JP4126198B2 - Swash plate type fluid pump / motor with sliding thrust plate - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is applied to a hydraulic or hydraulic pump, hydraulic or hydraulic motor, etc., and the piston is reciprocated in the cylinder by relative rotation of a swash plate inclined to a predetermined swash plate angle and a piston loaded with fluid pressure. The present invention relates to a swash plate type fluid pump / motor provided with a sliding type thrust plate configured to be moved.
[0002]
[Prior art]
A swash plate type hydraulic pump is often used in a fluid machine such as a hydraulic drive device for a construction machine or a marine steering machine. In such a swash plate type hydraulic pump, a slipper connected to the head of a piston that is reciprocally fitted in the cylinder by rotation of a cylinder block by a drive source such as an engine or an electric motor is an inclined surface of the swash plate. Therefore, the sliding surface between the slipper and the thrust plate slides while periodically receiving a large reaction force from the piston.
[0003]
FIG. 6 is a sectional view of the upper half of the swash plate type hydraulic pump proposed by Japanese Patent Laid-Open No. 2000-18150, but along the pump rotation axis near the connecting portion between the piston and the swash plate. In the figure, reference numeral 1 denotes a pump shaft which is connected to a drive source (not shown) such as an engine or an electric motor and is driven to rotate. 01 is the rotational axis of the pump shaft, 2 is the casing, and 3 is the base plate. A cylinder block 5 is fitted to the pump shaft 1 via a spline 18 and is driven to rotate in synchronization with the pump shaft 1.
A plurality of cylinders 6 are perforated in the cylinder block 5 at equal intervals in the circumferential direction. Reference numeral 7 denotes a piston fitted to each cylinder 6 so as to be reciprocally slidable. Reference numeral 8 denotes a swash plate attached to the base plate 3, and the swash plate angle can be changed by a swash plate angle adjusting device 80, as shown in FIG.
That is, as shown in FIG. 7, the swash plate angle adjusting device 80 rotates the lever 08a by means of a piston 08c reciprocating in the cylinder 08b, so that the swash plate shaft 08 fixed to the end of the lever 08a is moved. The angle of the swash plate is changed by rotating like the U arrow in the figure.
[0004]
Slippers 15 are slidably mounted along the spherical surface in the form of spherical bearings 015 at the roots of the pistons 7, and each slipper 15 slides on a thrust plate 14 fixed to the swash plate 8. It comes to be in sliding contact with. Reference numeral 17 denotes an annular retainer ring that supports each of the slippers 15.
Reference numeral 11 denotes a valve plate which is disposed on the side of the supply / discharge oil hole 011 (see FIG. 5) of each cylinder 6 and is fixed to the end plate 4.
[0005]
When the hydraulic pump is operated, the cylinder block 5 is rotated when the pump shaft 1 is rotationally driven by a drive source such as an engine or an electric motor. By the rotation of the cylinder block 5, the slipper 15 connected to the head of the piston 7 that is fitted in the cylinder 6 so as to be able to reciprocate is a sliding surface 23 with the thrust plate 14 that constitutes the inclined surface of the swash plate 8. As a result, the piston 7 reciprocates in the cylinder 6 while rotating together with the cylinder block 5 to pressurize the oil sucked from the suction hole of the valve plate 11 to the discharge hole of the valve plate 11. Send it out.
[0006]
[Problems to be solved by the invention]
As described above, in the swash plate type hydraulic pump, the slipper 15 connected to the head of the piston 7 reciprocatingly sliding in the cylinder 6 by the rotation of the cylinder block 5 via the spherical bearing 015 is provided. The sliding surface 23 between the thrust plate 14 and the thrust plate 14 is slid while periodically receiving a large reaction force from the piston 7, and oil is pumped to the sliding surface 23. A large reaction force from the piston 7 is acting periodically.
[0007]
Under such an operating state, hard dust floating in the pump chamber 19 or dust such as metal powder mixed in the oil has a small surface pressure of the sliding surface 23 such as the suction stroke of the piston 7. If the sliding surface 23 is intruded during a period, the thrust plate 14 is fixed to the swash plate 8 in the prior art such as that described in Japanese Patent Application Laid-Open No. 2000-18150. The hard dust that has entered easily tends to be dragged by the slipper 15 as the slipper 15 moves in the circumferential direction and bites into the sliding surface 23 to cause scratches.
