JP2009052540A - Fluid suction and discharge device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pump using a cam mechanism and being in a simple structure. <P>SOLUTION: Cam grooves 42, 43 formed on an outer peripheral surface of a piston 4 reciprocatively and rotatably arranged in a cylinder 2 have distance increase sections 42a, 43a where a distance from an end face in the cylinder increases and distance decrease sections 42b, 43b where a distance from the end face decreases in the cylinder while they advance around a center axis X of the cylinder in the direction R of a rotary motion. Connection pins 61, 62 projecting from a peripheral surface 21 in the cylinder to the inside are engaged with the cam grooves 42, 43. A suction port 23 and a discharge port 24 which can communicate with a separate chamber are formed in the cylinder 2. A notch 44 extending to the tip face 41 at an outer peripheral surface of a piston 4 is formed so as to selectively communicate with the suction port 23 and the discharge port 24 in the direction of an axis X and to correspond to the distance increase sections 42a, 43a regarding in the peripheral direction around the axis X. A sliding groove 45 formed on the piston 4 is engaged with driving force transmitting projections 82, 83 of a rotary driving means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fluid suction / discharge device such as a pump and a compressor, and more particularly to a fluid suction / discharge device using a cam mechanism.

  There are a reciprocating pump and a rotary pump as a positive displacement pump.

  In a typical reciprocating pump, the volume of the compartment is changed by reciprocating the piston or plunger in the cylinder or casing, and this volume change is combined with the operation of the valve on the suction side and the valve on the discharge side. Inhale and discharge fluid. In a diaphragm pump which is a kind of reciprocating pump, a diaphragm is vibrated and fluid is sucked and discharged by combining this vibration with the operation of a suction side valve and a discharge side valve. A diaphragm pump that uses a cam mechanism to drive the diaphragm vibration is described in Japanese Patent Laid-Open No. 8-121253 (Patent Document 1).

On the other hand, in a typical rotary pump, by rotating a rotating member such as a rotor with a movable vane, a gear, and a screw, a compartment formed by the rotating member and a casing is moved from the suction side to the discharge side, As a result, the fluid is sucked and discharged. A cam pump using a rotating cam is described in Japanese Patent Application Laid-Open No. 8-42448 (Patent Document 2).
JP-A-8-121253 JP-A-8-42448

  However, in the diaphragm pump using the cam mechanism described in Patent Document 1, it is essential to use a pump valve such as a check valve. Further, in the cam pump described in Patent Document 2, means for synchronously rotating the drive-side rotary cam and the driven-side rotary cam is essential. As described above, a pump using a conventional cam mechanism requires a pump valve and synchronous rotation means, and there is a problem that it is difficult to simplify the structure. Such difficulties also exist in compressors for compressing compressible fluids with a similar structure.

  In view of the above technical problems, an object of the present invention is to provide a fluid suction / discharge device such as a pump and a compressor using a cam mechanism and having a simple structure.

According to the present invention, the object as described above is achieved.
A cylinder having an inner peripheral surface with rotational symmetry about the central axis;
A piston arranged to allow both reciprocation in the direction of the central axis and rotational movement about the central axis in the cylinder;
Rotational drive means for driving the rotational movement of the piston while allowing reciprocal movement of the piston; and communication with a compartment formed by the front end surface of the piston and the inner peripheral surface and inner end surface of the cylinder; A suction port and a discharge port formed in the cylinder so as to be positioned on opposite sides of the central axis,
Between the piston and the cylinder is interposed a cam mechanism for converting the rotational movement of the piston into the reciprocating movement,
A notch portion that communicates with the compartment is formed in the outer peripheral portion of the piston, and the notch portion communicates with the suction port and the discharge port during the reciprocating motion of the piston with respect to the direction of the central axis. And with respect to the circumferential direction around the central axis, the piston is formed so as to be able to selectively communicate with the suction port and the discharge port during the rotational movement of the piston. Fluid suction and discharge device,
Is provided.

  In one aspect of the present invention, the cam mechanism includes an outward cam groove formed on an outer peripheral portion of the piston and circulated around the central axis, and an inner cam that is held by the cylinder and engages with the outward cam groove. And the outward cam groove extends from the inner end surface of the cylinder with respect to the direction of the central axis while proceeding around the central axis in the direction of the rotational movement along the direction. The distance is formed so as to gradually increase from the minimum value to the maximum value and gradually decrease from the maximum value to the minimum value.

