JPS6085284A - rotary oil pump - Google Patents

Abstract

PURPOSE:To prevent extinction of oil thus to prevent abrasion of housing, by forming a tapered land on the sliding face of a rotary piston in a rotary oil piston against the housing thereby forming a wedge-shaped oil film. CONSTITUTION:A tapered land 55 is formed on the sliding face of ring gear and gear rotor 50 of trocoid oil pump against the casing made of aluminum alloy. The ring gear and gear rotor 50 are made of low carbon steel or rat cast iron where a nitride layer is formed through soft nitride processing onto the surface to improve the abrasion-resistance of housing, ring gear and gear rotor 50. Upon rotation in the arrow direction (n), a wedge-shaped oil film directing reversely from the rotary direction is formed continuously by the tapered land 55. It can be applied on other rotary oil pump.

Description

[Detailed description of the invention] Technical field The present invention relates to a rotary oil pump.

Prior Art and Problems A rotary oil pump includes a housing having an oil suction port and an oil discharge port, and a rotating body that rotates within the housing while slidingly contacting the inner wall of the housing. Accordingly, the oil sucked into the pump operating space in the housing from the oil suction port is discharged from the oil discharge port. Typical examples of this type of rotary oil pump are the trochoid type oil pump,
Gear type oil pumps and crescent type oil pumps are widely known.

In a trochoid type oil pump, a ring gear, which is a first rotating body, is rotatably provided in a housing, and a gal rotor, which is a second rotating body, which meshes with the inner trochoid teeth of the ring gear, is rotatable eccentrically within the ring gear. A pump operating space is defined by the gear rotor, the ring gear, and the inner wall of the housing, and when the gear rotor is driven to rotate, the ring gear rotates in the same direction and repeatedly sucks and discharges oil.

In the case of this type of trochoid pump, both end surfaces and the outer peripheral surface of the ring gear are in sliding contact with the inner wall of the housing, which is usually made of an aluminum alloy or the like, and both end surfaces of the gear rotor are in sliding contact with the inner wall of the housing. Therefore, in the past, oil lubrication was performed by providing an appropriate clearance between these sliding surfaces and the inner wall of the housing, but the sliding surfaces of the conventional /S housing and the sliding surfaces of the ring gear, gear rotor, etc. were uneven. Despite having a smooth surface with no scratches, the oil film breaks down within the clearance, which causes wear on the inner wall of the housing or groove-like scratches in the direction of rotation, resulting in damage to the pump. This results in a decrease in efficiency and the generation of noise due to rattling.

This is particularly noticeable in pumps that are used at high speeds of several thousand revolutions per minute, such as rotary oil pumps for automobile internal combustion engines.

In a gear type oil pump, two gear rotors are provided in a housing and engage with each other in a circumscribed state, and oil is sucked into and discharged into a pump operating space in the housing by rotation of both gear rotors.

In the case of this gear-type oil pump, both end surfaces and tooth tips of the gear rotor come into sliding contact with the inner wall of the housing, but in conventional pumps of this type, the inner wall of the housing, both end surfaces of the gear rotor, and the tooth tip surfaces are uneven. Because the surface is finished with a smooth surface, an oil film breaks down between the gear rotor and the inner wall of the housing, which is usually made of aluminum alloy, etc., and this causes the inner wall of the housing to wear out or develop grooves in the direction of rotation. Scratches occur, resulting in a decrease in pump efficiency and the generation of noise due to rattling.

Furthermore, in the Talecent type oil pump, a ring gear that is a first rotating body is rotatably provided in the housing, and a gear rotor that is a second rotating body that meshes with the internal teeth of the ring gear is rotatable eccentrically within the ring gear. A crescent-shaped member forming a part of the housing is provided in an area where the ring gear and gear rotor are separated, and the ring gear and gear rotor are brought into sliding contact with this crescent-shaped member, and the ring gear is rotated in the same direction by rotationally driving the gear rotor. It is designed to repeatedly suck in and discharge oil while rotating.

In the case of this type of pump, both end surfaces and the outer peripheral surface of the ring gear are in sliding contact with the inner wall of the housing, both end surfaces of the gear rotor are in sliding contact with the inner wall of the housing, and further, the tooth tip surfaces of the ring gear and gear rotor are in sliding contact with the inner wall of the crescent-shaped member. However, in conventional pumps of this type, the inner wall of the housing, the inner and outer wall surfaces of the crescent-shaped member, both end surfaces and outer peripheral surfaces of the ring gear, both end surfaces of the gear rotor, and the tooth tip surfaces of the ring gear and gear rotor are in sliding contact with the outer wall surface. Because the surface is smooth and has no irregularities, oil film runs out between the housing, crescent-shaped member, etc., which is usually made of aluminum alloy, and the ring gear, gear rotor, etc.
The crescent-shaped members are worn out, or groove-like scratches occur in the direction of rotation, resulting in a decrease in pump efficiency and generation of noise due to rattling. As described above, conventional pumps of this type have drawbacks such as lack of oil film, and have been unable to maintain stable performance over a long period of time.

