claim 2, the first end surface (31) is a flat surface orthogonal to each central axis, and the second intersection line (62) has an obtuse angle (θ1) with respect to the first end surface. You may incline with respect to each said center axis so that it may form.

As in claim 3, the second intersecting line (62K) is parallel to each central axis, and a portion having the maximum protruding amount is provided on the high pressure chamber side portion of the first end face. Good.
According to a fourth aspect of the present invention, the portion having the maximum protrusion amount in the high pressure chamber side portion of the first end surface may include a flat portion (31KHF) that is parallel to the side surfaces of the pair of gears when the gear pump is operated. .

  In the first aspect of the present invention, the low pressure chamber side portion of the peripheral side surface intersects with the second plane and the second plane orthogonal to the first plane including the center axis of the pair of support holes with each central axis as the first intersection line. Cross at. Further, with respect to the protrusion amount from the orthogonal plane orthogonal to the second intersection line to the gear side through the intersection of the second intersection line and the first end surface, the protrusion amount of the high pressure chamber side portion of the first end surface is: It is larger than the protrusion amount of the low pressure chamber side portion of the first end face. For this reason, when the gear pump is operated, the high pressure chamber side minimum clearance between the high pressure chamber side portion of the first end surface and the pair of gears is smaller than the minimum clearance of the low pressure chamber side between the low pressure chamber side portion of the first end surface and the pair of gears. Become. Thereby, the flow efficiency with respect to the number of rotations of the pump can be improved.

According to the second aspect of the present invention, the flow efficiency can be improved with a simple configuration in which the low pressure chamber side portion (the second intersection line) on the peripheral side surface is inclined with respect to the central axis.
According to the third aspect of the present invention, the flow efficiency can be improved with a simple configuration in which a portion where the amount of protrusion to the gear side is maximized is provided on the high pressure chamber side portion of the first end face.
In the fourth aspect of the invention, when the gear pump is operated, the portion of the first end face that protrudes with the maximum amount of protrusion includes the flat portion that is parallel to the side surface of the gear. Stable and pump flow is stable.

1 is a plan view of a gear pump according to a first embodiment of the present invention. It is a longitudinal cross-sectional view of the gear pump of 1st Embodiment, and is equivalent to II-II sectional drawing of FIG. 1 is a schematic exploded perspective view of a gear pump according to a first embodiment. It is IV-IV sectional drawing of FIG. It is VV sectional drawing of FIG. (A)-(c) is the figure which looked at the side plate of 1st Embodiment from another angle. (A) is a partially broken side view of the side plate, (b) is an end view of the side plate on the gear side, and (c) is an end view of the side plate on the cover plate side. It is a schematic perspective view of the side plate of 1st Embodiment. It is a partially broken perspective view of the side plate of the first embodiment. It is a schematic sectional drawing of the gear pump which concerns on 1st Embodiment, and is equivalent to the IX-IX cross section of FIG. It is a schematic sectional drawing of the side plate of 1st Embodiment. It is a schematic sectional drawing of the side plate in 2nd Embodiment of this invention. It is a schematic sectional drawing of the side plate in 3rd Embodiment of this invention. It is sectional drawing of the principal part of the conventional gear pump, (a) shows the state at the time of gear pump non-operation, (b) has shown the state at the time of gear pump operation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings.
(First embodiment)
FIG. 1 is a plan view of a gear pump 1 according to the first embodiment of the present invention. The gear pump 1 includes a pump housing 2 and a pump shaft 3 partially protruding from the pump housing 2. Power for driving the gear pump 1 is transmitted to the pump shaft 3. The pump housing 2 includes a housing body 4 and a pair of lid plates 5 and 6.

The end surfaces 5a and 6a of the pair of cover plates 5 and 6 are provided along the pair of end surfaces 4a and 4b of the housing body 4 with respect to the pump shaft direction X which is the axial direction of the pump shaft 3, respectively. The pair of lid plates 5 and 6 and the housing body 4 are fastened together by a plurality of bolts 7 that pass through the lid plates 5 and 6 and the housing body 4 in the pump shaft direction X.
2 is a cross-sectional view taken along the line II-II in FIG. 1 and corresponds to a vertical cross-sectional view of the gear pump 1. In some of the cross sections in FIG. 2, hatching indicating the cross section is omitted. FIG. 3 is an exploded perspective view of the gear pump 1. 4 is a cross-sectional view taken along the line IV-IV of FIG. 2, and FIG. 5 is a cross-sectional view taken along the line V-V of FIG.

