Note: Descriptions are shown in the official language in which they were submitted.
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This application is a clivision oEapplication Serial No.
296,328, filed Februar~ 6, 1978.
This invention relates to a wobble plate refrigerant
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compressor and more particularly to an automotive air conditioning ~:
; variable displacement compressor having an improved three-piece
housing.
In U.S. Patent Mo. 4,061,443 to Dennis A~ Black and
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56
~3~-ron L. Bruc:ken, assigned to -the same assignee as the present
application, a variable displacemen-t automotive air conditioning
wobble plate cornpressor is described. The presen-t inventi.on
discloses an imporved three-piece housing, preferably formed
S as cast aluminum members, providing an economical compressor
ho~sing assembly with fewer parts thereby achieving a simpli-
fica-tion of the manufacturing andassembly operation.
In one of its broadest aspects, the object of this in-
vention is to provide an improved automobi:Le air conditioniny
wobble plate compressor housing wherein a first shell-like wobble
plate mechanism section, a second intermediate cylinder block
section and a rear cylinder head section are connected in
series to define a three~part housing.
It is another object of the present invention to provide
an improved cast aluminum three-part compressor housing for a
variable output axial compressor of the wobble plate type having
integral guide shoe means to prevent rotation of the wobble plate
element without preventing angular movement thereof relative to
the drive shafts. A pair of integral concave cylindrical opposed
guides are cast wi-th the f~-onthouSing shell for reception of a
substantially spherical guide shoe mounted in an axially shif-table
manner on a gu.ide pin projecting radially from one side of the
wobble plate. The spherical guide shoe is freely shiftable for
reciprocal movement on the gulde pin during angular movement of
the wobble plate, whereby only a line contact is maintained
between the shoe and each of its cylindrical guides.
Fur-ther objects and advantages of the present invention
will be apparent from the following description, reference being
had to the accompanying drawings wherein a prefer.red embodiment
of the present inven-tion is clearly shown~
In the Drawings:
s~
F:ig. 1 is a ver-tical sectional view showing a preferred
Lorm of the invention;
Fig. 2 is a vertical sectional view taken substan-ti-
ally along line 2-2 of Fig. l;
Fig. 3 is a vertical sectional view taken substanti-
ally along line 3-3 of Fig. l;
Figure 4 is an exploded perspective view of the compress-
or three-piece housing of the present invention; and
Fiy. 5 is an end elevational view, with parts broken
away, of the compressor rear head together with a schema-tic of
a cooling system.
Referring now to the drawings wherein a preferred
embodiment of the present invention has been disclosed, refer- ;
ence numeral 10 in Fig. 1 designates a variable displacement
axial compressor which is adapted to be driven by the main car
engine 12 through suitable belt means 14 in a manner shown and
described in the abave-mentioned Black et al patent. In the
clutch starting and stopping system, described in the mentloned
Black et al application, the compressor's principle of operation
involves reducing the refrigerant pressure drop between the e-
vaporator and the compressor by varying the compressor displace-
ment to match the cooling requirement of the car~ As a result,
at moderate temperatures the compressor capacity is modulated
to pump only the amount of refrigerant required to cool the
car. Suction gas is delivered from the evapora-tor to the com-
pressor at higher pressures and densities because, with the
elimination of the suction throttling valve there is a reduc-
tion oF line pressure drop. The fact -that suction gas enters the
compressor at a higher density together with the reduction of
mechanical or friction losses achieves a reduc-tion in the com-
pressor's power requirements.
As shown schematically in Fig. 5 f the re-Erigerating
system includes the usual refrigerant evaporator 16 having an
outlet line 18 leading to one inlet 19 of a receiver ~0 and exi-ts
at 21 into line 22 leading to ~he compressor inlet 24. The
compressed re~rigerant leaves the cc~mpressor 10 through an outlet
26 into line 27 connected to a conventional condenser 28. The
condensed refrigerant returns to a second inlet 29 of the receiver
20 by line 30 from whence the liquid re~rigerant flows through
a suitable pressure reducing meansl which for the purposes
of illustration has been shown as an expansion valve 32 in the
receiver/ and thereafter returns to the e~aporator by line 34.