  In one aspect of the present invention, the cam mechanism is formed on an inner peripheral portion of the cylinder, and rotates around the central axis. The cam mechanism is held by the piston and engages with the inward cam groove. And the inward cam groove extends from the inner end surface of the cylinder with respect to the direction of the central axis as it advances around the central axis in the direction of the rotational movement along the inward cam groove. The distance is gradually increased from the minimum value to the maximum value, and gradually decreased from the maximum value to reach the minimum value.

  In one aspect of the present invention, the notch of the piston is continuous with the tip surface. In one aspect of the present invention, the piston is formed with a communication hole for communicating the notch and the compartment. In one aspect of the present invention, piston rings are attached to both sides of the notch in the outer peripheral portion of the piston in the direction of the central axis.

  In one aspect of the present invention, the fluid suction / discharge device is a pump, and the cam mechanism is configured such that the volume of the compartment gradually decreases from a maximum value to a minimum value when the piston rotates. The rotation angle range of the piston around an axis is such that the rotation angle of the piston around the central axis when the volume of the compartment gradually increases from a minimum value to a maximum value during the rotation of the piston. It is formed to be equivalent to the range.

  In one aspect of the present invention, the fluid suction / discharge device is a compressor, and the cam mechanism is configured such that the volume of the compartment gradually decreases from a maximum value to a minimum value when the piston rotates. The rotation angle range of the piston around an axis is such that the rotation angle of the piston around the central axis when the volume of the compartment gradually increases from a minimum value to a maximum value during the rotation of the piston. It is formed to be larger than the range.

  According to the present invention, the piston is reciprocated in the cylinder by the action of the cam mechanism by rotating the piston by the rotation driving means, and at this time, the compartment volume increases and the suction port passes through the notch. The fluid is sucked into the compartment, the compartment volume is reduced, and the fluid in the compartment is discharged from the discharge port through the notch. As described above, in the present invention, the piston notch and the piston outer peripheral surface located at the same position as the notch with respect to the central axis direction have a valve function, so that a separate valve is unnecessary and the structure is simple. is there.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic exploded perspective view showing an embodiment of a pump as a fluid suction / discharge device according to the present invention, FIG. 2 is a longitudinal sectional view showing an assembled state thereof, and FIG. 3 is an upper plan sectional view of the pump. FIG. 4 is a cross-sectional view from above (FIG. 4), and FIG. 4 is a cross-sectional view from the bottom of this pump (cross-sectional view from below).

  The inner peripheral surface 21 of the cylinder 2 has rotational symmetry with respect to the central axis X. A piston 4 is disposed in the cylinder 2. The piston 4 can both reciprocate in the direction of the central axis X and rotate around the central axis X with respect to the cylinder 2. That is, the central axis X is also the rotation center when the piston 4 rotates. A compartment C is formed by the tip surface 41 of the piston 4 and the inner peripheral surface 21 and the inner end surface 22 of the cylinder 2. The cylinder 2 is formed with a suction port 23 and a discharge port 24 located on opposite sides of the central axis X. As will be described later, the suction port 23 and the discharge port 24 can communicate with the compartment C in a timely manner as the piston 4 reciprocates and rotates.

  On the outer peripheral portion of the piston 4, outward cam grooves (that is, cam grooves formed on the outer surface) 42 and 43 that circulate around the central axis X are formed. The “circulation” of the cam grooves 42 and 43 does not mean that the cam grooves 42 and 43 extend only in a plane orthogonal to the central axis X, but the cam grooves 42 and 43 It is meant to include extending at least a portion so as to cross at an angle. The cam grooves 42 and 43 advance around the central axis X with increasing angles with respect to the spatially fixed angular coordinates of the rotational movement direction of the piston 4 around the central axis X (the direction of the arrow R in FIG. 1). The distance from the inner end face 22 of the cylinder 2 in the direction of the central axis X is the minimum value (that is, the circuit travels around the central axis X in the direction of the piston rotational movement along the cam grooves 42 and 43). The cam groove 42 gradually increases from d1: d2 for the cam groove 43 to the maximum value (D1: for the cam groove 42: D2 for the cam groove 43), and further decreases gradually from the maximum value to the minimum value. It is formed to reach. Here, the cam groove portions 42a and 43a in which the distance from the inner end surface 22 of the cylinder 2 gradually increases from the minimum value to the maximum value are referred to as distance increasing portions, and the distance from the inner end surface 22 of the cylinder 2 increases from the maximum value. The cam groove portions 42b and 43b that gradually decrease and reach the minimum value are referred to as distance reduction portions. The cam groove 43 is in a position translated from the cam groove 42 in the direction of the central axis X. The cam grooves 42 and 43 are formed such that the distance decreasing portions 42b and 43b exist around the central axis X over the same angular range (180 degrees) as the distance increasing portions 42a and 43a.