As shown in FIGS. 2 to 3, the gear pump 1 includes a gear pair of a drive gear 8 and a driven gear 9, a pair of gear support shafts 10 and 11, a pair of side plates 12 and 13, and a pair of first seals. 14, 15, a pair of second seals 16, 17, a pair of positioning pins 18, 19, and a bearing bush 20 as each pair of slide bearings.
As shown in FIGS. 2 and 4, the housing body 4 of the pump housing 2 is formed with an accommodation hole 21 that penetrates the pair of end surfaces 4 a and 4 b in the pump axial direction X. The pair of gear support shafts 10, 11, the pair of side plates 12, 13, the pair of second seals 16, 17, and the pair of bearing bushes 20 are disposed in the accommodation hole 21.

  As shown in FIG. 3, the housing body 4 of the pump housing 2 has a pair of side surfaces 4 c and 4 d that face each other in a direction orthogonal to the pump shaft direction X. A suction port 22 communicating with the accommodation hole 21 is opened on one side surface 4c, and a discharge port 23 communicating with the accommodation hole 21 is opened on the other side surface 4d. The accommodation hole 21 is composed of a pair of cylindrical hole portions 24 and 25 that have central axes C1 and C2 parallel to each other and communicate with each other in a state of being arranged in parallel.

  As shown in FIG. 2, the pair of side plates 12 and 13 are disposed to face each other in the accommodation hole 21 with a distance so as to partition the gear chamber 50 therebetween. As shown in FIGS. 2 and 4, the drive gear 8 and the driven gear 9 are disposed in the gear chamber 50 and meshed with each other. In other words, as shown in FIG. 2, the pair of side plates 12 and 13 are arranged on both sides of the gear pair of the drive gear 8 and the driven gear 9 with respect to the pump axial direction X.

  The pair of side plates 12 and 13 rotatably support the pair of gear support shafts 10 and 11 while being held by the pump housing 2 in the accommodation hole 21. The gear support shaft 10 supports the drive gear 8 so as to be integrally rotatable, and the gear support shaft 11 supports the driven gear 9 so as to be integrally rotatable. In FIG. 4, the rotation direction of the drive gear 8 and the driven gear 9 interlocked with the drive gear 8 is indicated by arrows.

As shown in FIG. 2, the gear support shaft 10 of the drive gear 8 is extended to the outside through the insertion hole 5 e of the cover plate 5. A pump shaft 3 is configured by the gear support shaft 10. The axial direction of the gear support shaft 10 corresponds to the pump shaft direction X.
As shown in FIG. 4, when the gear chamber 50 is viewed from the axial direction of the gear support shafts 10 and 11, the working fluid is sucked into both sides of the gear chamber 50 with the meshing position MP of both the gears 8 and 9 sandwiched therebetween. A low-pressure chamber 51 communicating with the port 22 and a high-pressure chamber 52 communicating with the working fluid discharge port 23 are formed. The low pressure chamber 51 and the high pressure chamber 52 are connected to a suction destination and a discharge destination (not shown) via a suction port 22 and a discharge port 23, respectively.

When the gear pump 1 rotating both the gears 8 and 9 is driven, the working fluid introduced into the low pressure chamber 51 through the suction port 22 is received between the teeth of the drive gear 8 and the driven gear 9 facing the low pressure chamber 51. By the rotation of the gears 8 and 9, the gears 8 and 9 are conveyed in a sealed state between the teeth and the inner peripheral surface 21 a of the accommodation hole 21, and are sent out to the high pressure chamber 52.
As shown in FIG. 3, a plurality of bolt insertion holes 4 e are formed in the housing body 4 so as to penetrate the pair of end faces 4 a and 4 b in parallel with the pump axial direction X. Each bolt 7 is screwed into the corresponding screw hole 5 b of the lid plate 5 through the corresponding bolt insertion hole 6 b of the lid plate 6 and the corresponding bolt insertion hole 4 e of the housing body 4.