Purpose of the Invention In view of the above-mentioned problems, the present invention provides a rotary oil pump that reduces wear on the housing and rotating body and prevents scratches, thereby preventing a decrease in pump efficiency and generation of noise. The purpose is to provide

Structure of the Invention In order to achieve the above-mentioned object, the present invention provides a continuous connection between the inner wall of the housing and the sliding contact surface of the rotating body that slides on the inner wall of the housing. By forming a wedge-shaped swelling oil film layer between the sliding contact surface of the body and further forming a hard surface layer on the surface of the Chiba land, the wear of the housing and the rotating body is reduced and the occurrence of scratches is prevented. It is characterized by the following.

Example Hereinafter, the present invention will be described in detail with reference to the drawings.

1 to 5 show a first embodiment in which the present invention is applied to a trochoidal oil pump. Referring to FIG. 1, the pump housing 10 is a center housing having a cylindrical inner wall 21. 20, and a front side that is in close contact with both opening ends of the center housing 20, respectively.
It consists of a rear side plate 30.40. The center housing 20, front side plate 30, and rear side plate 40 are fastened and fixed with bolts (not shown). Note that the front side plate 30 or the rear side plate 4o may be formed integrally with the center housing 20.

An oil suction hole 31 is formed in the front side plate 3o, and an oil discharge hole 41 is formed in the rear side plate 4°.

Inside the center housing 20, as shown in FIG.
A ring gear 50 having trochoid teeth 51 is rotatably fitted inside the ring gear 50, and a gear rotor 6o having trochoid teeth 61 on its outer periphery that meshes with the trochoid teeth 51 is rotatably provided inside the ring gear 50. There is. The number of teeth of trochoid tooth 51.61 is 5 and 6 here.
However, for example, it may be four and five.

A drive shaft 70 is installed in the center hole 62 of the gear rotor 60.
is inserted, and the drive shaft 7o and gear rotor 60
is fixed by key binding. This is not limited to key binding, but may also be a caulking structure, for example. The drive shaft 7o is rotatably supported by the rear side plate 40, and one end extends outside so that it can be connected to a drive source (not shown).

When the gear rotor 60 is rotated in the direction of the arrow n in FIG.
The ring gear 50 rotates in the same direction at five-sixths of the rotation speed while always maintaining contact with each of the trochoid teeth 51 of 0. As a result, the space (1) formed between the ring gear 50 and the gear rotor 60 moves in the rotational direction and repeatedly increases and decreases in volume, and due to this action, oil flows from the oil suction hole 31 into the space (1). After being sucked in, the oil is discharged from the oil discharge hole 41.

When the gear rotor 60 and ring gear 50 rotate,
The outer peripheral surface 52 of the ring gear 50 slides against the inner wall 21 of the center housing 20, and both end surfaces 53.
54 and both end surfaces 63 and 64 of the gear rotor 60 slide against the inner wall 32 of the front side plate 30 and the inner wall 42 of the rear side plate 40, respectively.

A clearance of approximately 0.05 to 0.2 inches (approx. Inner wall 32 of both end faces 64.64 and front and rear side brakes) 30.40
', 42, a clearance of approximately 0.03 to 0.10 m1 in width is formed.

Therefore, the ring gear 50 and the gear rotor 60 may move somewhat within the housing 10. Therefore, if the oil supply to the clearance is insufficient, the ring gear 50 and the gear rotor 60 come into direct metal contact with the housing 10.

Therefore, in this first embodiment, as shown in FIGS. 2 to 4, both end surfaces 53.
54 and both end surfaces 63 and 64 of the gear rotor 6o, Chiba lands 55 and 65 are provided in succession in the circumferential direction, respectively. The Cheebird lands 55 and 65 basically have slopes 55a and 65a having a downward slope with respect to the rotation direction of the ring gear 50 and the gear rotor 60 (arrow n direction), and tops 55b and 65b of the slopes 55a and 65a, respectively. It consists of vertical surfaces 55c and 65C extending parallel to the central axis from the top 55b of the Cheebird land 55.65,
Here, the ridge lines (contour lines) 65b extend radially from the centers 01 and 02 of the ring gear 50 and the gear rotor 60, respectively, as shown in FIG.

Since the longitudinal cross-sectional shapes of the Cheebird lands 55, 65 are substantially the same, the preferred shape of only one Cheebird land 55 will be described with reference to FIG.

