JPH0752384Y2 - Swash plate type fluid pump / motor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a swash plate type fluid pump / motor.

2. Description of the Related Art As a conventional swash plate type fluid pump / motor, for example, the one described in Japanese Utility Model Laid-Open No. 61-58687 is known. This is a donut-shaped swash plate having an inclined surface inclined with respect to the rotation axis, a piston-cylinder assembly, and a substantially donut-shaped plate extending parallel to the inclined surface of the swash plate and having the front end of each piston locked. A retainer plate, a hemispherical thrust ball that is movably supported by a rotating shaft in the axial direction and is in spherical contact with the radially inner end of the retainer plate, and urges the thrust ball and the retainer plate toward the swash plate. Thus, each of the pistons is provided with a spring that presses it against the inclined surface of the swash plate.

However, in such a structure, in order to prevent the piston from floating from the inclined surface, thrust balls and springs are required in addition to the retainer plate, which makes the structure complicated and expensive. There is a problem that Further, since the pressing force for preventing the lifting is transmitted from the spring to the piston through the thrust ball and the retainer plate, manufacturing errors and assembly errors of the components interposed in the middle are accumulated, and the piston inclined surface There is also a problem in that the pressing force to the device varies, and as a result, in order to keep the pressing force within the set range, the pressing force must be finely adjusted after assembly.
Further, the retainer plate swings due to the rotation of the rotary shaft, but at this time, the retainer plate and the thrust ball make sliding contact with each other, which causes a problem of friction loss.

It is an object of the present invention to provide a swash plate type fluid pump / motor that has a simple structure and is inexpensive, does not require a pressing force adjustment work, and has a small friction loss.

Means for Solving the Problems The first purpose is to provide a swash plate type fluid pump / motor which has a substantially donut-shaped base portion which extends parallel to the inclined surface of the swash plate and in which the front end portion of each piston is locked. And a retainer plate made of a thin-walled material, the retainer plate being provided with an extension portion extending from an outer end in the radial direction of the base portion toward the inclined surface side and a first recess provided in an inner peripheral surface of the extension portion. A plurality of balls are formed between the first recess and the second recess in a state in which a second recess facing the first recess is formed on the outer peripheral surface of the swash plate and elastically deformed to expand the extension. Secondly, in the swash plate type fluid pump / motor, the piston is inserted and the elastic restoring force of the extension portion presses the piston against the slope surface. Stopped, substantially donut-shaped base and radial direction of the base A retainer plate made of a thin material is provided, which includes an extension portion extending from the inner end toward the inclined surface side, and a first recess provided on the outer peripheral surface of the extension portion, and the inner peripheral surface of the swash plate. A second concave portion opposed to the first concave portion is formed, and the first concave portion and the second concave portion are elastically deformed to reduce the diameter of the extension portion.
This can be achieved by interposing a plurality of balls between the recess and the recess and pressing the piston against the inclined surface by the elastic restoring force of the extension.

Action In this invention, the pressing force of each piston against the swash plate is elastically deformed to expand or contract the extension of the retainer plate so that the first recess of the extension and the second recess of the swash plate I give it by interposing a ball between them.
As described above, in the present invention, since a plurality of balls need to be present in addition to the retainer plate to apply the pressing force, the number of parts is reduced, the overall structure is simplified, and the manufacturing cost is low. Moreover, the source of this pressing force is the elastic restoring force of the deformation of the retainer plate itself as described above, but since the restoring force is applied directly to the piston without interposing anything in the middle, it is applied. Almost no variation occurs in the force value, and as a result, the work of adjusting the pressing force becomes unnecessary. Furthermore, the contact between the retainer plate and the swash plate is rolling contact via balls,
Friction loss is also small.

