Vane pump with annular ring and cylindrical slide as vane guide

Abstract

A vane pump in which a projection is provided on the end of a vane which radially slides as a rotor rotates, and an annular race concentric with an inner peripheral surface of a housing is provided in the inner surface of the end wall of the housing, the projection being brought into engagement with the annular race to control the slide of the vane.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a vane pump which is one of rotary pumps used for various kinds of apparatuses such as a supercharger of an engine, a compressor of a freezing cycle, and the like.

A vane pump schematically shown in FIG. 8 has been heretofore widely known.

In FIG. 8, reference numeral 101 designates a housing; 102, a rotor inserted eccentrically into an inner peripheral space of the housing 101 and rotatably supported by a rotational shaft 103; 105a, 105b and 105c, plate-like vanes disposed radially retractably from vane grooves 104a, 104b and 104c equally spaced apart so as to peripherally divide the outer peripheral side of the rotor 102 into three sections. When the rotor 102 is rotated in the direction as indicated by the arrow X by the rotational shaft 103, the vanes 105a, 105b and 105c are moved out in the direction of the outside diameter by the centrifugal force, and the end edges thereof rotate while slidably contacting the inner peripheral surface of the housing 101. Since the rotor 102 is eccentric with respect to the housing 101 as previously mentioned, as such rotation occurs, volumes of working spaces 106a, 106b and 106c defined by the housing 101, the rotor 102 and the vanes 105a, 105b and 105c are repeatedly enlarged and contracted to allow a fluid taken in from an intake port 107 to be discharged out of an outlet port 108.

However, the above-described conventional vane pump has problems that since the vanes slidably move along the inner peripheral surface of the housing at high speeds, the efficiency of the volume caused by the great power loss due to the sliding resistance and by the generation of high sliding heat unavoidably deteriorates; the vanes materially become worn; and the vanes are expanded due to the generation of sliding heat to produce a galling with the inner side surfaces of both end walls of the housing, and the like.

In view of these problems as noted above, it is an object of the present invention to enhance the efficiency of such a pump and enhance the durability thereof.

SUMMARY OF THE INVENTION

To achieve the aforementioned objects, a vane pump according to the present invention is characterized in that projections such as pins having cylindrical sliding members disposed thereon are provided on both ends of a vane, and an annular race in peripheral slidable engagement with the projections to define the protrusion of the vane from a vane groove is formed coaxially with the inner peripheral surface of the housing.

According to the present invention, the protrusion of the vane from the vane groove is not defined by the contact thereof with the inner peripheral surface of the housing, but it is defined in a manner such that the end edge of the vane depicts a certain locus by the engagement of the projections such as pins and sliding members provided on the vane with the annular race formed on the side of the housing. The vane may be rotated in the state in which the vane is not in contact with the inner surface of the housing, and therefore, the present invention has excellent advantages which can prevent the deterioration of the efficiency of the pump caused by the sliding resistance and the wear of the vane; and which can prevent occurrence of inconvenience resulting from an increase in sliding heat.

While the present invention has been briefly outlined, the above and other objects and new features of the present invention will be fully understood from the reading of the ensuing detailed description in conjunction with embodiments shown in the accompanying drawings. It is to be noted that the drawings are exclusively used to show certain embodiments for the understanding of the present invention and are not intended to limit the scope of this invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a vane pump according to a fundamental embodiment of the present invention;

FIG. 2 is a sectional view showing the pump of FIG. 1 assembled;

FIG. 3 is a side view of a rotor of the same pump of FIG. 1;

FIG. 4 is a perspective view of essential parts of a vane pump belonging to an embodiment of the invention;

FIG. 5 is a side view of the vane of the same pump shown in FIG. 4;

FIG. 6 is an exploded perspective view of the vane of the pump belonging to another embodiment of the invention;

FIG. 7 is a side view of a rotor of the same pump shown in FIG. 6; and

FIG. 8 is a sectional view showing one example of a vane pump according to the prior art;

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A fundamental exemplification of a vane pump according to the present invention will now be described with reference to FIGS. 1 to 3.