In particular, in a hydraulic pump that uses water as a working fluid, the sliding surface 23 is not good in lubricity, and therefore, the above-described sliding surface 23 tends to bite.
[0008]
In view of the problems of the prior art, the present invention avoids the occurrence of scratches due to the encroachment of dust on the sliding surface of the thrust plate, and the piston acting force support member between the piston including the thrust plate and the swash plate An object of the present invention is to provide a swash plate type fluid pump / motor provided with a sliding thrust plate capable of improving the durability of the swash plate.
[0009]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention provides a piston that is connected to the cylinder by relative rotation between a swash plate inclined at a predetermined swash plate angle and a piston that is reciprocally fitted in the cylinder and is loaded with fluid pressure. In a swash plate type fluid pump / motor configured to be reciprocated inside, a thrust plate attached to the swash plate so as to be relatively movable in a direction along a plate surface of the swash plate, and one end of the piston A slipper that is abutted on a spherical surface and that is slidably abutted against the surface of the thrust plate ;
Further, the thrust plate and the swash plate are configured to be movable relative to each other by allowing a fitting hole drilled in the thrust plate to loosely engage with a knock pin fixed to the swash plate. We propose a swash plate type fluid pump motor with a thrust plate.
[0010]
[0011]
According to this invention, when dust enters the sliding surface between the slipper and the thrust plate, the thrust plate is attached to the swash plate so as to be relatively movable in the direction along the plate surface of the swash plate. Therefore, the thrust plate moves in the direction along the plate surface of the swash plate to carry the dust out of the sliding surface, and the dust can be prevented from biting into the sliding surface.
Thereby, generation | occurrence | production of the damage | wound by the bite of the dust to the said sliding surface can be avoided, and durability of the piston action force support member between the piston containing this thrust plate and a swash plate can be improved.
In addition, since the thrust plate is movable relative to the swash plate, a lubricant such as oil easily enters the sliding surface between the slipper and the thrust plate, and the lubrication of the sliding surface is improved. Improved seizure resistance.
[0012]
Also, since the thrust plate within a loosely fitted gap between fitting hole drilled in the knock pin and the thrust plate is movable relative to the swash plate, larger relative thrust plate relative to the swash plate The movement is restrained, and the occurrence of the slipper and the thrust plate due to the movement is avoided.
[0013]
[0014]
[0015]
[0016]
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this example are not intended to limit the scope of the present invention only to specific examples unless otherwise specified. Only.
[0018]
FIG. 1 is a cross-sectional view of the upper half of the hydraulic pump according to the first embodiment of the present invention, taken along the axis of rotation of the pump in the vicinity of the connecting portion between the piston and the swash plate, and FIG. It is. Figure 3 is a diagram 1 corresponding view showing a reference example. FIG. 4 is a cross-sectional view taken along the axis of the pump showing the structure of the hydraulic pump to which the present invention is applied, and FIG. 5 is a view taken along the line BB in FIG. FIG. 7 is an enlarged view of a Z portion in FIGS. 1, 3, and 4.
[0019]
4 to 5 showing the structure of a hydraulic pump to which the present invention is applied, reference numeral 1 denotes a pump shaft which is connected to a drive source (not shown) such as an engine or an electric motor and is driven to rotate. Reference numeral 2 denotes a casing, and 3 and 4 denote a base plate and an end plate fixed to both front and rear ends of the casing 2. A cylinder block 5 is fitted to the pump shaft 1 via a spline 18 and is driven to rotate in synchronization with the pump shaft 1.
A plurality (six in this example) of cylinders 6 are perforated in the cylinder block 5 at equal intervals in the circumferential direction. Reference numeral 7 denotes a piston fitted to each cylinder 6 so as to be reciprocally slidable. A bush (not shown) may be press-fitted into the cylinder 6 and the piston 7 may be fitted into the bush so as to be capable of reciprocating.
