JP2012137137A - Shaft coupling of construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shaft coupling of a construction machine which has a torque transmission surface made of a high elastic material and a metallic material and which achieves reduction in the wear volume of the torque transmission surface with the lapse of duration of use.SOLUTION: A solid lubricant film made of a molybdenum disulfide, a graphite, calcium fluoride, or silicon dioxide is formed on the torque transmission surface 5b or 8g on a metal side. More preferably, a surface hardening layer obtained by salt bath nitriding, gas soft-nitriding, quenching and annealing, high-frequency quenching, carburizing quenching, or carbo-nitriding is formed on the torque transmission surface 5b or 8g on the metal side, and a solid lubricant film is formed on the surface hardening layer. More preferably, the surface hardening layer is roughened by manganese phosphate treatment or sand blasting or the like, and then a solid lubricant film is formed.

Description

  The present invention relates to a shaft coupling that transmits a rotational force between a rotational power source such as an engine and a driven rotating body such as a hydraulic pump in a construction machine such as a hydraulic excavator.

  In a construction machine such as a hydraulic excavator, a rotational force is transmitted by a shaft coupling between an engine that is a power source rotating body and a hydraulic pump that is a driven rotating body. In such a shaft coupling, as described in Patent Document 1, one of the torque transmission surfaces is made of metal to absorb the deviation between the shaft centers of the engine and the hydraulic pump, absorb the rotational torque fluctuation accompanying the rotation of the engine, and the like. The other is formed of a highly elastic material made of rubber or resin. If the torque transmission surface is formed in this way, torque can be transmitted with stable rotation by absorbing rotational torque fluctuations with a highly elastic material. In addition, since the combination of materials having good slidability is used, it is not necessary to supply lubricating oil to the contact surface, and the function can be realized at a low cost with a simple configuration.

JP-A-8-27835

  As described above, when one of the torque transmission surfaces is formed of a metal material and the other is formed of a high elastic material, the high elastic material generally has lower hardness and strength than the metal material, and has high elasticity with long-time use. The torque transmission surface of the material is subject to wear. For this reason, the highly elastic material used for this type of shaft coupling is a material with increased hardness and strength. As a result, the hardness difference between the highly elastic material and the metal material is reduced, and the torque transmission surface on the metal side is worn to some extent when used for a long time.

  Here, since the shaft coupling having a torque transmission surface made of a highly elastic material and a metal material does not use lubricating oil, wear powder containing metal powder tends to stay on the torque transmission surface, and wear is caused by this wear powder. This increases the amount of wear per hour on both the metal material side and the highly elastic material side. The amount of wear increases more remarkably when reinforcing fibers such as glass fibers and carbon fibers are added to the highly elastic material in order to increase the hardness and strength of the highly elastic material.

  In view of the above problems, the present invention provides a shaft for a construction machine that can reduce the amount of wear of the torque transmission surface with the passage of time of use in a shaft coupling in which the torque transmission surface is made of a highly elastic material and a metal material. The object is to provide a joint.

The shaft coupling of the construction machine according to claim 1 has a torque transmission surface on the driven rotor for the rotational force of the power source rotor, one of the torque transmission surfaces is made of a metal material, and the other is made of rubber or resin. In the shaft coupling of construction machinery formed of high elastic material,
A solid lubricating coating made of molybdenum disulfide, graphite, calcium fluoride or silicon dioxide is provided on the torque transmission surface on the metal side.

The shaft joint for a construction machine according to claim 2 is the shaft joint for a construction machine according to claim 1,
A surface hardened layer is formed on the metal side torque transmission surface by salt bath nitriding, gas soft nitriding, nitriding, quenching and tempering, induction hardening, carburizing quenching or carbonitriding, and the solid lubricating coating is provided on the surface hardened layer. It is characterized by that.

The shaft joint for a construction machine according to claim 3 is the shaft joint for a construction machine according to claim 1,
The metal-side torque transmission surface is roughened by chemical surface treatment or physical surface treatment, and the solid lubricant film is provided on the roughened surface.

  The shaft coupling of the construction machine according to claim 4 is characterized in that the hardened surface layer according to claim 2 is roughened by the surface treatment according to claim 3, and the solid lubricant film is provided on the roughened surface. Features.

