GB1589138A - Crosshead bearings - Google Patents
Crosshead bearings Download PDFInfo
- Publication number
- GB1589138A GB1589138A GB19584/78A GB1958478A GB1589138A GB 1589138 A GB1589138 A GB 1589138A GB 19584/78 A GB19584/78 A GB 19584/78A GB 1958478 A GB1958478 A GB 1958478A GB 1589138 A GB1589138 A GB 1589138A
- Authority
- GB
- United Kingdom
- Prior art keywords
- piston rod
- pin
- screw
- spigot
- crosshead
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 230000010006 flight Effects 0.000 abstract 1
- 125000006850 spacer group Chemical group 0.000 abstract 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C5/00—Crossheads; Constructions of connecting-rod heads or piston-rod connections rigid with crossheads
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B75/00—Other engines
- F02B75/02—Engines characterised by their cycles, e.g. six-stroke
- F02B2075/022—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle
- F02B2075/025—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle two
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B3/00—Engines characterised by air compression and subsequent fuel addition
- F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Pistons, Piston Rings, And Cylinders (AREA)
- Shafts, Cranks, Connecting Bars, And Related Bearings (AREA)
Abstract
The connection between a piston rod (1) and a cross head pin has a connecting bolt (8) which can be removed from the piston rod (1) and passes through the cross head pin (2) as an extension of the piston rod (1). A piston-rod spigot (11) provided at the end of the piston rod (1) is arranged centred relative to the cross head pin (2) and is guided in the latter. The threaded contact between the piston rod (1) or piston-rod spigot (11) and the connecting bolt (8) lies predominantly, i.e. more than 50%, on the crankshaft side, relative to the root plane (7) of the piston-rod spigot (11). The load-bearing thread flights of this screw joint (10) are thus in a region which lies outside the main flow of force caused by the gas forces. The stressing of the screw joint (10) by the alternating gas force flow is thereby considerably reduced. A smaller overall height is also possible. The screw connection (10) can be formed between an external thread of the connecting bolt (8) and an internal thread of the piston rod (1) or between an external thread of the piston rod (1) and an internal thread of the connecting bolt (8). The piston rod (1) can rest on the cross head pin (2) directly or via a spacer. <IMAGE>
Description
(54) IMPROVEMENTS IN OR RELATING TO CROSSHEAD BEARINGS
(71) We, SULZER BROTHERS LIMITED, a Company organised under the laws of
Switzerland, of Winterthur, Switzerland, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to a connection between the piston rod and the crosshead pin of a piston engine, more particularly a crosshead diesel engine, the piston rod having a piston rod pin rigidly connected thereto.
The connection between the piston rod and the crosshead pin is a component subjected to high stresses in a crosshead diesel engine and must satisfy rigorous conditions.
Firstly, it must be strong enough to transmit the gas and mass forces from the piston rod to the crosshead pin while secondly the piston and piston rod system must be kept short for certain applications, such as roll-on roll-off ships (i.e. those with a continuous loading plane) where it is necessary that the engine room height can be kept low, and thus it is necessary to provide an engine which is compact in height.
The connection is frequently made by means of a piston rod spigot which is constructed in the form of an extension of the piston rod and which passes through a bore extending transversely of the crosshead pin.
The crosshead pin is then fixed on the piston rod spigot by means of a screw-threaded nut which is screwed on to the free end of the piston rod spigot which is also suitably screw-threaded.
The main disadvantage of this arrangement is that the total length of the piston-piston rod system is longer than acceptable for some applications, because the engine room height required for removal of a piston with its piston rod becomes inadmissibly high.
The object of the invention is to provide a connection of the above kind which allows a reduced removal height, at the same time providing optimum strength properties.
