JPS5810568B2 - Rotating piston polygonal piston for internal combustion engine and method for manufacturing the piston - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a rotary piston of trochoidal design for an internal combustion engine, having an outer circumferential wall forming the piston sides, side parts parallel to each other, and an inner circumferential wall forming a central bearing boss. The present invention relates to a shaped piston, and further relates to a method of manufacturing the piston.

Pistons of this type have traditionally been formed as cast parts, which requires expensive molds and mold cores.

Castings must be machined on all surfaces.

Cleaning the sand inside is difficult. The wall thickness of cast pistons is relatively large and not completely uniform, thus creating an unbalanced weight on the piston that must later be removed.

SUMMARY OF THE INVENTION It is an object of the invention to provide a polygonal piston of the above-mentioned type which is easy to manufacture, has a reduced weight and a reduced unbalanced weight.

The piston according to the invention is characterized in that its wall is formed from a single steel plate member formed without cutting, and the members are welded or welded together at their contact points.

This proposal of the invention makes it possible for the can walls of the pistons to each have exactly the same wall thickness, which can be considerably thinner compared to the wall thickness of the cast piston, thereby reducing the weight and the stability. Guarantees low balance weight.

At least the outer circumferential surface forming the side surface of the piston does not require any finishing work.

The thin wall thickness also provides good cooling.

In particular, the outer circumferential walls of the pistons are each formed from the same dimensionally precisely press-stamped steel plate parts forming the side walls of the piston, and these parts are placed on the circumferential surfaces of the steel plate parts forming the side walls. , is welded or welded to this peripheral surface.

The bearing boss consists of a plate section formed by two members, optionally formed in mirror image, with a U-shaped cross section, the legs of the plate section being welded or welded to the inner surface of the side surface. There is.

The steel plate member forming the side surface of the piston is the same member as the steel plate forming the side wall, and can be easily manufactured by pressing and punching.

Since a radial groove is required for accommodating the sealing member in the piston corner, an insert made of material ( It is expedient to provide a profile material (hereinafter referred to as profile material) which is connected to the adjacent inner surface of the steel sheet member forming the side surface of the piston and has a radial groove for accommodating the sealing member. do.

The insert can also protrude through the steel plate forming the side wall, so that the airtightness is not compromised.

This is because radial grooves cannot be formed through multiple structural members that must be connected to each other.

One of the steel plate parts forming the side wall may be made of particularly hardenable steel and may be provided with internal teeth forming part of the transmission mechanism of the piston.

This internal toothing can be molded before installing the piston.

This process can be performed fairly easily on gears conventionally fixed to pistons.

The steel plate member forming the side wall may be provided with a groove on its inner surface that is parallel to the periphery and extends near the periphery.

The groove receives a flow of cooling medium, so that the area where the axial seal is attached to the outer surface of the side wall is cooled.

In order to ensure good circulation of the cooling medium in the inner chamber of the piston, a guide plate with a T-shaped cross section is provided between the piston side surface and the bearing boss, the central leg of which is provided in the bearing boss. Located at the center of the cooling medium supply port.

The supplied cooling medium is circulated circumferentially by these legs.
It is diverted to one piston corner and to the other piston corner.

Other embodiments proposed by the invention are also possible.

That is, the long lateral edge of the steel plate forming the piston side surface contacts the inner surface of the steel plate forming the side wall and is gripped in the radial direction by this steel plate, and at this time the outer surface of the piston side surface touches the periphery of the side wall. It is proposed that the piston side surface coincides with the surface and that the piston side surface is supported on the leg of the bearing boss.

In this proposal, the piston side surface provided between the side walls is
It is also possible that, in the edge region of its inner surface, it is supported radially on bearing hub legs that contact between the side walls.

This leg-shaped portion reaches near the peripheral surface of the peripheral wall.

In order to provide additional reinforcement in the area of the piston side and its recess, the piston side is supported in its center on the bearing boss via a reinforcing plate arranged parallel to the side wall, which reinforcing plate is provided with guide plates on the side. , a cooling medium in which the guide plate is provided within the bearing boss.
We suggest that it be placed in the center of the supply port.

