JP2018105265A - Hydraulic machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic machine with improved output.SOLUTION: The hydraulic machine comprises: a cam including a cam body that rotates about an axis and has a circular cross section with the axis as a center, and a plurality of concave and convex parts formed on an outer peripheral surface of the cam body; a ring part provided on the side of an outer periphery of the cam, and including an inner periphery contact surface that has a circular cross section when viewed from a direction of the axis; a plurality of rollers in contact with the inner periphery contact surface and an outer peripheral surface of the cam; and at least one piston attached to the ring part to move forward and backward in a radial direction of the axis.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hydraulic machine.

  Radial piston type hydraulic pumps and hydraulic motors are known as hydraulic machines that operate by hydraulic pressure. For example, in a hydraulic pump, hydraulic oil is pressure-fed by a piston housed in a cylinder moving up and down by rotation of a rotating shaft accompanying a driving force applied from the outside. In the hydraulic motor, a rotational force is applied to the rotating shaft as the piston to which hydraulic pressure is supplied moves up and down. As a specific example of this type of apparatus, an apparatus described in Patent Document 1 below is known. In the radial piston pump described in Patent Document 1, a plurality of pistons provided in the radial direction are operated by rotating a circular cam eccentric from the center of the rotation shaft.

JP-A-3-81575

  By the way, a demand for improving the output of a hydraulic machine has been increasing in recent years. Here, the apparatus described in Patent Document 1 employs a configuration in which the piston makes one stroke each time the cam rotates once. Therefore, by improving the relationship between the number of rotations of the cam and the number of strokes of the piston, the device described in Patent Document 1 still has room for improvement in output.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a hydraulic machine with improved output.

  The hydraulic machine according to the present invention includes a cam body having a circular cross section centered on the axis, a cam having a plurality of projections and depressions formed on an outer peripheral surface of the cam body, and an outer periphery of the cam. A ring portion having an inner peripheral contact surface having a circular cross section when viewed from the axial direction, a plurality of rollers contacting the inner peripheral contact surface and the outer peripheral surface of the cam, and attached to the ring portion And at least one piston that moves forward and backward in the radial direction of the axis.

  According to this configuration, when the cam rotates about the axis, the ring portion follows and turns through the plurality of rollers. Specifically, the ring portion turns around the axis in accordance with the unevenness formed on the cam. That is, an arbitrary portion on the outer peripheral surface of the ring portion reciprocates in the radial direction of the axis. As a result, the piston attached to the outer peripheral surface of the ring portion can be moved forward and backward.

  In the hydraulic machine according to the present invention, the roller may have a rotating shaft supported by the ring portion.

  According to this configuration, the roller can be stably supported by the ring portion. Thereby, a hydraulic machine can be operated smoothly. Moreover, possibility that a ring part will dissipate from a roller can be reduced.

  In the hydraulic machine of the present invention, the ring portion may be filled with lubricating oil in a region on the inner peripheral side.

  According to this configuration, it is possible to smoothly slide the ring portion and the roller, and the roller and the cam. In particular, the allowable surface pressure between the roller and the cam can be increased. Thereby, the hydraulic machine can be operated at a higher pressure.

  In the hydraulic machine according to the aspect of the invention, the unevenness may have a radius of curvature larger than a radius of the roller.

  According to this configuration, the sliding of the cam and the roller can be further smoothed.

  In the hydraulic machine according to the present invention, the ring portion is formed with a communication groove on the inner peripheral abutment surface for communicating spaces defined by the cam and the roller on the inner peripheral side of the ring portion. Also good.

  According to this configuration, a pressure difference generated between the plurality of spaces defined by the cam and the roller can be dispersed through the communication groove. Thereby, the hydraulic machine can be operated more smoothly.

  In the hydraulic machine according to the present invention, the number of the rollers may be m + 1, where m is the number of the convex and concave portions.

  According to this configuration, the ring portion can be stably supported by the plurality of rollers.

  In the hydraulic machine according to the present invention, the plurality of rollers may be arranged at each vertex of a regular (m + 1) square.