Accordingly the present invention provides an assembly of a piston rod and a crosshead pin, particularly for a crosshead diesel engine, the piston rod having a piston rod spigot comprising a connecting pin forming an extension of the piston rod and passing through a bore in the crosshead pin and in screw-threaded connection with the piston rod spigot, such screw-threaded connection having at least 50% of the length along which the threads of the spigot and the connecting pin are in contact, on the crankshaft side of the root plane of the piston rod spigot.
The main advantage offered by the invention is that a connection is provided by means of which the movement for removal of the connecting rod can be reduced, while the required strength properties are catered for by the fact that the screw-threaded connection is shifted, in respect of the greater part of its length, to a zone situated outside the main concentration of stress produced by the gas forces. The stresses on the screw connection caused by the removal of the gas forces in operation is thus largely reduced.
Preferably, the piston rod spigot is constructed as an extension of the piston rod and is located radially together with the connection pin in the bore of the crosshead pin.
This ensures that the screw-threaded connection is centred and more satisfactorily protected as regards fatigue strength.
Two variants of the screw-threaded connection are possible, one in which it is formed by an external screw-thread on the connecting pin and an internal screw-thread on the piston rod, and a second in which it is formed by an external screw-thread on the piston rod spigot and an internal screwthread in the connecting pin.
The piston rod may be in direct contact with the crosshead pin. If, however, the removal height has to be reduced still further, an intermediate member may be provided between the piston rod and the crosshead pin, in which case the piston rod is in contact with the intermediate member.
The connecting pin may have a screwthreaded fixing nut at its end adjacent the crankshaft. The screw-thread diameter of the fixing nut is preferably 20 to 40% larger than the screw-thread diameter of the screwthreaded connection with the spigot. The object of this is a substantially constant fatigue strength for the connecting pin. The nut screwed on to this end of the connecting pin then bears on a crosshead pin face adjacent the connecting rod. The connecting pin may also be in the form of a headed bolt, the head of which bears on the face of the crosshead pin adjacent the connecting rod.
In order to promote a fuller understanding of the above, and other aspects of the present invention, some embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which:
Figure 1 is a section through the crosshead of a diesel engine showing a first embodiment of the invention, in which an external screwthread of a connecting pin is screwed into an internal screw-thread in the piston rod pin,
Figure 2 is a similar section to Fig. 1, showing a second embodiment of the invention in which an external screw-thread on the piston rod pin is screwed into an internal screw-thread in the connecting pin, and
Figure 3 is a similar section to Fig. 1, showing a third embodiment of the invention in which an intermediate member is provided between the piston rod and the crosshead pin.
In the drawings, like parts in the various embodiments have like references.
The crossheads shown in Figs. 1 to 3 each have a crosshead pin 2 rigidly connected to the piston rod 1. The crosshead pin is pivotally mounted in a bearing housing 3 and in shoes 4, which are slidably carried in guides 5 of the engine housing (not shown). The bearing housing 3 is rigidly connected to the connecting rod 6 and transmits to the latter the gas and mass forces transmitted by the piston rod 1 to the crosshead pin 2. The piston rod 1 is formed with a piston rod spigot 11 which is an extension of the piston rod and which merges into the main body of the piston rod 1 via a root plane 7 which is defined by an undercut shoulder on the piston rod.
The piston rod 1 is connected to the crosshead pin 2 by means of the connecting pin 8, which extends through a bore 9 running transversely of the crosshead pin 2, and which is screw-threaded into the piston rod spigot 11 as indicated at 10. In all three Figures, it will be noted that the screw-threaded connection 10 is largely on the crankshaft side of the root plane 7.
In Fig. 1, the piston rod spigot 11 extends into the bore 9 of the crosshead pin 2 and is guided centrally therein. The external screwthread of the connecting pin 8 is screwed into an internal screw-thread of the piston rod 1, the internal screw-thread extending coaxially in the piston rod spigot 11. The piston rod 1 is in direct contact with the crosshead pin 2 through the undercut shoulder therein.
