Scroll-type compressor with a slider plate for smoothing the orbiting movement of a movable scroll

A scroll-type compressor includes a front housing, a rear housing, and stationary and movable scrolls engaging with each other to define a plurality of compression chambers therebetween. The stationary scroll is connected to the rear housing to define a discharge chamber therebetween. The stationary and movable scrolls are provided between the front and rear housings so that the movable scroll moves along an orbiting path. A drive shaft extends through the front housing and is drivingly connected to the movable scroll. The rotation of the drive shaft moves the movable scroll along the orbiting path to shift the compression chambers from the periphery to the center of the scrolls with the volume of the chambers reducing. A slider plate, substantially in the form of a ring, for providing a sliding surface for the movable scroll, relative to the front housing, is disposed between the front housing and the movable scroll. The slider plate includes first and second slots which are disposed diametrically opposite to each other and extend radially and circumferentially, respectively. A pair of pins are provided for engagement with the first and second slots of the slider plate to lock and secure the slider plate to the front housing or to the movable scroll.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to a scroll-type compressor improved to smooth the 
orbiting movement of a movable scroll. 
2. Description of the Related Art 
A scroll-type compressor generally comprises movable and stationary 
scrolls. The movable scroll includes a movable end wall and a movable 
spiral member which are connected to each other. The stationary scroll 
includes a stationary end wall and a stationary spiral member which are 
connected to each other. The movable and stationary scrolls engage with 
each other to define compression chambers therebetween. The movable scroll 
is held by front and rear housings to move along an orbiting path. The 
orbiting movement of the movable scroll shifts the compression chambers 
from the periphery to the center of the movable and stationary scrolls to 
reduce the volume of the respective compression chambers. 
In some scroll-type compressors a slider plate, for smoothing the orbiting 
movement of the movable scroll, is provided between the front housing and 
the movable end wall of the movable scroll. 
A scroll-type compressor described in Japanese Unexamined Patent 
Publication (Kokai) No. 6-121113 has fixed and movable slider plates which 
are provided between an inner end face of a front housing and a movable 
end wall of a movable scroll through an arrangement for preventing the 
movable scroll from rotating about its axis. The arrangement for 
preventing the movable scroll from rotating about its axis comprises a 
fixed ring with one or more recesses disposed along the periphery thereof, 
a movable ring with one or more recesses disposed along the periphery 
thereof, and ball elements inserted into each of the recesses of the fixed 
and movable rings. A fixed race is provided between the inner end face of 
the front housing and the fixed ring, which is secured to the front 
housing by means of a spring pin and caulking along the fixed ring. A 
movable race is provided between the movable end wall and the movable 
ring, which is fixed to the movable end wall by means of spring pins and 
caulking along the movable ring. 
The method of providing a slider plate described in the publication, 
however, inherently involves a problem that manufacturing cost is 
increased since the slider plates are secured by caulking, which increases 
the stages of the manufacturing process of a scroll-type compressor. In 
addition to this, the slider plate secured by means of caulking cannot be 
replaced at the end of its life because it is connected to the front 
housing by caulking, which results in the replacement of all of the 
associated components. 
On the other hand, connection by only the spring pins is insufficient to 
secure the slider plates since the spring pins are elastic members, and 
they may easily become loose against the associated elements such as the 
slider plates or the inner end face of the front housing, due to the 
compression load and vibration, etc., during operation of the compressor. 
Such loosening between the spring pins and the slider plates may result in 
the noise and friction which often appear in a compressor with a slider 
plate which is not secured so that the plate rotates with a movable 
scroll. Further, when the spring pins are loosened to fall off the front 
housing, they obstruct the operation of the compressor. 
SUMMARY OF THE INVENTION 
The invention is directed to solve the above mentioned prior art problems 
and the objective of the invention is to provide a scroll-type compressor 
improved to enable replacement of a slider plate, for providing a sliding 
surface between the front housing and the movable scroll, easily and to 
reduce the production cost of the compressor. 
According to the invention, a scroll-type compressor comprises a front 
housing having an axially inner end face; a rear housing; a stationary 
scroll including a stationary end wall and a stationary spiral member 
connected to each other, the stationary end wall being connected to the 
rear housing to define a discharge chamber therebetween, the stationary 
spiral member being connected to the front housing; a movable scroll 
including a movable end wall and movable spiral member connected to each 
other, the movable scroll being provided between the stationary scroll and 
the front housing to move along an orbiting path relative to the front 
housing and the stationary scroll, the movable and stationary scrolls 
engage with each other to define a plurality of compression chambers 
therebetween; a drive shaft drivingly connected to the movable scroll, the 
drive shaft being supported by the front housing for rotation, the 
rotation of the drive shaft moving the movable scroll along the orbiting 
path to shift the compression chambers from the periphery to the center of 
the scrolls with the volume of the chambers reducing; a slider plate 
substantially in the form of a ring, for providing a sliding surface for 
the movable scroll relative to the front housing, the slider plate being 
disposed between the front housing and the movable scroll, the slider 
plate including first and second slots which are disposed diametrically 
opposite to each other and extend radially and circumferentially; a pair 
of pins are provided for engagement with the first and second slots of the 
slider plate to lock and secure the slider plate to the front housing or 
to the movable scroll. 
