Vane pump with sliding members on axial vane projections

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.

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. 21 has been heretofore widely 
known. 
In FIG. 21, 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 sliding 
members rotatably mounted 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.

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 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, the 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. 
FIG. 4 shows a mode different from the above-described first embodiment 
with respect to the technique in which projections are provided on the 
vane. 
That is, in FIG. 4, cylindrical pins 13 made of iron or non-ferrous metal 
are embedded at positions one-sided on parts which form the inside 
diameter side in the state incorporated into the rotor 4 of opposite ends 
11" and 11" of a plate-like vane 11 which is made of carbon or the like 
and in which end edges 11' which form the outside diameter side in the 
state incorporated into the rotor 4 are formed into an arc. Alternatively, 
as shown in FIG. 5, a lengthy pin 13 is extended through and secured to 
the vane 11, and opposite ends of the pin 13 are projected; as shown in 
FIG. 6, pins 13 and 13 are embedded into the vane 11 and integrally 
provided by welding or the like on opposite ends of a plate-like 
reinforcing member 24 made of iron or non-ferrous metal such as aluminum; 
or as shown in FIG. 7, pins 13 and 13 are housed in tubular bodies 25 and 
25 formed on opposite ends of a reinforcing member 24. 
Several modes of embodiments of the present invention variously elaborated 
on the basis of the design of the pump according to the aforementioned 
first embodiment shown in FIGS. 1 to 3 will be discussed below. 
Type 1 
A vane pump belonging to the type 1 is characterized by having a vane 
wherein a vane body is coated with a non-lubricated sliding material using 
a metal plate having a required number of punched portions as a core, and 
projections are integrally secured to or integrally formed on the metal 
plate. 
In the vane pump according to the aforementioned first embodiment, a great 
outward force caused by a centrifugal force exerts on the pin which is a 
projection to define the protrusion of the vane and the fixed portion 
between the pin and the vane, and therefore the strength of the fixed 
portion and the reduction in weight of the vane need be taken into 
consideration. 
For this reason, an object of the aforesaid type 1 is to enhance the 
strength between the vane and the projection and reduce the weight of the 
vane. 
In the vane of the pump belonging to this type 1, the projection is 
integral with the metal plate as the reinforcing core, and the base of the 
projection on the side of the metal plate is coated with non-lubricated 
sliding material, and therefore the strength is great. In addition, since 
the metal plate has the punched portions thus considerably reducing the 
weight, and the non-lubricated sliding materials on both sides of the 
metal plate are fused to each other through the punched portions, the 
strength of the vane body itself also increases. 
One example of the vane belonging to the type 1 will be described below 
with reference to the drawings. 
Referring first to FIG. 8, reference numeral 11 designates a plate-like 
vane body coated with a non-lubricated sliding material 26 having 
excellent self-lubricating properties such as resins, molded carbon, etc. 
using a metal plate 27 made of steel or non-ferrous metal such as aluminum 
having a plurality of circular punched portions 28 as a core, and 
reference numeral 13 designates pins which are projections projected from 
opposite ends of the vane body 11. A base 13a of the pin 13 is caulked to 
one long side 27a of the metal plate 27 and is made integral with the 
metal plate 27 by applying spot welding at 29 to suitable points of the 
caulked portion. 
Modes of the fixed portion between the pin 13 and the metal plate 27 
include an arrangement as shown in FIG. 9 in which a base (not shown) of a 
pin 13 is joined to a groove 30 formed in the vicinity of one long side 
27a of the metal plate 27, and the base and the groove 30 are joined by 
spot welding at 29 at suitable points; an arrangement as shown in FIG. 10 
in which a base 13a of a pin 13 is joined to a trough portion 31 formed 
integral with one long side 27a of a metal plate 27, and the base 13a and 
the trough portion 31 are joined by spot welding at 29 at suitable points; 
an arrangement as shown in FIG. 11 in which a punched portion 28 of a 
metal plate 27 is formed into a square, and one long side 27a of the metal 
plate 27 and a base 13a of a pin 13 are applied with spot welding at 29 
from one edge 28a of the punched portion 28; and an arrangement as shown 
in FIG. 12 in which one long side 27a is interiorly formed with a pin 
receiving hole 32 from both ends 27h of a metal plate 27, and a pin 13 is 
hammered into the hole. 
In addition, the pin 13 and the metal plate 27 may be integrally molded by 
molding means such as casting or forging as shown in FIGS. 13 and 14. The 
shape of the punched portion 28 has various modifications such as circular 
shapes as in FIGS. 8 to 10 and 12, a square shape as in FIG. 11, a cutout 
shape as in FIG. 13, and a triangular shape as in FIG. 14. Other shapes 
such as an oblong shape, a shape with a large number of pores, etc. may be 
used. 
As described above, according to the vane for the pump described above, the 
supporting force against the protrusion of the vane during rotation by the 
