Oil condition sensor and method for making the same

• US 6,791,334 B2
• Filed: 02/21/2002
• Issued: 09/14/2004
• Est. Priority Date: 02/22/2001
• Status: Expired due to Fees

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Horie, Kazuyuki, Naito, Kiwamu
• Primary Examiner(s): Le, N.
• Assistant Examiner(s): Dole, Timothy J.
• Application Number:
  US10/078,425
• Publication Number:
  US 20020113596A1
• Time in Patent Office: 936 Days
• Field of Search: 324/438, 324/698, 324/715, 324/717, 73/530.5, 295/921, 298/25
• US Class Current: 324/438
• CPC Class Codes: G01N 27/4166 measuring a particular property of an electrolyte
• CPC Class Codes: G01N 33/2888 Lubricating oil characteristics, e.g. deterioration lubricating properties G01N33/30

Abstract

An oil condition sensor detects a condition of oil in response to the potential difference between electrodes. The electrodes include at least a first and second electrodes coaxially arranged. The electrodes have projections being arranged to face each other in an opposed manner. Therefore, the projections provide wide surface area that performs as electrodes. It is possible to provide compact oil condition sensor that is easy to install into an oil tank or oil pan.

Claims

1. An oil condition sensor for detecting a condition of oil in response to the potential difference between electrodes, comprising:

a cylindrical first electrode;

a cylindrical second electrode which is arranged around an outer periphery of the first electrode substantially coaxially with the first electrode;

first projections formed by bending respective portions of the cylindrical first electrode to project radially outwardly toward the second electrode side, and thereby defining first communication holes in the cylindrical first electrode; and

second projections formed by bending respective portions of the cylindrical second electrode to project radially inwardly toward the first electrode side, and thereby defining second communication holes in the cylindrical second electrode,

wherein the first projections and the second projections are arranged to face each other in an opposed manner as electrodes.

2. The oil condition sensor according to claim 1, wherein the first projections and the second projections are positioned in a circumferentially offset manner.

3. The oil condition sensor according to claim 1, wherein the first projections and the second projections are alternately arranged in the circumferential direction.

4. The oil condition sensor according to claim 1, wherein the first electrode and the second electrode are provided with communication holes which make the inside and the outside of the first electrode and the second electrode communicate with each other.

5. The oil condition sensor according to claim 1, wherein the oil condition sensor further includes a support member formed of an insulation material which supports the first electrode and the second electrode and the first projections and the second projections are disposed away from the support member.

6. An oil condition sensor for detecting a condition of oil in response to the potential difference between electrodes, comprising:

a cylindrical first electrode;

a cylindrical second electrode which is arranged around an outer periphery of the first electrode substantially coaxially with the first electrode;

first projections formed on the first electrode projecting radially outwardly toward the second electrode side;

second projections formed on the second electrode projecting radially inwardly toward the first electrode side, wherein the first projections and the second projections are arranged to face each other in an opposed manner as electrodes; and

another pair of electrodes including a first electrode and a second electrode, wherein a plurality of the pairs are coaxially arranged.

7. An oil condition sensor for detecting a condition of oil in response to the potential difference between electrodes, comprising:

a cylindrical first electrode;

a cylindrical second electrode which is arranged around an outer periphery of the first electrode substantially coaxially with the first electrode;

first projections formed on the first electrode projecting radially outwardly toward the second electrode side;

second projections formed on the second electrode projecting radially inwardly toward the first electrode side, wherein the first projections and the second projections are arranged to face each other in an opposed manner as electrodes; and

an oil level sensor which detects an oil level is mounted in the inside of the innermost electrode.

8. An oil condition sensor for detecting a condition of oil in response to the potential difference between electrodes, comprising:

a cylindrical first electrode;

a cylindrical second electrode which is arranged around an outer periphery of the first electrode substantially coaxially with the first electrode;

first projections formed on the first electrode projecting radially outwardly toward the second electrode side;

second projections formed on the second electrode projecting radially inwardly toward the first electrode side, wherein the first projections and the second projections are arranged to face each other in an opposed manner as electrodes; and

a support member formed of an insulation material which supports the first electrode and the second electrode and the first projections and the second projections are disposed away from the support member, and

wherein at least one of mounting portions of the first electrode and the second electrode which are mounted on the support member has a portion which is bent to be away from the other mounting portion.