The compressor lO and condensex ~8 are preferably located in
the engine compartment o~ the car while the evaporator 16 is
arranged in an enclosure so as to cool air ~or the passenger
compaxtment of the car in the usual manner.
As best seen in Figs. l and 4, the improved compressor
10 of the prese~t invention includes a three-part housing h~ving
a first shell-like cup-shaped front sectivn 36, a mating second :.:
or intermediate cylinder casing section 37 and a third rear cyl-
inder head section 38 adapted to be connected in series to form
the compressor housing assembly 40. The front shell section 36
has a rearwardly directed continuous peripheral edge 42. The
second cylinder casing section 37 has a ~orwardly directed face
44 and co-planar peripheral edge 46 which when abutted against
the front section edge 42 such that the fixst and second -
sections are in flush confronting engagement at a common t.rans-
verse plane. The ~irst and second sections are centered relative
to one another by alignment means such as pins 47 and a connector
tube portion 48 shown assembled in Fig. 4. Ax.ial bores 52
3~ in the second section 37 and at 54 in the ~irst section 36 are pro-
vided ~or the alignment pin 47 while axial passageways 56 and 57
in a second section 37 and firs-t section 36 respectively are
connected by tube portion 48. The first 36 and second 37
sections are sealed to one another by elastomeric sealing ring
58 (Fig. 1) compressed in an annular groove 59 formed in the
forwardly facing edge 44 of the second section 37.
The second intermediate cylinder section 37 has an
integral ex-tending peripheral flange portion 64, extending axi-
ally from circular internal shoulder 66, with the flange portion
inner wall 65 being of straight cylindrical form for receiving
or fitting over third rear head section 38 in a telescopic
manner. Located between the second and third sections, on shoul~
der 6~, is a valve plate 72 having concentric reed plate 74
interposed therebetween with the rear head section sealed to the
second section by an elast.omeric sealing xing 76.
As viewed in Fig. 4 securing means are provided for
removably attaching the rear head section 38 to the -front shell-
like section 36 by means of cap screws 78r In the disclosed form
four cap screws extend through circumferen~ially spaced holes
82 in an outwardly extending annular flange 84a-84d ~Fig. 3~
integr~l with said rear head member, said holes 82 bein~ axially
aligned ~i~h ~ plur~lîty o~. circum~erentially spacad holes 86
~Fiy. 2) in outwardly extending bosses 88 integral with front
shell-like portion 36. Extending through hole 82 and threaded
into hole 86 are a plurality of cap screws or bolts 78 (one being
shown~ ~or drawing the irst section 36 axially in one direction
enabling the edge 42 to abut against the seal ring 58 and rear
head 38 to contact seal ring means 76 for holding the housing
sections in assembled relationship. The sea~ rings 58 and 76
are thus deformed into sealing engagement with their adjacent
hou~ing sections.
The çompressor main drive shaft 90 has its forward
be~rillg por-tion end91 xotatably mounted or journaled o~ frorlt
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needle bearings 92 in axial bore ~3 fo.rmed i.n a protruding inte-
gral tubular extension 94 located on the front head end cover
portion 89 outer surface. The extension 94 is coaxial with and
sur.rounds the shaft intermediate end 95 in concentric ~ashion~
The shaft 90 has its rearward reduced end 96 terminating in shaft
end 97, journaled on rearward needle bearing 98 in rear axial
bore 99 of the housing inte~nediate cylinder portion 37.
As viewed in Fig. 1, the shell-like housing front por-
tion defines a ca~ity 101 which completely encloses compressor
wobble plate mechanism 100 and is provided with an integral dis~
tended bulge porticn 102 forming an oil sump or crankcase resion
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103. The s~np collects, by gravity ~low, oil and refrigerant
mixture therein received from piston blow-by ~or circulation
through the compressor by suitable oil flow passag~.3providing
a lubricating network ~or its associated bearings and seals.