A plurality of pin insertion holes 4f extending in parallel with the pump axis direction X are formed on one end surface 4a of the housing body 4, and a plurality of pin insertions extending in parallel with the pump axis direction X are formed on the other end surface 4b. A hole 4g is formed.
As shown in FIG. 2, the first seal 14 is an annular seal that seals between the cover plate 5 and the end surface 4 a of the housing body 4. The first seal 14 is accommodated in an annular seal accommodation groove 5 c provided on the end surface 5 a of the lid plate 5. The first seal 15 is an annular seal that seals between the cover plate 6 and the end surface 4 b of the housing body 4. The first seal 15 is accommodated in a seal accommodation groove 6 c provided on the end surface 6 a of the lid plate 6.

  As shown in FIG. 2, each positioning pin 18 is disposed across the pin insertion hole 5 d provided in the lid plate 5 and the pin insertion hole 4 f of the end surface 4 a of the housing body 4. The main body 4 is positioned. Each positioning pin 19 is disposed across the pin insertion hole 6 d provided in the lid plate 6 and the pin insertion hole 4 g of the end surface 4 b of the housing body 4, and positions the lid plate 6 and the housing body 4.

  Since the side plates 12 and 13 are formed of a common member, description will be made in accordance with the side plate 13 interposed between the gear pair and the cover plate 6. 6A is a partially cutaway side view of the side plate 13, FIG. 6B is an end view of the side plate 13 on the gear side, and FIG. 6C is a lid of the side plate 13. It is an end view by the side of a board. FIG. 9 is a cross-sectional view of the main part of the gear pump 1 during operation, and corresponds to a cross section IX-IX in FIG. 5.

  As shown in FIGS. 3 and 5, the side plate 13 has an “eight-letter shape” that fits into the accommodation hole 21. The side plate 13 includes a pair of disk-like portions 26 and 27 accommodated in the pair of cylindrical hole portions 24 and 25 of the accommodation hole 21, respectively. The outer peripheral surfaces of the pair of disk-shaped portions 26 and 27 are continuous with each other to form the peripheral side surface 33 (see FIG. 3) of the side plate 13. Each disk-shaped part 26 and 27 is fitted to the corresponding cylindrical hole parts 24 and 25 by clearance fitting.

  As shown in FIGS. 6A to 6C, the side plate 13 includes a first end surface 31 on the gear pair side, a second end surface 32 on the cover plate 6 side, a peripheral side surface 33, and a pair of supports. Holes 34 and 35. Each of the support holes 34 and 35 is a cylindrical hole formed concentrically with the corresponding disk-like portions 26 and 27. The support hole 34 has a central axis C3, and the support hole 35 has a central axis C4. Each support hole 34, 35 penetrates the first end surface 31 and the second end surface 32.

As shown in FIG. 2, the bearing bush 20 is fitted and held in each of the support holes 34 and 35. The side plate 13 rotatably supports the gear support shafts 10 and 11 via the bearing bushes 20 held in the support holes 34 and 35.
As shown in FIG. 6C, a substantially three-shaped seal groove 36 is formed on the second end surface 32. As shown in FIG. 2, the second seals 16, 17 are made of an elastic member formed in a substantially three-letter shape that is the same as the seal groove 36. Since the relationship between the side plate 12 and the second seal 16 is the same as the relationship between the side plate 13 and the second seal 17, the description will be made according to the side plate 13 and the second seal 17.

As shown in FIG. 5, the pair of end portions of the second seal 17 accommodated in the seal groove 36 are in elastic contact with the inner peripheral surfaces of the cylindrical hole portions 24 and 25 of the accommodation hole 21 of the housing body 4. Sealing surfaces 17a and 17b are provided.
As shown in FIG. 9, the side plate 13 is supported in a floating manner in the pump axial direction X. That is, the first area A1 is formed by the gap between the first end surface 31 of the side plate 13 and the side surface 9a of the gear 9. During the operation of the gear pump 1 (when the gears 8 and 9 are rotated), the first area A1 having a predetermined gap (corresponding to a so-called side clearance) is secured by the pressure in the gear chamber 50. When both the gears 8 and 9 rotate, the working fluid in the first area A1 performs a lubricating function.

  The second area A <b> 2 is formed by a gap between the second end surface 32 of the side plate 13 and the end surface 6 a of the lid plate 6. As shown in FIGS. 5 and 9, the second area A2 is divided into a low pressure chamber side area LA2 communicating with the low pressure chamber 51 and a high pressure chamber side area HA2 communicating with the high pressure chamber 52 with the second seal 17 as a boundary. Partitioned. As shown in FIGS. 5 and 6C, the second end face 32 of the side plate 13 includes a low pressure chamber side portion 32L facing the low pressure chamber side area LA2 of the second area A2, and a high pressure chamber side of the second area A2. And a high pressure chamber side portion 32H facing the area HA2.

