Method for converting the configuration of a transmission pump assembly

TECHNICAL FIELD

The invention relates generally to a method of converting the configuration of a transmission pump into a later model year configuration transmission pump assembly. More specifically the invention relates to a method of converting a 1984-1994 General Motors 700 R4 transmission pump assembly into a 1995 or later configuration General Motors transmission pump assembly allowing a low cost replacement transmission pump.

BACKGROUND OF THE INVENTION

An automotive transmission multiplies engine torque or reduces engine rpm to match varying operating conditions in a manner optimizing engine power and torque. An automatic transmission generally comprises a torque converter, automatic transmission shafts, planetary gearsets providing different gear ratios, planetary holding members or clutches, transmission fluid pump, transmission shafts, hydraulic valves, shift linkage, converter housing, transmission case, transmission fluid pan, and an extension housing.

The automatic transmission is generally operated by a hydraulic fluid circuit. Pressure is developed by the transmission fluid pump, sometimes called an oil pump or front pump. The pump draws fluid from the transmission fluid pan and creates hydraulic pressure, which is then directed to other parts of the transmission to fill the torque converter, operate the holding member band and clutch assemblies, control shifting, lubricate the moving parts of the transmission, and circulate the fluid to and from an oil cooler for heat transfer. The pump is driven by the engine typically through driving lugs on the torque converter. When the engine is running, the pump produces power to operate the hydraulic system.

General Motors introduced a second generation transmission pump on its model 700 R4 transmission assembly in model year 1984 that remained basically unchanged through model year 1994. The 700 R4, (also designated 4L60E) utilizes a C-Vane type transmission oil pump comprising a pump body, a pump vane assembly, and a pump cover assembly. The 700 R4 transmission has been modified several times over the years. Some of these changes directly affected the compatibility of the transmission pumps between different model years.

When a transmission pump fails and needs to be replaced, the vehicle owner typically has a new or remanufactured transmission pump installed. New transmission pumps direct from the original equipment manufacturer (OEM) can be quite expensive. Significant cost savings can be obtained by using a remanufactured part. For example, a salvaged and remanufactured transmission pump from a 1984 model year 700-R4 transmission could be used for the same transmission for 1984-1994 model years. As these are older cars and cover over ten years of production, the number of salvageable transmission pumps are plentiful and comparatively low cost. However due to later model year changes in the transmission, the same pump could not be used for the same transmission of a 1995 model year. The limited number of salvaged transmission pumps from a transmission pump having a run of one or two years makes it virtually impossible to get a remanufactured part, thereby forcing the consumer to pay for a new OEM transmission pump.

Therefore, there remains a need in the art for a method of converting an older version of the transmission pump into a configuration compatible with later model year transmission pumps.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an inexpensive and easily produced method for refurbishing transmission pump assemblies for later model year transmissions. These and other advantages are provided by a method of changing the configuration of a transmission pump assembly from a first configuration to a second configuration, the method comprising the following steps: a) providing a first configuration transmission pump assembly comprising a pump body and a pump cover, wherein the pump body and the pump cover each have a plurality of fluid passageways formed between worm tracks on at least one side thereof; b) removing a portion of the worm tracks from both the pump body and the pump cover; c) providing at least one insert; d) attaching the at least one insert into a predetermined position; and e) machining the pump cover and pump body to the second configuration.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention and developments thereof are described in more detail in the following by way of embodiments with reference to the drawings, in which:

FIG. 1

is an exploded perspective view of a typical automatic transmission showing the relative positions of the torque converter and fluid pump;

FIG. 2

is an exploded perspective view of a typical vane type fluid pump assembly;

FIG. 3

is a plan view of the worm track side of an unmodified pump body;

FIG. 4

is a perspective view of the front side of an unmodified pump body;

FIG. 5

is a plan view of the worm track side of a modified pump body;

FIG. 6

is a perspective view of the front side of a modified pump body;

FIG. 7

is a plan view of the worm track side of an unmodified pump cover;

FIG. 8

is a plan view of the worm track side of a modified pump cover;

FIG. 9

is a plan view of a portion of the worm track side of an unmodified pump body;

FIG. 10

is a plan view of the pump body shown in

FIG. 9

having portions of the worm track removed;

FIG. 11

is a plan view of the pump body shown in

FIG. 10

having grooves machined into the floor of the pump body;

FIG. 12

is a plan view of the pump body shown in

FIG. 11

having inserts attached to change the worm tracks to the modified configuration;

FIG. 13

is a perspective view of the cast insert shown in

FIG. 12

;

FIG. 14

is a plan view of a riser ring casting;

FIG. 15

is a plan view of a riser ring.

FIG. 16

is a plan view of the pump cover shown in

FIG. 7

having grooves machined into the floor of the pump body;

FIG. 17

is a perspective view of an insert;

FIG. 18

is a plan view of the pump cover shown in

FIG. 16

having three inserts attached;

FIG. 19

is a plan view of the pump cover shown in

FIG. 18

which is machined to its final configuration; and

FIG. 20

is a side elevational view of the pump cover.