The inclined surface 55a of the tapered dry ride 55 consists of a gently inclined surface 55a1 on the top 55b side and a surrounding slope 55a2 on the hem side. The steeply inclined surface 55a2 has an inclination angle β with respect to a horizontal line perpendicular to the central axis of the ring gear 50, and this i
'R oblique angle β is 0<β<9o.

Appropriately selected within the range. On the other hand, the gently inclined surface 55a1 has an inclination angle α with respect to a horizontal line perpendicular to the central axis of the ring gear 50, and this inclination angle α is appropriately selected in the range of 0°<α<β. Further, if the total length in the direction of the arrow n in an arbitrary cross section of the Chiba land 55 is 11, and at this time, the total length of the gently inclined surface 55a1 in the direction of the arrow n is 12,
The total length of Chiba Land 55! 1 is formed to have a length of, for example, about 1/24 of the circumference of the ring gear 50 at that cross-sectional position, and the total length 7!2 of the gently inclined surface 55a1 satisfies O<β.
It is formed to satisfy the relationship: 2 <0.6 zl.

Further, the boundary portion 55a3 between the gently sloped surface 55a1 and the steeply sloped surface 55a2 is rounded with a radius of, for example, about 40 to 50 μm, while the top portion 55b is rounded with a radius of, for example, 5 to 10 μm.
A roundness of about μm is given.

Further, the total height of the Chiba land 55 in the central axis direction is set to about 4 to 6 μm. The total height can be selected within a range not exceeding 50 μm, but from the viewpoint of oil leakage, it is more preferably 10 μm or less.

Therefore, when the ring gear 5o rotates in the direction of arrow n within the housing lo, both end surfaces 53 and 54 of the ring gear 5o
A wedge-shaped oil film layer is formed between each of the cheater lands 55 formed in the top and the inner wall surfaces 32, 42 of the front and rear side plates 30 and 40, and the oil, which is the compressed fluid, is always kept in the top. Birdland 55 m4 slope 55a and front and rear side plates 30.40
Since the gap between the inner wall surface 32.42 and the top 55b of the Chiba land 55 is guided by the rust action, the oil film does not run out.

Gear low cross 0 and front and rear side play) 30
．． A similar wedge cedar oil film forming action is performed between the inner wall surfaces 32 and 42 of 40.

In particular, as shown in FIG. 5, when the top 55b and boundary 55a3 of the Chiba land 55 are rounded, the occurrence of oil film failure can be further prevented. Moreover, a gentle slope 55 is provided on the slope 55a of the Chiba Land 55.
When a1 is provided, the oil film pressure of the oil film layer is further increased, so that the metal contact prevention effect is more reliably performed.

Here, the housing 10 is made of aluminum alloy. On the other hand, ring gear 50 and gear low cross 0 are 5L5C
It is made from low carbon m or gray cast iron etc.
As schematically shown in FIG. 5, a nitrided layer 55 is formed on the surface of the Chiba land 55 by soft nitriding, which is well known per se.
d is formed. Although not shown, a similar nitride layer is also formed on the surface of the other Chiever land 65.

Since a nitrided layer is formed on the surface of the Chiba lands 55, 65 by soft nitriding, the housing 10, ring gear 50, and gear rotor 60 are made more resistant to wear.

6 and 7 show a second embodiment of the present invention. In FIGS. 6 and 7, the same components as those in FIGS. 1 to 5 are given the same reference numerals.

The basic structure of the trochoid oil pump in this second embodiment is the same as that in the first embodiment, but both end faces of the ring gear 50 and the gear rotor 0 (only one end face 54, 64 is shown in the figure). ) is different from the first embodiment in the shape of each Chiever land 55,65 provided therein.

That is, in this second embodiment, inclined surfaces 55a, 65a of the same shape are symmetrically provided on both sides of the top portions 55b, 65b of each of the Chiba lands 55, 65. Also in this second embodiment, a nitrided layer 55d is formed by soft nitriding on the surface of the Chiever land 55, and a similar nitride layer is also formed on the other Chiever land 65. In this case, when the gear rotor 6o is rotated forward or backward, that is, when the trochoidal oil pump is used by switching between the suction and discharge directions of oil, the gear rotor 6o is effectively rotated in either direction. This makes it possible to prevent wear caused by metal contact between the ring gear 5o and the housing 10.

(The following is a blank space.) FIGS. 8 and 9 show a third embodiment of the present invention. In FIGS. 8 and 9, the same components as those in FIGS. 1 to 5 are given the same reference numerals.