  A notch 44 is formed in the outer peripheral portion of the piston 4 so as to be continuous with the front end surface 41. The notch 44 is formed so as to be able to communicate with the suction port 23 and the discharge port 24 when the piston 4 reciprocates in the direction of the central axis X. The notch 44 is formed so as to be able to selectively communicate with the suction port 23 and the discharge port 24 during the rotational movement of the piston 4 in the circumferential direction around the central axis X. 42 and 43 are located corresponding to a part of the distance increasing portions 42a and 43a. Here, the selective communication means that the communication is not performed at the same time as both the suction port 23 and the discharge port 24 but one is selected and communicated. A portion of the outer peripheral surface of the piston 4 other than the notch 44 and located at the same position as the notch 44 in the direction of the central axis X is in close contact with the inner peripheral surface 21 of the cylinder 2.

  From the inner peripheral surface 21 of the cylinder 2, inward engagement pins (that is, engagement pins that protrude inward) 61 and 62 that engage with the cam grooves 42 and 43, respectively, protrude inward. The protruding positions of the engaging pins 61 and 62 are adjusted by adjusting screws 63 and 64 that are respectively adapted to screw holes formed in the cylinder 2.

  That is, in this embodiment, the cam mechanism that is interposed between the piston 4 and the cylinder 2 and converts the rotational motion of the piston 4 into reciprocating motion is formed on the outer peripheral portion of the piston 4 and circulates around the central axis X. It includes orientation cam grooves 42 and 43 and inward engagement pins 61 and 62 as inward engagement portions that are held in the cylinder 2 and engage with the outward cam grooves 42 and 43.

  A pair of sliding grooves 45 and 46 extending in the direction of the central axis X are formed in the piston 4 on the side opposite to the tip surface 41 in the direction of the central axis X. The sliding grooves 45 and 46 are disposed on opposite sides of the central axis X. As described above, in the piston 4, the cam grooves 42 and 43 are arranged between the notch portion 44 and the sliding grooves 45 and 46 in the direction of the central axis X.

  Rotation driving means 8 is provided for driving the rotational movement of the piston 4 around the central axis X while allowing the reciprocating movement of the piston 4 in the direction of the central axis X. The rotary drive means 8 includes a rotary shaft 81 that receives a rotational force from a rotary drive source (not shown) such as an output shaft of an electric motor, and a pair of sliding grooves 45 and 46 of the piston attached to the rotary shaft 81. And a pair of driving force transmission protrusions 82 and 83 which engage with each other.

  In the present embodiment, a rotational force is transmitted from an output shaft of an electric motor (not shown), and the rotation shaft 81 rotates around the central axis X in the direction of arrow R. Accordingly, the direction of the arrow R around the central axis X in the cylinder 2 is determined based on the engagement relationship between the driving force transmission protrusions 82 and 83 attached to the rotating shaft 81 and the sliding grooves 45 and 46. Can be rotated. At that time, the piston 4 reciprocates in the direction of the central axis X in the cylinder 2 based on the engagement relationship between the engagement pins 61 and 62 and the cam grooves 42 and 43. This reciprocating motion is made to reciprocate once while the piston 4 makes one rotation, and the moving distance is D1-d1 = D2-d2.

