JP2857368B2 - Power take-off mechanism of tandem hydraulic pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power take-out mechanism for a tandem type hydraulic pump, and more particularly to a tandem type hydraulic pump which operates smoothly without being affected by the bending of a pump shaft.

[0002]

2. Description of the Related Art Conventionally, a tandem type hydraulic pump in which a pair of swash plate type hydraulic pumps are connected in series to each other has been widely used in construction machines and the like. In this tandem type hydraulic pump, the shaft ends of a pair of pump shafts are connected so as to rotate integrally with a coupling member, and the pair of hydraulic pumps are arranged symmetrically with respect to the coupling member, and a common suction pump is provided. It is configured to inhale from a port and discharge to a common discharge port.

In construction machines and the like, one or two small gear pumps may be provided in order to generate a control pressure different from the hydraulic pressure generated by a tandem hydraulic pump or a hydraulic pressure for driving auxiliary equipment. Conventionally, as a power take-out mechanism for driving these gear pumps, a power take-out mechanism that takes out power from a connecting portion that connects pump shafts of a tandem hydraulic pump has been proposed. As described above, when power is taken out from the connecting portion that connects the pump shafts, the pump unit including the tandem hydraulic pump and the small gear pump is reduced in size as a whole, which is variously advantageous.

For example, Japanese Patent Publication No. 3-59275 proposes a power take-off mechanism for a tandem type hydraulic pump as described above. This power take-off mechanism connects the shaft ends of a pair of pump shafts. A coupling member that is connected and has a gear formed on an outer peripheral portion thereof; and a gear train (consisting of a plurality of gear members arranged in series) that meshes with a gear on the outer periphery of the coupling member. , deflection of the pump shaft of the pair is disposed toward substantially along a direction to maximum deflection viewed surface to be the maximum. In the case of a swash plate type hydraulic pump, a load is applied from the swash plate via the cylinder block, and the pump shaft bends in the direction from the top dead center to the bottom dead center when the piston enters the cylinder hole of the cylinder block as much as possible. Be the largest. That maximum deflection of the pump shaft of the pair is maximum
The flexures seen face, a plane containing the top dead center and the bottom dead center position.

[0005]

In [0005] the power take-off mechanism of a tandem hydraulic pump of the publication, a gear train which meshes with the outer periphery of the gear coupling members, the maximum deflection of the pump shaft of the pair is maximum because it is arranged toward the substantially along a direction to see the surface deflection, when the deflection of the pump shaft of the pair becomes the maximum in the phase symmetry, the shaft end of the pump shaft is approximately 70~100μ
When the coupling member is displaced in the direction away from the axis by about m, the coupling member is also displaced in the direction away from the axis by the same degree.

As a result, the center distance between the coupling member and the gear member meshing with the coupling member in the gear train fluctuates by about 70 to 100 μm, so that the gear of the coupling member and the gear member There is a problem that the meshing of the gears is deteriorated, the tooth surfaces of the gears are abnormally worn, and the meshing noise is abnormally large. An object of the present invention is to provide a power take-out mechanism for a tandem hydraulic pump in which the fluctuation of the inter-axis distance due to the bending of the pump shaft is minimized.

[0007]

A power take-out mechanism for a tandem hydraulic pump according to claim 1 is a tandem hydraulic pump comprising a pair of swash plate hydraulic pumps arranged symmetrically and connected in series with pump shafts. A pump, wherein the shaft ends of the pair of pump shafts are connected so as to rotate integrally with each other and a gear is formed on the outer periphery;
Deflection of the pump shaft of the pair of disposed by the coupling member as the axis is located in the plane or vicinity thereof through the axis of the pump shaft orthogonally and one pair of maximum Deflection viewed surface to be the maximum And a gear member meshed with a gear, and configured to take out power to the outside via a gear member that is rotationally driven by the coupling member.