In FIGS. 1 and 2, a front housing 1 and a rear housing 2, both of which housings are made of non-ferrous metal such as aluminum, which is light in weight and is small in the coefficient of thermal expansion, are secured integral with each other by means of bolts 3. A rotor 4 made of iron eccentrically inserted into an inner peripheral space 5 of the housing is extended through both the housings 1 and 2 through a ball bearing 7a held by a fixed ring 6 in anti-slipout fashion in an axial shoulder of the front housing 1 and a ball bearing 7b held by a bearing cover 8 in anti-slipout fashion in an axial shoulder of the rear housing 2 and is rotatably mounted on a rotational shaft 10 to which a drive force is transmitted from a pulley 9. Plate-like vanes 11a, 11b and 11c principally made of a carbon material having an excellent slidability are disposed to be radially projected and retracted in vane grooves 12a, 12b and 12c, respectively, which are formed in the form of depressions equally spaced apart so as to peripherally divide the outer peripheral side of the rotor 4 into three sections, on the rotor 4. On opposite ends of each of the vanes 11a, 11b and 11c corresponding to axial opposite sides of the rotor 4 are projected steel pins 13 and 13, respectively, and a sleeve bearing 14 made of resin having excellent slidability and abrasion resistance is slipped over each of pins 13. In annular recesses 15a and 15b formed in inner surfaces 1' and 2' of end walls where the front housing 1 and the rear housing 2 are opposed to each other coaxial with the inner peripheral space 5 of the housing (coaxial with the inner peripheral surface 1" of the front housing 1), retainer rings 16a and 16b made of non-ferrous metal such as aluminum and each having an annular race 17 are rotatably fitted through ball bearings 18a and 18b, respectively. The pins 13 and 13 projected on the respective vanes 11a, 11b and 11c peripherally slidably engage the annular races 17 and 17 of the retainer rings 16a and 16b through the respective sleeve bearings 14. This engagement defines the radial movement of the vanes 11a, 11b and 11c during rotation so as to maintain a state in which there is formed a slight clearance between the end edges 11a', 11b' and 11c' (see FIG. 3) thereof and the inner peripheral surface 1" of the front housing 1. An intake port 19 for guiding a fluid into the inner peripheral space 5 of the housing from the exterior of the pump and an outlet port 20 for guiding a fluid to the exterior from the inner peripheral space 5 of the housing are formed in the rear housing 2. Reference numerals 21, 21 designate tubes mounted on the intake port 19 and outlet port 20, respectively; 22 a bolt used to secure the bearing cover 8 to the rear housing 2; and 23, a nut in engagement with an external thread 10' of the end of the rotational shaft 10 in order to secure the pulley 9 to the rotational shaft 10.

The operation of the above-described vane pump will be described hereinafter. When the rotational shaft 10 and rotor 4 are rotated by the drive force from the pulley 9, the vanes 11a, 11b and 11c also rotate, and the pins 13 and 13 projected on the vanes 11a, 11b and 11c, respectively, and the sleeve bearings 14 and 14 slipped over the pins 13 and 13 rotate along the annular races 17 and 17. Since as shown in FIG. 3, the inner peripheral surface 1" of the housing and the annular race 17 are in coaxial relation and the annular race 17 and the rotor 4 are in eccentric relation, the vanes 11a, 11b and 11c are radially slidably moved in the vane grooves 12a, 12b and 12c of the rotor 4 to be projected and retracted repeatedly with the result that the volumes of the working spaces 5a, 5b and 5c defined by both the housings 1, 2, and rotor 4 and the vanes 11a, 11b and 11c repeatedly increase and decrease. That is, in FIG. 3, the working space 5a, with the rotation, increases its volume to suck the fluid from the intake port 19 (not shown; see FIG. 1) opening to portion 5a; the working space 5c, with the rotation, decreases its volume to discharge the fluid into the outlet port 20 (not shown; see FIG. 1) opening to portion 5c; and the working space 5b transfers the thus sucked fluid toward the outlet port 20. In the above-described operation, the end edges 11a', 11b' and 11c' of the vanes 11a, 11b and 11c are not in sliding contact with the inner peripheral surface 1" of the front housing, as previously mentioned, and therefore, abrasion or high heat hardly occurs. In addition, the sleeve bearing 14 slipped over the pin 13 is slidably rotated while being pressed against the outside diameter side by the centrifugal force within the annular race 17 of the retainer rings 16a and 16b while the retainer rings 16a and 16b follow the sleeve bearing 14 for rotation because the former are in the state to be rotatable by the ball bearings 18a and 18b, respectively. The relative sliding speed between the sleeve bearing 14 and the annular race 17 is low whereby the abrasions of annular race 17, retainer rings 16a and 16b, the sleeve bearing 14 and the like can be minimized.

