JP3730781B2 - Multiple piston pump - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an expansion method of a parallel type swash plate type double piston pump and an expansion pump, and in particular, when used in a construction machine or the like, without increasing the dimension in the axial direction of the pump that determines the actual machine size. This is a multi-piston piston pump, which eliminates piping for full horsepower control and eliminates the suction pump piping for expansion pumps, improving the reliability and economic efficiency of expansion pump maintenance. The present invention relates to a multiple piston pump.
[0002]
[Prior art]
Conventionally, a swash plate type piston pump has been widely used as a hydraulic pressure supply source in construction machines and the like. However, as a pump that unitizes two swash plate type piston pumps, two swash plate type piston pumps are arranged in parallel. A parallel type swash plate type piston pump and a tandem type swash plate type piston pump formed by connecting two swash plate type piston pumps in series are known.
[0003]
However, today's construction machines and the like are often equipped with a plurality of actuators in addition to the traveling hydraulic motor and the turning hydraulic motor. Therefore, the parallel swash plate piston pump and the tandem swash plate piston pump have 1 Or, a plurality of gear pumps are often added to generate hydraulic pressure. For example, a parallel type swash plate type piston pump having a configuration in which an additional pump is connected in series on the side opposite to the input side of one swash plate type piston pump has been proposed (Japanese Utility Model Publication No. 54-21803). .
[0004]
In addition, the applicants of the parallel type swash plate type piston pump have the problems of shortening the length dimension of the rotary shafts of the two pumps to a small size and preventing the temperature rise of the lubricating oil due to the stirring resistance, respectively. A swash plate type piston pump that can be solved has been developed, and patent applications have been filed respectively (Japanese Patent Application Nos. 9-100591 and 9-309029).
[0005]
In addition, when adding one or more pumps to the tandem swash plate type piston pump, for example, a gear box incorporating three gears is attached to the input side of the tandem swash plate type piston pump, and driving force is input. Drive power is transmitted from the drive gear that rotates integrally with the drive shaft to the gears on both sides of the drive shaft, the drive force is input to the tandem swash plate piston pump via the gear, and to one or more additional pumps via the gear One configured to input a driving force is known.
[0006]
Further, in a conventional tandem swash plate type piston pump in which at least two swash plate type piston pumps are connected in series, a driving force is input to the pump, and the drive shafts of the two swash plate type piston pumps are connected to each other. There has been proposed one having a configuration in which a driving force extraction mechanism for extracting a part of the driving force to the outside is provided from the intermediate joint portion to be connected (Japanese Patent Laid-Open No. Hei 8-121328).
[0007]
That is, the tandem swash plate type piston pump according to the proposal includes a spline joint portion 10 for connecting the drive shafts 4 and 5 of the two swash plate type piston pumps 2 and 3, and the spline joint as shown in FIG. A first gear 14 that rotates integrally with the spline sleeve member 12, a driven gear 16 that meshes with the first gear 14 via an intermediate gear, and a drive force extraction member that rotates integrally with the driven gear 16 (spline sleeve member). ) 18, and a gear box having a gear case 20 that rotatably accommodates the driven gear 16 and the driving force extracting member 18, and is a gear that is detachably fixed to the housings 6 and 7 of the tandem swash plate type piston pump. The box 22 is configured to be provided.
[0008]
Therefore, the tandem swash plate type piston pump configured as described above transmits a part of the driving force from the spline joint portion 10 to the driven gear 16 via the first gear 14 and rotationally drives the driving force extracting member 18. The driving force extraction member 18 can drive a single or a plurality of additional pumps 24, 26, and 28 that are separately added.
[0009]
[Problems to be solved by the invention]
However, in the tandem swash plate type piston pump according to the prior art, the dimension in the pump axial direction is longer than that of the parallel type swash plate type piston pump, and the installation position when used in a construction machine or the like is greatly restricted. It is difficult to bring. In particular, when installing an expansion pump, a complicated device configuration is required to extract the power from the input shaft to the outside using a gear mechanism, etc., increasing the size of the equipment, increasing the weight and damage factors Furthermore, problems such as an increase in manufacturing cost due to an increase in the number of parts occur.
[0010]
Also, in terms of control technology, when total horsepower control is performed together with the expansion pump, external piping is necessary to guide the discharge pressure of the expansion pump to the horsepower control device on the swash plate type piston pump side. There is a problem in that reliability is lowered due to problems such as increase and oil leakage from piping.
