JPS6367032B2 - - Google Patents

Description

[Detailed Description of the Invention] A. Purpose of the Invention (1) Industrial Field of Application The present invention consists of a cylinder fitted with a large number of reciprocating plungers, and a shoe provided at the tip of each plunger that slides onto an opposing swash plate. A multi-plunger hydraulic pump that generates hydraulic pressure by relatively rotating the cylinder and swash plate, or a multi-plunger hydraulic pump that generates hydraulic pressure by rotating the cylinder and swash plate relative to each other, or a multi-plunger hydraulic pump that generates hydraulic pressure by reciprocating the plunger. The present invention relates to a multi-plunger type hydraulic motor that rotates a swash plate relative to each other, and particularly to a multi-plunger type hydraulic system that can reliably maintain sliding contact between a shoe and a swash plate.

(2) Prior Art An example of a multi-plunger type hydraulic pump as a conventional multi-plunger type hydraulic system will be explained with reference to FIGS. 1 causes the pump cylinder 2 to rotate around the axis 4. In the pump cylinder 2, a large number of cylinder holes 5, 5... parallel to the axis 4 are arranged in an annular shape surrounding the axis 4, and a pump plunger 6 is slidably fitted into each cylinder hole 5. has been done. A spherical surface 7 is formed at the tip of each pump plunger 6, and a shoe 8 is formed on this spherical surface 7.
The leading end 8a of the head 8a is swaged together so as to be freely swingable.

A swash plate 9 facing the front side of the pump cylinder 2 is provided. In the case of a variable discharge type pump, the inclination angle of this swash plate 9 can be adjusted. The oil chamber on the back side of each plunger 6 is filled with hydraulic oil, and due to the pressure of the hydraulic oil, each plunger 6 normally receives a force in the direction of protruding from the cylinder 2. Therefore, the sliding surface 10 of the flange-like base 8b of the shoe 8 that follows the plunger 6 is pressed against the sliding plate 11 of the swash plate 9. And plunger 6
A part of the hydraulic oil is guided between the sliding surface 10 and the sliding plate 11 from the oil chamber on the back of the shoe, and by lubricating the space between them, the base 8b of the shoe 8 is moved between the sliding plate 11 of the swash plate 9. It is said to be able to slide freely.

When the input shaft 1 is rotated in this state, the pump cylinder 2 rotates around the axis 4, and as the plunger 6 moves upward, it is pressed by the swash plate 9 and retreats. As a result, the oil chamber on the back surface of the plunger 6 is contracted, and the compressed hydraulic oil is discharged from the discharge port 13 of the distributor 12. On the other hand, as the upper plunger 6 moves downward, it protrudes and the oil chamber on the back surface of the plunger 6 expands, so that hydraulic oil is sucked in from the suction port 14 of the distributor 12.

During this suction stroke, the oil pressure on the back surface of the plunger 6 decreases, so the shoe 8 tends to move away from the sliding plate 11 of the swash plate 9. Also, at the top dead center where the discharge stroke changes to the suction stroke,
The plunger 6 receives a force in the direction in which the shoe 8 moves away from the swash plate 9 due to inertial force. Therefore, in order to resist these forces and keep the shoe base 8b in sliding contact with the swash plate 9, the back surface 1 of the shoe base 8b
A single pressing plate, that is, a pull-down plate 15, is provided to hold down the holding plate 7. This pull-dump plate 15 is rotatably supported on the swash plate 9 by a fixed plate 16.
The tip part 8a passes through a large number of through holes 18 provided in the plunger 5, and rotates together with the shoe 8 as the plunger 6 rotates.

(3) Problems to be Solved by the Invention By the way, since the surface of the sliding plate 11 on which the shoe base 8b comes into sliding contact is inclined, the shoe base 8
The center locus of the sliding surface 10 in b becomes an elliptical trajectory displaced upward with respect to the axis 4. On the other hand, since the pull-down plate 15 is a disc, sufficient play must be provided in the through hole 18 through which the shoe tip 8a passes. As a result, the area of the back surface 17 of the shoe base 8b pressed by the pull-down plate 15 is only the portion shown by the dotted line in FIG. becomes difficult. In order to increase this area, the area of the back surface 17 of the shoe base 8b may be increased, but in this case, the shoe 8 as a whole becomes large and the weight increases.
The friction area between b and the swash plate 9 increases, making it impossible to obtain smooth operation. In the case of a variable displacement pump, in order to change the inclination angle of the swash plate 9, the play in the through hole 18 must be larger, and how can the pull-down plate 15 ensure that the swash base One of the big questions is whether to hold down 8b.