It is believed that the fundamental mode of the present invention is now fully understood from the above-described description. The pump of the first embodiment shown in FIGS. 1 to 3 constitutes, in a sense, the core of the variations described below.

A vane pump according to the following embodiments has a vane for a pump characterized in that a vane body and the aforesaid projections are formed integral with each other of the same material. An object of the following embodiment is to enhance the strength between the vane and the projections and reduce the weight of the vane, similarly to the types 1 and 2.

According to the vane for the pump of the following embodiment, no local residual stress or stress concentration between the vane body and the projections is encountered, as in the case in which the vane body and the projections are formed from separate members, and they are joined together by fitting or the like, and the weight of the vane is small as compared to the case in which the projections are formed from metal rods fitted into the vane body.

One example of such van pump will now be described with reference to the drawings.

First, in FIG,. 4, vane indicated at 11 are disposed to be radially projected from and retracted into vane grooves 12, respectively, which are equally divided into there sections in a rotor 4 rotatably supported, in eccentric fashion, within a housing not shown, the vanes being formed of an iron sheet, light-weight non-ferrous metal such as aluminum, resine or the like, and prismatic projections 38 are projectingly molded integral with opposite ends in a longitudinal direction of the vane body taking the form of a plate. Sliding members indicatedx at 39 each having an approximately cylindrical contour are externally fitted at cutouts 40 having a ]-shaped section in the projections 38, respectively, the sliding members being formed of resins having excellent self-lubricating properties and abrasion resistance. A retainer ring indicated at 16 is rotatably mounted through a ball bearing not shown on each of the inner surfaces of the housing opposed to each of the end surfaces of the rotor 4 in the state in which the retainer is coaxial with the inner peripheral surface of the housing, in other words, it is eccentric at A with the rotor 4. The sliding members 39 externally fitted on the projections 38 of the vanes 11, respectively, peripherally slidably engage the annular races 17 formed in the opposed end of the retainer rings 16, whereby the protrusion of the vanes 11 from the vane grooves 12 caused by the centrifugal force during rotation are defined, and the vanes 11 are radially projected and retracted and rotated in the state of non-contact with the inner peripheral surface of the housing.

According to the aove-described arrangement, since the vane body of the vane 11 is molded integral with the projections 38, the local stress concentration caused by the load during rotation hardly occurs, and the weight of the vane is small. Therefore, the projections 38 can sufficiently support the vane body even during rotation at high speeds. As the vanes 11 rotate, the sliding members 39 smoothly slidably move along the peripheral wall 17' (shown in FIG. 5) on the outer peripheral side of the annular race 17, but the amount of slidable movement thereof is small because the annular race 17 (the retainer ring 16) is also synchronously rotated by the sliding contact therebetween.

Next, the FIG. 6 arrangement is characterized in that projections 38 provided on opposite ends in a longitudinal direction of a vane body are formed into a cylindrical configuration, and sliding members 39 are formed into a somewhat elongated configuration having arched surfaces 39a and 39b; since an angle of the vane 11 to the annular race 17 is repeatedly varied within a predetermined range with rotation as shown in FIG. 7, the sliding members 39 are slipped over the projections 38 at circular holes 41 bored in the sliding members 39, respectively, to thereby enable relative oscillation with respect to the vane 11.

According to the aforesaid arrangement, the arched surface 39a of the sliding member 39 comes into contact with the paripheral wall 17' of the annular race 17 by virtue of the centrifugal force during rotation, and the contact area is large so that the annular race 17 (the retainer ring 16) may be smoothly rotated along therewith at the start. Moreover, since the pressing force per unit area in the contact surface lowers, mutual abrasion is also suppressed.

A described above, according to the above-described vane for the pump, the vane body and the projections to define the protrusion of the vane caused by the centrifugal force, by engagement with the annular race rotatably provided on the side of the housing, thereby enhance the supporting force of the projections with respect to the vane body and reduce the weight of the vane. Thereby, the pump may be run at high spees, thus providing the excellent effects of realization of the miniaturization and reduction in weight of the pump.