The basic structure of the trochoidal oil pump in this third embodiment is the same as that in the first embodiment, but both end faces of the ring gear 50 and gear rotor 60 (only one end face 54, 64 is shown in the figure). ) is different from the first embodiment in the shape of each Chiever land 55,65 provided therein.

That is, in this third embodiment, the ridgelines of the tops 55b and 65b of each Chiba land 55.65 are the centers o1 and o2 of the ring gear 50 and the gear rotor 60, respectively.
It extends in a direction shifted from the direction of radiation from. To explain more clearly, the ridgeline of the top portion 65b of each Chiever land 65 in the gear rotor 60 extends in a tangential direction with respect to the inner circumference of the center hole 62 of the gear rotor 60, and each Chiever land 5 in the ring gear 50
Each of the ridgelines of the top portion 65b of 5 extends in a tangential direction to a circle (not shown) centered on the center o2. A nitrided layer is formed on the surface of the Chiba lands 55 and 65 by soft nitriding.

In the case of this third embodiment, each Cheebird land is 55.65
The height of the radial cross section of the inclined surfaces 55a and 65a gradually increases from the inner side to the outer circumferential side, so that scattering of oil in the radial direction due to centrifugal force can be suppressed. Even more oil can be retained on the inclined surfaces 55a, 65a of each Cheebird land 55.65.Moreover, the length of the ridgeline of the top 55b, 65b of each Cheebird land 55.65 is longer. Therefore, the wedge-shaped cross section between the top portions 55b, 65b and the inner surface of the housing can be increased by the increase in the ridge length.Therefore, the lubrication by the wedge-swelled oil film layer can be performed more effectively. You will be able to do this.

FIG. 10 shows a fourth embodiment of the present invention. The basic configuration of the trochoid oil pump in this fourth embodiment is the same as that in the first embodiment, but instead of providing continuous Chiever lands on both end faces of the ring gear and gear rotor, the front side plate and the rear side plate are Each of the inner wall surfaces (only the inner wall surface 42 of the barrier side plate 40 is shown in the figure) is provided with Chiever lands connected in the circumferential direction. On the inner wall 41 of the rear side plate 40, each Chiba land 44
extends over a section from the inner periphery of the drive shaft through hole 43 to the inner periphery of the center housing (not shown),
The ridgeline of the top 44b of each Chiba land 44 corresponds to the through hole 4.
It extends radially toward the center 02 of 3. The inclined surface 44b of each Chiba land 44 has an upward slope from the top 44b toward the rotational direction (direction of arrow n) of a gear rotor (not shown). Note that the cross-sectional shape of the Cheebird land 44 may be as shown in FIGS. 5 and 7. Further, the ridgeline of the top portion 44b may be formed to be tangent to the inner circumference of the through hole 43.

Front side plate and rear side plate are 31
Low carbon steel such as 5C or gray cast iron can be used to reduce the number of machining steps.

FIG. 11 shows a fifth embodiment of the present invention.
The basic configuration of the trochoidal oil pump in this embodiment is the same as that in the first embodiment, but in this fifth embodiment,
A chibered land 56 is provided continuously in the circumferential direction on the outer peripheral surface 52 of the ring gear 5o. The top 5 surface 56a of each Chiba land 56 slopes downward from the top 56b toward the rotational direction of the gear rotor (arrow n direction).

The cross-sectional shape of each Chiba land 56 may be as shown in FIGS. 5 and 7, or may be formed.

Here, the ring gear 50 is made of low carbon steel such as 515C, gray cast iron, etc.
A nitrided layer is formed on the surface of 6 by soft nitriding treatment.

FIG. 12 shows a sixth embodiment of the present invention.
The basic structure of the trochoidal oil pump in this embodiment is the same as that in the first embodiment, except that: (1) In this sixth embodiment, a chibered land 22 is arranged circumferentially on the cylindrical inner wall 21 of the center housing 20. This differs from the first embodiment in this point. The ridgeline at the top 22b of each Chiever land 22 extends parallel to the axial direction, and the inclined surface 22a of each Chiever land 22 has an upward slope from the top 22b toward the rotation direction (direction of arrow n) of the ring gear (not shown). It becomes. The cross-sectional shape of each of the top lands 22 may be as shown in FIGS. 5 and 7.
The ridgeline 2b may be formed to have an inclination angle in the circumferential direction.

FIG. 13 shows a seventh embodiment of the present invention.
The embodiment is a combination of the first embodiment and the fifth embodiment. In the figures, Figures 1 to 5 and 1
The same reference numerals as in FIG. 1 indicate the same components as in the first and fifth embodiments. In this seventh embodiment, both end faces of a ring gear 5° and a gear rotor 60 (only one end face 54, 64 of each is shown in the figure).
Cheever lands 55 and 65 are circumferentially connected to each other, and a Cheever's land 56 is circumferentially continuous to the outer circumferential surface 52 of the ring gear 5o. Arrow n indicates the rotation direction of ring gear 50 and gear rotor 60.

