Vane-type compressor with at least one suction hole

In a suction port for a vane-type compressor in which suction holes 15a and 15 a along the inner peripheral edge 1a of the cylinder 1 are disposed in the read side block 4 and notch portions 15b and 15b opposing to the suction holes 15a are disposed at the opening edge on he suction side of cylinder 1, the suction holes 15a and 15a are arranged outside the vane sliding zone of the rotor-side end face 4a of the rear side block 4. If a vane juts out of a vane groove, the tip of vane does not enter the suction holes 15a and 15a even if the tip of a vane is inclined, so that the vane does not heavily rub the end portion of the suction hole on the rotor-side end face 4a.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a vane-type compressor and, more 
particularly, to vane-type compressor which prevents the separation of a 
plating layer near the end of a suction hole on the end face on the rotor 
side of side block. 
2. Description of the Prior Art 
A vane-type compressor of prior art comprises a cylinder, two side blocks 
fixed to each end face of the cylinder, a rotor tolerably incorporated in 
the cylinder, and a vane slidably inserted in each of a plurality of vane 
grooves formed in the substantially radial direction of the rotor, in 
which one of the two side blocks is provided with a suction hole, and a 
notch portion opposing to the suction hole is disposed at the opening edge 
of cylinder block, so that a refrigerant gas is sent from a suction 
chamber to a compression chamber in the cylinder through the suction hole 
and the notch portion, which compose a suction port (Published Unexamined 
Japanese Utility Model No. 190985/1984). 
When the rotor rotates, the vanes jut out of the vane grooves, so that the 
rotation is effected with the tip of the vane being in contact with the 
inner peripheral surface of cylinder and the side of vane being in contact 
with the end face on the rotor side of side block. 
In this vane-type compressor, the transverse width of the vane is a little 
smaller than the width of cylinder to prevent the difficulty in jutting of 
the vane due to the difference in thermal expansion between the vane and 
the cylinder. Also, most of the suction hole 115a is located within the 
vane sliding zone (hatched portion in FIG. 10) of the end face on the 
rotor side of side block, and some of the suction hole 115a is located 
outside the vane sliding zone as shown in FIG. 10. Therefore, there has 
been a problem in that if the vane juts out while being inclined when 
starting, the tip of the vane enters the suction hole 115a, and heavily 
rubs the portion 121 near the end of the suction hole of the end face on 
the rotor side of side block, by which the plating layer on the end face 
on the rotor side separated. If the separation of plating layer due to the 
tip of vane proceeds, there are possibilities of damage caused by wear 
particles entering the sliding portion and improper compression. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide a vane-type compressor 
which prevents the separation of plating layer on the rotor-side end face 
of side block caused by the side of vane. 
According to the present invention, the tip of vane does not enter the 
suction hole during the rotation of rotor, and the portion near the end of 
the suction port of the rotor-side end face of side block is not rubbed 
heavily, so that the plating layer is not separated, by which the damage 
due to wear particles and improper compression are prevented. 
The suction port for vane-type compressor in accordance with the present 
invention is characterized by the following improvements: 
In a suction port for a vane-type compressor comprising a cylinder, two 
side blocks fixed to both end faces of the cylinder, a rotor rotatably 
incorporated in the cylinder, a plurality of vanes slidably inserted in a 
plurality of vane grooves formed substantially in the radial direction of 
the rotor, a suction hole along the inner peripheral edge of the cylinder 
disposed on at least one of the side blocks, and a notch portion opposing 
to the suction hole disposed at the opening edge of the cylinder, the 
suction hole is arranged outside the vane sliding zone on the rotor-side 
end face of said one of side blocks. 
Preferably, in a suction port for a vane-type compressor comprising a 
cylinder, two side blocks fixed to both end faces of the cylinder, a rotor 
rotatably incorporated in the cylinder, a plurality of vanes slidably 
inserted in a plurality of vane grooves formed substantially in the radial 
direction of the rotor, and a suction hole along the inner peripheral edge 
of the cylinder disposed on at least one of the side blocks, the suction 
hole is arranged within the vane sliding zone on the rotor-side end face 
of said one of side blocks, and a vane tip guide portion is disposed so 
that the suction hole is apart from the outer peripheral edge of the vane 
sliding zone on the rotor-side end face thereof toward the center by a 
predetermined distance. 
Preferably, a notch portion is disposed at the opening edge of the 
cylinder, and an auxiliary suction hole is disposed outside the vane 
sliding zone on the rotor-side end face of said one of side blocks.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The embodiments of the present invention will be described below with 
reference to the drawings. 
FIG. 2 is a sectional view of a vane-type compressor in accordance with one 
embodiment of the present invention. This vane-type compressor includes a 
cylinder 1, a front side block 3 and a rear side block 4 which are fixed 
so as to close each end Face of cylinder 1, a rotor rotatably incorporated 
in the cylinder 1, a front head 5 and a rear head 6 fixed to the end face 
of side blocks 3 and 4, respectively, and a rotating shaft 7. The rotating 
shaft 7 is rotatably supported by bearings 8 and 9 mounted on the side 
blocks 3 and 4. 
The front head 5 has a discharge port 5a of refrigerant gas, while the rear 
head 6 has a suction port 6a thereof. The discharge port 5a is connected 
to a discharge chamber 10 defined by the front head 5 and the front side 
block 3, while the suction port 6a is connected to a suction chamber 11 
defined by the rear head 6 and the rear side block 4. 