Reference numeral 8 denotes a swash plate attached to the base plate 3, and the swash plate angle can be changed by a swash plate angle adjusting device 08.
That is, as shown in FIG. 7, the swash plate angle adjusting device 80 rotates the lever 08a by means of a piston 08c reciprocating in the cylinder 08b, so that the swash plate shaft 08 fixed to the end of the lever 08a is moved. The angle of the swash plate is changed by rotating like the U arrow in the figure.
[0020]
Reference numeral 11 denotes a valve plate that is disposed on the supply / discharge oil hole 011 side of each cylinder 6 and is fixed to the end plate 4. As shown in FIG. 5, the valve plate 11 is provided with a bowl-shaped suction hole 09 and a discharge hole 010 facing both sides of the rotary shaft 20 of the pump. Further, a suction passage 9 and a discharge passage 10 are formed in the end plate 4, the suction passage 9 communicates with the suction hole 09 of the valve plate 11, and the discharge passage 10 communicates with the discharge hole 010.
Reference numerals 12 and 13 denote a bearing on the base plate side and a bearing on the end plate side that support the pump shaft 1. 16 is an oil seal and 19 is a pump chamber.
[0021]
The present invention relates to an improvement in a coupling mechanism between a piston and a swash plate in a hydraulic pump, a hydraulic motor, a hydraulic pump, and a hydraulic motor having a structure as shown in FIGS.
In FIG. 1 and FIG. 2 showing the first embodiment of the present invention, reference numeral 15 denotes a slipper having a central hole 24 for retaining oil therein, and a spherical bearing 015 is provided along the spherical surface at the root of each piston 7. And is slidably attached. Reference numeral 17 denotes an annular retainer ring that supports each of the slippers 15.
[0022]
A thrust plate 14 is fitted in a mounting groove 30 recessed from the slipper 15 side surface of the swash plate 8 so as to be movable in the circumferential direction via a thrust plate sliding surface 22 of the mounting groove 30. Yes. The slipper 15 is in contact with the slipper sliding surface 23 of the thrust plate 14 so as to be capable of relative sliding.
As shown in FIG. 2, the thrust plate 14 and the swash plate 8 are connected to the knock pin 21 fixedly inserted into the swash plate 8 at two circumferential positions (a plurality of positions may be used). A fitting hole 25 made of a long hole in the circumferential direction perforated is loosened and configured to be relatively movable. The knock pin 21 and the fitting hole 25 may be loosely coupled so as to be relatively movable in the radial direction.
The other structure is the same as that of FIGS. 4-5, and the same member is shown with the same code | symbol.
[0023]
When the hydraulic pump is operated, as shown in FIGS. 4 to 5, when the pump shaft 1 is rotationally driven by a drive source such as an engine or an electric motor, the cylinder block 5 rotates. As the cylinder block 5 rotates, a slipper 15 connected via a spherical bearing 015 to the head of a piston 7 that is reciprocally fitted to the cylinder 6 slides on the thrust plate 14 as will be described later. As a result, the piston 7 reciprocates in the cylinder 6 while rotating together with the cylinder block 5.
[0024]
When the piston 7 moves to the left in FIG. 4, the oil supply / discharge hole 011 of the piston 7 communicates with the suction hole 09 of the valve plate 11 and oil is sucked from the suction passage 9. On the other hand, when the piston 7 moves to the right in FIG. 4, the supply / discharge oil hole 011 of the piston 7 communicates with the discharge hole 010 of the valve plate 11, and the oil in the cylinder 6 is discharged by the piston 7. It is delivered to the passage 10.
Even if water is used as the working fluid instead of oil as the working fluid in the hydraulic pump, a hydraulic pump having the same structure as that shown in FIGS.
[0025]
During the reciprocating operation of the piston 7, the slipper 15 connected to the head of the piston 7 via the spherical bearing 015 moves the inclined surface of the swash plate 8 whose swash plate angle is adjusted by the swash plate angle adjusting device 08. It slides on the slipper sliding surface 23 of the thrust plate 14 to be constituted.