Here, the ring gear 50- and the gear 0-ta 6 degrees are 51 degrees.
It is made of low carbon steel such as 5C, gray cast iron, etc., and a nitrided layer is formed on the surface of each Chiba land 55°65.56 by soft nitriding treatment.

In the case of this seventh embodiment, the housing lO and the gear rotor 6
0, a wedge cedar oil film layer is formed in all the sliding gaps between the ring gear 50, etc., and each Chiba land 55,
Since a nitride layer is formed by soft nitriding on the surfaces of the housing 10 and the gear rotor 60, ring gear 50, etc., wear between the housing 10 and the gear rotor 60, ring gear 50, etc. is most effectively prevented.

Note that it is clear that various aspects of the first to sixth embodiments described above can be selected and combined as appropriate as aspects other than the seventh embodiment.

FIGS. 14 and 15 show an eighth embodiment of the present invention in which the present invention is applied to a gear type oil pump.

Referring to FIG. 14, the pump housing 110 includes a center housing 120, a front side plate 130,
and a rear side plate 140, which are fastened and fixed by bolts (not shown).

As shown in FIG. 15, one of the two gear rotors 150 and 160, which are rotating bodies, is fixed to a drive shaft 170, and the other is fixed to an idle shaft 180. An oil suction hole 121 and an oil discharge hole 122 are formed in the center housing 120 . When drive shaft 170 is rotated in the direction of arrow m in FIG. 5 by a rotational drive source (not shown), gear rotors 150 and 160 mesh with each other and rotate in the direction of arrow m and n, respectively. At this time, both end surfaces 151 and 152 of the gear rotor 150 and the gear rotor 160
Both end surfaces 161 and 162 of the front side plate 13
0 inner wall 131 and rear side plate 140 inner wall 1
41, respectively, usually 0.03 to 0. The gear rotor 150,
The tips of the teeth 160 slide against the two arcuate inner walls 123 and 124 of the center housing 120 with a clearance of usually about 0.05 to 0.20. In this case, since the gear rotors 150 and 160 may move somewhat within the housing 110, if the oil supply to the above-mentioned clearance is insufficient, the gear rotors 150 and 160 and the housing 110
Metallic contact occurs between the housing 110 and the gear rotor 150. '160 may wear out or groove-like scratches may occur along the direction of rotation.

Therefore, in this eighth embodiment, the gear rotor 150
Cheebird lands 1 are placed on both end faces 151 and 152, respectively.
53 are arranged in a row in the circumferential direction (in the figure, one end surface 15
Only 2 are shown. ), Chiba lands 16 are provided on both end surfaces 161 and 162 of the gear rotor 160, respectively.
3 are connected in the circumferential direction (in the figure, one end surface 162
only shown. ), furthermore, two arcuate inner walls 123 and 124 of the center housing 120 are provided with Chiever lands 125 and 126, respectively, which are connected in the circumferential direction.

The top 1 of each Chiba land 153 of the gear rotor 150
The ridgeline 53b extends radially from the rotation center 01 of the gear rotor 150, and the inclined surface 153a of each Chiever land 153 slopes downward from the top 153b toward the direction of the arrow m.

Furthermore, the ridgeline of the top 163b of each Chiba land 163 of the gear rotor 160 is aligned with the rotation center 02 of the gear rotor 160.
The inclined surface 163a of each Chiba land 163 slopes downward from the top 163b toward the direction of arrow n.

On the other hand, the tops 125b and 126b of each of the Chiba lands 125 and 126 in the center housing 120 extend parallel to the central axis direction, and the inclined surfaces 125a and 126a of the Chiba lands 125 and 126 are in the directions of arrows m and n, respectively. It is sloped upwards.

In the case of this eighth embodiment, since a wedge cedar oil film layer is formed in all the sliding gaps between the gear rotors 150, 160 and the housing 110, the metal contact between the gear rotors 150, 160 and the housing 110 is most effective. This will be prevented.

Further, here, the gear rotors 150, 160 and the center housing 120 are made of low carbon steel such as 315C or gray cast iron, and the surfaces of the respective Chiba lands 153, 163, 125° 126 are treated by soft nitriding. Since the nitrided layer is formed, the gear rotor 150
．． "Contact wear between 160 and housing 110 is more effectively prevented.

In addition, each Chiba land 15 in this eighth example
The cross-sectional shapes of 3,163, 125, and 126 may be as shown in FIG. 5 and FIG. The shaft attachment can be made tangential to the inner circumference of the holes 154, 164.