Conventionally, due to such problems, the inclination angle of the swash plate had to be made small, and the device became larger accordingly.

The above discussion has been about a multi-plunger type hydraulic pump that rotates a cylinder, but the same problem also exists in a multi-plunger type hydraulic pump that rotates a swash plate and a multi-plunger type hydraulic motor that rotates either a cylinder or a swash plate. .

An object of the present invention is to provide a multi-plunger type hydraulic system that can solve the above problems.

B. Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention includes a cylinder, and a cylinder arranged in an annular shape surrounding the axis of rotation of the cylinder and along the axis. a number of plungers that are slidably fitted together; a shoe whose tip is swingably attached to the outer end of each plunger; and a swash plate that is arranged opposite to the cylinder and is rotatable relative to the cylinder. and a pull-dump plate having a through hole into which the tip of each shoe is loosely inserted, and the pull-dump plate holds the base of each shoe in contact with the swash plate. In the multi-plunger type hydraulic system, an intermediate plate sandwiched between the base and the pull-down plate is fitted to the tip of each shoe, and each intermediate plate has a substantially fan shape larger than the through hole. The short circular arc portion is positioned radially inward of the pull-down plate relative to the long circular arc portion so that the pull-down plate can move relative to the adjacent intermediate plate in the radial direction.

(2) Effect Even if a large through hole is formed in the pull-down plate, the substantially fan-shaped intermediate plate, which is sandwiched between the pull-down plate and the shoe and larger than the through-hole, prevents the substantial connection between the pull-down plate and the shoe base. Since a sufficiently large contact area can be secured, even the pull-down plate with a large through hole can effectively prevent the shoe base from separating from the swash plate, ensuring that the sliding contact between the two is maintained. Therefore, even if the inclination angle of the swash plate is increased and the through hole is enlarged, reliable operation of the plunger is ensured.

In particular, each approximately fan-shaped intermediate plate has its short arc portion located radially inward of the pull-down plate than the long arc portion so that it can move relative to the adjacent intermediate plate in the radial direction of the pull-down plate. Since the adjacent intermediate plates are arranged as close as possible to each other, it is possible to secure a sufficiently large effective area for each intermediate plate. However, the intermediate plate can easily follow the movement of the shoe as it attempts to draw an elliptical trajectory around the cylinder axis without being hindered by other adjacent intermediate plates.

(3) Examples Examples of the present invention will be described below with reference to the drawings. Figures 3 and 4 show the main parts of an embodiment of the multi-plunger hydraulic pump according to the present invention, and the only difference from the conventional example shown in Figures 1 and 2 is the mechanism for pressing the back surface 17 of the shoe base 8b. Therefore, other explanations will be omitted.

Similar to the conventional one, the pull-down plate 15 is rotatably supported on the swash plate 9 by a fixed plate 16, and a large number of through holes 18 formed in the pull-down plate 15 are connected to the front end 8a of the shoe 8. penetrates with sufficient play. A large number of fan-shaped intermediate plates 19 are provided between the pull-down plate 15 and the back surface 17 of the flange-shaped base 8b of the shoe 8, as shown by dotted lines in FIG. Each fan-shaped intermediate plate 19 has a tip 8a of each shoe 8.
It is fitted into the pull-down plate 15, and is larger than the through-hole 18 of the pull-down plate 15, and is arranged with the short arc portion located radially inward of the pull-down plate 15 than the long arc portion. Therefore, the sector-shaped intermediate plate 19
completely covers the back surface 17 of the shoe base 8b, and normally closes the entire surface of the through hole 18. As a result, the entire back surface 17 of the base 8b of the shoe 8 is pressed by the fan-shaped intermediate plate 19, and the fan-shaped intermediate plate 19 is
The shoe base 8
The area of the portion that presses b can be made sufficiently large. That is, it is possible to reliably prevent the shoe 8 from separating from the swash plate 9. At top dead center or bottom dead center, etc., the through hole 18 is inserted into the fan-shaped intermediate plate 1.
It will be clear that even if it partially deviates from 9, a larger pressing area can be obtained compared to the conventional one.