In this power take-off mechanism, when a pair of pump shafts are driven to rotate, a coupling member is driven to rotate integrally with the pump shafts, and a gear member meshed with a gear on the outer periphery of the coupling member. Is also driven to rotate, so that power can be taken out from this gear member to drive, for example, a small gear pump or the like. Here, as the shaft center of the gear member, the deflection of the pump shaft of the pair is positioned on the surface or vicinity thereof through the axis of the pump shaft orthogonally and one pair of maximum Deflection viewed surface to be the maximum Since the fluctuation of the distance between the coupling member and the gear member due to the bending of the pair of pump shafts is substantially minimized, the meshing between the gear of the coupling member and the gear of the gear member is provided. And the occurrence of abnormal wear and abnormal meshing noise of the gear tooth surfaces is remarkably improved, and the durability is also improved.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIGS.
In the tandem type hydraulic pump 1, the pump shafts 4 and 5 of the swash plate type hydraulic pump 2 and the swash plate type hydraulic pump 3 are connected in series by a coupling member 6, and power is taken out from the coupling member 6 to the outside. A power take-out mechanism 7 is provided.

Since the structures of the hydraulic pumps 2 and 3 are general structures, they will be briefly described. In the left hydraulic pump 2, the pump housing 8 includes the intermediate block 9 and the case 1.
0 and an end plate 11, a swash plate 15 and a cylinder block 16 are accommodated in a pump housing 8, the cylinder block 16 is spherically supported by a spherical seat member 17, and the pump shaft 4 is a pump housing 8 and a swash plate 15 And an input shaft portion 4 a located outside the pump housing 8 is formed at the left end of the pump shaft 4, and the pump shaft 4 has a bearing 18. , 19 are rotatably supported by the pump housing 8, and a spline shaft portion 20 is formed at a shaft end portion of the pump shaft 4 on the intermediate block 10 side.

A tilt angle adjusting mechanism 21 for adjusting the tilt angle is provided at an upper portion of the pump housing 8. The shoes 24 at the ends of the plurality of pistons 23 slidably inserted into the plurality of cylinder holes 22 of the cylinder block 16 slidably contact the guide surface 15a of the swash plate 15, respectively. A suction port 25 and a discharge port 26 are formed in the cylinder block 16 and the spherical seat member 17 in a curved arc shape, respectively.

The right hydraulic pump 3 is symmetrical to the hydraulic pump 2 except for the pump shaft 5, so that
The same components are denoted by the same reference numerals and description thereof is omitted. A spline shaft portion 27 is formed at a shaft end of the right hydraulic pump 3 on the intermediate block 9 side of the pump shaft 5. In the intermediate block 9, a suction port 28 and a discharge port 29 common to the two hydraulic pumps 2 and 3 are formed. In FIG. 2, the side at which the piston 23 enters the cylinder hole 22 at the maximum is the top dead center, and the side at which the piston 23 retreats from the cylinder hole 22 at the maximum is the bottom dead center.

Next, the power take-out mechanism 7 will be described. The spline shaft portion 20 of the pump shaft 4 and the spline shaft portion 27 of the pump shaft 5 are connected by a coupling member 6 so as to rotate integrally with each other in a housing portion 29 formed in the intermediate block 9. A gear 6a is formed on the outer peripheral portion of. The power take-out mechanism 7 includes a coupling member 6, an idle gear 30 meshed with a gear 6a on the outer periphery of the coupling member 6, and an output gear 31 meshed with the idle gear 30, and drives, for example, a small gear pump 40. And a case member 32 fixed to the intermediate block 9 with bolts and supporting the idle gear 30 and the output gear 31.

[0014] and the idle gear 30, the output gear 31, and perpendicular to a deflection of the pair of pump shaft 4 and 5 is maximum Maximum Deflection viewed surface 33 (surface corresponding to the plane of FIG. 2) The shafts 35 and 36 are disposed so as to be located on a surface including the shaft centers 4c and 5c of the pair of pump shafts 4 and 5 (a surface corresponding to the paper surface in FIG. 1) or in the vicinity thereof (FIG. 3). reference). The idle gear 30 is rotatably supported by a support shaft 37 supported by a case member 32 via a bearing 38, and the output gear 31 is supported by the case member 32 via a pair of bearings 39. The spline shaft 31 has a spline shaft hole 31a into which the input shaft 41 of the gear pump 40 is spline-fitted.

Next, the operation of the tandem hydraulic pump 1 and the power take-out mechanism 7 will be described. As shown in FIG. 2, when the tandem hydraulic pump 1 is driven, a vertical force acts on the pump shaft 4 from the swash plate 15 via the cylinder block 16. The core 4c is elastically deformed downward as shown by a broken line. The same applies to the pump shaft 5. Since a vertical force acts on the pump shaft 5 from the swash plate 15 via the cylinder block 16, the shaft center 5 c of the pump shaft 5 moves downward as shown by a chain line. Elastically deform.