Furthermore, as a modification of this eighth embodiment, the gear rotor 15
0,160, the inner wall 131 of the front side plate 130 and the rear side plate 140 is
, 141 may be provided with Chiever lands in succession in the circumferential direction. In this case, the front side plate 130 and the rear side plate 140 may be made of low carbon steel such as 315C or gray cast iron, and a nitrided layer may be formed on the surface of the Chiba land by soft nitriding. Also, both end surfaces 151, 152 of the gear rotors 150, 160
, 161, 162 only, the arcuate inner walls 123, 124 of the center housing 120, or the inner walls 131,
The intended purpose of the present invention can also be achieved by forming a Chiever's land only on each of the Chiever's lands and forming a nitrided layer by soft nitriding on the surface of the Chiever's land.

16 and 17 show a ninth embodiment of the present invention in which the present invention is applied to a talent type oil pump. Referring to FIG. 16, the pump housing 210 has a center housing 220, a front side plate 23
The center housing 220, the front side plate 230, and the rear side plate 240 are fastened and fixed by bolts (not shown), and the crescent member 250 is connected to the rear side plate 240 here. It is formed in one piece.

The center housing 220 has a cylindrical inner wall 221, and a ring gear 260, which is a first rotating body, is rotatably fitted inside the center housing 220. 26
A gear rotor 270, which is a second rotating body that meshes with the gear rotor 1, is provided so as to be eccentrically rotatable. A drive shaft 280 fixed to the gear rotor 270 passes through the rear side plate 240 and extends to the outside. In FIG. 17, reference numeral 231 indicates an oil suction hole 231 provided in the front side plate 230, and reference numeral 241 indicates an oil discharge hole provided in the rear side plate 240.

When drive shaft 280 is rotated in the direction of arrow n in FIG. 17, gear rotor 270 rotates around center 02 while being partially engaged with ring gear 260, and ring gear 260 rotates around center 01. During this time, both end surfaces 262 and 263 of the ring gear 260 are connected to the inner wall 232 of the front side plate 230 and the rear side plate 230.
Normally 0.03 to 0.1 for each inner wall 242 of 0.0
The outer circumferential surface of the ring gear 260 and the tooth tips of the internal teeth 261 are connected to the inner wall 221 of the center housing 220 and the crescent-shaped member 25.
Usually 0.05 to 0.0 for the outer wall surface 251 of 0.0.
It slides with a clearance of about 20m. On the other hand, both end surfaces 271 and 272 of the gear rotor 270 are connected to the inner wall 232 of the front side plate 230 and the inner wall 242 of the rear side plate 240, respectively.
．． It slides with a clearance of about 10m, and
The tooth tip surface of the external teeth 273 of the gear rotor 270 is usually 0.05 to 0.20 relative to the inner wall surface 252 of the crescent-shaped member 250.
It slides with a clearance of approximately fi. in this case,
Gear rotor 270 and ring gear 260 are connected to housing 2
10, so if the above-mentioned clearance is not sufficiently supplied with oil, metal contact will occur between the ring gear 260, gear rotor 270, etc. and the housing 210, and the housing 210, the ring gear 260, and the gear rotor 270 will wear out. Otherwise, it may cause groove-like scratches to occur along the rotation direction.

Therefore, in this ninth embodiment, the ring gear 260
0 on both end faces 262 and 263, respectively
65 are arranged in a row in the circumferential direction (in the figure, one end surface 26
Only 3 are shown. ), Chiba lands 27 are provided on both end surfaces 271 and 272 of the gear rotor 270, respectively.
4 are connected in the circumferential direction (in the figure, one end surface 27
Only 2 are shown. ), also ring gear 2
A Chiever's land 26.6 is continuous in the circumferential direction on the outer peripheral surface 264 of the crescent-shaped member 250, and Chiever's lands 253 and 254 are formed on the outer wall surface 251 and the inner wall surface 252 of the crescent-shaped member 250, respectively.

Here, ring gear 260. The gear rotor 270, rear side plate 240, and crescent-shaped part shrine 250 are 315
It is made of low carbon steel such as C or gray cast iron,
Chiba Land 265, 266.274, respectively.
A nitrided layer is formed on the surfaces of 253 and 254 by soft nitriding.

The ridgeline of the top 265b of each Cheebird land 265 on both end surfaces 262, 263 of the ring gear 260 extends radially from the center 01, and the inclined surface 265a of each Cheebird land 265 slopes downward from the top 265b in the direction of arrow n. It becomes.