When the slipper 15 slides on the slipper sliding surface 23, dust enters the sliding surface 23 during a period when the surface pressure of the slipper sliding surface 23 is small, such as the suction stroke of the piston 7. As shown in FIG. 2, the thrust plate 14 is loosely coupled between a knock pin 21 press-fitted into the swash plate 8 with respect to the swash plate 8 and a fitting hole 25 drilled in the thrust plate 14. The thrust plate 14 is attached to the swash plate 8 so as to be relatively movable in the circumferential direction within the clearance, so that the thrust plate 14 is circumferentially moved along the plate surface thrust plate sliding surface 22 of the swash plate 8. Alternatively, the dust is carried out into the pump chamber 19 outside the sliding surface 23 by moving a small amount in the radial direction.
[0026]
Accordingly, it is possible to prevent dust from getting into the sliding surface 23, and to prevent generation of scratches due to the biting of dust on the sliding surface 23. The piston 7 including the thrust plate 14 and the slipper 15 is inclined. The durability of the piston acting force support member between the plate 8 can be improved. Further, since the thrust plate 14 is attached so as to be movable relative to the swash plate 8, the oil scattered in the pump chamber 19 enters the slipper sliding surface 23 between the slipper 15 and the thrust plate 14. This facilitates the lubrication of the sliding surface 23 and improves the seizure resistance.
[0027]
Further, since the thrust plate 14 is movable relative to the swash plate 8 within the range of the loose clearance between the knock pin 21 and the fitting hole 25 drilled in the thrust plate 14, the thrust plate Thus, the relative movement of the swash plate 14 with respect to the swash plate 8 is restricted, and the occurrence of the slipping of the slipper 15 and the thrust plate 14 due to the excessive shift is avoided.
[0031]
The above embodiment is a case where the present invention is applied to a hydraulic pump, but the present invention can be widely applied to a swash plate type pump motor having a piston and a swash plate such as a hydraulic pump, a hydraulic motor or a hydraulic motor.
[0032]
【The invention's effect】
As described above, according to the present invention, since the thrust plate is attached to the swash plate so as to be relatively movable in the plate surface direction of the swash plate, the thrust plate moves in the plate surface direction of the swash plate. It is possible to carry out the dust that has entered the sliding surface to the outside of the sliding surface and prevent the dust from biting into the sliding surface. Thereby, generation | occurrence | production of the damage | wound by the bite of the dust to the said sliding surface can be avoided, and durability of the piston action force support member between the piston containing this thrust plate and a swash plate can be improved.
In addition, since the thrust plate is movable relative to the swash plate, a lubricant such as oil easily enters the sliding surface between the slipper and the thrust plate, and the lubrication of the sliding surface is improved. Improved seizure resistance.
Further, according to the present invention , the thrust plate can move relative to the swash plate within the range of the loose clearance between the knock pin and the fitting hole drilled in the thrust plate. The relative movement is largely prevented, and the occurrence of the slipper and the thrust plate due to the movement can be avoided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of the upper half of a hydraulic pump according to a first embodiment of the present invention along a pump rotation axis near the connecting portion between a piston and a swash plate.
2 is an AA arrow view of FIG. 1. FIG.
FIG. 3 is a cross-sectional view taken along a pump shaft center line showing a structure of a hydraulic pump to which the present invention is applied.
[4] a B-B arrow view of FIG.
FIG. 5 is a diagram corresponding to FIG.
6 is an enlarged view of a portion Z in FIGS . 1, 3 and 5. FIG.

Claims (1)

The piston is reciprocated in the cylinder by relative rotation between a swash plate inclined to a predetermined swash plate angle and a piston that is reciprocally fitted in the cylinder and loaded with fluid pressure. In the swash plate type fluid pump / motor, a thrust plate attached to the swash plate so as to be relatively movable in the direction along the plate surface of the swash plate, and a spherical surface abutted on one end of the piston A slipper that is slidably contacted with the surface ,
Further, the thrust plate and the swash plate are configured to be movable relative to each other by allowing a fitting hole drilled in the thrust plate to loosely engage with a knock pin fixed to the swash plate. Swash plate type fluid pump motor with a thrust plate.

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