Lubricating oil gear pump means .in the ~orm of an oil gear pump
assembly 104, driven by shaft en~ ~7 providing a D-shaped quill,
in the ~orm of a reduced extension of the shaft rearward end g7,
serves to withdraw oil and refrigerant solution.from the sump
103 through an oil pickup passage or conduit 105~ As seen in
Fig. 4, the passage 105 is ~ormed in bottom lobe portion 106 of
the intermediate cylinder section 37, by means of integral lobe
boss 107, with passage 105 having its inlet end 108 in the plane
of face 44. Th~ passage 105, upper outlet end la9 co~nunicates
via an aperture 110 in reed valve disc 74 with an aligned verti-
cal slotted pas~age 112, formed in the inner face of val~e plate
72 as seen in Fig. 3. The passa~e 11~ has an arcuate shaped
upper end 113 positioned in communication with inlet side 114 of
the year pump 104.
- 30 The gear pump outlet con~nunicates with an arcuate por
tion 116 of an upper oil outle~ gro~ve 11~ wi*h the groove
extending radially outwardly at an acute angle from the vertical
Sd~
of about 30, to an outer angled or dogleg portion 120 which
terminates adjacent the periphery of the valve plate 72. The
angled portion 120 of the groove terminates in valve plate ori-
ice 122 which communicates with the oil outlet passage 282 in
the rear head section 38 (Fig. 5~ comm~micating with the entrance
to a hydraulic control valve to be described. The plate orifice
122 is aliyned with a hold 121 in the reed disc 74 which is in
turn aligned with axial passageway means in the housing sections
36 and 37, located outboard of the wobble plate mechanism 100.
The axial passageway means includes intermediate casing section
37 crossover passageway or duct in its internal boss 123 (Fig. 4),
and the front crosso~er passageway or duct 57 in the front casing ;-
~section 36 in internal bo~s 124. The crossover ducts 56 and 57
have aligned juxtaposed counterbores 125 and 126 respectively to
receive either e~d of alignment tube 48 in a press fit manner.
The front section 36 includes radial passage 128 communicating at
a T-connection with crossover duct 57. The outer end of radial
passage 128 is sealed b~ a plug member 129 while the inner end
of radial passage 128 i~ opened to expansible chamber 138 deflned
by blind boxe 132 and piston means in the form of disc-shaped
piston 134.
The modulation piston 134 has a rectangular shaped
peripheral edge groove 136 for reception o a resilient rim seal
member 138 formed with a reduced annular U-shaped groove on its
inner face so as to bias its sealing lip or V ring 139 inwardly.
In this way the lip 139 can flex, as necessary, to conform to the
walls of bore 132 to further insure proper wiping sealed contact
at all times~ As the compressor pressurized hydraulic ~luid or
lubricant is effectively sealed in the expansible chamher 130
except fox controlled exit means, w~ich in the disclosed form is
a single ~leed orifice 142 in modulating piston 134. In the dis-
closed form the bleed orifice 142 has a diameter o abou~ 0~031
inches. In this way the unloadin~ or outward flow of hydraulic
fluid from the chamber 130 via orifice 142 for yravity return to
the sump 103 is controlled upon the wobble plate : mechanism
moving toward its full stroke position as explained in the
afore-mentioned Black et al patent.