The tops 274b of each of the Chiba lands 274 on both end surfaces 271 and 272 of the gear rotor 270 extend radially from the center 02, and the slopes 274 of each Chiba lands 274 extend radially from the center 02.
a slopes downward from the top 274b in the direction of arrow n. Furthermore, the top portion 266b of each Cheebird land 266 on the outer peripheral surface 264 of the ring gear 260 extends parallel to the central axis direction, and the inclined surface 266a of each Cheebird land 266 slopes downward from the top portion 266b toward the direction of arrow n. It has become. Furthermore, the top portion 253 of each Chiba land 253 on the outer wall surface 251 of the crescent-shaped member 250
The ridge line b extends parallel to the central axis, and the inclined surface 253a of each Chiba land 253 slopes upward in the direction of arrow n toward the top 253b. In addition, each Chiba land 25 on the inner wall surface 252 of the crescent-shaped member 250
The top portion 254b of each Chiba land 254 extends parallel to the central axis, and the slope 254a of each Chiba land 254 extends parallel to the top portion 254b.
It slopes upward in the direction of arrow n.

In the case of the ninth embodiment, since a wedge-shaped swelling oil film layer is formed in all the sliding gaps between the ring gear 260, gear rotor 270, etc. and the housing 210, the ring gear 260,
Metallic contact between the gear rotor 270 and the housing 210 is most effectively prevented. In addition, a nitrided layer is formed on the surface of the Chiba lands 265° 266, 274, 253, 254 by soft nitriding treatment, so that the ring gear 260, gear rotor 270, etc. and the housing 21
The occurrence of wear and scratches between the rotary body and the housing can be better prevented, and the secondary effect is that the clearance between the rotating body and the housing can be made smaller. Thereby, the amount of oil leakage can be reduced and pump efficiency can be increased. For example, this clearance may be reduced from the conventional clearance to about 20 μm on the side plate side, or may be reduced to about 10 to 5 μm if the machining accuracy is good, such as in an oil pump for an internal combustion engine. Furthermore, if machining accuracy and cost permit, the clearance can be reduced to a minimum oil film thickness of approximately 1 μm.

In addition, each Chiba land 25 in this ninth embodiment
The cross-sectional shape of 3,254,265,266.274 is the fifth
The top portion 265b of each of the Chiever lands 265, 274 provided on both end surfaces 262, 263 of the ring gear 260 and both end surfaces 271, 272 of the gear rotor 270, 274
The edge line b may be formed to be tangent to the reference circle.

Furthermore, as a modification of this ninth embodiment, the ring gear 26
0 and both end surfaces 271, 272 of the gear rotor 270, respectively.
274, the front side plate 23
0 and the inner walls 232, 242 of the rear side plate 240
Chiever lands may be arranged in succession in the circumferential direction, respectively, and a nitrided layer may be formed on the surface of the Chiever lands by soft nitriding treatment. In addition, the outer peripheral surface 2 of the ring gear 260
Instead of providing the Chiever's land 266 on the center housing 220, the Chiever's land 266 may be provided in a circumferential direction on the cylindrical inner wall 221 of the center housing 220, and a nitride layer may be formed on the surface of the Chiever's land by soft nitriding. good.

Furthermore, only both end surfaces of the ring gear 260 and gear rotor 270, front and rear side plays) 230, 2
40, only on the outer circumferential surface of the ring gear 260, or only on the inner wall of the center housing 220, and a nitrided layer is formed on the surface of the Chiever land by soft nitriding. The intended purpose of the invention is achieved.

FIG. 18 shows the test results of the anti-wear effect of the housing according to the present invention. In the figure, A is the test result of the trochoid type oil pump, B is the test result of the gear type oil pump, and C is the test result of the talent type oil pump. In the figure, (1) shows the test results for a conventional configuration in which a wedge-shaped oil film layer is not formed in the sliding gap between the rotating body and the housing, and (2) ) shows the test results according to an embodiment of the present invention in which a Chivord land is formed on both end faces of the rotating body and a nitrided layer is formed by soft nitriding on the surface of the Chievered land, and (3) shows the test result on the outer periphery of the rotating body. The test results are shown according to another embodiment of the present invention in which a nitrided layer was formed on the surface of the Chiba land by soft nitriding treatment, and (
4) is a test according to yet another embodiment of the present invention in which Chivord lands were formed on both end faces of the rotating body and the outer peripheral surface of the rotating body, and a nitrided layer was formed by soft nitriding on the surface of each Chieverd land. No results shown.

The test conditions were gear rotor rotation speed = 300, O
r, p, m, pump operating time: 100 tlr1 Oil temperature during operation: 80°C, oil type: SAE 30, gear rotor material: 315G, housing material: 80C12 (aluminum alloy). Further, the clearance between both end surfaces of the rotating body and the inner wall of the housing was 0.05 mm, and the clearance between the outer peripheral surface of the rotating body and the inner wall of the housing was 0.12 mm. Soft nitriding is degreasing,
After washing, it is preheated, immersed in a salt bath, taken out, cooled, and washed. The immersion was carried out at a salt bath temperature of 570° C. and an immersion time of 90 minutes.