The pair of pins are secured to the inner end face of the front housing to 
extend from the end face toward the movable scroll, or to the end wall of 
the movable scroll to extend toward the front housing. 
The invention simplifies the assembly of the scroll-type compressor since 
the slider plate can be secured only by the pins being pressed to fit into 
the slots without caulking. This reduces the number of stages in the 
manufacturing process and the cost. The slider plate can be replaced with 
a new one at the end of the life of the slider plate by pulling off the 
slider plate from the pins which are left on the front housing or the 
movable scroll. A new slider plate for replacement can be secured by 
pressing it to fit onto the pins, thus the replacement of a slider plate 
alone is possible. 
Further, the pins can firmly secure the slider plate and the front housing 
or a movable scroll since the pins are solid and do not allow looseness 
between the pins, the slider plate and the front housing or the movable 
end wall in spite of the vibration during operation of the compressor. 
Therefore, the slider plate is held tightly, and no noise and friction can 
occur. Also, since the pins do not fall off the front housing or the 
movable end wall, they do not obstruct the operation of the compressor. 
In this way, this method realizes reduction of the manufacturing cost, a 
replacement of the slider plate alone, and the prevention of noise and 
friction.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
With reference to FIGS. 1-6, a first embodiment of the invention will be 
described hereinafter. 
A scroll-type compressor 100 according to the first embodiment of the 
invention comprises front and rear housings 1 and 3 between which movable 
and stationary scroll members 4 and 2 are provided to engage with each 
other. The movable and stationary scrolls 4 and 2 engaging with each other 
define a plurality of compression chambers 13. The front housing 1 
rotatably supports a drive shaft 8 for driving the movable scroll 4 via a 
seal 6 and a boaring 7. The drive shaft 8 includes a slide key 8a which is 
eccentrically provided on the inner end face of the drive shaft 8, and a 
drive bush 9 which engages the slide key 8a. A counterweight 10 is secured 
to the front side of the drive bush 9. 
The drive shaft 8 is operatively connected to a rotational power source, 
such as an automobile engine 104 by an appropriate transmission device 
which may include a pulley, V-belts and a electromagnetic clutch. 
The movable scroll 4 includes a movable end wall 41 and a movable spiral 
member 42 in the form of a spirally extending wall which may be made of 
aluminum alloy. The stationary scroll 2 may also made of aluminum alloy 
and includes a stationary end wall 21 which is sealingly attached to the 
rear housing 3 by bolts 3b to define a discharge chamber 3a therebetween, 
and a stationary spiral member 22 in the form of a spirally extending wall 
which is sealingly connected to the front housing 1 by a plurality of 
bolts (not shown). 
The movable scroll 4 is provided between the front housing 1 and the 
stationary scroll 2 and is connected to the drive bush 9 so that the 
rotation of the drive shaft 8 moves the movable scroll 4 along a 
predetermined orbiting path around the longitudinal axis of the compressor 
100. A slider plate 30, in the form of a ring of ferric alloy, for 
providing a sliding surface between the front housing 1 and the movable 
scroll 4 is disposed between the front housing 1 and the movable scroll 4 
to smooth the orbiting movement of the movable scroll 4. 
The orbiting movement of the movable scroll 4 causes gradual shifting of 
the compression chambers 13 from the periphery to the center of the 
scrolls 4 and 2. During the shifting of each of the compression chambers 
13, the volume thereof is gradually reduced. The pressure in the 
respective compression chambers 13 gradually increases. 
The stationary scroll 2 includes a discharge passage 21a through the center 
of the end wall 21 to fluidly connect the compression chamber 13 which has 
moved to the center of the scrolls 2 and 4 to the discharge chamber 3a. 
FIG. 1 shows the compressor 1 in which the movable scroll 4 is displaced 
at an orbiting position where a compression chamber 13 is not at the 
center of the scrolls 4 and 2. A valve retainer 5 for a valve 5a is 
provided in the discharge chamber 3a. 
The discharge chamber 3a is fluidly connected to an outside refrigerating 
circuit 102 through a discharge port 21b formed in the end wall 21 of the 
stationary scroll 2. The discharge port 21b may be defined in the rear 
housing 3. The lower pressure side of the refrigerating circuit 102 is 
fluidly connected to the compressor 100 through a suction port 1k which is 
defined in the front housing 1 (FIG. 2). 