At its end adjacent the crankshaft, the connecting pin 8 has another screw connection
12 consisting of an external screw-thread 13
on the connecting pin 8 and a screw-threaded nut 14 screwed thereon. Nut 14 bears against
an end face of the crosshead pin 2 adjacent the connecting rod 6. The diameter of the
screw-thread of the connection 12 is prefer
ably 20 to 40% larger than that of the screw
connection 10 so that a substantially constant fatigue strength is obtained for the connecting pin 8.
The connecting rod pin is provided with a hexagon cross-section at its lower end to which a spanner may be applied to unscrew it from the connecting rod.
In Fig. 2, the piston rod spigot 11 is provided with an external screw-thread 15, which is screwed into an internal screwthread of the connecting pin 8. Here again the
shoulder of the piston rod 1 is in direct contact with the crosshead pin 2. In this embodiment, the height for removal is larger than that in Fig. 1, but the screw connection 10 is situated entirely on the crankshaft side of the root plane 7 of the connecting rod spigot.
In Fig. 3, an intermediate member 16 is provided between the piston rod 1 and the crosshead pin 2, and is connected to and radially located in the crosshead pin 2 so that it may be dismantled, e.g. by means of screws
or studs (not shown), and has a bore 17 coaxial with the bore 9 of the crosshead pin 2 for the radial location of the piston rod spigot 11. The piston rod shoulder is in contact with the top face of the intermediate member 16. With this embodiment, the height for removal is additionally reduced by the height of the intermediate member 16.
In all three embodiments of the invention, the connecting pin 8 may be in the form of a headed bolt (not shown), the head of which bears on the end face of the crosshead pin 2 adjacent the crankshaft.
WHAT WE CLAIM IS:
1. An assembly of a piston rod and a crosshead pin, particularly for a crosshead diesel engine, the piston rod having a piston rod spigot, comprising a connecting pin forming an extension of the piston rod and passing through a bore in the crosshead pin
and in screw-threaded connection with the piston rod spigot, such screw-threaded connection having at least 50% of the length
along which the threads of the spigot and the connecting pin are in contact, on the crank
shaft side of the root plane of the piston rod
spigot.
2. An assembly as claimed in Claim 1, in which the piston rod spigot is formed as an extension of the piston rod and is radially located together with the connecting pin in the crosshead pin.
3. An assembly as claimed in Claim 1 or
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (9)
- **WARNING** start of CLMS field may overlap end of DESC **.the screw-thread diameter of the screwthreaded connection with the spigot. The object of this is a substantially constant fatigue strength for the connecting pin. The nut screwed on to this end of the connecting pin then bears on a crosshead pin face adjacent the connecting rod. The connecting pin may also be in the form of a headed bolt, the head of which bears on the face of the crosshead pin adjacent the connecting rod.In order to promote a fuller understanding of the above, and other aspects of the present invention, some embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a section through the crosshead of a diesel engine showing a first embodiment of the invention, in which an external screwthread of a connecting pin is screwed into an internal screw-thread in the piston rod pin, Figure 2 is a similar section to Fig. 1, showing a second embodiment of the invention in which an external screw-thread on the piston rod pin is screwed into an internal screw-thread in the connecting pin, and Figure 3 is a similar section to Fig. 1, showing a third embodiment of the invention in which an intermediate member is provided between the piston rod and the crosshead pin.In the drawings, like parts in the various embodiments have like references.The crossheads shown in Figs. 1 to 3 each have a crosshead pin 2 rigidly connected to the piston rod 1. The crosshead pin is pivotally mounted in a bearing housing 3 and in shoes 4, which are slidably carried in guides 5 of the engine housing (not shown). The bearing housing 3 is rigidly connected to the connecting rod 6 and transmits to the latter the gas and mass forces transmitted by the piston rod 1 to the crosshead pin 2. The piston rod 1 is formed with a piston rod spigot 11 which is an extension of the piston rod and which merges into the main body of the piston rod 1 via a root plane 