Between the inner peripheral surface of the cylinder 1 and the outer 
peripheral surface of the rotor 2, two compression chambers 12 are formed 
(in FIG. 2, only one compression chamber is seen). As shown in FIG. 3, the 
rotor 2 is provided with a plurality of vane grooves 13, and a vane 14 is 
slidably inserted in each of the vane grooves 13. 
The rear side block 4 has two suction holes 15a and 15a as shown in FIG. 4. 
The suction holes 15a and 15a are located outside the vane sliding zone 
(the zone where the side of the vane 14 slides) on the end face 4a facing 
the rotor 2, which is indicated by hatching in FIG. 5. Also, a back 
pressure groove 22 is formed on the end face 4a of the rear side block 4. 
The cylinder 1 has formed at the opening edge of a rear end thereof, notch 
portions 15b and 15b as shown in FIGS. 1, 6, and 7. The notch portions 
15b, 15b are respectively in communication with the suction holes 15a, 
15a, as is clearly shown in the drawings. The suction hole 15a and the 
notch portion 15b constitute a suction port, and refrigerant gas is sucked 
from the suction chamber 11 into the compressor 12 through the suction 
hole 15a and the notch portion 15b. Both the cylinder 1 and the rear side 
block 4 are manufactured by casting. 
Two discharge ports 16 corresponding to two compression chambers 12 are 
disposed in the outer peripheral wall of the cylinder 1 (only one 
discharge port 16 is seen in FIG. 2). To the outer peripheral wall of the 
cylinder 1, a discharge valve cover 17 having a valve stop portion 17a is 
fixed by means of bolts 18. A discharge valve 19 held on the side of 
discharge cover 17 is interposed between the outer peripheral wall of the 
cylinder 1 and the valve stop portion 17a. 
Next, the operation of this vane-type compressor will be described. 
When a rotational power of engine (not shown) is transmitted to the drive 
shaft 7, the rotor 2 rotates. The refrigerant gas, which flows from the 
outlet of an evaporator (not shown), enters the suction chamber 11 through 
the suction port 6a, and is sucked from the suction chamber 11 to the 
compression chamber 12 through the suction hole 15a and the notch portion 
15b. The compression chamber 12 is divided into a plurality of spaces by 
vanes 14. The volume of each space changes as the rotor 2 rotates, so that 
the refrigerant gas captured between the vanes 14 is compressed. The 
compressed gas opens the discharge valve 19 to flow to the discharge 
chamber 10 through the discharge port 16, and is then discharged through 
the discharge port 5a. 
When the rotor 2 rotates, the vane 14 juts out of the vane groove 13, so 
that the tip of the vane 14 moves while being in contact with the inner 
peripheral surface 1a of the cylinder 1, and the sides of the vane 14 move 
while being in contact with the rotor-side end faces 3a and 4a of the 
front side block 3 and the rear side block 4. 
Since the suction hole 15a is arranged outside the vane sliding zone as 
described above, even if the vane 14 juts out while being inclined, for 
example, when starting, the tip of the vane 14 does not enter the suction 
hole 15a, so that it does not heavily rub the vane sliding zone near the 
end 21 of the suction hole. As a result, the separation of plating layer 
on the rotor-side end face 4a of the rear side block 4 can be prevented, 
thereby the damage to the sliding portion due to wear particles and 
improper compression being prevented. 
FIG. 8 is a front view of the rotor-side end face of a rear side block of 
vane-type compressor in accordance with another embodiment of the present 
invention. The like reference characters are applied to the parts common 
to those of the above-described embodiment, and its explanation is 
omitted. 
In the above-described embodiment, the suction hole 15a is arranged outside 
the vane sliding zone of the end face 4a of the rear side block 4 facing 
the rotor 2. Instead, in the second embodiment, the suction holes 25a, 
25a, are arranged within the vane sliding zone S on the end face 24a of a 
rear side block 24 facing said rotor 2 (hatched portion in FIG. 9), and 
the outer peripheral edge of each suction hole 25a is spaced from the 
outer peripheral edge Sa of the vane sliding zone S (FIG. 9) toward the 
center by a predetermined distance (for example, 1 mm), so that a vane tip 
guide portion 20 is formed between the outer peripheral edge of the 
suction hole 25a and the outer peripheral edge Sa of the vane sliding zone 
S. Further, auxiliary suction holes 25c, 25c respectively communicated 
with the notch portions 15b, 15b of the cylinder 1 are disposed near the 
suction holes 25a, 25a of the rear side block 24 outside the vane sliding 
zones. 
In this embodiment, the refrigerant gas in the suction chamber 11 is not 
only directly sucked into the compression chamber 12 through the suction 
hole 25a, but also sucked into the compression chamber 12 through the 
auxiliary suction hole 25c and the notch portion 15b of the cylinder 1. 
File decrease in suction efficiency, which is caused by the fact that the 
suction hole 25a is arranged within the outer peripheral edge 1a of the 
vane sliding zone, is prevented by the installation of the auxiliary 
suction hole 25c. 
Since the tip portion of the side of the vane 14 jutting out of the vane 
groove 13 slides while being supported by the vane tip guide portion 20, 
the tip of the vane 14 does not enter the suction hole 25a even if the 
vane 14 is inclined, so that the vane 14 does not heavily rub the vane 
sliding zone, by which the same effect as that of the above-described 
embodiment can be achieved.