Due to this reinforcing plate, the force acting on the side surface of the piston does not have any negative effect on the shape stability of the piston, while the guide plate diverts the supplied cooling medium in the circumferential direction to one and the other of the adjacent piston corners. do.

The circumferential walls, i.e. the individual piston sides, are further strengthened relative to each other, i.e. in the circumferential direction, by means of inserts provided at the piston corners that connect the inner surfaces of the piston sides and are gripped by correspondingly bent connections. This is carried out by permanently connecting the connecting member to the respective steel plate part of the piston side surface by welding.

The proposed technical idea improves the strength and stability of the piston (steel column) to the extent that under the influence of the forces and temperature acting on the piston it never produces deformations that deteriorate the tightness of the piston.

According to a further proposal of the invention, the side wall contacts flatly on its inside the radially outwardly extending bearing boss leg and the piston side, so that the side wall is shaped in the bearing hub leg and in contact with the piston side. Aligned.

The centering is formed, for example, by a through shaft, which passes through the side wall and the leg in common.

However, the centering may also be formed by half-cuts.

The half-cut portion projects from the side wall and fits exactly into a corresponding hole or recess in the leg of the bearing boss.

The invention also relates to a method for manufacturing a piston according to the invention.

This method involves press punching a steel plate member with accurate dimensions.
Inserts for the piston corners made of profile material are cut out and preformed by precision punching of the inner teeth of the steel plate parts forming one side wall, and then welded gaps are formed in order to fix all the parts together with one side wall. The welding material is placed at the abutting position, the second side wall is attached, and then all the parts are welded together in a welding furnace, and the side wall with internal teeth is preformed. It is characterized in that it is hardened by, for example, an induction hardening method, and furthermore, the grooves for accommodating the bearing hole, the internal teeth, and the sealing member are manufactured by machining.

In a variant of this method, the steel plate parts forming the piston sides and the steel plate parts forming the side walls are joined to each other, for example by electronic or laser welding.

Other methods are also possible for manufacturing the piston.

In this case, the piston side surface is welded together with the connecting member in a fixed position, and then the reinforcing plate to which the guide plate is welded and the bearing boss are inserted into the peripheral wall formed by the piston side surface,
They are joined by partial welding to each other and to the peripheral wall, leaving a maximum welding gap of 0.3 mm, especially 0.2 mm, and furthermore, the long lateral edge of the piston side surface and the outer surface of the leg of the bearing boss are common. After applying a paste welding material to the abutting positions, both side walls are applied to the polished surfaces and fixed in position, and then all the parts are welded together.

This method requires, on the one hand, that the parallelism between the piston side face and the leg of the bearing boss and between the two side walls be maintained without any problems, so that by means of a planar contact a particularly narrow gap can be achieved by the aforementioned components. The narrow gap created between the welding material and the welding material makes it possible to save on the welding material, in particular to improve the fluidity and bonding properties of the welding material, and thus:
It has the advantage of guaranteeing complete tightness and a welded joint that can withstand high loads.

Instead of applying a pasty welding material, all parts can be electroplated with copper instead of being partially welded.

When heated in a welding furnace, the flowing copper is drawn by capillary action into the welding gap between each structural member.

This proposal has the advantage that the entire inner surface of the piston is coated as manufactured with a thin copper layer, which prevents corrosion by the cooling medium.

An embodiment of the piston according to the present invention will be described in detail with reference to the drawings.

The triangular piston shown in FIGS. 1 to 4 has an outer peripheral wall,
The outer peripheral wall includes three dimensionally accurate press-cut plate members;
It is formed from two mutually parallel side walls formed by press punched steel plate members 2 and 3, and a piston boss having a U-shaped cross section and formed by two mirror-image members.

The piston side 1 grips the side walls 2, 3 in order to prevent separation in the area directly exposed to combustion gases and pressure.

The piston corner is formed by the abutment position of the adjacent piston side face 1 and is provided with an insert 5 made of profiled material and serving to contain a radial groove (not shown) for the sealing element. .

As shown in FIG. 2, this insert 5
Although extending in between, it is possible for the insert to protrude through the sidewall to the outer surface of the sidewall.

This has the advantage that the radial grooves do not extend through the separation plane between the interconnected structural parts.

