JP5064459B2 - Torque converter pump impeller - Google Patents

Description

  The present invention relates to a pump impeller for a torque converter in an automatic transmission.

In an automatic transmission for a vehicle, a torque converter is disposed between the transmission mechanism and a power source.
The torque converter is a pump impeller connected to the power source side as an input element, a turbine runner connected to the input shaft of the transmission mechanism as an output element, and rectification of working fluid returning from the turbine runner to the pump impeller as a reaction element. A working fluid circulation path is formed with a stator to perform power transmission through the working fluid.
As shown in FIG. 7, the pump impeller 1 ′ is formed by fixing an impeller blade 2 to an impeller shell 10 ′. That is, the impeller shell 10 ′ has a cross-sectional shape having an annular recess 13, and a large number of impeller blades 2 are arranged in the circumferential direction on the inner surface of the annular recess 13. Further, a torque converter sleeve 20 ′ is welded to the impeller shell 10 ′ in the center in order to rotate coaxially with the input shaft.

The impeller blade 2 includes a plurality of claws 6 on the outer peripheral edge along the inner surface shape of the annular recess 13 and also includes a claw 7 on the inner peripheral edge. The impeller shell 10 ′ is formed with a recess 15 corresponding to the claw 6 on the outer peripheral edge of the impeller blade 2.
The impeller blade 2 is engaged with the core ring 30 by locking the outer peripheral claw 6 to the recess 15 of the impeller shell 10 ′ and bending the inner peripheral claw 7 after passing through the slit of the core ring 30.
The annular recess 13 of the impeller shell 10 'forms a part of the outer peripheral wall in the working fluid circulation path, and the coring 30 forms a part of the inner peripheral wall in the working fluid circulation path.

By the way, the torque converter incorporating the pump impeller 1 ′ is exposed to various environmental changes before and after driving the vehicle or during driving. For example, there is an increase in the temperature of the working fluid due to operation and an increase in internal pressure at the time of lockup.
For this reason, even if all the impeller blades 2 are coupled to the core ring 30, the impeller shell 10 ′ can be obtained only by locking the claw 6 on the outer peripheral edge of the impeller blade 2 in the recess 15 of the impeller shell 10 ′. When the swell expands, the claw 6 receiving the reaction force of the working fluid comes out of the recess 15 and the impeller blade 2 as a whole is detached from the impeller shell 10 '.

Conventionally, as countermeasures, for example, brazing as shown in Japanese Utility Model Laid-Open No. 63-171758, spot welding as shown in Japanese Patent Laid-Open No. 9-257114, or Japanese Patent Laid-Open No. 5-104268 is shown. The impeller blade is prevented from being detached from the impeller shell by welding with such a laser beam.
However, these measures require an expensive brazing material or an expensive welding apparatus, and both of them require labor.
Therefore, there is a pump impeller in which the brazing and welding are omitted in production, and the impeller blade is fixed to the impeller shell by caulking.

Such a pump impeller is conventionally manufactured by the following procedure.
First, as shown in FIG. 8A, an impeller shell 10 ′ having a central hole 11 ′ corresponding to the outer peripheral surface of the flange 24 ′ of the torque converter sleeve 20 ′ is press-molded, and then as shown in FIG. 8B. The outer peripheral edge of the flange 24 ′ of the torque converter sleeve 20 ′ and the inner peripheral edge of the central hole 11 ′ of the impeller shell 10 ′ are butt welded to integrate the impeller shell 10 ′ and the torque converter sleeve 20 ′.

Then, as shown in FIG. 9C, the claws 6 of the respective impeller blades 2 are fitted into the recesses 15 of the impeller shell 10 ′, and the core ring 30 is coupled to all the impeller blades 2.
Thereafter, as shown in (d), a caulking tool K in which a portion of each impeller blade 2 in the impeller shell 10 ′ where the inner diameter side end Ei, which is the inner diameter direction tip, is located with respect to the center of the center hole 11 ′ is attached to the press. The inner diameter side end Ei of the impeller blade 2 and the impeller shell 10 ′ are caulked.
As a result, the impeller blade 2 was expected not only to have its claw 6 locked to the recess 15 of the impeller shell 10 'but also to be fixed by caulking and securely coupled to the impeller shell 10'.