  Assuming that the cylinder 2 is space-fixed, and the space-fixed rotation angle of the piston 4 around the central axis X is θ, the change in the volume V of the compartment C accompanying the reciprocating motion of the piston 4 is shown in FIG. It becomes like this. That is, when the rotation angle θ of the piston 4 changes from 0 degrees to 180 degrees, the engagement pins 61 and 62 engage with the distance increasing portions 42a and 43a of the cam grooves 42 and 43, and the compartment volume V is the minimum value. It changes from V1 to the maximum value V2. Subsequently, when the rotation angle θ of the piston 4 changes from 180 degrees to 360 degrees (= 0 degrees), the engagement pins 61 and 62 engage with the distance reducing portions 42b and 43b of the cam grooves 42 and 43, and the distance between them is increased. The chamber volume V changes from the maximum value V2 to the minimum value V1. Thereafter, the same is repeated. Note that the patterns of the cam groove distance increasing portions 42a and 43a and the distance decreasing portions 42b and 43b (that is, the pattern of the change in the distance from the inner end face 22 of the cylinder 2 in the direction of the central axis X with respect to the change in the angle θ) are It can be changed as appropriate.

  FIG. 5 also shows changes in the communication state between the piston notch 44 and the suction port 23 and the discharge port 24 as the piston 4 reciprocates and rotates. The notch 44 communicates with the suction port 23 (suction port communication ON) and communicates with the discharge port 24 when the rotation angle θ of the piston 4 is from θ1 slightly larger than 0 degrees to θ2 slightly smaller than 180 degrees. No (Discharge port communication OFF). The notch 44 communicates with the discharge port 24 (discharge port communication ON) and communicates with the suction port 23 between the rotation angle θ of the piston 4 slightly larger than 180 degrees and θ4 slightly smaller than 360 degrees. No (suction port communication OFF). When the rotation angle θ of the piston 4 is between 0 degrees and θ1, between θ2 and θ3, and between θ4 and 360 degrees, the notch 44 does not communicate with either the suction port 23 or the discharge port 24. Between these, the distance of the reciprocating motion of the piston 4 is small, and the change in the volume V of the compartment C is small. Thereafter, the same is repeated. 2 to 4 show a state where the rotation angle θ of the piston is 0 degree.

  As described above, in the present embodiment, the cam mechanism rotates the piston 4 around the central axis X where the volume of the compartment C gradually decreases from the maximum value to the minimum value when the piston 4 rotates. The angular range is formed to be equivalent to the rotational angle range of the piston 4 around the central axis X in which the volume of the compartment C gradually increases from the minimum value to the maximum value during the rotational movement of the piston 4. Has been.

  Thus, while the rotation angle θ of the piston 4 changes from 0 degree to 360 degrees (that is, the piston 4 makes one revolution), the fluid is sucked into the compartment C from the suction port 23, and the fluid is contained in the compartment C. Is discharged to the discharge port 24 to perform a pumping action.

  According to the present embodiment, the notch portion 44 of the piston 4 and the piston outer surface portion (portion other than the notch portion 44) located at the same position as the notch portion 44 in the direction of the central axis X have a pump valve function. A separate pump valve is unnecessary and the structure is simple. In the present embodiment, the cam mechanism in which the cam grooves 42 and 43 are engaged with the engagement pins 61 and 62 is used to generate the reciprocating motion of the piston 4 from the rotational motion of the piston 4. Since the volume change itself of the compartment C is realized by the reciprocating motion of the piston 4, the pump of the present embodiment is a kind of reciprocating pump. However, from the meaning that the piston 4 that realizes the volume change of the compartment C rotates, it can be said that the pump of the present embodiment is a composite type pump that also has elements of a rotary pump.

  FIG. 6 is a schematic perspective view showing another embodiment of a pump as a fluid suction / discharge device according to the present invention, and FIG. 7 is an exploded perspective view thereof. 8 is a longitudinal sectional view showing the assembled state, FIG. 9 is a plan sectional view of the A part in FIG. 8 (cross sectional view seen from above), and FIG. 10 is a sectional plan view of the B part in FIG. FIG. 11 is a cross-sectional view of the C part bottom surface of FIG. 8 (a cross-sectional view seen from below). In these drawings, members similar to those in FIGS. 1 to 4 are given the same reference numerals.

  In the present embodiment, an electric motor 10 as a rotational drive source is attached to the upper part of the cylinder 2. The output rotation shaft 101 of the electric motor is coupled to the rotation shaft 81 of the rotation driving means 8 so as to be able to transmit the rotational force. Further, one cam groove 42 is provided on the outer peripheral portion of the piston 4. Correspondingly, one inward engagement pin 65 as an inward engagement portion that engages with the cam groove 42 is attached to the cylinder 2. The engagement pin 65 corresponds to a combination of the engagement pin 61 and the adjustment screw 63 of the embodiment described with reference to FIGS.