The inner end face of the front housing 1 defines recesses 1c to 1f which 
are equally disposed around the longitudinal axis of the front housing 1. 
Stationary pins 1g to 1j are fixed to the front housing 1 at the centers 
of the recesses 1c to 1f, respectively. The stationary pins 1g to 1j 
support retainers 12 (only one of them is shown in FIG. 1) for rotation 
within the recesses about the pins 1g to 1j. Four movable pins 41a (only 
one of them is shown) are connected to the movable scroll 4 to extend 
toward the inner end face of the front housing 1. The movable pins 4a are 
also connected to the retainers 12. The stationary pins 1g to 1j, the pins 
41a and the retainers 12 constitute an arrangement for preventing the 
movable scroll from rotating about its axis. 
With reference to FIGS. 3 and 4, the slider plate 30 is provided with first 
and second slots 30a and 30b. In the preferred embodiment shown in FIGS. 3 
and 4, the first and second slots 30a and 30b are disposed advantageously 
diametrically opposite to each other. In particular, the first slot 30a is 
provided so that it is directed toward the center of the axis, while the 
second slot 30b is provided perpendicular to the first slot 30a. 
The slider plate 30 is further provided with an aperture 30c and a notch 
30d which is formed in the outer periphery of the slider plate 30. The 
aperture 30c and the notch 30d provide a suction passage between the 
suction port 1K in the front housing 1 and the outermost compression 
chamber 13. In the inner periphery of the slider plate 30, recesses 30e to 
30h are provided to prevent the rotation of the slider plate 30 about its 
axis. 
Two pins 1a and 1b of ferric alloy which have a circular section are 
pressed to fit into bores (not shown) provided in the inner end face of 
the front housing 1 so that they extend from the end face toward the 
movable scroll 4. The pins 1a and 1b are disposed diametrically opposite 
to each other. The slider plate 30 is secured to the housing 1 by the pins 
1a and 1bpressed to fit into the slots 30a and 30b in the slider plate 30, 
respectively, as illustrated in FIGS. 2 and 4. 
The arrangement of the pins 1a and 1b may include errors in dimensions and 
positioning. According to the invention, the error in the diametrical 
distance between the pins 1a and 1b can be compensated for by the first 
slot 30a which is oriented in the radial direction, and the directional 
error between the pins 1a and 1b can be compensated by the second slot 30b 
which is oriented in the circumferential direction. 
The possible fluctuation in the fitting interference between the slots and 
the pins does not substantially change the load to the plate 30 for the 
fitting of the pins 1a and 1b, from production to production, since the 
plate 30 is secured by only the pins 1a and 1b fitted into the first and 
second slots 30a and 30b. Thus, the slider plate 30 does not deform in the 
axial direction around the slots 30a and 30b. Therefore, the arrangement 
of pins 1a and 1b and the slots 30a and 30b for securing the plate 30 does 
not deteriorate the ability of the movable end wall 41 to slide relative 
to the front housing. 
Further, the possible errors in the longitudinal dimensions of the housings 
1 and 3 and scrolls 4 and 2 can be compensated for by preparing various 
slider plates 30 of different thickness and by selecting the one which can 
cancel the error. 
In the scroll-type compressor 100, the pins 1a and 1b firmly secure the 
slider plate 30 to the front housing 1 since the pins are solid and do not 
allow loosening between the pins, the slider plate 30 and the front 
housing 1 due to the vibration during operation of the compressor 100. 
Therefore, the slider plate 30 is held tight, and no noise and friction 
occur. Also, as the pins 1a and 1b do not fall off the front housing 1, 
they cannot obstruct the operation of the compressor. 
Thus, according to the scroll-type compressor, the number of stages in 
production process and the production cost can be reduced since the slider 
plate 30 can be secured to the front housing 1 without caulking. 
Refrigerant gas is introduced into the compression chambers 13 through the 
suction port 1k and the suction passages 30c and 30d from the 
refrigerating circuit 102. The rotation of the drive shaft 8 moves the 
movable scroll 4 along a predetermined orbiting path around the 
longitudinal axis of the compressor 100. The orbiting movement of the 
movable scroll 4 causes gradual shifting of the compression chambers 13 
from the periphery to the center of the scrolls 4 and 2. During the 
shifting of each of the compression chambers 13, the volume thereof is 
gradually reduced to increase the pressure of the refrigerant gas in the 
respective compression chambers 13. When one of the compression chambers 
13 moves to the center of the scrolls 4 and 2, the compressed refrigerant 
gas is discharge to the discharge chamber 3a through the discharge passage 
21a, from which the refrigerant gas will be further discharged to the 
refrigerating circuit 102 through the discharge port 21b. 