Embodiment A first embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 is a swash plate type fluid motor, and this fluid motor 1 has a casing 3 in which a storage chamber 2 is formed.
An output shaft 4 as a rotating shaft is rotatably supported on a front end wall 3a of the casing 3 via a bearing 5. Reference numeral 8 denotes a substantially cylindrical swash plate that is provided inside the storage chamber 2 and surrounds the periphery of the output shaft 4. The swash plate 8 is attached to the inner surface of the front end wall 8a. The swash plate 8 has a sloping surface 9 at the rear end that is inclined at an acute angle with respect to the rotation axis of the output shaft 4, and the swash plate 8 extends along the outer edge of the swash plate 8 and has a groove 10 having an arc-shaped cross section.
Are formed. Reference numeral 14 is a substantially cylindrical cylinder block housed in the housing chamber 2 behind the swash plate 8. This cylinder block 14 is attached to the rear end of the output shaft 4 by spline coupling, whereby the output shaft 4 The cylinder block 14 and the cylinder block 14 can rotate integrally. A plurality of cylinder holes 15 extending in the front-rear direction are formed in the front end surface of the cylinder block 14 facing the inclined surface 9.
These cylinder holes 15 are arranged equidistantly in the circumferential direction. A piston 18 is movably inserted in each cylinder hole 15 in the front-rear direction, and a hemispherical spherical recess 19 is formed at the front end of each piston 18. Part of the balls 20 are inserted into the spherical recesses 19 and are in rolling contact with each other, and these balls 20 are also partially inserted into the grooves 10 and are in rolling contact with each other. The cylinder block 14, the pistons 18, and the balls 20 described above collectively form a piston / cylinder assembly 21. Between the cylinder block 14 and the rear end wall 3b of the casing 3,
A timing plate 24 fixed to the rear end wall 3b is interposed, and the timing plate 24 has an arc-shaped supply port 25.
And an exhaust port 26 is formed.

Reference numeral 31 is a retainer plate made of a thin material, and the retainer plate 31 has a substantially donut-shaped base portion 32. The base 32 is arranged between the cylinder block 14 and the swash plate 8 and extends parallel to the inclined surface 9 of the swash plate 8. Also, as shown in FIGS. 1 and 2, a plurality of elongated holes 33 extending in the radial direction are formed in the base portion 32 at equal distances in the circumferential direction, that is, the same number as the pistons 18, and these elongated holes 33 are formed. The front end portions of all the pistons 18 are inserted into and locked in each of them. In FIGS. 1 and 3, the retainer plate 31 has an extension 38 extending from the radially outer end of the base 32 toward the inclined surface 9, and the extension 38 passes through the center of the inclined surface 9. It has a cylindrical shape with a straight line perpendicular to the inclined surface 9 as the central axis. A plurality of hemispherical recesses (first recesses) 39 are formed on the inner peripheral surface of the extension 38 in the circumferential direction. On the other hand, the outer peripheral surface of the swash plate 8 has a V-shaped continuous groove (second recess).
45 is formed, and the continuous groove 45 faces the hemispherical recess 39. A ball 48 is interposed between each of the hemispherical concave portions 39 and the continuous groove 45 so as to be in rolling contact therewith. In the state where these balls 48 are interposed as described above, the extension portion 38 elastically deforms so as to expand its diameter, and the elastic restoring force generated by this deformation is transmitted to the piston 18 via the base 32,
The piston 18 is configured to press the groove 10 of the inclined surface 9 with a predetermined pressing force. Also, in this state, the retainer plate 31 can rotate with respect to the swash plate 8.

Next, the operation of the first embodiment of the present invention will be described.

In this embodiment, the pressing force of each piston 18 against the swash plate 8 is
A ball 48 is provided between each hemispherical recess 39 of the extension 38 and the continuous groove 45 of the swash plate 8 in a state where the extension 38 of the retainer plate 31 is elastically deformed to expand its diameter. I have to. As described above, in this embodiment, since it is sufficient that a plurality of balls 48 be present in addition to the retainer plate 31 for imparting the pressing force, the number of parts is reduced, the overall structure is simplified, and the cost is low. Can be manufactured. Moreover, the source of this pressing force is the elastic restoring force of the deformation of the extension 38 itself of the retainer plate 31 as described above, but the restoring force is not directly interposed in the piston 18 directly.
Therefore, the value of the applied force hardly varies, and as a result, the work of adjusting the pressing force becomes unnecessary. Further, since the contact between the retainer plate 31 and the swash plate 8 is rolling contact via the plurality of balls 48, friction loss is also small.

