JPH06100215B2 - Reciprocating engine crosshead - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a reciprocating engine crosshead, and in particular to
A crosshead has a pivot with shoes disposed at its ends and is diametrically mounted and pressurized on the guide surfaces of the crankcase during reciprocation of the crosshead. The present invention relates to a reciprocating engine crosshead in which a shoe is guided by two sliding surfaces to which a lubricant is supplied.

PRIOR ART, and PROBLEMS TO BE SOLVED BY THE INVENTION In a known crosshead of this kind, each shoe slides on adjacent guide surfaces alternately as one flat sliding contact surface, depending on the crosshead movement direction, A lubricant is supplied between the guide surface and the sliding contact surface. The contact of the sliding surface with the guide surface, despite the presence of lubricant, can be a significant source of friction and power loss when the crosshead is used in prime movers such as diesel engines.

It is an object of the present invention to improve a crosshead of the kind mentioned so as to significantly reduce the power losses caused by friction.

The object is to provide a crosshead of a reciprocating engine having a pivot on which shoes are arranged at both ends, during the reciprocating movement of the crosshead a plurality of guide surfaces of the crankcase. The crosshead, in which the shoe is guided by the two sliding contact surfaces provided in the diametrical direction of the pivot shaft and supplied with the lubricant under pressure, at both ends of each sliding contact surface of the two shoes. Between each sliding contact surface and the adjacent guide surface along the moving direction of the crosshead, a spring force is applied, and a sliding contact engagement with the corresponding guide surface is formed to form a hydrostatic bearing. The crankcase has lateral constraining surfaces (ie, constraining sides) that are located on opposite sides of and contiguous with each guide surface and that extend parallel to the direction of movement of the shoe. The lateral restraint surface and each guide surface Defines a groove by which the outer portion of the shoe fits,
A close contact between the lateral restraining surface and the outer portion of the shoe near the hydrostatic bearing and a passage communicating with the passage in the shoe is formed in the pivot for supplying pressurized lubricant to the cross shaft. During the reciprocating motion of the head, the lubricant flows toward the hydrostatic bearing in the unloaded state, and at the hydrostatic bearing in the loaded state, the backflow of the lubricant is prevented so that each hydrostatic pressure is This is accomplished by providing a reciprocating engine crosshead in which the supply of lubricant to the bearing is controlled.

If the sliding surface is a hydrostatic bearing, there is a cushion or lubricant film between any bearing under load and the adjacent guide surface. There is no metal-to-metal contact between the guide surface and the guide surface.

Therefore, there is no appreciable friction between their surfaces. When the particular bearing surface concerned is unloaded, lubricant may enter the gap between the two surfaces but cannot return to the opposite side of the lubricant feed direction during the next loading phase. The lubricant control is performed as described above. Lateral restraint surface,
The arrangement of the sealing strips has the result that during the loading phase a very small amount of lubricant escapes from the lubricant cushion or membrane, which is maintained for a relatively long time.

According to another characteristic of the invention, in addition to the spring pressure, the pressure of the lubricant supplied to the hydrostatic bearing can act on the sealing strip.

Hereinafter, two embodiments of the present invention will be described with reference to the drawings.

EXAMPLE Referring to FIG. 1, the upper end of the connecting rod 2 is not shown in detail but is pivotally attached to the crosshead pivot 1 of a two-stroke diesel engine, as is known, and the lower end of the connecting rod (not shown) is shown. ) Is connected to the crankpin. The piston rod fixed to the drive of the crank and the crosshead pivot 1 is not shown, but the piston rod extends upwards in FIG. Shoe 3 at each end of crosshead pivot 1
, But only one shoe is shown in FIG. A bush 5 is arranged between the shoe 3 and the pivot 1 and is fixed to the shoe 3 so as not to rotate. A bore 4 extends longitudinally in the connecting rod 2 and continues to a longitudinal axis position in the pivot 1. The supply of the pressure liquid lubricant, which also functions as the hydrostatic fluid for the shoe 3, takes place in a known manner through the hole 4. A longitudinal center hole 6 is formed in the pivot 1 and its outermost end is closed (not shown). At a position corresponding to the center of the shoe 3, the center hole 6 to the radial hole 7,
A branch 8 extends through the bush 5 and continues in the shoe 3 as holes 7 ', 8'to the flat outer surface 9, 10 of the shoe 3, respectively. Check valves 11 and 12 are arranged in the holes 7'and 8'of the shoe 3, respectively, and these check valves allow the lubricant to flow outward, but to the opposite direction. Obstruct the flow of. On the shoe 3, parallel to the holes 7'and 8 ',
Two holes 13 and 14 are respectively formed, which holes 13 and 14 extend to the respective surfaces 9 and 10 and communicate with the lubricant supply holes 7'and 8'through ducts 15 and 16, respectively. There is. Each plane 9, 10 of the shoe functions as a hydrostatic bearing surface, between each bearing surface and each adjacent guide surface 17, 18 of the crankcase 19,
Each gap 21, 22 is left.

Each gap 21,22 is externally sealed at the two ends of the shoe 3 by sealing strips 23,23 'and 24,24', respectively. A spring 25 is arranged between each sealing strip and the shoulder surface of the shoe 3 and presses the sealing strip against the corresponding adjacent guide surface 17,18. A corresponding sealing strip and a retaining strip 26 for the spring are fastened to the shoe 3 close to each sealing strip. Also, the ducts 15,16 are in communication with the chambers that receive the springs 25, so that the pressurized lubricant acting in the gaps 21,22 acts on the strips 23,23 'and 24,24'. And press them against the guide surface 17 or 18. Two lateral restraining surfaces 27, 28 are formed on the crankcase 19, which extend parallel to the direction of movement of the shoe and are located on either side of each guide surface 17, 18. As shown in FIG. 3, the lateral restraining surfaces 27, 28 extend in a groove around the outer portion of the shoe and cooperate with adjacent lateral restraining surfaces in the corresponding portion of the shoe to form a long sealing gap 30. To do.