  Further, as shown in FIG. 9, the first area A1 has a low pressure chamber side area LA1 disposed behind the low pressure chamber side area LA2 of the second area A2 and a high pressure of the second area A2 with respect to the pump axis direction X. And a high pressure chamber side area HA1 disposed on the back side of the chamber side area HA2. As shown in FIG. 6B, the first end face 31 is disposed in the low pressure chamber side portion 31L disposed in the low pressure chamber side area LA1 of the first area A1, and in the high pressure chamber side area HA1 of the first area A1. And the high pressure chamber side portion 31H.

FIG. 7 is a schematic perspective view of the side plate 13. As shown in FIG. 7, a plane including the central axes C3 and C4 of the pair of support holes 34 and 35 is defined as a first plane P1. Further, a plane orthogonal to the first plane P1 with the central axes C3 and C4 as the first intersecting line 61 is defined as a second plane P2.
FIG. 8 is a partially broken perspective view of the side plate 13 cut along the second plane P2 that passes through the central axis C4 of the support hole 35. FIG. In FIG. 8, the hatching indicating the cross section is omitted. The peripheral side surface 33 includes a high pressure chamber side portion 33H connected to the high pressure chamber side portion 32H of the second end surface 32, and a low pressure chamber side portion 33L connected to the low pressure chamber side portion 32L of the second end surface 32.

As shown in FIGS. 8 and 9, the first end surface 31 and the second end surface 32 are formed of flat surfaces orthogonal to the central axis C4.
As shown in FIG. 8, the low pressure chamber side portion 33 </ b> L of the peripheral side surface 33 of the side plate 13 intersects the second plane P <b> 2 at the second intersection line 62. A plane that passes through the intersection point 62A between the second intersection line 62 and the first end face 31 and is orthogonal to the second intersection line 62 is defined as an orthogonal plane PV.

  As shown in FIGS. 8 and 9, the second intersecting line 62 forms a central axis C4 (the central axis C4 is the first axis so as to form an obtuse angle θ1 (θ1> 90 °) with respect to the first end surface 31. 1 coincident line 61). For this reason, as shown in FIG. 8, the maximum protrusion amount TH of the high pressure chamber side portion 31H of the first end surface 31 is equal to the low pressure chamber side portion 31L of the first end surface 31 with respect to the protrusion amount from the orthogonal plane PV to the gear side. It is larger than the maximum protrusion amount TL (TH> TL).

FIG. 10 is a cross-sectional view of the side plate 13 cut along a third plane P3 parallel to the second plane P2. As shown in FIG. 10, the low pressure chamber side portion 33 </ b> L of the peripheral side surface 33 intersects the third plane P <b> 3 at the third intersection line 63. The third intersection line 63 forms an obtuse angle θ2 (θ2> 90 °) with respect to the first end surface 31. The angle θ2 is equal to the angle θ1.
In the present embodiment, the following effects are achieved. That is, as shown in FIG. 5, when the gear pump 1 is operated (when the gear pair of the drive gear 8 and the driven gear 9 is rotated), the side plate 13 receives pressure from the high pressure chamber 52 side and receives the low pressure chamber 51. It is urged to the side by the urging force F.

  For this reason, as shown in FIG. 9, the second intersecting line 62 of the low pressure chamber side portion 33 </ b> L of the peripheral side surface 33 extends along the bus line of the cylindrical hole portion 25 of the accommodation hole 21. Here, as shown in FIG. 8, the second intersecting line 62 intersects the first end surface 31 at an angle θ <b> 1 that is an obtuse angle. Therefore, the maximum protrusion amount TH of the high pressure chamber side portion 31H of the first end face 31 is larger than the maximum protrusion amount TL of the low pressure chamber side portion 31L of the first end face 31 with respect to the protrusion amount from the orthogonal plane PV to the gear side. (TH> TL).