Japanese Utility Model Publication No. 63-171758 Japanese Patent Laid-Open No. 5-104268 JP-A-9-257114

However, the pump impeller 1 ′ having the above-described caulking impeller blade fixing structure retains the expected coupling effect for a while, but after a long period of time, the impeller blade 2 loses its effect and the impeller blade 2 becomes impeller shell. There is a concern from 10 '.
The inventor has studied the cause, and when the above-described expansion phenomenon due to the temperature rise or the internal pressure rise in the torque converter is repeated every time the operation is performed, the impeller blade 2 and the impeller shell 10 'are brought into contact with each other at the caulking portion. It has been found that the end of the impeller blade 2 is worn by rubbing due to expansion / contraction deformation on the surface.
If the end portion of the impeller blade 2 in the caulking portion is worn out, the fixing function by caulking is naturally lost, so the impeller blade 2 simply has its pawl 6 locked in the recess 15 of the impeller shell 10 '. When the impeller shell 10 'expands, it comes off.

  Therefore, in view of the above-described problems, the present invention ensures that the fixed state of the impeller blade is reliably maintained without causing an increase in cost in the torque converter in which the impeller blade of the pump impeller is fixed to the impeller shell by caulking. An object is to provide a pump impeller.

  Therefore, the present invention includes an impeller shell having an annular recess surrounding the central hole, a torque converter sleeve welded to the impeller shell at a hole edge of the central hole, and a plurality of impeller blades disposed in the annular recess of the impeller shell, A pump impeller having a core ring connected to each impeller blade and caulking and fixing the inner diameter side end of the impeller blade and the vicinity of the center hole of the impeller shell, and by performing the above-described welding after fixing the caulking The inner diameter side end portion of the impeller blade in the caulking fixing portion is assumed to be quenched by welding heat.

  According to the present invention, the inner diameter side end portion of the impeller blade in the caulking fixing portion is hardened by welding heat to increase the hardness, and even if there is rubbing between the impeller blade and the impeller shell due to expansion / contraction, the impeller blade Therefore, the fixed state of the impeller blade is reliably maintained, and therefore, the situation where the impeller blade is detached from the impeller shell is prevented.

It is sectional drawing which shows the pump impeller of embodiment. It is the elements on larger scale of a pump impeller. It is a figure which shows a torque converter sleeve. It is explanatory drawing which shows the manufacture procedure of a pump impeller. It is explanatory drawing which shows the manufacture procedure of a pump impeller. It is a figure which shows the surface hardness of an impeller blade. It is a figure which shows the prior art example of a pump impeller. It is explanatory drawing which shows the manufacture procedure of the conventional pump impeller. It is explanatory drawing which shows the manufacture procedure of the conventional pump impeller.

Next, embodiments of the present invention will be described in detail.
FIG. 1 is a cross-sectional view showing a pump impeller according to an embodiment.
The pump impeller 1 is configured by attaching a large number of impeller blades 2 to an impeller shell 10 to which a torque converter sleeve 20 is welded, and connecting each impeller blade 2 to one core ring 30.
The impeller shell 10 is a metal molded product, has a bowl-shaped annular recess 13 surrounding the central hole 11, and the impeller blade 2 is disposed on the inner surface of the annular recess 13. Although not particularly shown, the impeller blades 2 are arranged at equal intervals in the circumferential direction of the annular recess 13 as is well known. The impeller blade 2 is press-formed from a metal plate thinner than the impeller shell 10.

As shown in the enlarged view of FIG. 2, the impeller blade 2 projects three pieces of claws 6 (6 a, 6 b, 6 c) from the outer peripheral edge 3 along the inner shape of the annular recess 13, and also shows a broken line from the inner peripheral edge 4. As shown by, the claw 7 (7a, 7b) is projected.
The impeller shell 10 is formed with recesses 15 (15a, 15b, 15c) corresponding to the claw 6 on the outer peripheral edge of the impeller blade 2, and each claw is fitted therein.
In addition, in the state fitted in the dent 15, the protruding tip edge of the claw 6 is set so as to leave a minute gap between the bottom wall of the dent 15, whereby the outer peripheral edge 3 of the impeller blade 2 is It contacts the inner surface of the annular recess 13 of the impeller shell 10 without a gap.

The claw 7 on the inner peripheral edge passes through the slits 31 and 32 of the core ring 30, and is then bent and joined to the core ring 30 by rolling as indicated by a solid line.
Each impeller blade 2 is inclined with respect to a diameter line passing through the center of the central hole 11 of the impeller shell 10, and FIG. 2 shows a cross section along the outer peripheral edge 3 of the impeller blade 2.