projections on the opposite ends of the vane is strengthened, and 
therefore high-speed rotation becomes possible to enhance the feed force 
of the fluid under pressure. Accordingly, the pump may be miniaturized and 
reduced in weight. Furthermore, the metal plate serving as the core of the 
vane has the punched holes to suppress the increase in weight of the vane 
and the increase in the centrifugal force acting on the vane. Moreover, 
the non-lubricated sliding materials coated on both sides of the metal 
plate become fused to each other through the punched portions, and 
therefore the strength of the vane body itself also increases, thus 
providing a significant practical effect. 
Type 2 
A vane pump belonging to this type 2 has a vane for a pump characterized in 
that a cavity such as a cutout is formed in the base of the vane, mounting 
holes are made coaxially to each other in sleeves which are located on 
opposite sides of the cavity in a longitudinal direction, and projections 
of a single pin are inserted into the mounting holes, respectively. An 
object of the type 2 is, likewise to type 1, to enhance the projections 
and the fixed portion between the projections and the vane. 
In the vane of the pump belonging to the type 2, the projections on the 
opposite ends of the vane are in the form of a single rod, and therefore, 
there is no local stress concentrated on the fixed portion relative to the 
vane (the fitted portion to the mounting hole), and the supporting force 
against the protrusion of the vane is enhanced. In addition, since the 
mounting holes through which the pin extends are divided by the cavity, a 
drilling process may be executed with high accuracy as compared to the 
case in which a single mounting hole passing through and between the 
opposite ends of the vane is bored, and in addition, the weight of the 
vane is reduced through a portion of the cavity. 
One example of the vane belonging to the type 2 will be described below 
with reference to the drawings. 
First, in FIG. 15, a vane indicated at 11 is formed of a non-lubricated 
sliding material such as resin or molded carbon having excellent self 
lubricating properties, and a cutout 33 is made in the central portion of 
the base 11'" of the vane 11 to form a cavity 34. Mounting holes 36 are 
coaxially bored in sleeves 35 and 35, respectively, on opposite sides in a 
longitudinal direction of the cutout 33. Reference numeral 13 designates a 
single rod-like pin inserted into and secured in the mounting holes 36 and 
36, and opposite ends of the pin 13 projecting from the sleeves 35 and 35 
constitute projections, which peripherally slidably engage the annular 
race (see the number 17 of FIGS. 1 and 2) on the side of the pump housing 
to define the protrusion of the vane 11 during rotation. 
Next, in FIG. 16, a window portion 37 is provided in the vicinity of the 
base 11'" in place of the cutout 33 shown in FIG. 15 to form a cavity 34, 
and other structures of FIG. 16 are similar to those shown in FIG. 15. 
In the FIGS. 15 and 16 structure, local stress concentration hardly occurs 
between the vane 11 which tends to be moved out by the centrifugal force 
during rotation and the pin 13 to define it, as previously mentioned. 
Since each of the mounting holes 36 is short, their working may be carried 
out easily and with high accuracy, and the weight of the vane 11 is 
reduced through the portion of the cavity 34. 
It is to be noted that the cavity 34 is subsequently filled with resins or 
the like whereby the fixing strength between the vane 11 and the pin 13 
may be further increased. 
As described above, according to the above-described vane, the fixing 
strength between the projections (pins) provided on the opposite ends of 
the vane and the vane is high to increase the supporting force against the 
protrusion of the vane during rotation, and therefore, high speed rotation 
becomes possible to enhance the feed force of the fluid under pressure. 
Accordingly, the pump may be miniaturized and reduced in weight. Moreover, 
the mounting holes through which the pins extend are divided by the cavity 
and shortened, and therefore drilling of the mounting holes may be carried 
out easily and with accuracy, thus providing a great practical effect. 
Type 3 
A vane pump belonging to this type 3 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 type 3 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 belonging to the type 3, 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 the vane belonging to the type 3 will now be described with 
reference to the drawings. 
First, in FIG. 17, vanes indicated at 11 are disposed to be radially 
projected from and retracted into vane grooves 12, respectively, which are 
equally divided into three 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, resins 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 indicated 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 vane 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 above-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. 18) 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. 19 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 
forming a radial thickness of the sliding member which is less than the 
radial width of the annular race 17 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. 20, 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 peripheral 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. 
As 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 speeds, 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 July 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.