Sealing of a gear pump

Patent metadata

Field	Value
Publication number	US-9835155-B2
Application number	US-201514796198-A
Country	US
Kind code	B2
Filing date	Jul 10, 2015
Priority date	Jul 11, 2014
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

A gear pump apparatus includes a gear pump and a sealing mechanism which includes an annular rubber member, an outer member, and an inner member. One of the outer member and a casing of the gear pump apparatus has a contact member located outside a portion of the outer member which contacts the gear pump in a radial direction of the gear pump. The contact member is placed to create a physical contact between the outer member and the casing to absorb a part of force by which the outer member is pressed against the gear pump. This results in a decrease in pressure acting on an area of contact between the outer member and the gear pump, which leads to a drop in resistance to sliding between the gear pump and the outer member, thus decreasing a loss of torque required for the pumping operation of the gear pump.

First claim

What is claimed is:

1. A gear pump apparatus comprising:
a gear pump which includes an outer gear and an inner gear meshing with the outer gear so as to define a plurality of cavities, the outer and inner gears being rotated through a drive shaft to suck and discharge fluid in a pumping operation;
a casing which has defined therein a chamber in which the gear pump is disposed;
a sealing mechanism which is disposed between an outer wall of the casing and said gear pump, said sealing mechanism working to create a hermetical seal between a low-pressure region and a high-pressure region, the low-pressure region including a suction side of the gear pump into which the fluid is sucked and a peripheral region of the drive shaft, the high-pressure region including a discharge side from which the fluid is discharged, said sealing mechanism including an annular rubber member, an outer member, and an inner member, the annular rubber member surrounding the low-pressure region to create a hermetical seal between the low-pressure region and the high-pressure region, the outer member being placed in contact with one of axially opposed ends of the casing and one of axially opposed ends of the gear pump, the inner member having an outer peripheral wall on which the annular rubber member is fit and being disposed inside the outer member, the inner member being arranged in contact with an inner surface of the outer wall of said casing, the inner surface facing an opposite side of the inner member to said gear pump; and
a contact member which is provided on one of said outer member and said casing and located outside a portion of the outer member which contacts the one of the axially opposed ends of the gear pump in a radial direction of the gear pump, the contact member being placed to create a physical contact between the outer member and the one of the axially opposed ends of the casing.

2. A gear pump apparatus as set forth in claim 1 , wherein said contact member is disposed within a suction rotational range that is defined by an angle through which the gear pump rotates to suck the fluid in the pumping operation.

3. A gear pump apparatus as set forth in claim 1 , wherein said outer member has formed on one of end surfaces which faces the gear pump a protrusion placed in contact with the casing and the gear pump to hermetically seal between the low-pressure region and the high-pressure region, said outer member also having formed on the one of the end surfaces a recess placed out of contact with the casing and the gear pump, and wherein the contact member is defined by a protrusion formed on the recess of the outer member.

4. A gear pump apparatus as set forth in claim 3 , wherein said protrusion includes a first hermetically-sealing portion, a second hermetically-sealing portion, and a third hermetically-sealing portion, the first hermetically-sealing portion serving to close one of the cavities which is the largest in volume thereof, the second hermetically-sealing portion serving to close one of the cavities which is the smallest in volume thereof, the third hermetically-sealing portion being located between the first and second hermetically-sealing portions, and wherein the contact member is shaped to connect with the third hermetically-sealing portion.

5. A gear pump apparatus as set forth in claim 4 , wherein the contact member is connected to the third hermetically-sealing portion outside an outer circumference of the outer rotor.

6. A gear pump apparatus as set forth in claim 4 , wherein at least one of the first and second hermetically-sealing portions is shaped to have an area whose outline which faces an outer periphery of the gear pump extends along a periphery of a region through which the cavities pass and additionally has an extended area which extends outside said area toward the outer periphery of the gear pump.

7. A gear pump apparatus as set forth in claim 6 , wherein the extended area is shaped to have a dimension, as defined in a radial direction of the gear pump, which gradually increases from the suction side toward the discharge side of the gear pump.

8. A gear pump apparatus as set forth in claim 1 , wherein an outer peripheral wall of said inner member has formed thereon a flange which is shaped to have a pressure-exerted surface to which pressure, as produced by deformation of the annular rubber member arising from application of discharge pressure of said gear pump, is applied to create thrust to move the inner member toward the inner surface of the outer wall of said casing.

9. A gear pump apparatus comprising:
a gear pump which includes an outer gear and an inner gear meshing with the outer gear so as to define a plurality of cavities, the outer and inner gears being rotated through a drive shaft to suck and discharge fluid in a pumping operation;
a casing which has defined therein a chamber in which the gear pump is disposed; and
a sealing mechanism which is disposed between an outer wall of said casing and said gear pump, said sealing mechanism working to create a hermetical seal between a low-pressure region and a high-pressure region, the low-pressure region including a suction side of the gear pump into which the fluid is sucked and a peripheral region of the drive shaft, the high-pressure region including a discharge side from which the fluid is discharged, said sealing mechanism including an annular rubber member, an outer member, and an inner member, the annular rubber member surrounding the low-pressure region to create a hermetical seal between the low-pressure region and the high-pressure region, the outer member being placed in contact with one of axially opposed ends of the casing and one of axially opposed ends of the gear pump, the inner member having an outer peripheral wall on which the annular rubber member is fit and being disposed inside the outer member, the inner member being arranged in contact with an inner surface of the outer wall of said casing, the inner surface facing an opposite side of the inner member to said gear pump,
wherein said outer member has formed on one of end surfaces thereof which faces the gear pump a protrusion placed in contact with one of the casing and the gear pump to define the low-pressure region and the high-pressure region, said outer member also having formed on the one of the end surfaces a recess placed out of contact with the casing and the gear pump,
wherein said protrusion includes a first hermetically-sealing portion, a second hermetically-sealing portion, and a third hermetically-sealing portion, the first hermetically-sealing portion serving to close one of the cavities which is the largest in volume thereof, the second hermetically-sealing portion serving to close one of the cavities which is the smallest in volume thereof, the third hermetically-sealing portion being located between the first and second hermetically-sealing portions on a suction side of the gear pump, and
wherein at least one of the first and second hermetically-sealing portions also includes an extended area which extends toward the outer periphery of the gear pump outside an area whose outline which faces an outer periphery of the gear pump extends along a periphery of a region through which the cavities pass.

10. A gear pump apparatus as set forth in claim 9 , wherein the extended area is shaped to have a dimension, as defined in a radial direction of the gear pump, which gradually increases from the suction side toward the discharge side of the gear pump.

11. A gear pump apparatus as set forth in claim 9 , wherein the outer member includes a contact member which is located outside a portion of the outer member which contacts the one of the axially opposed end

Assignees

• Denso Corp
• Advics Co Ltd

Inventors

• Hashiba Takashi
• Hakamada Naoki
• Naganuma Takahiro
• Kawabata Tomoaki

Classifications

• B60T8/4031

  Pump units characterised by their construction or mounting (pump units in combination with valve blocks B60T8/36) · CPC title

• B60T7/042

  by electrical means, e.g. using travel or force sensors · CPC title

• F04C15/0057

  Driving elements, brakes, couplings, transmission specially adapted for machines or pumps (brakes, couplings, transmissions per se F16, B60) · CPC title

• F04C15/0034

  for other than the working fluid, i.e. the sealing arrangements are not between working chambers of the machine · CPC title

• B60T13/686

  in hydraulic systems or parts thereof · CPC title