9. An oil condition sensor for detecting a condition of oil in response to the potential difference between electrodes, the oil condition sensor comprising:

a first electrode;

a second electrode which generate the potential difference when the first electrode and the second electrode are immersed in oil in the state that the both electrodes face each other in an opposed manner; and

a support member which is formed of insulation material and supports the first electrode and the second electrode, wherein at least one of mounting portions of the first electrode and the second electrode which are mounted on the support member has a portion which is bent in a direction away from the other mounting portion.

10. An oil conditions sensor for detecting a condition of oil in response to the potential difference between electrodes, comprising:

a cylindrical first electrode;

a cylindrical second electrode which is arranged around an outer periphery of the first electrode substantially coaxially with the first electrode;

first projections formed on the first electrode projecting radially outwardly toward the second electrode side;

second projections formed on the second electrode projecting radially inwardly toward the first electrode side, wherein the first projections and the second projections are arranged to face each other in an opposed manner as electrodes; and

a support member formed of an insulation material which supports the first electrode and the second electrode and the first projections and the second projections are disposed away from the support member, and

wherein on a surface of the support member at a side on which both electrodes are mounted, an uneven surface is formed between the first electrode and the second electrode.

11. An oil condition sensor for detecting a condition of oil in response to the potential difference between electrodes, the oil condition sensor comprising:

a first electrode;

a second electrode which generate the potential difference when the first electrode and the second electrode are immersed in oil in the state that the both electrodes face each other in an opposed manner; and

a support member which is formed of insulation material and supports the first electrode and the second electrode, wherein on a surface of the support member on which the both electrodes are supported, an uneven surface is formed between the first electrode and the second electrode.

12. An oil condition sensor for detecting a condition of oil in response to the potential difference between electrodes comprising:

a cylindrical first electrode; and

a cylindrical second electrode which is arranged around an outer periphery of the first electrode substantially coaxially with the first electrode, wherein

portions of a cylindrical surface of the first electrode are bent by an angle of less than 90°

toward the second electrode as first fins thus forming communication holes which make the inside and the outside of the cylindrical surface communicate with each other therethrough,

portions of a cylindrical surface of the second electrode are bent by an angle of less than 90°

toward the first electrode as second fins thus forming communication holes which make the inside and the outside of the cylindrical surface communicate with each other therethrough, and

a distance between opposing faces of the fins and a distance between a distal end portion of the each fin and the cylindrical surface of the electrode which faces the fin are set substantially equal.

13. The oil condition sensor according to claim 12, wherein the first fins and the second fins are formed by cutting portions of pre-forms for first and second electrodes and then bending cut portions.

14. The oil condition sensor according to claim 12, wherein a distance between the first electrode and the second electrode is set to not more than 1 mm.

15. The oil condition sensor according to claim 12, further comprising another pair of electrodes including the first electrode and the second electrode, wherein a plurality of the pairs are coaxially arranged.

16. The oil condition sensor according to claim 12, wherein the oil condition sensor further includes a support member which is formed of an insulation material and supports the first electrode and the second electrode thereon, and a contact prevention member which is formed of an insulation material and is disposed at end portions of the first electrode and the second electrode opposite to the support member for preventing the both electrodes from coming into contact with each other.

17. An oil condition sensor for detecting a condition of oil in response to the potential difference between electrodes comprising:

a cylindrical first electrode; and

a cylindrical second electrode which is arranged in the outside of the first electrode substantially coaxially with the first electrode, wherein

a thickness of a cylindrical wall of the each electrodes is fixed;

cross-sectional shapes of the first electrode and the second electrode on planes which are perpendicular to an axis are similar to each other;

the cylindrical first electrode has first slits that are extended in an axial direction of the cylindrical first electrode; and

the cylindrical second electrode has second slits that are extended in an axial direction of the cylindrical second electrode so that the second slits are radially opposed to the first slits.