The rear cylinder head section 38 for cylinder bores
140' includes an outer suction or inlet chamber 143 and a center
discharge chamber 144 D As shown in Fig. 1, each compression
chamber or cylinder bore 140 communicates with the suction cham-
ber 143 through an inle~ port such as the port 145 (Fig. 3).The inlet reed valve disc 72 J having inle~ reeds 147, controls
the flow of refrigerant through the suction inlet ports 145 in
accordance with standard practice. The compressed refrigerant
leaves each compression bore 140 through a discharge port 149,
while a reed valve 150, in a discharge reed valve disc lSl, at
each discharge port 149 is provided in accordance with standard
practice. It will be noted in Fig. 1 that the extent of the
opening of the reed valve 150 is limited by a rigid back-up
plate member 148 suitably secured to the valve plate 72 as b~
a rivet~
For purposes of illustrating this invention, a vari~
able displacement five cylinder axial compressor 10 will be
described whereas it will be understood that the number of cyl-
inders may be varied withou-t departing rom the spiritand scope
of the i~vention~ The wobble plate drive mechanism assembly 100
includes a socket plate 152 and a journal element or wobble
plate 154. The wobble plate 154 and socket plate 152 define
a plane bearing surface 156 and an outer cylindrical journal
surface 158 with the wobble plate rotating in unison with the shaft
90. The socket plate 152 has five sockets, one of th2 sockets
being shown at 162 J for receiving the spherical ends 161 of five
connecting rods, like the connecting rods 1631 ~s see:n in Fig. 1.
5~i
The free ends of each of the connect.ing rodc; 163 are provided
with spherical portions 164 as shown. The plurality of axial
cylinder bores 140 in cylindri.cal casing sec~tion 37, -there being
five in the preferred embodimen-t, receive pistons 166 therein.
The piston~ 166 ar~sealed by rings 167 which in the disclosed
form are ~ Teflon washers as described in U.S. Patent 3,885,460,
assigned to the assignee of the present application. Piston
166, shown in its top-dead-center position, has a socket-like
formation 168 for engaging one end of the connecting rod 163.
The pistons 166 operate within their associated compression cham-
bers or bores 140 whereby upon rotation of the drive sha:Ek 90
and the wobble plate 154 will cause reciprocation of the pistons
166 within their bores 140.
The shaft 90 has a generall~ cylindrical sleeve and :.
integral counterbalanc.ing member 170 with the sleeve 180
surrounding or circumscxibing the shaft in hydraulic sealing
relation therewith by means of compressible sealing means such
as O-ring seal 181 located in a groove in the inner surface 182
of the sleeve. The sleeve 180 has formed therein a longitudinal
slot 183 extending rom the sleeve inner or rearward ace 184
substantially the full length of the sleeve and te.rminates in a ..
U-shaped radiused portion 186 within the confines of the cylin-
der bore 132~ The sleeve face 184 includes a chamfered front
edge 187. It will be noted that the slee~e 180 has a flat face
portion 188 located in.180 opposed relation to the slot 1~3.
As seen in Fig~ 2, inteyral counterweight or counterbalance 189
has a generally ons-half disc shape with its arcuate outer edge
190 de~ined by a radius centered an the axis of sha~t 90 and of
a predetermined distance less than the radius o ~he bore 132
to:a1low the disc 189 to t~lescope within the bore 132 during
maximum piston stroke as shown in Fig~ 1. The member 170
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includes an integral forwardly projecting hub 191 whose forward
shoulder 192 is in rotatable abut~in~ contact with thrust bearing
194. The thrust bearing 194 is located i.n concentric recess 196
formed in the cover 79 of the front section 36~
In the disclosed e~bodiment the modulating piston 134
is retained on the hub portion 191 by C-clip 193 where~y the
sleeve and counterhalance member 170 rotate with the shaft while
the piston 134 moves axially with the member 170 but do~es not
rotate therewith. A return spring member 20Q, having a ~adiating
leaf spring finger 201, as seen in Fig. 2, is positionea by means
of its C-shaped retainer 202 concentrically on the sleeve within
sleeve groove 203 for rotational and axial movement therewith.
The spring member 200 is operative upon the modulating piston 134
and sleeve member 170 being moved axially to the left xom its
position in Fig. 1 to a compressed position contacting drive lug
210 with the wobble plate mechanism 100 being pivoted to a vexti-
cal or normal position relative to the shaft 90 ~s indicated by
dash-dot lines. Thus, the spring ~inger member 200 functions to
move the wobble plate mechanism 100 of its dead center or zaro
; 20 s~roke position wherein the pistons 166 start pumping by biasing
the disc-shaped piston 134 toward its full stro~e position ~Fig.
l)o ~
As explained above, the modulating disc-shaped piston
member 134 cooperates with the cylinder bore 132 to form the
expansible chamber 130 the size of which is varied by supplying
lubricant under pressure into ~h~~chamber. At high lu~ricant
pressures, the piston 134 sleeve 18~ an~ co~terbalance 18g will
be shifted axially to the left as shown by phantom lines. The
chamber 130 may be unloaded when the piston 134 is moved to the
right by removal of hydraulic fluid from chamber 1.30 by hleed
aperture 110.