While we have described the preferred embodiment of the present invention, it will be obvious that various other modifications can be made without departing from the principle of the present invention. Accordingly, it is desired that all the modifications that may substantially obtain the effect of the present invention through the use of the structure substantially identical with or corresponding to the present invention are included in the scope of the present invention.

This application incorporates herein the disclosures of U.S. Ser. No. 075,006, filed Jul. 17, 1987; U.S. Ser. No. 110,919 filed Oct. 21, 1987; U.S. Ser. No. 113,568 filed Oct. 26, 1987; and U.S. Ser. No. 115,677 filed Oct. 30, 1987.

Claims

1. A rotary machine for handing a fluid comprising a housing means having a rotor chamber, said rotor chamber having an inner peripheral surface, a rotor means rotatably mounted in said rotor chamber, said rotor means having a rotor axis, said inner peripheral surface having a central axis which is eccentrically disposed relative to said rotor axis, said rotor means having a plurality of generally radially disposed vane slots, a plurality of vane means slidably mounted in said vane slots and operable to define variable volume chamber for said fluid as said rotor means rotates and said vane means move generally radially in and out of sand vane slots, said housing means having housing end walls which define longitudinal ends of said rotor chamber, annular recesses in said housing end walls coaxial with said central axis, annular ring means rotatable in said annular recesses about said central axis, an annular channel in each of said ring means coaxial with said central axis, said vane means having longitudinal vane end walls, projection means projecting from said vane end walls, said projection means extending into said annular channels, said projection means comprising projecting vane parts integrally formed with said vane means and projecting from said vane end walls, said projecting vane parts having a radially outer wall extending generally perpendicular to said vane end walls, said projection means further comprising a sliding member having an outer cylindrical wall and a U-shaped cutout opening up on to said cylindrical wall, said annular channel in said ring means having a radial width, said outer cylindrical wall of said sliding member having a diameter substantially equal to said radial width of said annular channel, said U-shaped cutout having a bottom wall, said U-shaped cutout receiving said projecting vane part with said radially outer wall of said projecting vane part being juxtaposed to said bottom wall of said cutout such that said U-shaped cutout opens up radially inwardly toward said rotor axis, whereby during rotation of said rotor means, the resulting centrifugal force urges said vane means radially outwardly of the respective vane slot such that said sliding member engages said channel to limit the extent of outward radial movement of said vane means from its respective vane slot to preclude sliding contact between said vane mans and said inner peripheral surface of said housing means, said ring means being rotated in approximate synchronism with said rotor means by the frictional contact between said sliding member and said channel in said ring means.

2. A rotary machine for handling a fluid comprising a housing means having a rotor member, said rotor chamber having an inner peripheral surface, a rotor means rotatably mounted in said rotor chamber, said rotor means having a rotor axis, said inner peripheral surface having a central axis which is eccentrically disposed relative to said rotor axis, said rotor means having a plurality of generally radially disposed vane slots, a plurality fo vane means slidably mounted in said vane slots and operable to define variable volume chambers for said fluid as said rotor means rotates and said vane means move generally radially in and out of said vane slots, said housing means having hosuing end walls which define longitudinal ends of said rotor chamber, annular recesses in said housing end walls coaxial with said central axis, annular ring means rotatable in said annular recesses about said central axis, an annular channel in each of said ring means coaxial with said central axis, said vane means having longitudinal vane end walls, projection means projecting from said vane end walls, said projection means extending into said annular channels, said projection means comprising projecting vane parts projecting from said vane end walls, said projection means further comprising a sliding member having an outer cylindrical wall and a U-shaped cutout which opens up onto said outer cylindrical wall, said annular channel in said ring means having a radial width, said outer cylindrical wall of said sliding member having a diameter substantially equal to said radial width of said annular channel, said sliding member being disposed on said projecting vane part, said U-shaped cutout having means cooperable with said projecting vane part to preclude relative rotation between said sliding member and said projecting vane part, said U-shaped cutout opening up radially inwardly toward said rotor axis such that said sliding member is thereby slidable radially outwardly on said vane part, whereby during rotation of said rotor means, the resulting centrifugal force urges said vane means radially outwardly of the respective vane slot such that said sliding member engages said channel to limit the extent of outward radial movement of said vane means from its respective vane slot to preclude sliding contact between said vane means and said inner peripheral surface of said housing means, said ring means being rotated in approximate synchronism with said rotor means by the frictional contact between said sliding member and said channel in said ring means.