The shaft coupling for a construction machine according to claim 5 is the shaft coupling for a construction machine according to any one of claims 1 to 4,
A first gear comprising an internal gear or an external gear attached to the output shaft of the power source rotor and having a torque transmission surface formed on the teeth;
An external gear or an internal gear that is attached to the input shaft of the driven rotating body and meshes with the first gear, the second gear having a torque transmission surface formed on the teeth;
One of the first gear and the second gear is made of a metal material and the other is made of a highly elastic material.

The shaft coupling for a construction machine according to claim 6 is the shaft coupling for a construction machine according to any one of claims 1 to 4,
A plurality of first members attached to the output disk of the power source rotor at equal intervals in the circumferential direction and having torque transmission surfaces formed on both sides in the rotational direction;
A second member having a torque transmission surface attached to the input shaft of the driven rotating body and installed at intervals on the torque transmission surfaces of the first members;
A third surface that is sandwiched between the first member and the second member and that is in contact with the torque transmission surface of the first member and the torque transmission surface of the second member is a torque transmission surface. And a member of
The first member and the second member are made of a metal material and the third member is made of a highly elastic material, or the first member and the second member are made of a highly elastic material and the third member. Is made of a metal material.

The shaft coupling for a construction machine according to claim 7 is the shaft coupling for a construction machine according to any one of claims 1 to 6,
The high-elasticity material is characterized by comprising reinforcing fibers.

  According to the first aspect of the present invention, since a solid lubricating film such as molybdenum disulfide is provided on the surface of the metal material in the shaft joint that does not use the lubricating oil, the slidability with the highly elastic material is improved, and the high elasticity The amount of material wear can be reduced, and the life of the shaft joint can be extended.

  According to the invention of claim 2, since the surface of the metal material is hardened by the various surface treatments such as salt bath nitriding, the life of the shaft coupling can be further extended.

  According to the invention of claim 3, since the surface of the metal material is roughened and the solid lubricant film is provided, the solid lubricant film is firmly fixed to the surface of the metal material, and the life of the shaft joint can be further extended.

  According to the invention of claim 4, compared with the case where the surface is simply cured or roughened by the formation of the surface hardened layer of claim 2 and the solid lubricating film by the roughening of claim 3, Further life extension of the shaft coupling is achieved.

  According to the fifth and sixth aspects of the present invention, the metal material subjected to the treatment of the present invention in the shaft joint having such a configuration can contribute to extending the life of the shaft joint.

  According to the seventh aspect of the present invention, since the reinforcing fiber is added to the highly elastic material, the life of the shaft joint can be further extended by reducing the wear amount of the highly elastic material.

It is a side view which shows one Embodiment of the shaft coupling of the construction machine of this invention. It is EE sectional drawing of FIG. It is sectional drawing which shows the attachment structure of the external gear with respect to the hydraulic pump input shaft of embodiment shown in FIG. 1, FIG. FIG. 3 is a partially enlarged view of FIG. 2. It is a side view which shows other embodiment of the shaft coupling of the construction machine of this invention. It is FF sectional drawing of FIG. It is a disassembled perspective view which shows the structure of the power transmission member of embodiment shown in FIG. 5, FIG. It is the elements on larger scale of FIG. It is the elements on larger scale of FIG. It is a graph which shows the abrasion loss in the sliding experiment of the highly elastic material with respect to the metal material of the Example of this invention, and a prior art example.

  1 is a side sectional view showing an embodiment of a shaft coupling of a construction machine according to the present invention, FIG. 2 is an EE sectional view thereof, and FIG. 3 is a partially enlarged view of FIG. Reference numeral 1 denotes an engine serving as a power source, and 2 denotes a hydraulic pump driven by the engine. Reference numeral 3 denotes a disk-shaped power source rotating body provided on an output shaft (not shown) of the engine 1 and constitutes a flywheel. A housing 4 accommodates the power source rotor 3. In the engine 1, the explosive force is converted into a reciprocating motion of a piston, the reciprocating motion of the piston is converted into a rotational force of an output shaft (none of which is shown) by a crankshaft, and a power source attached to the output shaft is rotated. The body 3 is rotated.