  For this reason, as shown in FIG. 9, when the gear pump 1 is operated (when both gears 8 and 9 are rotated), the high pressure chamber side minimum gap between the high pressure chamber side portion 31H of the first end surface 31 and the side surface 9a of the gear 9 is used. HS becomes smaller than the low pressure chamber side minimum gap LS between the low pressure chamber side portion 31L of the first end surface 31 and the side surface 9a of the gear 9 (HS <LS). Thereby, the flow efficiency with respect to the number of rotations of the pump can be improved. Further, the flow efficiency can be improved with a simple configuration in which the low pressure chamber side portion 33L (second intersecting line 62 and third intersecting line 63) of the peripheral side surface 33 is inclined with respect to the central axis C4 of the support hole 35. Can do.

Further, the urging force G due to the pressure in the high pressure chamber side area HA1 of the first area A1 is the high pressure of the first end surface 31 with the intersection 62A between the second intersection line 62 and the first end surface 31 of the low pressure chamber side portion 33L as a fulcrum. A moment force M is generated to increase the high-pressure chamber-side minimum clearance HS, which is a clearance between the chamber-side portion 31H and the side surface 9a of the gear 9. However, the second intersecting line 62 of the low pressure chamber side portion 33L is along the bus on the inner peripheral surface of the cylindrical hole portion 25 of the accommodation hole 21. For this reason, the inner peripheral surface of the cylindrical hole portion 25 along the second intersecting line 62 resists the moment force M and suppresses the inclination of the side plate 13 that enlarges the high-pressure chamber-side minimum gap HS. The expansion of the high-pressure chamber side minimum gap HS is suppressed as much as possible.
(Second Embodiment)
FIG. 11 is a cross-sectional view of the side plate 13K cut along the second plane P2 in the second embodiment of the present invention. Referring to FIG. 11, in the present embodiment, the peripheral side surface 33K of the side plate 13K includes a low pressure chamber side portion 33KL and a high pressure chamber side portion 33KH. A second intersecting line 62K, which is an intersecting line between the low pressure chamber side portion 33KL of the peripheral side surface 33 and the second plane P2, is parallel to the central axis C4 of the support hole 35. That is, the low pressure chamber side portion 33KL of the peripheral side surface 33 is formed on a part of a cylindrical surface centering on the central axis C4.

  The first end surface 31K of the side plate 13K includes a low pressure chamber side portion 31KL and a high pressure chamber side portion 31KH. The first end face 31K intersects the second intersection line 62K at an angle θ1 that is an obtuse angle. A plane that passes through the intersection point 62KA between the second intersection line 62K and the first end face 31K and is orthogonal to the second intersection line 62K is defined as an orthogonal plane PKV. Regarding the amount of protrusion from the orthogonal plane PKV toward the gear side, the maximum protrusion amount TKH of the high pressure chamber side portion 31KH of the first end face 31K is made larger than the maximum protrusion amount TKL of the low pressure chamber side portion 31KL of the first end face 31K. (TKH> TKL). In other words, the high pressure chamber side portion 31KH of the first end surface 31 is provided with a portion having the maximum protrusion amount TKH.

In the constituent elements of the second embodiment of FIG. 11, the same constituent elements as those of the first embodiment of FIGS. 8 and 9 are the same as the reference numerals of the constituent elements of the first embodiment of FIGS. Reference numerals are attached.
Also in the second embodiment, as in the first embodiment, it is possible to improve the flow efficiency by suppressing the high-pressure chamber-side minimum gap HS during operation of the gear pump. Further, the flow rate efficiency can be improved with a simple configuration in which the portion (K portion having the maximum protrusion amount TKH) in which the protrusion amount to the gear side is maximized is provided in the high pressure chamber side portion 31KH of the first end face 31K.

Further, in the example of FIG. 11, the first end face 31K is easy to manufacture because it is uniformly inclined with respect to the orthogonal plane PKV. However, the first end face 31K may be inclined in a plurality of stages.
(Third embodiment)
FIG. 12 is a cross-sectional view of the side plate 13KF cut along the second plane P2 in the third embodiment of the present invention. Referring to FIG. 12, the side plate 13KF of the third embodiment is mainly different from the side plate 13K of the second embodiment in that the portion having the maximum protrusion amount in the high pressure chamber side portion 31KH of the first end surface 31K. However, it includes a flat portion 31KHF that is parallel to the side surface 9a of the gear 9 when the gear pump 1 is operated.