The impeller blade 2 tapers inwardly (in the inner diameter direction with respect to the center of the central hole 11 of the impeller shell 10) from the coupling portion with the core ring 30. One of the claws 6 (claw 6 a) on the outer peripheral edge 3 of the impeller blade is provided at the inner tip of the impeller blade 2, and the side of the claw 6 a is the inner diameter side end Ei of the impeller blade 2.
The remaining two claws 6b, 6c of the impeller blade outer peripheral edge 3 are provided closer to the opposite outer diameter side end Eo.
Since the inner diameter side end Ei of the impeller blade 2 is a part of the claw 6 a, the impeller blade 2 is in a state of sinking in the recess 15 a of the impeller shell 10. The wall surface on the inner diameter side of the recess 15 a into which the claw 6 a is fitted in the impeller shell 10 is crushed by the caulking tool and partially rides on the inner diameter side end Ei of the impeller blade 2 and is crimped.

As shown in FIG. 3, the torque converter sleeve 20 includes a cylindrical portion 22 and a flange 24 that extends in a radial direction from one end of the cylindrical portion 22. The flange 24 has an outer diameter that matches the inner diameter surface 12 of the central hole 11 of the impeller shell 10.
The flange 24 has a restriction wall 27 protruding outward in the radial direction from the outer peripheral surface 25 in order to align the impeller shell 10 and the flange 24 in the axial direction during welding.

Returning to FIG. 2, the impeller shell 10 makes the hole edge of the central hole 11 abut against the regulating wall 27 of the torque converter sleeve 20, the inner surface 12 of the central hole 11 is abutted with the outer peripheral surface 25 of the flange 24, and they are welded together. Are combined. W is a weld bead.
The distance L between the butting surface F (the inner diameter surface 12 of the central hole 11) with the flange 24 and the wall surface on the inner diameter side of the recess 15a is set to be not more than three times the plate thickness t around the central hole 11 of the impeller shell 10. Is done. Correspondingly, the diameter of the central hole 11 and the outer diameter of the flange 24 are set.

The pump impeller 1 having the above configuration is manufactured by the following procedure.
First, as shown in FIG. 4A, the first step has a central hole 11 having a diameter corresponding to the outer peripheral surface 25 (see FIG. 3) of the flange 24 of the torque converter sleeve 20 and is recessed in the annular recess 13. The impeller shell 10 having 15 (15a, 15b, 15c) is press-molded.
In the second step, the impeller blade 2 having the claws 6 (6a, 6b, 6c) on the outer peripheral edge 3 and the claws 7 (7a, 7b) on the inner peripheral edge 4 is formed.
The first step and the second step do not have a temporal order and may be executed in parallel, and the impeller shell 10 and the impeller blade 2 may be used for the next third step.
In the third step, the claws 6 of the impeller blades 2 are fitted into the recesses 15 of the impeller shell 10 as shown in FIG. The impeller blades 2 are arranged in the circumferential direction in the annular recess 13.
In the fourth step, the core ring 30 is coupled to all the impeller blades 2.
Note that the order of the third step and the fourth step may be reversed.

Then, in the fifth step, as shown in FIG. 5C, the portion where the inner diameter side end Ei of the impeller blade 2 in the impeller shell 10 is deformed by a caulking tool, and the inner diameter side end Ei of the impeller blade is The impeller shell 10 is fixed by caulking.
Thereafter, in the sixth step, as shown in (d), the flange outer peripheral surface 25 (see FIG. 3) of the torque converter sleeve 20 and the inner diameter surface 12 of the central hole 11 of the impeller shell 10 are butt welded to form an impeller. The shell 10 and the torque converter sleeve 20 are integrated to form a completed pump impeller 1.

By caulking in the fifth step, the inner diameter side end Ei of the impeller blade 2 and the wall surface of the recess 15a of the impeller shell 10 are brought into close contact with each other, and welding in step 6 is performed in this close state, so that welding heat is transferred from the impeller shell 10 to the impeller. It is transmitted to the inner diameter side end Ei of the blade 2, and the end portion of the impeller blade 2 exhibits a temper collar indicating a heat treatment state.
FIG. 6 shows the measurement results of the surface hardness of the impeller blade 2 after the welding. A typical SAPH440 material having a thickness of 3.6 mm is shown as an impeller shell of a passenger car torque converter. The impeller blade is an SPCC material thinner than the impeller shell and has a plate thickness of 1.0 mm.
The hardness of the impeller blade 2 increases toward the tip (inner diameter side end Ei), and the end of the impeller blade 2 is in a quenched state.