18. The oil condition sensor according to claim 17, wherein the first electrode and the second electrode are formed of circular cylinders.

19. An oil condition sensor for detecting a condition of oil in response to the potential difference between electrodes comprising:

a cylindrical first electrode;

a cylindrical second electrode which is arranged in the outside of the first electrode substantially coaxially with the first electrode;

first projections formed by bending respective portions of the cylindrical first electrode to project outwardly from the cylinder toward the second electrode, and thereby defining first communication holes in the cylindrical first electrode; and

second projections formed by bending respective portions of the cylindrical second electrode to project inwardly from the cylinder toward the first electrode, and thereby defining second communication holes in the cylindrical second electrode,

wherein the first projections and the second projections are arranged alternately in the circumferential direction, and a distance which is formed between the one projection out of the first projection and the second projection and the neighboring other projections disposed at both sides of the one projection is set equal to a distance between a distal end of the one projection and a wall surface disposed between the neighboring other projections in the circumferential direction.

20. An oil condition sensor for detecting a condition of oil in response to the potential difference between electrodes comprising:

a cylindrical first electrode;

a cylindrical second electrode which is arranged in the outside of the first electrode substantially coaxially with the first electrode; and

a support member which supports the first and second electrodes and is formed of an insulation material, wherein

the first and second electrodes include first and second projections which are projected axially from respective one ends of the first and second electrodes,

the first and second electrodes are mounted on the support member by connecting the first and second projections to the support member, and

the first and second projections are connected to the support member at positions where the first and second projections are offset from each other in the rotational direction with respect to an axis,

wherein the oil condition sensor further includes a first wall member which defines a first measurement chamber in which the first and second electrodes are accommodated, and the support member includes a connection surface to which the first and second electrodes are connected, and a hole portion which allows oil to flow along the connection surface is formed in a first wall portion of the first measurement chamber, and

wherein the hole portion is formed at a position below the connection surface.

21. An oil condition sensor for detecting a condition of oil in response to the potential difference between electrodes comprising:

a cylindrical first electrode;

a cylindrical second electrode which is arranged in the outside of the first electrode substantially coaxially with the first electrode; and

a support member which supports the first and second electrodes and is formed of an insulation material, wherein

the first and second electrodes include first and second projections which are projected axially from respective one ends of the first and second electrodes,

the first and second electrodes are mounted on the support member by connecting the first and second projections to the support member, and

the first and second projections are connected to the support member at positions where the first and second projections are offset from each other in the rotational direction with respect to an axis,

wherein the oil condition sensor further includes a first wall member which defines a first measurement chamber in which the first and second electrodes are accommodated, and the support member includes a connection surface to which the first and second electrodes are connected, and a hole portion which allows oil to flow along the connection surface is formed in a first wall portion of the first measurement chamber, and

wherein a lower surface among surfaces which define the hole portion is downwardly inclined from the inside to the outside of the first measurement chamber.

22. The oil condition sensor according to claim 21, wherein the inner cylindrical electrode has first projections that are formed by bending corresponding portions of the inner cylindrical electrode so that the first projections of the inner electrode projects radially outwardly toward the second electrode side and thereby form first communication holes in the inner cylindrical electrode, and

the outer cylindrical electrode has second projections that are formed by bending corresponding portions of the outer cylindrical electrode so that the second projections of the outer electrode project radially inwardly toward the inner electrode side and thereby form second communication holes in the outer cylindrical electrode.

23. An oil condition sensor comprising:

a cylindrical first electrode;

a cylindrical second electrode which is arranged in the outside of the first electrode substantially coaxially with the first electrode;

a support member which is formed of an insulation material and on which the first and second electrodes are mounted;

an oil level sensor for detecting an oil level which is disposed in the inside of the first electrode;

a first wall portion which defines a first measurement chamber in which the first and second electrodes are arranged, and a first hole portion which introduces oil into the first measurement chamber; and

a second wall portion which defines a second measurement chamber in which the oil level sensor is arranged, and a second hole portion which introduces oil into the second measurement chamber from the first measurement chamber, wherein an opening area of the first hole portion is larger than that of the second hole portion.