FIG. 21

is a listing of the steps of the method of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1

illustrates a partial exploded view of a typical automatic transmission assembly

110

. The torque converter

112

is housed in a converter housing

114

. Fluid pump assembly

116

is housed within a transmission case

118

. Extension housing

120

is attached to an end of the transmission case

118

opposite the converter housing

114

. Fluid pan

122

is attached to the bottom of transmission case

118

. The transmission assembly

110

also comprises a input shaft

124

which is driven by the engine (not shown).

Referring now to

FIG. 2

, a typical 1984 and on C-vane type fluid pump assembly

126

as used in a GM 700-R4 transmission is shown in an exploded perspective view. The major components of the fluid pump assembly

126

are the pump vane rotor assembly

128

, pump slide

130

, pump body

132

, pump stator, or cover

134

, and stator shaft

136

, shown herein attached to pump cover

134

. The pump body

132

and pump cover

134

each have corresponding fluid passageways

137

also referred to as worm grooves, separated from each other by passageway walls

160

, or worm tracks. Some of the passageways

137

have holes designed for fluid passage which allow fluid flow in a particular direction or that can open or close on demand. It is noted that the configuration shown is a 7-vane fluid pump. The number of vanes was increased to 10 staggered vanes in the 1986 model year, and then 13 vanes in 1997 model year.

Pump body

132

is shown in

FIGS. 3 and 4

, with

FIG. 3

showing a plan view of the worm track side

138

of pump body

132

and

FIG. 4

showing a perspective view of the front side

140

of the pump body

132

. A 10 vane rotor assembly

228

and associated pump slide

230

are shown mounted in the central recess of the worm track side

138

of pump body

132

. A seal drain passageway

152

is also partially shown as it is contiguous through the side of the pump body (not shown). A mounting register face

142

is shown machined into the radial outward portion of the front side

140

of the pump body

132

. Mounting bolt holes

144

are positioned about the mounting face

142

.

As previously mentioned, a series of changes were made to the fluid pump assembly

126

starting with the 1995 model year. These changes primarily involved changes to the configuration of the fluid passageways

137

to incorporate pulse width modulation. These changes were intended to help the transmission

110

run more smoothly and eliminate pressure spikes from the transmission pump assembly. Referring now to

FIG. 5

, a plan view of the worm track side

138

′ of a 1995 and on model year configuration pump body

132

′ is shown. The fluid passageways

137

that are modified are highlighted by being shown as darkened areas

146

. In addition, the seal drain passageway

152

was enlarged to improve fluid flow. Changes in the 1996 model year involved primarily the addition of risers on the torque converter side of the pump body. Referring now to

FIG. 6

, a perspective view of the front side

140

′ of a 1996 and on model year configuration pump body

132

″ is shown. Risers

148

are positioned about the circumference of register face

142

′. The risers

148

were added to center the pump assembly

116

in the bell housing (not shown).

Referring now to

FIG. 7

, a plan view of the worm track side

150

of an unmodified pump cover

134

is shown. The fluid passageways

137

of the pump cover were also modified in the 1996 model year. A plan view of the worm track side

150

′ of a modified pump cover

134

′ is shown in FIG.

8

. The fluid passageways

137

that are modified are highlighted by being shown as darkened areas

146

.

The method

10

of converting the configuration of a transmission fluid pump assembly

116

in accordance with the present invention will now be described in detail and are listed for reference in FIG.

21

. The initial step is providing

12

a 1984-1994 model year transmission pump assembly

116

for a 700-R4 transmission assembly

110

. While a new OEM pump assembly

116

could be used, it is more economical to use a salvaged used pump assembly

116

.

The next step is to disassemble

14

the used, transmission pump core

116

into its three major components, the pump body

132

, pump cover

134

, and stator shaft

136

. The components are then degreased

16

. The modification of the pump body

132

is described next.

Transmission pumps are subjected to significant heat/cooling cycles during their operation and a used pump

126

may be slightly warped. Accordingly, the mounting register face

142

of the front side

140

of the pump body

132

is cut

18

on a lathe to remove any warpage due to service. The seal drain passage

152

is then machined

20

to enlarge the passageway

152

to the modified pump specifications. The pump body

132

is then bead-blasted

22

to clean up the surfaces for machining.

Referring now to

FIGS. 9-13

, the modification of the fluid passageways

137

is shown.

FIG. 9

shows a partial plan view of a portion of an unmodified pump body

132

. The pump body is then placed on a CNC mill and portions

154

of the worm track wall

160

are cut away

24

as best shown in FIG.

10

. Special care is taken to the radius on the four sides created in the cavity. The next step is to cut

26

grooves

156

,

157

into the floor

158

of the pump body

132

which corresponds to the localized changes to the worm track wall

160

of the 1995 model of the pump body

132

′. The grooves

156

,

157

are shown in dotted lines in

FIG. 11

Referring now to

FIGS. 12 and 13

, insert

170

is created

28

to provide the new configuration of the worm track walls

160

and is generally shaped like the number “2”. The insert is made as an aluminum casting, however, it is not intended to be limited as such and may be machined or formed by any suitable means. The insert

170

is secured

30

within the corresponding groove

156

by an industrial adhesive

168

which is applied to the bottom and sides of the insert

170

. The industrial adhesive

168

may be any suitable adhesive which will permanently hold the insert

170

, even when post machining work is being done on the insert. An additional piece of aluminum

172

is secured

32

with industrial adhesive

168

within groove

157

to duplicate a second modification to the worm track walls

160

. The smaller insert

172

is typically oversize and then machined

34

(after the adhesive is dried) to its final dimensions to correspond with the specification of the modified pump body

132

′ as shown in FIG.