FIG. 4 is a diagram showing a second embodiment of the present invention. In this embodiment, the retainer plate 51 is provided with a cylindrical extension portion 53 extending from the radially inner end of the base portion 52 toward the inclined surface 9, and the outer peripheral surface of the extension portion 53 has a circumferential groove (first A recess 54 is formed. On the other hand, on the inner peripheral surface of the swash plate 8, a circumferential groove (second groove) which faces the circumferential groove 54 of the retainer plate 51 is formed.
Recesses) 56 are formed. A plurality of balls 57 are provided between the circumferential grooves 54 and 56 in a state where the extension portion 53 is elastically deformed so as to reduce its diameter. As a result, the elastic restoring force due to the deformation of the extension portion 53 is transmitted to the piston 18, whereby the front end of the piston 18, that is, the ball 20 is pressed against the groove 10 of the inclined surface 9, and the front end of the piston 18 is inclined. The situation of rising from 9 is prevented. The other structure and operation are similar to those of the first embodiment.

Although the retainer plate is directly engaged with the piston 18 in the above-described embodiment, in the present invention, the retainer plate 63 is engaged with the piston 61 via the shoe 62 as shown in FIG. Alternatively, the retainer plate 63 may apply a pressing force to the shoe 62 toward the inclined surface 9.

Effects of the Invention As described above, according to the present invention, the structure is simple and the manufacturing cost is low, and the work of adjusting the pressing force is unnecessary, and the friction loss is small. can do.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention, FIG. 2 is a sectional view taken along the line II of FIG. 1, FIG. 3 is a sectional view in the vicinity of an extension portion of a retainer plate, and FIG. FIG. 5 is a sectional view showing a main part of a second embodiment of the present invention, and FIG. 5 is a sectional view showing another embodiment of the piston. 4 ... Rotary axis, 8 ... Swash plate 9 ... Inclined surface, 18 ... Piston 21 ... Piston / cylinder assembly 31, 51, 63 ... Retainer plate 32, 52 ...... Base, 38, 53 ... Extensions 39, 54 ... First recess, 45,56 ... Second recess

Claims (2)

[Scope of utility model registration request] 1. A swash plate type fluid pump / motor comprising a swash plate having an inclined surface inclined with respect to a rotation axis, and a piston / cylinder assembly, wherein each piston extends parallel to the inclined surface of the swash plate. A substantially doughnut-shaped base having a front end locked, an extension extending from the radial outer end of the base toward the inclined surface, and a first recess provided on the inner peripheral surface of the extension.
A retainer plate made of a thin material is provided, a second recess facing the first recess is formed on the outer peripheral surface of the swash plate, and the extension is elastically deformed to expand its diameter. A swash plate type fluid pump / motor, wherein a plurality of balls are interposed between the first recess and the second recess, and the piston is pressed against the inclined surface by the elastic restoring force of the extension. 2. A swash plate type fluid pump / motor comprising a swash plate having an inclined surface inclined with respect to a rotation axis, and a piston / cylinder assembly, wherein each piston extends parallel to the inclined surface of the swash plate. A substantially doughnut-shaped base with the front end locked, an extension extending from the radial inner end of the base toward the inclined surface, and a first recess provided on the outer peripheral surface of the extension.
A retainer plate made of a thin material is provided, a second recess facing the first recess is formed on the inner peripheral surface of the swash plate, and the extension is elastically deformed to reduce the diameter. A swash plate type fluid pump / motor, wherein a plurality of balls are interposed between the first concave portion and the second concave portion, and the elastic restoring force of the extension portion presses the piston against the inclined surface.