[0011]
Furthermore, in terms of workability for maintenance of expansion pumps, in conventional multiple piston pumps, expansion pumps are added in series in the axial direction, so if one of the expansion pumps is damaged, all expansion pumps It is necessary to carry out the maintenance with removing, and there is a problem that workability is remarkably deteriorated.
[0012]
Therefore, as a result of intensive studies, the present inventors have required a device or means for taking out power from the input shaft in order to install an additional pump in the conventional multiple piston pump. By taking advantage of the features of the swash plate type double piston pump, it is possible to install a plurality of additional pumps directly on the cover of the double piston pump, without the need for a device to extract the power for the additional pumps. In full horsepower control, the discharge pressure of the expansion pump can be introduced directly into the cover of the dual piston pump, and oil can be introduced to the control device only by the internal passage provided in the main body of the dual piston pump. No need for external piping as in the past, and additional pumps are installed directly and independently on the input shaft side and driven shaft side of the dual piston pump. As a result, the maintenance work of the expansion pump can be improved, and a suction passage for the expansion pump can be provided in the cover. This makes it possible to omit an external suction pipe in the actual machine. It has been found that a multiple piston pump having many excellent advantages can be obtained.
[0013]
Accordingly, an object of the present invention is to provide a gearbox that is enlarged to take out power from the pump input shaft when an additional pump is installed as in the prior art, taking advantage of the characteristics of the parallel swash plate type piston pump. In addition, the length of the actual machine size of the entire equipment is shortened to facilitate the installation of the double piston pump in construction machinery and the like, and the discharge pressure of the expansion pump necessary for the suction passage of the expansion pump and full horsepower control is guided An object of the present invention is to provide a double piston pump that can remarkably improve the workability and space saving of an extension pump without using a passage as an external pipe.
[0014]
[Means for Solving the Problems]
In order to achieve the above object, a multiple piston pump according to the present invention has a pair of rotating shafts arranged in parallel and close to each other, and a cylinder block configured integrally with these rotating shafts, each provided with a gear mechanism on the outer periphery. And a swash plate type double piston pump that transmits a driving force applied to one rotary shaft from the rotary drive mechanism to the other rotary shaft via the gear mechanism to simultaneously drive the two pumps. The casing of the swash plate type double piston pump is configured such that the swash plate side is surrounded by a housing and the port plate side is surrounded by a cover. the outer surface of the wherein in correspondence with each rotary shaft extension pump mounted respectively, and configured to perform the operation of the additional pump by the rotary shafts That.
[0015]
In this case, the the end of each rotary shaft, via a coupling having a coupling spline, can each be configured to couple said additional pump directly.
[0016]
Moreover, the additional pump, the outer surface of the cover can be detachably connected and fastened by their respective bolts.
[0017]
Furthermore, a suction port that communicates with the additional pump can be provided inside the cover with respect to the suction port of the dual piston pump provided inside the cover.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Next, as an embodiment of the multiple piston pump according to the present invention, a parallel swash plate type dual piston pump will be described in detail with reference to the accompanying drawings.
[0019]
1 and 2 show an embodiment of a parallel swash plate type double piston pump as a multiple piston pump according to the present invention. That is, in the parallel swash plate type double piston pump in this embodiment, a housing 30 as a pump casing is basically provided with a pair of swash plates 32a and 32b which are in sliding contact with the inner surface 30a. 32a and 32b are respectively inserted so as to be able to tilt at right angles to the axial direction of the rotary shafts 34a and 34b. The one rotary shaft 34a is a drive shaft, and one end of the rotary shaft 34a protrudes outside the housing 30 and is appropriately coupled to the rotary drive mechanism.
[0020]
The rotary shafts 34a and 34b are provided with cylinder blocks 36a and 36b integrally therewith, and a plurality of pistons 38 are slidable in the direction of the rotary shaft with respect to the cylinder blocks 36a and 36b. And it is liquid-tightly integrated. Each piston 38 has a spherical head 38a slidably coupled to the shoe 40, and these shoes 40 are arranged in sliding contact with the sliding surfaces of the swash plates 32a and 32b. Yes.