Then, the pull-down plate 15 and the shoe base 8
By forming the intermediate plate 19 interposed between the pull-down plate 15 and the pull-down plate 15 into a fan shape, the pressing area by the pull-down plate 15 is maximized. Furthermore, as a result of the shoe 8 drawing an elliptical orbit, the fan-shaped intermediate plate 19 that moves together with the shoe 8 causes a radial deviation between adjacent intermediate plates 19. Mutual interference is prevented.

Although the above embodiment describes a multi-plunger type hydraulic pump in which the swash plate 9 is fixed and the cylinder 2 is rotated, the swash plate 9 and the cylinder 2 may be In multi-plunger type hydraulic equipment that rotates relatively,
A sector-shaped intermediate plate 19 as described above can be provided.

C. Effects of the Invention As described above, the present invention includes a cylinder and a large number of plungers arranged in an annular shape surrounding the rotational axis of the cylinder and slidably fitted along the axis. , a shoe whose tip is swingably attached to the outer end of each plunger; a swash plate disposed opposite to the cylinder and rotatable relative to the cylinder; and a transparent shoe into which the tip of each shoe is loosely inserted. one pull-dump plate having a hole, the pull-dump plate holds the base of each shoe in contact with the swash plate;
In the multi-plunger type hydraulic system, a substantially fan-shaped intermediate plate which is sandwiched between the base and the pull-down plate and is larger than the through-hole is fitted to the tip of each shoe, so that a large through-hole is formed in the pull-down plate. Even if a large hole is formed, the fan-shaped intermediate plate interposed between the pull-down plate and the shoe base can ensure a sufficiently large contact area between the pull-down plate and the shoe base. The damp plate can also effectively prevent the shoe base from separating from the swash plate, and can reliably maintain the sliding contact between the two. Therefore, even if the inclination angle of the swash plate is increased and the through hole is enlarged, reliable operation of the plunger is ensured, so it is possible to obtain an axial plunger type hydraulic device that is small in size and has a large capacity.

In particular, each approximately fan-shaped intermediate plate interposed between the pull-down plate and the shoe base has its short arc portion pulled out more than the long arc portion so that it can move relative to the adjacent intermediate plate in the radial direction of the pull-down plate. Because it is located radially inward of the dump plate,
Adjacent intermediate plates can be brought as close together as possible to ensure a sufficiently large effective area for each intermediate plate,
Furthermore, by arranging the intermediate plates close to each other, the intermediate plates can easily follow the movement of the shoe, which attempts to draw an elliptical orbit around the cylinder axis, without being hindered by other adjacent intermediate plates. be able to.

[Brief explanation of drawings]

FIG. 1 is a vertical side view showing an example of a conventional multi-plunger hydraulic pump, and FIG.
FIG. 3 is a front view of the swash plate section drawn by lines, FIG.
FIG. 3 is a front view of the swash plate portion according to lines. 1...Input shaft, 2...Pump cylinder, 4...
Axis line, 6... pump plunger, 8... shoe,
8a... tip, 8b... base, 9... swash plate, 15
...pull-dump plate, 16... fixed plate,
17...Back side of shoe base, 18...Through hole, 19
...Fan shaped intermediate plate.

Claims (1)

[Claims] 1 a cylinder 2, which is arranged in an annular manner surrounding the rotational axis 4 of the cylinder 2;
A number of plungers 6 are fitted to be slidable along the cylinder 2, a shoe 8 having a tip 8a swingably attached to the outer end of each plunger 6, and a shoe 8 which is disposed opposite to the cylinder 2 and is connected to the cylinder 2. 2 and a swash plate 9 that is rotatable relative to the shoe 2, and one pull-down plate 15 having a through hole 18 into which the tip 8a of each shoe 8 is loosely inserted. In the multi-plunger type hydraulic system, the tip portion 8a of each shoe 8 is provided with an intermediate portion held between the base portion 8b and the pull damp plate 15. The plates 19 are fitted, and each intermediate plate 19 is formed into a substantially fan shape larger than the through hole 18, and is movable relative to the adjacent intermediate plate 19 in the radial direction of the pull-down plate 15. , a multi-plunger type hydraulic device characterized in that the short circular arc portion is located radially inward of the pull-dump plate 15 than the long circular arc portion.