  According to this structure, the load applied to each roller from a cam and a ring part can be disperse | distributed equally.

  In the hydraulic machine according to the aspect of the invention, the radial position of the outer circumferential surface of the cam may periodically change from one circumferential side to the other side of the axis.

  According to this configuration, the piston can be moved forward and backward periodically and smoothly.

  In the hydraulic machine according to the present invention, the rotation center of the ring portion may be eccentric from the axis that is the rotation center of the cam.

  According to this configuration, since the ring portion turns at a position eccentric from the axis, the piston provided on the ring portion can be smoothly advanced and retracted.

  According to the present invention, a hydraulic machine with improved output can be provided.

FIG. 1 is a schematic diagram showing the configuration of the hydraulic machine according to the first embodiment. FIG. 2 is a sectional view in a plane including the axis of the hydraulic machine according to the first embodiment. FIG. 3 is an explanatory view showing the operation of the hydraulic machine according to the first embodiment. FIG. 4 is a schematic diagram showing the configuration of the hydraulic machine according to the second embodiment.

[First embodiment]
Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto. The components of each embodiment described below can be combined as appropriate. Some components may not be used. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

  As shown in FIG. 1, the hydraulic machine 100 is used as a radial piston type hydraulic pump or a hydraulic motor. In the present embodiment, the configuration and operation will be described taking the case where the hydraulic machine 100 is used as a hydraulic pump as an example.

  The hydraulic machine 100 includes a rotary shaft 1, a cam 2, a ring portion 3, a roller 4, a cylinder portion 5, and a casing (not shown). The rotating shaft 1 extends along the axis A. The rotating shaft 1 rotates around the axis A by a driving force supplied from an external driving source.

  The cam 2 is integrally provided at a midway position in the extending direction of the rotary shaft 1. The cam 2 includes a columnar cam main body 21 extending in the direction of the axis A, and a plurality of concave portions 22 and convex portions 23 provided on the outer peripheral side of the cam main body 21. The cam body 21 has a circular virtual cross section P when viewed from the direction of the axis A. The concave portions 22 and the convex portions 23 are periodically arranged in the circumferential direction of the axis A on the outer peripheral surface of the cam body 21. That is, continuous irregularities are formed on the outer peripheral surface of the cam 2.

  In the present embodiment, the cam 2 has two concave portions 22 and two convex portions 23. Specifically, the cam 2 has two concave portions 22 and two convex portions 23 that are periodically arranged along the circumferential direction of the axis A. The recess 22 is recessed from the virtual cross section P of the cam body 21 toward the radially inner side. The protrusion 23 protrudes radially outward from the virtual cross section P of the cam body 21.

  The pair of recesses 22 have the same curved shape. The pair of convex portions 23 have the same curved shape. The end of one side in the circumferential direction of the recess 22 is connected to the end of the other side in the circumferential direction of the projection 23 when viewed from the direction of the axis A. One end in the circumferential direction of the protrusion 23 is connected to the other end in the circumferential direction of the recess 22. That is, the outer peripheral surface of the cam 2 has a continuous curved shape having the concave portion 22 and the convex portion 23 when viewed from the direction of the axis A. The outer peripheral surface of the cam 2 is line symmetric with respect to a symmetry axis X extending in a direction orthogonal to the axis A. In other words, periodic irregularities are formed on the outer peripheral surface of the cam 2 every 180 ° as viewed from the direction of the axis A.

  The ring portion 3 is an annular member that covers the cam 2 from the outer peripheral side. The ring portion 3 is an inner peripheral contact surface 31 whose inner peripheral surface is in contact with a roller 4 described later. The inner peripheral contact surface 31 has a circular cross section when viewed from the direction of the axis A. A plurality (three) of cylinder portions 5 are connected to the outer peripheral side of the ring portion 3 via rods 51. The space inside the ring portion 3 is filled with a lubricant having a relatively high viscosity. That is, a plurality of spaces (small spaces V) formed by the inner peripheral contact surface 31 of the ring portion 3, a roller contact surface 41 (described later), and the outer peripheral surface of the cam 2 are filled with lubricating oil. Yes.