[0016] deflect the pump shaft 4 and 5 as described above occurs, the position of the coupling member 6, will vary up and down in the maximum flexures viewed surface 33 which corresponds to the plane of FIG. 2, this variation δ is about 70 to 100 μm. Assuming that the axis 35 of the idle gear 30 and the output gear 31 is assumed to be placed at the large Deflection seen face 33 or near part thereof, the center distance D of the coupling member 6 and the idle gear 30 is the variation δ, the meshing between the coupling member 6, the idle gear 30, and the output gear 31 is deteriorated, the gear tooth surfaces are abnormally worn, and the durability is extremely reduced. A meshing sound will be generated.

However, in the power take-out mechanism 7 of the present application, the shaft centers 35 and 36 of the idle gear 30 and the output gear 31 are provided.
A 1 deflection pair of pump shaft 4 and 5 are orthogonal to the maximum Deflection viewed surface 33 as a maximum and a pair of axis 4c of the pump shaft 4 and 5,
5c (or a plane corresponding to the plane of FIG. 1) or in the vicinity thereof, the center distance D between the coupling member 6 and the idle gear 30 hardly changes, and the center distance D Is about 75 mm, the fluctuation amount δ of the inter-axis distance D is about 0.05 μm. As a result, the meshing between the coupling member 6, the idle gear 30, and the output gear 31 is significantly improved, abnormal wear does not occur, durability is improved, and abnormal meshing noise does not occur.

As a modification of the above-described embodiment, the diameter of the coupling member 6 and the output gear 31 can be increased, and the gear 6a on the outer periphery of the coupling member 6 can be meshed with the output gear 31. In this case, the idle gear 30 can be omitted, and the number of parts can be reduced. In some cases, the case member 32 is changed, and a gear pump different from the gear pump 40 is mounted on the left side of the output gear 31 so as to be driven by the output gear 31.

[0019]

According to the power take-out mechanism for a tandem hydraulic pump according to the first aspect, the shaft ends of a pair of pump shafts arranged symmetrically with each other are connected so as to rotate integrally with each other, and the outer peripheral portion has a gear. a coupling member formed with, and orthogonal to the maximum deflection viewed surface deflection of the pump shaft of the pair becomes the maximum 1
A gear member that is disposed so that the axis is located on a surface including the axis of the pair of pump shafts or in the vicinity thereof and that meshes with the gear of the coupling member; and a gear member that is rotationally driven by the coupling member. Since the power is taken out to the outside via the shaft, the fluctuation of the distance between the coupling member and the gear member due to the bending of the pair of pump shafts is minimized. The meshing with the gears is improved, and the occurrence of abnormal wear and abnormal meshing noise of the tooth surfaces of the gears is remarkably improved, and the durability is also improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a tandem hydraulic pump according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a sectional view taken along line III-III of FIG.

[Explanation of symbols]

1 tandem hydraulic pumps 2 swash plate type hydraulic pumps 4,5 pump shaft 4c, 5c axis 6 coupling member 6a gear 7 power take off mechanism 30 idle gear 31 Output gear 33 Maximum Deflection seen face 34 Maximum Deflection observed surface 35, 36 axis perpendicular to

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroshi Shimazaki 234 Matsumoto, Hazeya-cho, Nishi-ku, Kobe Kawasaki Heavy Industries, Ltd. Nishi-Kobe Plant (58) Field surveyed (Int.Cl. ⁶ , DB name) F04B 23 / 00 F04B 1/00

Claims (1)

(57) [Claims] 1. A tandem hydraulic pump in which pump shafts of a pair of swash plate type hydraulic pumps arranged symmetrically with each other are connected in series, and the shaft ends of the pair of pump shafts are integrally rotated. plane including a coupling member formed with a gear on an outer peripheral portion, the axis of said pair deflection of the pump shaft of perpendicular to the maximum deflection viewed surface to be the maximum and a pair of pump shaft with coupling as Or a gear member which is disposed so that an axis thereof is located in the vicinity thereof, and which meshes with a gear of the coupling member, and extracts power to the outside via a gear member which is rotationally driven by the coupling member. A power take-out mechanism for a tandem-type hydraulic pump, wherein