As is clear from FIG. 18, the amount of wear on the housing in the configurations (2) to (4) of the present invention is reduced compared to the conventional configuration fil. In particular, the wear prevention effect in the case of configuration (4) is remarkable.

In addition, we tried adding a sulfurized layer, a carbonitrided layer, a carburized layer, a quenched layer to low carbon chrome steel, etc., and the effects were found in all cases. These treated layers can be regarded as a hard surface layer together with the previous nitrided layer. The hard surface layer is most preferably a nitrided layer formed by soft nitriding.

As is clear from the test results above and beyond the effects of the invention, according to the present invention, by forming a wedge-shaped swelling oil film layer due to Chiever lands in the sliding gap between the housing and the rotating body of a rotary oil pump, Since it becomes possible to effectively prevent the oil film from running out between the housing and the rotating body, metal contact between the housing and the rotating body can be reduced.

In addition, since a hard surface layer is formed on the surface of the Cheever Land, it is possible to more effectively reduce the wear between the housing and the rotating body, and it is possible to prevent groove-like scratches in the direction of rotation. occurrence can be reduced. As a result, it is possible to prevent a decrease in pump efficiency and the generation of noise, and it is also possible to prevent seizure inside the pump, providing a rotary oil pump that maintains stable pump performance over a long period of time. It becomes possible.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing a first embodiment of the present invention when the present invention is applied to a trochoidal oil pump, FIG. 2 is a cross-sectional view taken along line nn in FIG. 1, and FIG. FIG. 1 is a side view of the gear rotor in the first embodiment shown in FIG. 1, FIG. 4 is a side view of the ring gear in the first embodiment shown in FIG. 1, and FIG. 5 is an enlarged cross section taken along line nn in FIG. 6 is a plan view of a main part showing a second embodiment of the present invention when the present invention is applied to a trochoid type oil pump, and FIG. 7 is a plan view of main parts shown in FIG.
FIG. 8 is an enlarged cross-sectional view taken along the line, FIG. 8 is a plan view of main parts showing a third embodiment of the present invention when the present invention is applied to a trochoid type oil pump, and FIG. 9 is a third embodiment shown in FIG. 8. Fig. 10 is a bottom view of the main part showing a fourth embodiment of the present invention when the present invention is applied to a trochoid type oil pump;
FIG. 11 is a cross-sectional view of main parts showing a fifth embodiment of the present invention when the present invention is applied to a trochoid type oil pump;
The figure is a plan view of essential parts showing a sixth embodiment of the present invention when the present invention is applied to a trochoid type oil pump, and Fig. 13 is a seventh embodiment of the present invention when the present invention is applied to a trochoid type oil pump. FIG. 14 is a vertical sectional view showing an eighth embodiment of the present invention when the present invention is applied to a gear type oil pump, and FIG. 15 is a cross-sectional view showing the main parts of an example.
, FIG. 16 is a longitudinal sectional view showing a ninth embodiment of the present invention when the present invention is applied to a crescent type oil pump, and FIG. 17 is a cross-sectional view taken along line X-X in FIG. 16. FIG. 18, which is a sectional view taken along the line, is a graph showing the wear prevention effect of the housing according to the present invention in comparison with that of the prior art. io, ito, 2io-housing, 50, 60.
150.160.260.270-Rotating body, 3L 12
1.231--Oil suction hole, 41, 122.241
-・-Oil discharge hole, 22, 44.55.56.65.
125.126.153.163゜253, 254.2
65.266, 274--Cheever Land, 55d-
nitride layer. Figure 34Figure 5Figure 6Figure 7Figure 8Figure 9Figure 55a 55bFigure 12Figure 16Figure ■DFigure 17

Claims (1)

[Claims] 1. A housing having an oil suction hole and an oil discharge hole, and a rotating body that rotates within the housing while slidingly contacting the inner wall of the housing, and as the rotating body rotates, the oil suction hole opens. In a rotary oil pump that sucks oil into a pump operating space in a housing and discharges it from an oil discharge hole, a chie bar is installed on either the inner wall of the housing or the sliding surface of the rotating body that slides on the inner wall. A rotation characterized in that a wedge-shaped cedar oil film layer is formed between the inner wall of the housing and the sliding surface of the rotating body by consecutively providing lands, and a hard surface layer is formed on the surface of the Chiba land. type oil pump. 2. The rotary oil pump according to claim 1, wherein the hard surface layer is a nitrided layer formed by soft nitriding treatment.