  Each cylinder part 5 is a hydraulic cylinder driven by hydraulic pressure. The cylinder part 5 forms the hydraulic chamber 54 by covering the piston body 52 from the outside, the rod 51 connected to the outer peripheral surface of the ring part 3, the piston body 52 rotatably connected to the tip of the rod 51. And a cylinder 53. The rod 51 is in contact with the outer peripheral surface of the ring portion 3 via an arc surface having a radius of curvature equivalent to the diameter of the outer peripheral surface of the ring portion 3, and the arc surface is on the outer peripheral surface of the ring portion 3. It can slide in the circumferential direction of the axis A. The hydraulic oil supplied from an external hydraulic oil supply source flows into the hydraulic chamber 54. As the rod 51 advances and retracts, the pressure in the hydraulic chamber 54 increases and decreases. As a result, as the rod 51 advances and retreats, the hydraulic oil is discharged into the hydraulic chamber 54 and sucked.

  The roller 4 is a member that rotates while contacting the inner peripheral contact surface 31 of the ring portion 3 and the outer peripheral surface of the cam 2. The number of rollers 4 is determined according to the number of convex portions 23 (or concave portions 22) provided on the cam 2. Specifically, the number of rollers 4 is (m + 1), where m is the number of convex portions 23 (or concave portions 22). That is, in the present embodiment, since the cam 2 is formed with the two convex portions 23, the number of the rollers 4 is three. Further, the three rollers 4 are arranged on each vertex of the equilateral triangle. More generally, when the number of rollers 4 is n, each roller 4 is arranged on each vertex of a regular n-square, that is, a regular (m + 1) square.

  Specifically, as shown in FIG. 2, each roller 4 is supported on the ring portion 3 by a pair of holding members 61 and support pins 62 from both sides in the axis A direction. One holding member 61 is provided on each end face on both sides of the ring portion 3 in the axis A direction. In a cross-sectional view including the axis A, each holding member 61 has a plate shape that extends radially inward from the ring portion 3. Both ends of the roller 4 are held by a pair of holding members 61, and the roller 4 can be rotated around a central axis parallel to the axis A. A roller contact surface 41, which is an outer peripheral surface of the roller 4, is in contact with the outer peripheral surface of the cam 2 and the inner peripheral contact surface 31 of the ring portion 3. The radius of curvature of the roller contact surface 41 is smaller than the radius of curvature of the recess 22 formed in the cam 2. In other words, the curvature radius of the recess 22 is larger than the curvature radius of the roller contact surface 41.

  Communication grooves 32 that are concave grooves extending in the circumferential direction are formed on surfaces of the pair of holding members 61 that face each other. The communication groove 32 is formed over the entire circumferential direction of the holding member 61. The communication groove 32 communicates a pair of adjacent small spaces V with each other.

  The operation of the hydraulic machine 100 configured as described above will be described. When the driving force is applied to the rotating shaft 1 and the cam 1 is rotated, the cam 2 provided integrally with the rotating shaft 1 also rotates about the axis A. As shown in FIG. 3, when the cam 2 rotates, the ring portion 3 turns around the axis A following the movement of the roller 4. That is, the ring portion 3 turns at a position eccentric from the axis A that is the rotation center of the cam 2. The direction in which the ring portion 3 turns is opposite to the direction in which the cam 2 rotates. In the following description, an angle is used as a value indicating the rotation amount of the rotary shaft 1 and the cam 2. That is, one rotation is made when the rotating shaft 1 and the cam 2 are rotated by 360 °.

  When the ring part 3 turns, the cylinder part 5 attached to the ring part 3 repeats advancing and retreating at phases different from each other. Here, representatively, only the operation of one cylinder portion 5 will be representatively described. As shown in step S <b> 12 in the figure, when the cam 2 is at the 0 ° position, the piston main body 52 is located at the top dead center in the cylinder 53. That is, the volume of the hydraulic chamber 54 in the cylinder part 5 is minimum.