[0021]
Port plates 42 are disposed in contact with the suction and / or discharge port side end surfaces of the cylinder blocks 36a and 36b, respectively, and are in contact with and held on the back surfaces of the port plates 42, and the cylinder blocks 36a and 36b. A cover 44 as a pump casing that surrounds the housing 30 together with the housing 30 is attached.
[0022]
The rotary shafts 34a and 34b are rotatably supported with respect to the housing 30 and the cover 44 through bearings 46 and 48, respectively. The bearing 46 that supports the housing 30 is of a type that can also support axial force from the cylinder blocks 36a and 36b.
[0023]
Further, the cylinder blocks 36a and 36b configured integrally with the rotary shafts 34a and 34b are provided with gear mechanisms 50a and 50b on the outer peripheral portions thereof, respectively, and mesh with these gear mechanisms 50a and 50b to rotate integrally. Is configured to do. The contact surface of the port plate 42 with the cylinder blocks 36a, 36b is slid with the cylinder blocks 36a, 36b by a spring 52 provided on the back side of the port plate 42 and a bush 54 into which high-pressure oil is introduced. It is configured to be slidably and liquid-tightly slidable with respect to the moving surface and hydraulically floated.
[0024]
In the parallel swash plate type double piston pump configured as described above, when one rotary shaft 34a is rotationally driven by a drive mechanism (not shown), this rotational driving force is configured integrally with the rotary shaft 34a. At the same time as being transmitted to one cylinder block 36a, it is also transmitted to the other cylinder block 36b via gear mechanisms 50a, 50b provided on the outer periphery of each cylinder block 36a, 36b.
[0025]
The cylinder blocks 36a and 36b are integrally formed with the rotary shafts 34a and 34b, and the rotary shafts 34a and 34b, that is, the cylinder blocks 36a and 36b, are bearings 46 and 48 attached to the housing 30 and the cover 44. Is surely supported. Since the port plate 42 is hydraulically floated while being pressed against the sliding surfaces of the cylinder blocks 36a and 36b that are securely supported, the port plate 42 is transferred to the cylinder blocks 36a and 36b by the transmission of the rotational driving force. Even if a radial force or a frictional force is applied from the gear mechanisms 50a and 50b, the lightweight port plate 42 is pressed against the cylinder blocks 36a and 36b that are reliably positioned in the radial direction and the axial direction. By setting to be in contact with each other, extremely high reliability can be obtained without any influence on the pump function or its performance.
[0026]
In the parallel type swash plate type double piston pump of the present embodiment, the rotary shafts 34a and 34b and the cylinder blocks 36a and 36b are shown integrally formed by separate members, respectively. The driving force from one rotating shaft 34a is smoothly supplied to the other rotating shaft 34b as a driven shaft through spline coupling with the rotating shafts 34a and 34b by splines provided on the inner diameter portions of the cylinder blocks 36a and 36b, respectively. It is configured to be transmitted.
[0027]
However, the multiple piston pump in the present embodiment includes one rotary shaft 34a as an input shaft for rotationally driving the parallel type swash plate type dual piston pump having the above-described configuration, and the other rotary shaft 34b as a driven shaft. Couplings 58a and 58b in which coupling splines 56a and 56b for coupling to the additional pumps 60a and 60b are respectively provided are provided on the extensions on the cover 44 side. The additional pumps 60a and 60b are configured and arranged so as to be directly coupled to the rotary shafts 34a and 34b on the outer surface of the cover 44 through 58b.
[0028]
The multiple piston pump according to the present embodiment configured as described above has a rotational driving force from the input shaft of the main body of the parallel type swash plate type double piston pump, without requiring a special device or the like. Power can be transmitted easily and reliably to the pumps 60a and 60b.
[0029]
In this case, the extension pumps 60a and 60b are coupled and fixed directly and detachably to the outer surface of the cover 44 by bolts 62, respectively. This makes it possible to perform maintenance work on each of the additional pumps 60a and 60b individually.
[0030]
In addition, suction ports 66 a and 66 b for the additional pumps 60 a and 60 b are provided in the cover 44 for the suction ports 64 a and 64 b of the dual piston pump provided in the cover 44. As a result, the extension pumps 60a and 60b can be added without separately providing external piping, and the length in the axial direction of the pump can be increased only by the extension pump dimension. By taking advantage of the features of the above, compared to the tandem swash plate type piston pump of the prior art, the space of the equipment can be saved, and the installation of a double piston pump with an additional pump in construction machines can be easily realized. .