During the operation of the compressor, the slider plate 30 smoothes the 
sliding between the front housing 1 and movable end wall 41 of the movable 
scroll 4. The slider plate 30 is firmly secured to the front housing 1 and 
is not displaced by a radial force on the slider plate 30 since the 
longitudinal axes of the slots 30a and 30b are oriented perpendicular to 
each other. 
When the slider plate 30 must be replaced with a new one due to the end of 
its life, the slider plate 30 only can be simply removed from the pins 1a 
and 1b without a substantial change in the condition of the pins 1a and 
1b. A new slider plate for replacement can be attached by pressing the 
original pins 1a and 1b to fit into the slots 30a and 30b in the new 
slider plate 30. Thus, according to the invention, the slider plate 30 
only can be replaced while in a compressor according to the prior art a 
front housing must be replaced with a slider plate attached thereto by 
caulking. 
According to the invention, noise and friction can be reduced, the 
manufacturing cost can be lowered, and replacement of only the slider 
plate 30 is possible. 
As described above, the plate 30 is secured to the inner end face of the 
front housing 1. With reference to FIG. 7, in a variant embodiment, a 
plate 30' for providing a sliding surface between the front housing 1 and 
the movable scroll 4 is secured to the end face of the end wall 41 of the 
scroll 4 by two pins 1b', only one of which is shown in FIG. 7, to smooth 
the orbiting movement of the movable scroll 4. The rest of the 
configuration of the compressor is substantially the same as the preceding 
embodiment. 
In order to make clear the advantage of the invention, comparative examples 
shown in FIGS. 5 and 6 will be described. 
FIG. 5 shows a slider plate 31 according to a first comparative example. 
The slider plate 31 is provided with a slot 31a and a circular aperture 
31b which are disposed diametrically opposite to each other. The slot 31a 
is oriented to the center. The other configuration is identical to that of 
the embodiment described above. 
The slider plate 31 can cancel the error in the radial distance between the 
pins 1a and 1b. However, the pressing load for fitting the pins 1a and 1b 
into the circular aperture 31b is higher than that for fitting the pin 
into the slot 31a, which causes an inclination of the slider plate 31 
relative to the end face of the housing 1, which makes the assembly of the 
compressor difficult. 
Also, as all of the circumference of the circular aperture 31b is pressed 
to fit to the pin 1b, the slider plate 31 may easily deform in the axial 
direction along the periphery of the circular aperture 31b due to an error 
in the fitting interference. This impairs the sliding of the movable end 
wall 41 on the slider plate 31, and the assembly of the components. 
FIG. 6 shows a second comparative example. A slider plate 32 is provided 
with slots 32a and 32b disposed diametrically opposite to each other. The 
slots 32a and 32b are formed to be oriented in the same direction. The 
rest of the configuration is identical to that of the above-described 
embodiment of the invention. 
When the slider plate 32 is attached to the inner end face of the housing 
1, and error in the radial dimension between the pins 1a and 1b can be 
compensated for by the slots 32a and 32b. However, the slider plate 32 may 
move in the direction of the slots 32a and 32b due to the radial load 
applied to the slider plate 32. 
Thus, the configuration of the slots 30a and 30b in the slider plate 30 of 
the invention, that is, one extends radially and the other extends 
circumferentially, is advantageous. 
A variation can be considered where two solid pins which have circle 
section are connected to a slider plate 30 to extend axially to the front 
housing 1. The pins are pressed to fit into slots, similar to the slots 
30a and 30b, which may be provided in the inner end face of the front 
housing 1 or in the end face of the movable end wall 41. In this case, 
however, an error in the axial dimensions of the housings and the scrolls 
will not be compensated for since preparation of various slider plates 
which have different thickness is difficult. 
In the embodiment described above, the slider plate 30 includes the first 
and second slots 30a and 30b which are oriented perpendicular to each 
other and disposed diametrically opposite to each other. However, the 
present invention is not limited to this configuration. The first and 
second slots 30a and 30b can be arranged so that they are oriented in 
directions, including the radial and circumferential components, 
respectively, different from each other, beyond the above-described 
perpendicular configuration of the slots. The radial component of the 
direction compensates for the error in the radial distance between the 
pins 30a and 30b while the circumferential component of the direction 
restrains the radial movement of the slide plate 30. Further, the first 
and second slots 30a and 30b are not necessarily disposed diametrically 
opposite to each other. In this case, the first slots 30a are oriented 
toward the second slots 30b. 
It will also be understood by those skilled in the art that the forgoing 
description is a preferred embodiment of the disclosed device and that 
various changes and modifications may be made without departing from the 
spirit and scope of the invention.