  As shown in step S14 of FIG. 3, when the cam 2 rotates and is at a 45 ° position, the piston main body 52 is lowered in the cylinder 53 by the length of half of the stroke. As shown in step S <b> 16, when the cam 2 further rotates and is at the 90 ° position, the piston main body 52 reaches the bottom dead center in the cylinder 53. That is, the volume of the hydraulic chamber 54 in the cylinder part 5 is the maximum. At this time, as the piston main body 52 is lowered, the pressure in the hydraulic chamber 54 is lowered, and hydraulic oil is sucked.

  Next, as shown in step S18, when the cam 2 rotates and is at the 135 ° position, the piston main body 52 is lifted in the cylinder 53 by the length of half of the stroke. As shown in step S <b> 20, when the cam 2 further rotates and is at the 180 ° position, the piston body 52 reaches the top dead center again in the cylinder 53. As the piston body 52 rises, the pressure in the hydraulic chamber 54 rises and hydraulic oil is discharged to the outside. The moving distance of the rod 51 between the top dead center and the bottom dead center is the stroke amount S. The stroke amount S is proportional to the eccentric distance from the axis A to the center of the ring portion 3.

  In this way, every time the cam 2 makes a half rotation (180 ° rotation) about the axis A, the cylinder portion 5 performs one advance / retreat (one stroke). In other words, when the cam 2 makes one rotation (360 ° rotation), the cylinder portion 5 performs two strokes. That is, when the cam 2 rotates r, the cylinder portion 5 can perform 2 × r strokes. In other words, in the hydraulic machine 100 according to the present embodiment, the cam 2 has the two convex portions 23 (and the two concave portions 22), and accordingly, when the cam 2 makes one rotation, The cylinder part 5 performs two strokes.

  As the cam 2 rotates, the lubricating oil flows through the communication groove 32 between the small spaces V adjacent to each other. More specifically, when the cam 2 rotates around the axis A and the convex portion 23 passes through the small space V, the volume of the small space V decreases by the volume of the convex portion 23. The internal pressure of V increases. As the internal pressure increases, the lubricating oil in the small space V flows out to the outside, that is, another adjacent small space V through the communication groove 32.

  As described above, in the hydraulic machine 100 according to the present embodiment, when the cam 2 rotates around the axis A, the ring portion 3 follows and turns through the plurality of rollers 4. Specifically, the ring portion 3 turns around the axis A in accordance with the concave portion 22 and the convex portion 23 formed in the cam 2. That is, an arbitrary portion on the outer peripheral surface of the ring portion 3 reciprocates in the radial direction of the axis A. As a result, the cylinder part 5 attached to the outer peripheral surface of the ring part 3 can be moved forward and backward. Furthermore, the number of strokes of the cylinder portion 5 per rotation of the cam 2 can be changed according to the number of irregularities formed on the cam 2. That is, the output of the hydraulic machine 100 per rotation of the cam 2 can be improved.

  In the hydraulic machine 100 according to the present embodiment, the roller 4 is rotatably supported by the ring portion 3. Thereby, the roller 4 can be stably supported by the ring portion 3. Furthermore, the hydraulic machine 100 can be operated smoothly. Further, the possibility that the ring portion 3 is dissipated from the roller 4 can be reduced.

  In the hydraulic machine 100 according to the present embodiment, the region (small space V) on the inner peripheral side of the ring portion 3 is filled with lubricating oil. According to this structure, sliding of the ring part 3 and the roller 4, and the roller 4 and the cam 2 can be made smooth. In particular, the allowable surface pressure between the roller 4 and the cam 2 can be increased. Thereby, the hydraulic machine 100 can be operated at higher speed.

  In the hydraulic machine 100 according to the present embodiment, the radius of curvature of the recess 22 may be larger than the radius of the roller 4. According to this configuration, the sliding of the cam 2 and the roller 4 can be further smoothed.

  In the hydraulic machine 100 according to the present embodiment, a communication groove 32 that communicates the small spaces V with each other is formed on the inner peripheral contact surface 31 of the ring portion 3. According to this configuration, the pressure difference generated between the plurality of small spaces V can be dispersed through the communication groove 32. Thereby, the hydraulic machine 100 can be operated more smoothly.