7 which is defined by an undercut shoulder on the piston rod.The piston rod 1 is connected to the crosshead pin 2 by means of the connecting pin 8, which extends through a bore 9 running transversely of the crosshead pin 2, and which is screw-threaded into the piston rod spigot 11 as indicated at 10. In all three Figures, it will be noted that the screw-threaded connection 10 is largely on the crankshaft side of the root plane 7.In Fig. 1, the piston rod spigot 11 extends into the bore 9 of the crosshead pin 2 and is guided centrally therein. The external screwthread of the connecting pin 8 is screwed into an internal screw-thread of the piston rod 1, the internal screw-thread extending coaxially in the piston rod spigot 11. The piston rod 1 is in direct contact with the crosshead pin 2 through the undercut shoulder therein.At its end adjacent the crankshaft, the connecting pin 8 has another screw connection12 consisting of an external screw-thread 13 on the connecting pin 8 and a screw-threaded nut 14 screwed thereon. Nut 14 bears against an end face of the crosshead pin 2 adjacent the connecting rod 6. The diameter of the screw-thread of the connection 12 is prefer ably 20 to 40% larger than that of the screw connection 10 so that a substantially constant fatigue strength is obtained for the connecting pin 8.The connecting rod pin is provided with a hexagon cross-section at its lower end to which a spanner may be applied to unscrew it from the connecting rod.In Fig. 2, the piston rod spigot 11 is provided with an external screw-thread 15, which is screwed into an internal screwthread of the connecting pin 8. Here again the shoulder of the piston rod 1 is in direct contact with the crosshead pin 2. In this embodiment, the height for removal is larger than that in Fig. 1, but the screw connection 10 is situated entirely on the crankshaft side of the root plane 7 of the connecting rod spigot.In Fig. 3, an intermediate member 16 is provided between the piston rod 1 and the crosshead pin 2, and is connected to and radially located in the crosshead pin 2 so that it may be dismantled, e.g. by means of screws or studs (not shown), and has a bore 17 coaxial with the bore 9 of the crosshead pin 2 for the radial location of the piston rod spigot 11. The piston rod shoulder is in contact with the top face of the intermediate member 16. With this embodiment, the height for removal is additionally reduced by the height of the intermediate member 16.In all three embodiments of the invention, the connecting pin 8 may be in the form of a headed bolt (not shown), the head of which bears on the end face of the crosshead pin 2 adjacent the crankshaft.WHAT WE CLAIM IS: 1. An assembly of a piston rod and a crosshead pin, particularly for a crosshead diesel engine, the piston rod having a piston rod spigot, comprising a connecting pin forming an extension of the piston rod and passing through a bore in the crosshead pin and in screw-threaded connection with the piston rod spigot, such screw-threaded connection having at least 50% of the length along which the threads of the spigot and the connecting pin are in contact, on the crank shaft side of the root plane of the piston rod spigot.
- 2. An assembly as claimed in Claim 1, in which the piston rod spigot is formed as an extension of the piston rod and is radially located together with the connecting pin in the crosshead pin.
- 3. An assembly as claimed in Claim 1 or2, in which the screw-threaded connection is formed between an external screw-thread of the connecting pin and an internal screwthread in the piston rod spigot.
- 4. An assembly as claimed in Claim 1 or 2, in which the screw-threaded connection is formed between an external screw-thread on the piston rod spigot and an internal screwthread in the connecting pin.
- 5. An assembly as claimed in any one of Claims 1 to 4, in which the piston rod is in direct engagement with the crosshead pin.
- 6. An assembly as claimed in any one of Claims 1 to 4, in which an intermediate member is disposed between the piston rod and the crosshead pin, the intermediate member having a bore adapted to radially locate the piston rod spigot.
- 7. An assembly as claimed in any preceding Claim, in which a screw-threaded nut member is provided at the end thereof remote from the piston rod, the screw-thread diameter of the nut member being 20 to 40 /O larger than the screw-thread diameter of the screw connection between the connecting pin and the connecting rod, and the nut member bearing against a face of the crosshead pin remote from the piston rod.