  Reference numeral 5 denotes an internal gear fixed to the power source rotating body 3 by a bolt 6 as a power transmission member. Reference numeral 7 denotes a driven rotor, which is provided as an input shaft of the hydraulic pump 2. Reference numeral 8 denotes an external gear having teeth 8 a that mesh with the teeth 5 a of the internal gear 5. As shown in FIG. 3, the external gear 8 is attached by fitting a groove 8 c of the boss portion 8 b to a spline groove 7 a provided on the input shaft 7 of the hydraulic pump 2. Further, the external gear 8 has a slit 8d formed radially from the center thereof, and a boss portion 8b is provided with a bolt insertion hole 8e and a screw hole 8f so as to pass through the slit 8d. The external gear 8 is fixed to the input shaft 7 by being inserted through the insertion hole 8e, screwed into the screw hole 8f, and fastened. The hydraulic pump 2 has a built-in cylinder block and piston, and has a function of sucking oil and discharging pressure oil when the input shaft 7 rotates.

  As shown in FIG. 4, each tooth 5a of the internal gear 5 is in contact with each tooth 8a of the external gear 8 at the side surface so as to be slidable in the rotational direction to form torque transmitting surfaces 5b and 8g. .

  In such a shaft coupling, at least one of the teeth 5a and 8a of the internal gear 5 and the external gear 8 is made of a metal material, and the other is reinforced fiber such as glass fiber or carbon fiber added to rubber or resin. Use highly elastic materials. By configuring the torque transmission surfaces 5b and 8g with a metal material and a highly elastic material in this way, absorption of the shift between the axial centers of the engine 1 and the hydraulic pump 2 and absorption of rotational torque fluctuation accompanying the rotation of the engine can be absorbed. The torque can be transmitted with stable rotation. In addition, since the combination of materials having good slidability is used, it is not necessary to supply lubricating oil to the contact surface, and the function can be realized at a low cost with a simple configuration.

  In the present invention, of the internal gear 5 and the external gear 8, those made of a metal material are baked with a solid lubricating film made of molybdenum disulfide, graphite, calcium fluoride or silicon dioxide on the torque transmission surface 5b or 8g. Thus, the slidability with the highly elastic material is improved, the wear amount of the highly elastic material is reduced, and the life of the shaft coupling can be extended.

  When such a solid lubricating coating is formed on the torque transmission surface 5b or 8g, a surface hardened layer is formed by salt bath nitriding, gas soft nitriding, nitriding, quenching and tempering, induction quenching, carburizing quenching or carbonitriding, and this surface hardening If the solid lubricant film is provided on the layer, the slidability with the torque transmission surface on the high elastic material side can be improved, and the wear amount of the high elastic material can be further reduced.

  Further, if the metal side torque transmission surface 5b or 8g is roughened by chemical surface treatment such as manganese phosphate treatment or physical surface treatment such as sandblasting, and a solid lubricant film is provided on the roughened surface, solid lubrication can be achieved. The coating can be more stably fixed on the torque transmission surface, can improve the slidability with the highly elastic material for a longer period of time, and can contribute to the reduction of the amount of wear.

  In addition, after performing both the formation of a hardened surface layer on the metal side torque transmission surface and the roughening, the formation of a solid lubricating film improves the slidability with a highly elastic material over a longer period of time, This can contribute to a reduction in the amount of wear.

  1 and 2, the internal gear 5 is attached to the power source rotor 3, and the external gear 8 that meshes with the internal gear 5 is attached to the driven rotor (input shaft) 7 side. However, on the contrary, it is also possible to adopt a structure in which an external gear is attached to the power source rotating body 3 and an internal gear that meshes with the external gear is mounted on the driven rotating body (input shaft) 7 side. In this case, one is made of a metal material and the other is used as a highly elastic material.

  FIG. 5 is a side sectional view showing another embodiment of the shaft coupling of the construction machine according to the present invention, FIG. 6 is a sectional view taken along line F-F, and FIG. 7 is a perspective view showing a power transmission member of this embodiment. 5 and FIG. 6, the same reference numerals as those in FIG. 1 and FIG. Reference numeral 10 denotes a first member fixed to the power source rotating body 3 by a bolt 11 inserted through the bolt insertion hole 10a, and is made of a metal block.