  In the hydraulic machine 100 according to the present embodiment, the number of the rollers 4 is n + 1 when the number of the convex and concave portions 23 is n. According to this configuration, the ring portion 3 can be more stably supported by the plurality of rollers 4.

  In the hydraulic machine 100 according to the present embodiment, the three rollers 4 are arranged on each vertex of the equilateral triangle. More generally, m rollers 4 are arranged at each apex of a regular m-gon. According to this structure, the pressure applied to each roller 4 from the cam 2 and the ring part 3 can be disperse | distributed equally.

  In the hydraulic machine 100 according to the present embodiment, the radial position of the outer peripheral surface of the cam 2 is periodically changed from one side in the circumferential direction of the axis A to the other side. According to this configuration, the cylinder portion 5 can be moved forward and backward periodically and smoothly in accordance with the shape of the outer peripheral surface of the cam 2.

  In the hydraulic machine 100 according to the present embodiment, the rotation center of the ring portion 3 is eccentric from the axis A that is the rotation center of the cam 2. According to this structure, since the ring part 3 turns in the position eccentric from the axis A, the cylinder part 5 provided in the ring part 3 can be smoothly advanced and retracted.

  The first embodiment of the present invention has been described above with reference to the drawings. Note that various modifications can be made to the above-described configuration without departing from the gist of the present invention. For example, in the first embodiment, the example in which the hydraulic machine 100 is used as a hydraulic pump has been described. However, the aspect of the hydraulic machine 100 is not limited to the hydraulic pump, and the hydraulic machine 100 can be used as a hydraulic motor.

  When using the hydraulic machine 100 as a hydraulic motor, the structure which drives the cylinder part 5 by supplying hydraulic fluid from the exterior in the cylinder 53 of each cylinder part 5 is taken. The ring portion 3 turns around the axis A by driving the cylinder portion 5. The turning motion of the ring portion 3 is transmitted to the cam 2 via the roller 4. As a result, the cam 2 and the rotating shaft 1 rotate around the axis A. By extracting the rotation of the rotary shaft 1 to the outside, the hydraulic machine 100 can be used as a hydraulic motor.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG. In addition, about the structure similar to said 1st embodiment, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted. As shown in FIG. 4, in the hydraulic machine 200 according to the present embodiment, three irregularities are formed on the cam 2B. That is, the cam 2B has three convex portions 23B and three concave portions 22B. Furthermore, the hydraulic machine 200 according to the present embodiment includes four rollers 4.

  Specifically, the cam 2B has three concave portions 22 and convex portions 23B that are periodically arranged along the circumferential direction of the axis A. The recess 22B is recessed from the virtual cross section P of the cam body 21B toward the inside in the radial direction. The convex portion 23B protrudes radially outward from the virtual cross section P of the cam body 21B.

  Each recess 22 </ b> B has an equivalent curved shape. Each convex part 23B has mutually equivalent curve shape. When viewed from the direction of the axis A, the end on one side in the circumferential direction of the recess 22B is continuously connected to the end on the other side in the circumferential direction of the projection 23B. The end portion on one side in the circumferential direction of the convex portion 23B is continuously connected to the end portion on the other side in the circumferential direction of the concave portion 22B. That is, the outer peripheral surface of the cam 2B has a continuous curved shape having the concave portion 22B and the convex portion 23B when viewed from the direction of the axis A. In addition, periodic irregularities are formed on the outer peripheral surface of the cam 2B every 120 ° as viewed from the direction of the axis A.

  As described above, the number of rollers 4 is determined according to the number of convex portions 23B (or concave portions 22B) provided on the cam 2B. Specifically, the number of rollers 4 is (m + 1), where m is the number of convex portions 23B (or concave portions 22B). That is, in this embodiment, since the three convex parts 23B are formed in the cam 2B, the number of rollers 4 is four. Further, the four rollers 4 are arranged on each vertex of the square.