  Therefore, even if the friction between the impeller blade 2 and the impeller shell 10 due to expansion / contraction deformation occurs in the crimping portion, not only the impeller shell 10 that receives direct welding heat, but also the end portion of the impeller blade 2 Since it is hardened by quenching, it does not wear out.

  The distance L between the contact surface between the impeller blade 2 and the impeller shell 10 and the welding abutting surface F is 3 times or less the plate thickness around the central hole 11 of the impeller shell 10 as described above. If it is too close, the weld bead W is applied to the curvature radius (R) portion of the rising base of the bulging portion 17 that appears on the outer surface of the impeller shell 10 according to the formation of the recess 15a, and an edge is generated, which may cause stress concentration. . For this reason, the distance L is set to be twice the thickness t in particular, because the weld bead W is not applied to the radius of curvature, and the maximum amount of heat is avoided while avoiding stress concentration (the inner diameter of the impeller blade 2). Most preferred since it can affect the side edges.

The embodiment is configured as described above, and includes an impeller shell 10 that surrounds the central hole 11 and has an annular recess 13, a torque converter sleeve 20 that is welded to the impeller shell 10 on the inner diameter surface 12 of the central hole 11, and the impeller shell 10. A plurality of impeller blades 2 disposed in the annular recess 13 and a core ring 30 connected to each impeller blade 2, and the inner diameter side end Ei of the impeller blade 2 and the vicinity of the central hole 11 of the impeller shell 10 are caulked. Since it is a fixed pump impeller, and the above welding is performed after caulking, the inner diameter side end Ei portion of the impeller blade 2 in the caulking fixing portion is in a quenched state by welding heat. The impeller blade 2 in the caulking portion has a higher hardness, and the impeller blade 2 and the impeller due to expansion / contraction Without impeller blade 2 even rubbing between E le 10 wears, the fixed state of the impeller blade 2 is securely held.
As a result, the situation where the impeller blade 2 is detached from the impeller shell 10 is prevented. (Effects corresponding to claim 1)

  The distance L between the inner diameter side end Ei of the impeller blade 2 and the welding butting surface F is such that the weld bead W rises in the annular recess 13 (particularly the bulging portion 17 of the recess 15a) on the outer surface of the impeller shell 10. Since the distance does not extend to the radius of curvature (R) at the base, the weld bead is not welded to the radius of curvature, and deformation corresponding to the expansion or contraction of the impeller shell is possible at the radius of curvature, and stress concentration Is not invited. (Effects corresponding to claim 2)

  In particular, the distance L between the inner diameter side end Ei of the impeller blade 2 and the weld butting surface F (the inner diameter surface 12 of the central hole 11 of the impeller shell) is set to be not more than three times the plate thickness t around the central hole 11 of the impeller shell. As a result, the welding heat sufficiently reaches the inner diameter side end Ei of the impeller blade 2 and the quenching state can be ensured. Here, since the torque converter sleeve 20 has the cylindrical part 22 and the flange 24 extended from the cylindrical part 22 in the radial direction, the center hole 11 can be enlarged according to the setting of the distance L. This can be dealt with by simply increasing the outer diameter of the flange 24 for butt welding with the inner diameter surface 12 of the central hole 11. (Effects corresponding to claim 3)

  In particular, the distance L between the inner diameter side end Ei of the impeller blade 2 and the welding butting surface F is twice the thickness t around the central hole 11 of the impeller shell 10, thereby forming the thickness of the impeller blade 2. With the size of the weld bead W, the welded part can be brought close to the caulking part to the limit that does not reach the radius of curvature, and the deformation corresponding to the expansion or contraction of the impeller shell described above can be accommodated, and the maximum heat can be applied to the welded part. To the inner diameter side end Ei of the impeller blade 2 in the caulking portion. (Effects corresponding to claim 4)

  Further, the impeller blade 2 projects a claw 6 a having a side edge Ei on the outer peripheral edge 3 along the annular recess 13, and the impeller shell 10 is formed on the inner surface of the annular recess 13 on the claw 6 a of the impeller blade 2. Since the corresponding recess 15a is provided and the inner wall surface of the recess 15a serves as a contact surface with the inner diameter side end Ei of the impeller blade 2, the inner wall surface on the inner diameter side of the recess 15a is crushed. The upper portion easily rides on the inner diameter side end Ei of the impeller blade 2, and simple and reliable caulking is obtained.