In the components of the third embodiment in FIG. 12, the same components as those in the second embodiment in FIG. 11 are denoted by the same reference symbols as the components in the second embodiment in FIG. is there. In the present embodiment, the same operational effects as in the second embodiment are achieved. Further, when the gear pump is operated, the amount of the high-pressure chamber side minimum gap HS is stabilized, and the pump flow rate is stabilized.
The present invention is not limited to the above-described embodiment, and the present invention can be variously modified within the scope of the claims.

  DESCRIPTION OF SYMBOLS 1 ... Gear pump, 2 ... Pump housing, 3 ... Pump shaft, 4 ... Housing main body, 5, 6 ... Cover plate, 8 ... Drive gear, 9 ... Driven gear, 9a ... Side surface, 10, 11 ... Gear support shaft, 12, 13; 13K; 13KF ... side plate, 16, 17 ... second seal, 20 ... bearing bush, 21 ... receiving hole, 21a ... inner peripheral surface, 22 ... suction port, 23 ... discharge port, 24, 25 ... cylindrical hole , 26, 27 ... disk-like portion, 31; 31K ... first end face, 31H; 31KH ... high pressure chamber side portion, 32 ... second end face, 32H ... high pressure chamber side portion, 32L ... low pressure chamber side portion, 33; 33K ... peripheral side surface, 33H; 33KH ... high pressure chamber side portion, 33L; 33KL ... low pressure chamber side portion, 34, 35 ... support hole, 36 ... seal groove, 50 ... gear chamber, 51 ... low pressure chamber, 52 ... high pressure chamber, 61 ... 1st intersection line, 62; 62K ... 2nd intersection line, 62A 62KA ... intersection, A1 ... first area, A2 ... second area, C3, C4 ... center axis, HS ... high pressure chamber side minimum clearance, LS ... low pressure chamber side minimum clearance, MP ... engagement position, P1 ... first plane, P2 ... 2nd plane, PV; PKV ... orthogonal plane, TH; TKH ... (high-pressure chamber side portion of the first end face from the orthogonal plane) maximum protrusion amount, TL; TKL ... (first end face from the orthogonal plane) Of the low-pressure chamber side), θ1, ... angle

Claims (4)

A pump housing having a receiving hole formed therein;
A pair of side plates each formed with a support hole made of a pair of cylindrical holes disposed in the accommodation hole facing each other so that a gear chamber is partitioned between each other and having a pair of central axes parallel to each other;
A pair of gears arranged in the gear chamber in mesh with each other, and rotatably supported by the side plates via gear support shafts inserted into the pair of support holes,
When viewed from the axial direction of the gear support shaft during rotation of the pair of gears, a low pressure chamber and a high pressure chamber higher in pressure than the low pressure chamber sandwich the meshing position of the pair of gears inside the gear chamber. Formed, a gear pump,
Each of the side plates includes a first end surface on the gear side, a second end surface opposite to the first end surface, and a peripheral side surface facing the inner peripheral surface of the accommodation hole,
The low pressure chamber side portion of the peripheral side surface of each side plate intersects with a second plane perpendicular to the first plane including the pair of central axes with each central axis as a first intersection line. And
During the rotation of the pair of gears, the high pressure chamber side minimum gap, which is the minimum gap between the high pressure chamber side portion of the first end face and the pair of gears, is the low pressure of the first end face with respect to the axial direction of the gear support shaft. Passing through the intersection of the second intersection line and the first end surface so as to be smaller than the minimum gap of the low pressure chamber side, which is the minimum gap between the chamber side portion and the pair of gears, is orthogonal to the second intersection line With respect to the amount of protrusion from the orthogonal plane to the gear side, the maximum protrusion amount of the high pressure chamber side portion of the first end surface is larger than the maximum protrusion amount of the low pressure chamber side portion of the first end surface. The first end surface is a flat surface orthogonal to each central axis,
2. The gear pump according to claim 1, wherein the second intersection line is inclined with respect to the central axis so as to form an obtuse angle with respect to the first end surface. The second intersection line is parallel to each of the central axis lines,
2. The gear pump according to claim 1, wherein a portion having the maximum protrusion amount is provided in a portion of the first end face on a high pressure chamber side.   The part which has the largest protrusion amount in the high pressure chamber side part of the first end face includes a flat part which is parallel to the side surfaces of the pair of gears when the pair of gears rotates. The gear pump according to item.

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