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56
The shaft 90 drive lug portion 210, which in the dis-
closed form is tapered or conical iIl vertical ~ection, extends in
a transverse or normal direction to the drive shaft axis. The lug
210 ha~ formed therein a guide slot or cam track 212 which ex-
tends radially along the axis of the drive shaft~ The journal
element 154 carr.ies an ear-like member 214 projecting normal
to the journal forward face 216 and has a ~hrough bore for receiv-
ing cam follower means in the form of a cross pin driving member
220~ ~s seen in the above-mentioned U.S. Patent No. 4,061,443,
the ear 214 is offset from but parallel to a plane common to
drive shaft principal a~is and the sleeve slo:t 183 ~n amount
which allows the pin 220 to seat in bottom radius 213 of -the
cam track 212, wi-th the journal element 154 disposed in a
plane perpendicular to the axis o~ rotation of the shaft 90, xen-
dering the compressor ine~fective to compress re-Erigerant gas.
This is because the pin 220 is located at the radially inward
limit of cam track 212 defining minimum or zero stroke len~th ~or
each of the pistons 166. Fig. 1 shows the arrangement of the
wobble plate mechanism 100 for maximum compressor capacity
wherein the pin 220 is positioned at the radially ou~er end o~ cam
t.rack 212 deining the maximum stroke lengths for each of the
pistons 166. It will be noted in Fig. 1 that the drive luy 210
i~ received in a complementary cone-shaped bore 215 in drive
shaft 90 and suita~ly secured therein as by a cross pin 217 to
properly align and lock the .lug 210 against any rotational move-
ment in shaft bore 2150
As shown and described in the abo~e-mentioned U.S.
Patent NoO 4J061~443~ journal p1ate hub ~.24 has trans~er~e bores
226 the axis of which intersect the rotational axi~ of shaft 90.
3Q Thus~ the journal plate huh 224 r~ceives the sleeve 180 in the
hub'~ generally rectangular sectioned axial opening, defined in
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part by upper and lower faces 227 and 228. The charnfered sur~
face 229, which provides a clearance with sleeve sur~ace 188 in
the full stroke position, can be a cast-in-place surface for use
as is. Upon a~sembly the journal cross bores 226 are aligned
with sleeve bores (not shown) for the reception of the hollow
transverse pivot or trunnion pins 230 permitting the wobble plate
assembly 40 to pivot thereabout.
As explained in the Black et al Patent No. 4,061,443,
the above-described arrangement of parts have opposite radiused
ends 211 and 213 of the cam track 212 which provide one method
to define respectively, khe maximum and minimum stroke
lengths for each of the pistons 166 in a manner to constrain
t.he wobble plate assembly 40 providing essentially constant
top-dead~center (TDC) positions ~or each of the pistons.
Cam follower means in the ~orm of the pin follower 220 inter-
connects the wobble plate mechanism.100 and the drive sha~t 90
and is movable radially with respect to the lug 210 and the
wobble plate mechanism 100 in response to the movement of the
sleeve member 170, whereby the angle of the wobble plate mecha-
nism is varied with respect to the drive sha~t 90 to infinitelyvary the stroke lengths of the pistons 166 and thus the output
of the compressor.