- 8. An assembly as claimed in any one of Claims 1 to 6 in which the connecting pin is in the form of a headed bolt, the head of which bears on a face of the crosshead pin remote from the piston rod.
- 9. As assembly of a piston rod and a crosshead pin substantially as herein described with reference to the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH622577A CH620276A5 (en) | 1977-05-20 | 1977-05-20 | Connection between a piston rod and a cross head pin for a piston machine, in particular for a cross head diesel engine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1589138A true GB1589138A (en) | 1981-05-07 |
Family
ID=4306243
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB19584/78A Expired GB1589138A (en) | 1977-05-20 | 1978-05-15 | Crosshead bearings |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS53143819A (en) |
| AT (1) | AT370218B (en) |
| BR (1) | BR7803168A (en) |
| CH (1) | CH620276A5 (en) |
| DE (1) | DE2724042C3 (en) |
| DK (1) | DK147382C (en) |
| GB (1) | GB1589138A (en) |
| IT (1) | IT1095124B (en) |
| SU (1) | SU772496A3 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1283362A3 (en) * | 2001-08-09 | 2009-09-09 | Nuovo Pignone Holding S.P.A. | Means for connection between a rod and crosshead in a reciprocating compressor |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5931685U (en) * | 1982-08-20 | 1984-02-27 | 共同コンクリ−ト株式会社 | drain |
| US4872395A (en) * | 1987-11-23 | 1989-10-10 | Dresser-Rand Company | Crosshead per se, and in combination with a connecting rod assembly and a piston rod |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH167876A (en) * | 1932-02-19 | 1934-03-15 | William Doxford & Sons Limited | Single-acting piston machine with cross head. |
| CH540442A (en) * | 1971-07-13 | 1973-08-15 | Sulzer Ag | Cross-head journal bearings for piston engines, in particular for diesel internal combustion engines |
-
1977
- 1977-05-20 CH CH622577A patent/CH620276A5/en not_active IP Right Cessation
- 1977-05-26 AT AT0375677A patent/AT370218B/en not_active IP Right Cessation
- 1977-05-27 DE DE2724042A patent/DE2724042C3/en not_active Expired
-
1978
- 1978-04-20 JP JP4716678A patent/JPS53143819A/en active Granted
- 1978-05-11 IT IT23243/78A patent/IT1095124B/en active
- 1978-05-15 GB GB19584/78A patent/GB1589138A/en not_active Expired
- 1978-05-16 SU SU782613996A patent/SU772496A3/en active
- 1978-05-16 DK DK213178A patent/DK147382C/en active
- 1978-05-19 BR BR7803168A patent/BR7803168A/en unknown
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1283362A3 (en) * | 2001-08-09 | 2009-09-09 | Nuovo Pignone Holding S.P.A. | Means for connection between a rod and crosshead in a reciprocating compressor |
Also Published As
| Publication number | Publication date |
|---|---|
| DK147382B (en) | 1984-07-09 |
| IT7823243A0 (en) | 1978-05-11 |
| BR7803168A (en) | 1979-01-02 |
| JPS53143819A (en) | 1978-12-14 |
| DK213178A (en) | 1978-11-21 |
| DK147382C (en) | 1985-01-28 |
| JPS5738811B2 (en) | 1982-08-18 |
| CH620276A5 (en) | 1980-11-14 |
| DE2724042A1 (en) | 1978-11-23 |
| DE2724042B2 (en) | 1980-07-24 |
| IT1095124B (en) | 1985-08-10 |
| AT370218B (en) | 1983-03-10 |
| SU772496A3 (en) | 1980-10-15 |
| DE2724042C3 (en) | 1981-04-23 |
| ATA375677A (en) | 1982-07-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed [section 19, patents act 1949] | ||
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19920515 |