  In the hydraulic machine 200 configured as described above, every time the cam 2B rotates about 1/3 of a rotation around the axis A (120 ° rotation), the cylinder portion 5 performs one advance / retreat (one stroke). In other words, when the cam 2 makes one rotation (360 ° rotation), the cylinder portion 5 performs three strokes.

  According to the configuration of the present embodiment, when the cam 2 </ b> B rotates around the axis A, the ring portion 3 follows and turns via the plurality of rollers 4. Specifically, the ring portion 3 turns around the axis A in accordance with the concave portion 22B and the convex portion 23B formed in the cam 2B. That is, an arbitrary portion on the outer peripheral surface of the ring portion 3 reciprocates in the radial direction of the axis A. As a result, the cylinder part 5 attached to the outer peripheral surface of the ring part 3 can be moved forward and backward. Furthermore, the number of strokes of the cylinder part 5 per rotation of the cam 2B can be changed according to the number of irregularities formed on the cam 2B. That is, the output of the hydraulic machine 200 per rotation of the cam 2B can be improved.

The embodiments of the present invention have been described above with reference to the drawings. Various modifications can be made to the above configuration without departing from the gist of the present invention. For example, in the first embodiment, an example in which the cam 2 has two irregularities has been described, and in the second embodiment, an example in which the cam 2B has three irregularities has been described. However, the number of irregularities is not limited to the above, and may be four or five or more. The greater the number of irregularities provided on the cam 2, the smaller the swing angle of the rod 51 of the cylinder part 5 described above. That is, power can be transmitted to the cylinder unit 5 more efficiently.
Further, when actually determining the number of rollers 4, the diameter of the rollers 4, and the minimum curvature radius of the unevenness of the cam 2, the cam 2 obtained based on the number of cylinder portions 5 and the pressure received by the cylinder portions 5. And the line contact hertz surface pressure of the roller 4 is used.

DESCRIPTION OF SYMBOLS 100,200 Hydraulic machine 1 Rotating shaft 2, 2B Cam 3 Ring part 4 Roller 5 Cylinder part 21, 21B Cam main body 22, 22B Concave part 23, 23B Convex part 31 Inner peripheral contact surface 32 Communication groove 41 Roller contact surface 51 Rod 52 Piston body 53 Cylinder 54 Hydraulic chamber 61 Holding member 62 Support pin A Axis P Virtual cross section V Small space

Claims (9)

A cam body that rotates around an axis and has a circular cross section centered on the axis, and a cam having a plurality of irregularities formed on the outer peripheral surface of the cam body;
A ring portion provided on the outer peripheral side of the cam and having an inner peripheral abutting surface having a circular cross section when viewed from the axial direction;
A plurality of rollers in contact with the inner peripheral contact surface and the outer peripheral surface of the cam;
At least one piston attached to the ring portion and moving back and forth in the radial direction of the axis;
Hydraulic machine with   The hydraulic machine according to claim 1, wherein the roller has a rotating shaft supported by the ring portion.   The hydraulic machine according to claim 1, wherein the ring portion is filled with lubricating oil in a region on an inner peripheral side.   The hydraulic machine according to any one of claims 1 to 3, wherein the unevenness has a radius of curvature larger than a radius of the roller.   5. The communication ring according to claim 1, wherein the ring portion is formed with a communication groove on the inner peripheral abutting surface for communicating between the spaces defined by the cam and the roller on the inner peripheral side of the ring portion. A hydraulic machine according to claim 1.   6. The hydraulic machine according to claim 1, wherein the number of the rollers is m + 1, where m is the number of convex portions of the unevenness.   The hydraulic machine according to claim 6, wherein the plurality of rollers are arranged at each vertex of a regular (m + 1) square.   The hydraulic machine according to any one of claims 1 to 7, wherein a radial position of an outer peripheral surface of the cam changes periodically from one side to the other side in the circumferential direction of the axis.   The hydraulic machine according to any one of claims 1 to 8, wherein a rotation center of the ring portion is eccentric from an axis that is a rotation center of the cam.

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