The lubricating arrangement for applicants' compressor, .
as indicated in part by short arrows in Yig. 1, traces ~he oil
being drawn up from the compressor 6ump area 10~ in front section
36 through the pick-up passage 105 in section 37 for exiting its
outlet 109 and through an aperture 110 in the suction inlet reed
disc 7~ and thence into the passage means ln ~he foxm of the
gen~rally vertical slot or groove 112 formed in the inner face
30: of the valve plate 72. The groove 112 upper arcùate portion. 113
: communi~ates with a kidney-shaped aperture 254 in the valve disc
1~ ~
3~ aligned for connection with the second section duct 56 o~
the axial crossover passage means. The duct portlon 55 communi-
ca~es with crossover duct portion 57, which in turn is connected
to the front section radial passage 128 opening into -the modula-
ting chamber 130. The bores 326 and 327 in third section 38
(Fig. 4) receive locator pins 328 and 329 to align sections 37
and 38.
As seen in Fig. 1, the socket plate 152 is prevented
from rotating without preventin~ angular movemen-t thereof rela-
tive to the drive shaft 90 by a pair of complementary guide
members 332 and 333. The guide members are formed integral with
the front shell-like section 36 by means of webs 334 and 335
respectively, extending longitudinally along the interior of
section 37 inner surface so as to terminate in the plane of edge
42. Each guide member includes a head portion 336, 337 having
opposed conca~e cylindrical guides 338, 339 dimensioned to cap-
ture therebetween a guide in the form of a generally spherical
guide shoe 340 for longitudinal travel between a ~orward solid
llne position and a rearward dash-dot line position.
The spherical guide shoe is mounted on a guide pin 342
projecting radially from one side o~ the socket plate 152 with
the pin 342 rigidly retained by a press fit within plate bore
344. The shoe core 346 is of a diameter whereby the shoe 340 is
axially slidable or shiftable on pin 142 from its radial extend~
ed solid line position to its intermediate retracted dot-dash
position wherein the socket p~ate 152 and wobble plate mechanism
is ~ormal to the axis of shaft 90. Thus, the spherical shoe
provides an economical easily assembled arran~ement whereby a
friction reducing rolling line contact is maintained between the
30 spher1cal shoe and each c~lindrical sec~ion guide surface 33~, -
339O
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74 arranged directly o~er th~ intake side 114 of the gear pump
104. The oil gear pump assembly 104 pressurizes the oil as the
pump is rotated on the quill end 97 of the compressor shaft.
An internal ~low path for the pump luhrication system
is established by oil under pressure being discharged from the
pump outlet through a slot 255 in the xeed disc 74 into region
251 at the rear of the shaft end portion 97 for flow through an
axial bore 262 in shaft 90 ~or travel forwardly to a pair of
transverse shaft bores 264 aligned with wobble plate pin bores
(no~ shown) for flow between the journal hub 224 and the socket
plate hub 268 to lubricate the journal bearing surfaces 156
and 158.
The modulation oil flow path, indicated by dashed
arrows 272 in Fig. 3, involves flow from the outlet of the pump
104 into the arcuate portion 116 and radial portion of the upper
oil outlet groove 118 into the outer angled groove portion 120
for travel rearwardly through the orifice 122 in ~he valve plate
72 (Fig. 3) and thence via rear h~ad passage 282 ~Figs. 1 and 5)
for en~rancainto the blind end region or bore 284 of a hydrau-
lic control valve generally indicated at 290 in Fig. 5. Thevalve 290 functions to control the amount of piston stroke by
means o~ ball valve membex ~96 contrclled by valve bellows 2~8
which senses evaporator pressure from the evaporator control unit
20 via line 302~ passage 304 in the rear head sectio~ valve -
housing 306 and passage 3~8 in the valve casing 310~
As seen in Fig. ~, upon reaching the bli~d bore 284,
he oil will flow through inlet 312 of valve stem 314 past the
ball valve member 296 and t~ence into region 316 via axial stem
bore 318 ~or ~xiting via exit bo~e 320. Fr~m exit bore 320 the
oil .returns to the comp~essor via rear head suction return bore
322 (Fig. 5) which communicates with valve plate hole ~23 (Fig.
13
~ hile the emb~diment o~ the present invention as
herein disclosed const.itutes a preerred form, it is -~o be
understood that other forms might be adopted~
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