  Reference numeral 12 denotes a second member attached to the driven rotating body (input shaft) 7. As shown in FIG. 7, the second member 12 includes a boss 12a and a projecting member 12b provided on the outer periphery of the boss 12a so as to project in the radial direction. As shown in FIG. 8, the groove 12c provided in the center hole of the boss 12a is fitted into the spline groove 7a of the input shaft 7, and the bolt 13 is screwed into the screw hole 12d provided in the radial direction of the boss 12a. The bolt 13 is fastened and fixed to the input shaft 7 to fix the boss 12 a to the input shaft 7.

  The projecting member 12b is made of a metal material, and is provided in the same number as the first member 10. Bolts 14 are inserted into bolt insertion holes 12e provided through the projecting member 12b, and screw holes 12f provided in the boss 12a. The protruding member 12b is fixed to the boss 12a by screwing and fastening.

  Reference numeral 15 denotes a third member made of a highly elastic material made of rubber or resin. The third member 15 has a substantially annular shape, and has the same number of U-shaped portions 15 a as the first member 10 fitted between the protruding members 12 b and 12 b of the second member 12. As shown in FIG. 8, the third member 15 is fitted between the first member 10 and the second member 12 between the U-shaped portions 15a and 15a, and the first member 15a is inserted into the U-shaped portion 15a. The members 10 are fitted and combined. The outer periphery of each U-shaped portion 15 a abuts and is fixed to a protruding piece 12 g provided at the outer end of the protruding member 12 b and a protruding piece 10 b provided at the outer end of the first member 10.

  FIG. 9 is a partially enlarged view of FIG. 8. In FIG. 9, the first member 10 and the third member 15 have their contact surfaces 10c and 15b as torque transmission surfaces, and the third member 15 and the second member 15. The contact surfaces 15b and 12h with the member 12 also serve as torque transmission surfaces.

  In this embodiment, the solid lubricant film as described above is formed on at least the torque transmission surfaces of the first member 10 and the second member 12 made of a metal material, respectively. By improving the slidability between the member 15 and the torque transmission surface, the amount of wear of the third member 15 can be reduced, and the life of the shaft joint can be extended. Further, when forming such a solid lubricating film on the torque transmission surface, if a surface hardened layer is formed by the means as described above and the solid lubricating film is provided on this surface hardened layer, The slidability with the torque transmission surface can be improved, and the wear amount of the highly elastic material can be further reduced. Further, as described above, if a solid lubricating film is provided on the roughened surface, the solid lubricating film can be more stably formed on the torque transmission surface.

  In the embodiment shown in FIGS. 5 to 9, the first member 10 and the second member 12 are made of a metal material, and the third member 15 is made of a highly elastic material. The member 10 and at least the protruding member 12b of the second member 12 may be made of a highly elastic material, and the third member 15 may be made of a metal material.

  Next, examples will be described. A steel material of S45C is used as the metal material used for the shaft joint, a polyamide resin added with glass fiber (a coupling made by KTR) as a highly elastic material, and a solid lubricating film according to the present invention is formed. A wear test was conducted with a conventional example in which no film was formed. In the wear test, a high-elastic material is reciprocally slid at 10 MPa on a surface of a metal material on which a solid lubricant film is formed and not formed, and the high-elastic material is passed over time. This was done by measuring the amount of wear. The size of the sliding surface of the highly elastic material was 1 mm × 6 mm.

  The solid lubricating film was formed by baking molybdenum disulfide. That is, using molybdenum disulfide particles having an average particle size of about 10 μm liquefied with a binder (Deflic Coat A or B manufactured by Kawamata Laboratories Co., Ltd.) was sprayed on the surface and then baked. Here, the deflick coat A and the deflick coat B are different in terms of molybdenum disulfide content.

  Further, in order to cure the surface of the metal material before the formation of the solid lubricant film, a surface hardening treatment by salt bath nitriding was performed. The salt bath nitriding was performed using potassium cyanide, potassium carbonate, sodium carbonate or the like as a nitride material.

  In addition, in order to achieve stable fixation of the solid lubricant film, the surface-hardened treatment as described above is roughened with manganese phosphate, and then the solid lubricant film is formed and the roughening treatment is not performed. Compared with the ones.