During operation of the engine, the crosshead reciprocates vertically, for example, the hydrostatic bearing surface 9 is loaded during the upward movement and the hydrostatic bearing surface 10 is loaded during the upward movement. I do not receive it. The pressurized lubricant continuously supplied to the shoe 3 through the connecting rod 4 is used for the check valve 12 during the upward movement of the crosshead.
Flow through into the gap 22 on the unloaded side of the crosshead. The lubricant that entered the gap 21 during the downward movement of the crosshead in the previous stage is
The hydrostatic bearing surface is resisted against the force of the connecting rod 2 which is retained in the chamber downstream of the check valve 11 and is applied to the crosshead via the pivot 1 to press the shoe 3 against the guide surface 17. 9
Form a thick cushion or film of lubricant that prevents metal-to-metal contact between the and guide surface 17. The sealing of the gap 21 by the gap sealing on the strips 23, 23 'and the lateral constraining surface 27 means that the hydrostatic bearing of the lubricant cushion or membrane in the gap 21 during the upward movement of the crosshead. It means that the department has practical effect. When the crosshead descends, the above phenomenon that occurs in the gap 21 during the ascending motion is caused by the gap 22.
Occurs within. That is, the bearing surface 9 is released during the descent of the crosshead, so that the pressurized lubricant flowing through the bore 4 is supplied through the check valve 11 into the gap 21.

In the embodiment shown in FIG. 4, the lubricant holes 7 and 8 in the pivot 1 of the crosshead form an obtuse angle with each other, and the obtuse angle is released toward the connecting rod 2 side. In this example, the outer peripheral surface of the pivot 1 that rotates together with the connecting rod 2 is the bush 5 in the shoe 3.
Cooperates with the inner surface of the to form a valve surface, which is communicated alternately between the holes 7, 7'or between the holes 8, 8 ', depending on the position of the connecting rod. For example, when the holes 7, 7 ′ are in communication with each other and the pressure lubricant supplied through the holes 4 reaches the gap 21,
There is no communication between 8, 8'and the lubricant cannot flow back from the gap 22 to the hole 8.

[Brief description of drawings]

1 is a cross-sectional view of the crosshead near the shoe, FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1, and FIG. 3 is a cross-sectional view taken along line III-III of FIG. FIG. 4 is a cross-sectional view corresponding to FIG. 1 of a crosshead having a different form of lubricant supply control. 1 ... Crosshead pivot, 2 ... Connecting rod, 3 ... Shoe, 4,6,
7,7 ', 8,8', 13,14 ... Hole, 5 ... Bushing, 9,10 ... Bearing surface, 11,12 ... Check valve, 17,18 ... Guide surface, 19 ... Crankcase, 21,22 ... gaps, 23,23 ', 24,24', 26 ... strips, 25 ... springs, 27,28 ... lateral restraining surfaces.

Claims (5)

[Claims] 1. A crosshead has a pivot with shoes disposed at both ends thereof, during reciprocation of the crosshead,
A plurality of guide surfaces of the crankcase are provided with a lubricant which is provided in the diameter direction of the pivot shaft and is pressurized 2.
In a crosshead of a reciprocating engine in which a shoe is guided by one sliding contact surface, at each end of each sliding contact surface of the two shoes,
Between the adjacent guide surface along the moving direction of the crosshead,
Sealing strips are provided which are biased by spring force and which are in sliding contact engagement with corresponding guide surfaces to form hydrostatic bearings, located on opposite sides of each said guide surface and in the direction of movement of the shoe. The crankcase has a lateral restraint surface extending parallel to
A groove is defined by the two lateral constraining surfaces and each of the guide surfaces, and an outer portion of the shoe fits into the groove to engage the lateral constraining surface and an outer portion of the shoe near the hydrostatic bearing. A passage is formed in the pivot for communicating with the passage in the shoe for tightly engaging with and for supplying pressurized lubricant, and the lubricant is in an unloaded state during the reciprocating movement of the crosshead. In order to prevent the lubricant from flowing backward in the hydrostatic bearing under load while flowing toward the hydrostatic bearing,
A reciprocating engine crosshead, characterized in that the supply of lubricant to each hydrostatic bearing is controlled. 2. The crosshead of a reciprocating engine according to claim 1, wherein the sealing strip is supplied with a lubricant at a portion opposite to a side facing the guide surface. 3. A reciprocating engine according to claim 2, wherein the lubricant is supplied to the sealing strip by branching from the lubricant supply passage to the corresponding hydrostatic bearing. Crosshead. 4. A check valve for controlling the supply of lubricant to each hydrostatic bearing part is provided in the shoe, and the check valve according to any one of claims 1 to 3. The reciprocating engine crosshead described in. 5. Lubricant is supplied to the shoe through a hole in the connecting rod and a plurality of holes in the pivot, the plurality of holes in the pivot being arranged at an obtuse angle to each other, the obtuse angle being the connecting rod. Angle of opening in each direction, one lubricant hole is provided in each shoe, and the lubricant hole does not communicate with the hole in the pivot when the connecting rod is in the neutral position, but When the rod moves away from the neutral position, it communicates with the adjacent obtuse-angled lubricant, according to any one of claims 1 to 3. Reciprocating engine crosshead.