A guide plate 6 is provided between the piston side face 1 and the bearing boss 4, each of which has a T-shaped cross section.
It is formed from individual plates.

The central legs 7 with a T-shaped cross section formed in this way are each arranged centrally in a feed hole 8 provided in the bearing boss 4 .

The cooling medium flowing in through this bore 8 is diverted by the legs 7 to the adjacent piston corners in the direction of the arrow 9 to the left and right.

A cooling medium discharge hole 10 is provided on the other side of the piston boss 4.
is provided.

The inner surface of the side wall 2 is provided with a groove 11, which extends parallel to and near the periphery.

During operation, this groove 11 receives the flow of a cooling medium.
The side wall is cooled in the area of the outer surface of the axial seal of the piston.

The side wall 3 is made of hardenable steel and is provided with internal teeth 12.

Internal toothing 12 forms part of the piston transmission mechanism.

In the illustrated embodiment, a tube 13 passing through the piston is inserted in the area of each piston corner, which tube 13 serves for pressure compensation between the two sides of the piston.

All parts of the piston according to FIGS. 1 to 4 are preferably co-welded.

In this case, all the members except for one side wall are placed on the other side wall in a holding device (jig) and fixed by spot welding, leaving a welding gap of, for example, 0.2 mm.

Furthermore, a paste-like welding material, in particular a copper solder containing a nickel additive, is applied to the abutments or contact points of all the parts, and then the other side walls are attached, and the piston thus assembled is placed in a welding furnace. There, all the parts are hermetically welded together at a temperature of approximately 1100°C.

The side wall 3 carrying the internal toothing 12 is hardened in the preformed area, for example by radiofrequency, and then the grooves accommodating the bearing bore, the internal toothing and the sealing element are finished by mechanical machining.

The connection of all parts of the piston takes place on the one hand by welding, that is, in particular, the piston side surface 1 and the side wall 2.degree. 3 are connected by welding.

For this purpose, it is particularly suitable to use electronic or laser beam welding.

In the case of the piston shown in Figures 5-9, identical or similar parts have been provided with the same reference numerals as in Figures 1-4.

In contrast to the embodiment of FIGS. 1-4, the piston side surface 1' has a side wall 2' at its lateral long edge.

3' and is supported in the edge area of its inner surface on the radial leg of the bearing boss 4', so that the outer surface of the piston side surface 1' coincides with the circumferential surface of the side walls 2', 3'. .

An insert 5' made of profiled material is provided at the piston corner of the outer circumferential wall, which serves to accommodate a radial groove for the sealing element.

As shown in FIG. 6, this insert 5' is attached to both side walls 2'.
.

A reinforcing plate 15 is provided between the piston side surface 1' and the bearing boss 4' to increase rigidity.

A guide plate 16 is attached to the reinforcing plate 15, and each guide plate 16 is arranged at the center of a supply hole 8' provided in the bearing boss 4', and projects through the supply hole 8' together with an oil guide rib 16'. ing.

The cooling medium flowing through the supply hole 8' is supplied to the guide plate 16.
The piston is deflected to the horizontally adjacent piston corner in the direction of arrow 9'.

A cooling medium discharge hole 10 is provided on the other side of the bearing boss 4'.

The side wall 3' is also made of hardenable steel in this embodiment and is provided with internal teeth 12'.

This internal toothing 12' forms part of a conventional piston transmission mechanism.

In the case of the embodiments shown in FIGS. 5 to 9, in the range of each piston corner,
A through shaft 17 is inserted which centers the side walls 2', 3' on the legs of the bearing boss 4', which through shaft aligns the position of the flat side parts 2', 3' with the bearing boss 4. ' and the piston side surface 1' with respect to the structure formed with the other parts, and serves to facilitate assembly.

However, the centering can also be formed by a half-punched part 18, which part 18 is located on the side wall 2' and/or 3'.
It is pressed out and fitted precisely into the corresponding hole in the leg of the bearing boss 4'.

An alternative centering is shown in FIG.

This centering consists of one through shaft 19, this shaft 19
penetrates the entire piston.

That is, the side walls 2', 3' are commonly fixed to the bearing boss 4'.

The through shaft is hollow at both ends and widened to create a very narrow welding gap in this area.