[0031]
Further, when performing full horsepower control including the expansion pump, as shown in FIG. 2, the discharge pressure of the expansion pump is directly introduced into the cover of the dual piston pump, and the internal passage 68 provided in the main body is used. Since it is possible to guide to the horsepower control device 70 and no external piping is required as in the prior art, troubles such as oil leakage in the external piping are eliminated, and simplification and reliability can be improved.
[0032]
The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and many design changes can be made without departing from the spirit of the present invention.
[0033]
【The invention's effect】
As is clear from the above-described embodiments, the multiple piston pump according to the present invention has a pair of rotating shafts arranged in parallel and close to each other, and a cylinder block integrally formed with these rotating shafts, and a gear mechanism on each outer peripheral portion. A swash plate type double piston pump that transmits a driving force applied to one rotary shaft from the rotary drive mechanism to the other rotary shaft via the gear mechanism to simultaneously drive the two pumps. In the multiple piston pump constructed such that the casing of the swash plate type dual piston pump is configured such that the swash plate side is surrounded by the housing and the port plate side is surrounded by the cover, an outer surface of the cover, the mounting each of the rotating shaft and the additional pump in correspondence, that was configured to perform the operation of the additional pump by the rotary shafts Taking advantage of the features of the parallel swash plate type piston pump, when installing an additional pump, the expansion pump is a double piston pump without providing a large gearbox for extracting power from the pump input shaft. It is structured to be directly and independently mounted on the input shaft side and output shaft side of the pump, improving the workability and space saving of the expansion pump, and the length of the entire equipment in the axial direction of the pump as a whole The dimensions can be shortened and the installation of the double piston pump in a construction machine or the like can be facilitated.
[0034]
In addition, a suction passage for the additional pump can be provided in the cover, which makes it possible to omit an external suction pipe in the actual machine. It can be introduced directly into the pump cover, and oil transmission to the horsepower control device is possible only with the internal passage provided in the main body of the dual piston pump, which eliminates the need for external piping as in the past and simplifies In addition, troubles such as oil leakage in the external piping can be solved and reliability can be improved, and many excellent advantages can be obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional side view of an essential part showing an embodiment of a multiple piston pump according to the present invention.
2 is a cross-sectional view of a principal part of the multiple piston pump shown in FIG. 1 taken along the line II-II.
FIG. 3 is a schematic structural diagram of a conventional tandem swash plate double piston pump.
[Explanation of symbols]
30 Housing 30a End face 32a, 32b Swash plate 34a, 34b Rotating shaft 36a, 36b Cylinder block 38 Piston 38a Ball head 40 Shoe 42 Port plate 44 Cover 46, 48 Bearing 50a, 50b Gear mechanism 52 Spring 54 Bush 56a, 56b For coupling Spline 58a, 58b Coupling 60a, 60b Expansion pump 62 Bolt 64a, 64b Suction port 66a, 66b Suction port 68 Internal passage 70 Horsepower control device

Claims (4)

A driving force applied from a rotary drive mechanism to one rotary shaft by connecting a pair of rotary shafts in close proximity to each other and connecting the cylinder blocks formed integrally with these rotary shafts to each other by providing a gear mechanism on the outer periphery. Is composed of a swash plate type double piston pump that transmits two pumps simultaneously by transmitting to the other rotating shaft through the gear mechanism, and the casing of the swash plate type double piston pump is surrounded by a housing on the swash plate side. In the multiple piston pump configured to surround the port plate side with a cover,
And wherein the outer surface of the cover on the extension of the rotary shaft, the mounting each of the rotating shaft and the additional pump in correspondence, and configured to perform the operation of the additional pump by the rotary shafts A multiple piston pump. 2. The multiple piston pump according to claim 1, wherein the additional pumps are directly coupled to each end of each rotary shaft via a coupling provided with a coupling spline. Said additional pump, an outer surface of the cover, according to claim 1 or 2 multiple-piston pump according formed by detachably connected and fastened by their respective bolts. To the suction port of the twin piston pump provided inside the cover, multiple-piston pump according to any one of claims 1 to 3 comprising providing said additional pump and communication with suction port to said inner cover, respectively .

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