Moreover, in the manufacturing procedure of the pump impeller in the embodiment, the first step of forming the impeller shell 10 having the central hole 11 and the annular recess 13 and including the depressions 15 arranged in the annular recess 13 in the circumferential direction; A second step of forming the impeller blade 2 having the claw 6 at least on the outer peripheral edge 3; and a third step of fitting the claw 6 of each impeller blade 2 into the recess 15 of the impeller shell 10 and arranging them in the annular recess 13 A fourth step of coupling the core ring 30 to the impeller blades 2 arranged in the annular recess 13, a fifth step of caulking and fixing the inner diameter side end Ei of the impeller blade 2 to the impeller shell 10, and a fifth step After that, since the torque converter sleeve 20 and the impeller shell 10 are welded to each other at the hole edge of the central hole 11, the sixth step is performed. The inner diameter side end Ei portion Pella blade 2 in a state quenching by receiving heat transfer welding heat. This increases the hardness of the impeller blade 2 in the caulking fixing portion, and the impeller blade 2 is not worn even if the impeller blade 2 and the impeller shell 10 are rubbed due to expansion / contraction, and the impeller blade 2 is fixed. Is securely held.
Since a separate quenching process is not required to increase the hardness of the impeller blade 2, this is realized without an increase in manufacturing time and cost.

In the embodiment, the example in which the claw 6a is formed at the inner tip of the outer peripheral edge 3 of the impeller blade 2 and the side end of the claw 6a is the inner diameter side end Ei of the impeller blade 2 has been described. When the claw is formed at a position separated from the tip of the outer peripheral edge 3, the tapered tip of the main body portion of the impeller blade 2 excluding the claw becomes the inner diameter side end Ei of the impeller blade 2. . In this case, the impeller shell 10 can be caulked easily by providing a wall surface in contact with the inner diameter side end Ei in addition to the recess 15.
In the embodiment, the impeller shell 10 side is crushed and the impeller blade 2 is fixed to the impeller shell 10 as caulking. However, the present invention is not limited to this, and the impeller blade 2 side is crushed and fixed, or both are crushed. And may be fixed.

  The present invention is particularly effective when applied to a torque converter for other automatic transmissions for vehicles.

DESCRIPTION OF SYMBOLS 1 Pump impeller 2 Impeller blade 3 Outer peripheral edge 6a, 6b, 6c Claw 7a, 7b Claw 10 Impeller shell 11 Center hole 12 Inner diameter surface 13 Annular recessed part 15a, 15b, 15c Indentation 17 Expansion part 20 Torcon sleeve 22 Cylinder part 24 Flange 25 Outer peripheral surface 27 Restriction wall 30 Coring 31, 32 Slit Ei Inner diameter side end Eo Outer diameter side end F Abutting surface K Caulking tool W Weld bead

Claims (4)

An impeller shell surrounding the central hole and having an annular recess; a torque converter sleeve welded to the impeller shell at the hole edge of the central hole; a plurality of impeller blades disposed in the annular recess of the impeller shell; and each impeller blade A pump impeller having a connected core ring, and caulking and fixing the inner diameter side end of the impeller blade and the vicinity of the center hole of the impeller shell,
A pump impeller for a torque converter, wherein the inner diameter side end portion of the impeller blade in the caulking fixing portion is quenched by welding heat by performing the welding after the caulking fixing.   The distance between the inner diameter side end of the impeller blade and the inner diameter surface of the central hole of the impeller shell is a distance such that the weld bead does not reach the radius of curvature of the rising root of the annular recess on the outer surface of the impeller shell. The pump impeller for a torque converter according to claim 1. The distance between the inner diameter side end of the impeller blade and the inner diameter surface of the central hole of the impeller shell is not more than three times the plate thickness around the central hole of the impeller shell;
The torque converter sleeve has a cylindrical portion and a flange extending in a radial direction from the cylindrical portion, and is butt welded to an inner diameter surface of the central hole on an outer peripheral surface of the flange. The pump impeller of the torque converter described in 1.   The distance between the inner diameter side end of the impeller blade and the inner diameter surface of the central hole of the impeller shell is twice the plate thickness around the central hole of the impeller shell. Torque converter pump impeller.

Images