24. The oil condition sensor according to claim 23, wherein the opening area of the second hole portion is adjusted so that a change speed of an oil level in the inside of the second measurement chamber is lower than a change speed of an oil level in the outside of the second measurement chamber.

25. The oil condition sensor according to claim 23, wherein the oil conditions sensor further includes a temperature sensor which is capable of detecting an oil temperature and the temperature sensor is disposed in the vicinity of the second hole portion in the inside of the second measurement chamber.

26. The oil condition sensor according to claim 25, wherein the oil condition sensor further includes a substrate on which the oil level sensor and the temperature sensor are mounted.

27. An oil condition sensor for detecting a condition of oil in response to the potential difference between electrodes comprising:

a cylindrical first electrode;

a cylindrical second electrode which is arranged in the outside of the first electrode substantially coaxially with the first electrode; and

a support member which supports the first and second electrodes and is formed of an insulation material, wherein

the first and second electrodes include first and second projections which are projected axially from respective one ends of the first and second electrodes,

the first and second electrodes are mounted on the support member by connecting the first and second projections to the support member, and

the first and second projections are connected to the support member at positions where the first and second projections are offset from each other in the rotational direction with respect to an axis,

wherein the support member includes a body, a columnar body which is projected from the body in a columnar shape to support the oil level sensor, and an annular body which is positioned approximately coaxially with the columnar body and is projected from the body and is formed in an annular shape,

the annular body includes at least two opening portions which are arranged to face the columnar body in an opposed manner and have upper open ends,

an opening width size L1 of the opening portions is set to L1>

L2 with respect to a width size L2 of the columnar body so as to ensure the withdrawing direction of molds which form the columnar body and the annular body, and the body, the columnar body and the annular body are integrally formed.

28. An oil condition sensor comprising:

a pair of inner and outer cylindrical electrodes; and

an oil temperature sensor in the inside of the electrodes,

wherein the inner and outer cylindrical electrodes have communication holes that are disposed around the oil temperature sensor in a radial direction of the oil temperature sensor.

29. The oil condition sensor according to claim 28, wherein the oil condition sensor further includes a housing which supports a pair of the electrodes and the housing includes a cylindrical portion which is projected along an axis and the oil temperature sensor is disposed in the inside of the cylindrical portion.

30. The oil condition sensor according to claim 29, wherein the cylindrical portion has a thin wall portion at least in the vicinity of the oil temperature sensor.

31. The oil condition sensor according to claim 29, wherein the cylindrical portion has a thin wall portion made of material having a favorable heat conduction at least in the vicinity of the oil temperature sensor.

32. The oil condition sensor according to claim 29, wherein a cross-sectional area of a supporting portion of the cylindrical portion is set smaller than a cross-sectional area of a distal end side of the cylindrical portion.

33. The oil condition sensor according to claim 29, further comprising a filler filled in the inside of the cylindrical portion, the filler covering the oil temperature sensor.

34. An oil condition sensor for detecting a condition of oil in response to the potential difference between electrodes, comprising:

a first electrode made of a metal being formed in a plate shape; and

a second electrode made of a different metal that generates potential difference to the first electrode in the oil, the second electrode being formed in a plate shape and being arranged to face the first electrode in parallel with each other, wherein the first and second electrodes define oil passage having a first opening defined between the first and second electrode and a second opening defined by a through hole formed on the first electrode, wherein the first electrode has a fin extended into the oil passage, and the second electrode has a fin extended into the oil passage, the fins being arranged in parallel.

35. An oil condition sensor for detecting a condition of oil in response to the potential difference between electrodes, comprising:

a first electrode made of a metal;

a second electrode made of a different metal that generates potential difference to the first electrode in the oil; and

a support member made of resin which supports the first and second electrodes, the support member having a vertical or inclined surface between the first and second electrode.

36. The oil condition sensor according to claim 35, wherein the vertical or inclined surface is provided by an uneven surface formed on the support member.