  FIG. 10 shows a case where a solid lubricating film is not formed on the surface of a metal material (S45C) (prior art), a case where a solid lubricating film is formed by molybdenum disulfide coating A after salt bath nitriding, and a salt bath nitriding after It is a graph which compares and shows the abrasion loss of the highly elastic material per sliding time of what performed the manganese phosphate process before solid lubricant film formation by molybdenum disulfide coating.

  As can be seen from FIG. 10, the formation of a solid lubricating film made of molybdenum disulfide improves the slidability with the highly elastic material, reduces the amount of wear of the highly elastic material, and extends the life of the shaft coupling. can do. Further, the roughening by the manganese phosphate treatment further improves the slidability with the highly elastic material, further reduces the amount of wear of the highly elastic material, and further extends the life of the shaft joint. Note that it is possible to reduce the amount of wear of a highly elastic material as compared with the conventional example even when the surface of the metal material is not cured or when neither the curing process nor the roughening process is performed. It has been confirmed.

  The present invention can also be applied when the power source is an electric motor and the driven rotor is a hydraulic pump.

1: Engine, 2: Hydraulic pump, 3: Power source rotor, 4: Housing, 5: Internal gear, 5a: Teeth, 5b: Torque transmission surface, 6: Bolt, 7: Driven rotor (input shaft) 7a: spline groove, 8: external gear, 8a: teeth, 8b: boss, 8c: groove, 8d: slit, 8e: bolt insertion hole, 8f: screw hole, 8g: torque transmission surface, 9: bolt, 10: first member, 10a: bolt insertion hole, 10b: protruding piece, 10c: torque transmission surface, 11: bolt, 12: second member, 12a: boss, 12b: protruding member, 12c: groove, 12d: Screw hole, 12e: Bolt insertion hole, 12f: Screw hole, 12g: Projection piece, 12h: Torque transmission surface, 13: Bolt, 14: Bolt, 15: Third member, 15a: U-shaped part, 15b, 15c: Torque transmission surface

Claims (7)

One of the torque transmission surfaces is formed of a metal material, and the other is a shaft joint of a construction machine formed of a highly elastic material made of rubber or resin
A shaft coupling for a construction machine, characterized in that a solid lubricating film made of molybdenum disulfide, graphite, calcium fluoride, or silicon dioxide is provided on the surface of the torque transmission surface on the metal side. In the shaft coupling of the construction machine according to claim 1,
A surface hardened layer is formed on the metal side torque transmission surface by salt bath nitriding, gas soft nitriding, nitriding, quenching and tempering, induction hardening, carburizing quenching or carbonitriding, and the solid lubricant film is provided on the surface hardened layer. A shaft joint of a construction machine characterized by the above. In the shaft coupling of the construction machine according to claim 1,
A shaft joint for a construction machine, wherein the metal side torque transmission surface is roughened by chemical surface treatment or physical surface treatment, and the solid lubricant film is provided on the roughened surface.   A shaft coupling for a construction machine, wherein the hardened surface layer according to claim 2 is roughened by the surface treatment according to claim 3, and the solid lubricant film is provided on the roughened surface. In the shaft coupling of the construction machine according to any one of claims 1 to 4,
A first gear comprising an internal gear or an external gear attached to the output shaft of the power source rotor and having a torque transmission surface on the teeth;
An external gear or an internal gear that is attached to the input shaft of the driven rotating body and meshes with the first gear, and a second gear having a torque transmission surface on the teeth;
One of the first gear and the second gear is made of a metal material, and the other is made of a highly elastic material. In the shaft coupling of the construction machine according to any one of claims 1 to 4,
A plurality of first members attached to the output disk of the power source rotor at equal intervals in the circumferential direction and having torque transmission surfaces formed on both sides in the rotational direction;
A second member having a torque transmission surface attached to the input shaft of the driven rotating body and installed at intervals on the torque transmission surfaces of the first members;
A surface that is sandwiched between the first member and the second member and that contacts the torque transmission surface of the first member and the torque transmission surface of the second member is a torque transmission surface. 3 members,
The first member and the second member are made of a metal material and the third member is made of a highly elastic material, or the first member and the second member are made of a highly elastic material and the third member. A shaft joint for construction machinery, characterized in that is made of a metal material. In the shaft coupling of the construction machine according to any one of claims 1 to 6,
A shaft joint for construction machinery, wherein the high-elasticity material is a material to which reinforcing fibers are added.

Images