12

.

After the adhesive is dried, the pump body

132

′ is placed on a lathe. The register face

174

and the pump assembly recess face

176

are cut

36

to a tolerance of plus or minus two tenthousandths (0.0002) of an inch. The slide

230

, rotor vane assembly

228

, and other associated parts are installed

36

on the pump body. The pump body is now configured as 1995 model year modified pump body

132

′ (see FIG.

5

).

As previously discussed with relation to

FIG. 6

, the pump body

132

′ was modified in the 1996 model year. For 1996 and on model years, the method of conversion

10

further comprises the addition of a riser ring

180

. The riser ring

180

is produced as follows. An aluminum ring

180

with risers

148

generally corresponding to the dimensions of the mounting register face

142

of the front side

140

of the pump body

132

, is cast

40

in a mold (a ring could also be machined but would be more costly if a significant number of pumps are being remanufactured). The as-cast ring

180

is placed on a lathe and the bottom

182

of the ring

180

is cut

42

flat. The outside diameter

184

and the inside diameter

186

are hand filed

44

to assure that it fits in a fixture (not shown). The fixture is a device used to hold

46

the ring

180

under the pump body

132

′ in a manner that the bolt holes

144

in the pump body are used as guides to drill

48

the mounting holes

144

′ in the ring

180

. Because these bolt holes

144

vary slightly from one pump to another, the pump body

132

′ used to drill the holes

144

′ is mated to the particular riser ring

180

. Industrial adhesive

168

is placed on the bottom face

182

of the ring

180

and the bottom face

182

is attached

50

to the register face

142

of the front side

140

of the pump body

132

such that the mounting holes

144

,

144

′ are properly aligned.

After the adhesive has dried, the pump body

132

is placed in another special set of jaws on the lathe. The outside diameter of the riser ring is cut

52

to match the outside diameter of the pump body. The top face

183

of the ring is then cut

54

so that the thickness of the pump body

132

with the ring installed meets the dimension specification of the modified pump body

132

′.

Referring again to

FIGS. 7 and 8

, the pump cover

134

must also be modified in a similar manner as the pump body

132

to convert it to the modified pump cover

134

′ configuration. Referring now to

FIGS. 16-20

, the modification of the fluid passageways

137

on the pump cover

134

is shown.

FIG. 16

shows a partial plan view of a portion of pump cover

134

. Hole

188

is plugged

56

with an aluminum rivet

192

. Grooves

194

,

196

, and

198

are cut

57

into the floor of the pump cover

134

to allow three inserts to be installed. Although not shown, portions of the worm groove walls may also be milled to allow additional room for installation of the inserts. Referring now to

FIGS. 17 and 18

, cast aluminum insert

190

is created

58

to provide portion of the new configuration of the worm track walls

160

and is generally shaped like the letter “L”. A second insert

200

is provided

60

and machined as a one inch square piece of aluminum, {fraction (3/16)}″ thick, with full radius on two sides. A third insert

202

is also provided

62

. The inserts

190

,

200

,

202

are attached

64

to the pump cover

134

with a suitable industrial adhesive. After the adhesive has dried sufficiently, the pump cover

134

is then milled

66

at locations

204

to the modified pump cover configuration

134

′ as shown in FIG.

19

.

The pump cover

134

′ is placed in the lathe and the back side, the side opposite the worm track side

138

, is cut

68

parallel to the worm track side

138

.

Referring now to

FIG. 20

, the three major holes

206

,

207

,

208

are centered, drilled, and reamed

70

to the larger hole specifications of the modified pump cover

134

′ to a tolerance of plus or minus 0.0002″. The stator shaft

136

is then installed

72

through pump cover

134

′ and it is placed back on the lathe. The worm track side

138

′ of pump cover

134

′ is faced

74

and it is now ready for assembly

76

with pump body

132

′.

Although not specifically discussed several additional holes are enlarged and/or plugged to finalize the conversion. These operations are omitted as they are common machining procedures understood by those in the art.

The present invention provides a method of conversion of a transmission pump without requiring any welding. It is contemplated that the inserts could be replaced by direct welding in the locations to be modified and then machined to the proper configuration. However, the welds sections may have problems with porosity that even peening of the weld areas may not solve. In addition, the high temperatures involved in the welding process may warp the pump cover and the pump body.

The present invention shows a particular transmission pump assembly used in a General Motors application. It is contemplated that the method of the present invention could easily be adapted to be used to convert other transmission pump assemblies that have been changed by the manufacturer under similar conditions.

Although the present invention has been described above in detail, the same is by way of illustration and example only and is not to be taken as a limitation on the present invention. Accordingly, the scope and content of the present invention are to be defined only by the terms of the appended claims.