In the embodiment shown in FIGS. 5-9, the individual parts are co-welded.

In this case, unlike the piston manufacturing method shown in Figs.
4, the reinforcing plate 15 is fixedly welded to the guide plate 16.

Further, a reinforcing plate 15 and a bearing boss 4' are inserted into the peripheral wall formed by the piston side surface 1', and the reinforcement plate 15 and the bearing boss 4' are inserted, for example, by 0.2 mm.
Leaving a welding gap of (can be made as small as 0.05 mm),
It is fixed by spot welding and Y-face polished on both sides.

Next, a paste-like welding material, especially copper 33 containing a nickel additive, is applied to the abutment or contact position of the members, and the both side walls 2 are
, 3 is placed and fixed by a through shaft or a half punched part.

The piston formed and assembled in this manner is finished into a product in the same manner as shown in FIGS. 1 to 4.

The piston according to the invention is suitable for mass production since machining is required only in limited parts.

The piston is also lighter in weight than a cast piston, and the large number of identical parts does not create substantial unbalanced weight.

[Brief explanation of drawings]

FIG. 1 shows the side surface of the piston along the cross-sectional line A-A in FIG. 2, FIG. 2 is a vertical cross-sectional view along the cross-sectional line B-B in FIG. 1, and FIG. Showing the X arrow view in Figure 1,
The figure is an exploded view of the piston shown in Figures 1 to 3 before being assembled, and Figure 5 is a side view of the piston of the second embodiment taken along the cross-sectional line C--C in Figure 6. Yes, Figure 6 is the 5th
The section line D-D in the figure is shown, and FIG. 7 shows the section line D-D in FIG.
FIG. 8 is an exploded view of the piston shown in FIGS. 5 to 8 before assembly. 1.1', 2,2', 3,3', 4,4'...
Piston wall, 2, 3, 2', 3'...Side wall, 4
'...Bearing boss, 15...Reinforcement plate, 1
6... Information board.

Claims (1)

[Scope of Claims] 1. A polygonal piston for an internal combustion engine with a trochoidal structure rotary piston, comprising an outer circumferential wall forming each piston side surface, side walls parallel to each other, and an inner circumferential wall forming a central bearing boss. , outer peripheral wall 1゜1', side walls 2, 2', 3
, 3' and the inner peripheral wall 4° 4' are each made of a single member made of a steel plate formed without cutting, and the members are welded or welded to each other at their contact positions, and the outer peripheral wall is They are formed from the same steel plate member that forms the piston side surface and are press punched with exact dimensions, and the bearing boss is formed from a plate member having a U-shaped cross section, and the leg-like portions of the plate material are are side walls 2 and 3
A polygonal piston characterized by being welded or welded to the inner surface of the piston. 2. Claim 1, characterized in that the member forming the outer peripheral wall is placed on the surface of the steel plate member forming the side walls 2, 3, and is welded or welded to the steel plate member 2.3.
Polygonal piston as described in Section. 3. The steel plate member forming the piston side surface 1 is in contact with the inner surface of the steel plate member forming the side walls 2', 3' with its long lateral edges and is gripped in the radial direction by the steel plate member, in which case the piston side surface The outer surface of the piston 1' coincides with the circumferential surface of the side walls 2' and 3', and the piston side surface 1' is supported by the leg-shaped portion of the bearing boss 4'. Polygonal piston according to item 1. 4. A steel plate member is press punched with exact dimensions, the insert material for the piston corner made of profile material is cut to size, the internal teeth of the steel plate material forming one side wall are formed by precision press punching, and then one side wall is formed by precision press punching. All parts except the other side wall are partially welded to fix the position, leaving a maximum welding gap of 0.37 mm, then a paste welding material is applied to the abutment position, and the other side wall is welded together with the other side wall. are mounted, all the parts are welded together, then the side walls carrying the internal teeth are hardened by induction hardening in the area where the teeth have been preformed, and finally the grooves for receiving the bearing bore, the internal teeth and the sealing elements are formed. 2. The method of manufacturing a polygonal piston according to claim 1, wherein the piston is finished by machining. 5. The manufacturing method according to claim 4, characterized in that all the members are plated with copper by electroforming after or before fixed welding instead of distributing the welding material.