  The operation and effect of the pump of this embodiment are essentially the same as those of the embodiment described with reference to FIGS.

  In the above embodiment, the fluid suction / discharge device is a pump used for suction / discharge of fluid. However, in the present invention, the fluid suction / discharge device may be a compressor used for suction / discharge of compressible fluid. In this case, the same components as the above pump can be used as an element constituting the device. However, unlike the pump, a fluid compression process is required, so the cam groove pattern and the notch portion Make the shape different from that of the pump. Hereinafter, although the embodiment of a compressor is shown, it demonstrates using the code | symbol same as embodiment regarding the said pump here.

  FIG. 12 shows the change in the volume V of the compartment C accompanying the reciprocating motion and the rotational motion of the piston 4 as in FIG. 5 and the communication state between the piston notch 44 and the suction port 23 and the discharge port 24 in the case of the compressor. An example of the change is shown. The notch 44 is selectively communicated with the suction port 23 and the discharge port 24 within an angle range sufficiently smaller than that of the pump when the piston 4 rotates around the central axis X in the direction of the rotational movement. To form. Further, the cam grooves 42 and 43 are formed so that the distance decreasing portions 42b and 43b exist over the central axis X over a larger angle range than the distance increasing portions 42a and 43a. That is, the angle range of the distance increasing portions 42a and 43a is slightly larger than [θ2-θ1], and the angle range of the distance decreasing portions 42b and 43b is slightly smaller than [θ4-θ2]. Within the range from the angle θ4 to an angle slightly smaller than θ1, the cam grooves 42 and 43 are distance constant portions where the distance from the inner end face 22 of the cylinder 2 in the direction of the central axis X is constant. The patterns of the cam groove distance increasing portions 42a and 43a and the distance decreasing portions 42b and 43b can be changed as appropriate. In particular, with respect to the distance reduction portions 42b and 43b, the fluid compression process is performed while the engagement pins 61 and 62 are engaged in most of the regions except the final region of this portion, and the cylinder 2 in the direction of the central axis X is The distance from the inner end face 22 may change abruptly in the first half region and gently in the second half region, or may change gradually in the first half region and abruptly in the second half region (excluding the final region).

  As described above, when the fluid suction / discharge device is a compressor, the cam mechanism is configured such that when the piston 4 rotates, the volume of the compartment C gradually decreases from the maximum value to reach the minimum value. The rotation angle range of the piston 4 around is larger than the rotation angle range of the piston around the central axis X in which the volume of the compartment C gradually increases from the minimum value to the maximum value when the piston 4 rotates. To be formed.

  The operation and effect of the compressor of the present embodiment is essentially the above figure except that the pattern of the cam grooves 42 and 43 and the shape of the notch 44 are as described above because there is a fluid compression process. 1 to 5 is the same as that of the embodiment described for the pump.

  FIG. 13 is a schematic partial cross-sectional view showing another embodiment of a pump as a fluid suction / discharge device according to the present invention. In this figure, the same members as those in FIGS. 1 to 4 and FIGS.

  In this embodiment, the cross-sectional shape of the outward cam groove 42 that is formed on the outer peripheral portion of the piston 4 and circulates around the central axis X is a semicircular shape. As an inward engagement portion that is held by the cylinder 2 and engages with the outward cam groove 42, an inward engagement ball 67 whose inward protruding position is adjusted by an adjustment screw 66 is used.

  A plurality of piston rings 5 are attached to the outer periphery of the piston 4. These piston rings 5 are located above the outward cam groove 42, between the outward cam groove 42 and the notch 44, and below the notch 44 in the direction of the central axis X, respectively. Thus, the piston ring 5 is attached to the outer periphery of the piston 4 on both sides of the notch 44 in the direction of the central axis X. The notch 44 is not continuous with the tip surface 41. Therefore, the piston 4 is formed with a communication hole 48 that allows the notch 44 and the compartment C to communicate with each other.

  The operation and effects of the pump of this embodiment are essentially the same as those of the embodiment described with reference to FIGS.

  FIG. 14 is a schematic exploded perspective view showing another embodiment of a pump as a fluid suction / discharge device according to the present invention. FIG. 15 is a schematic perspective view showing the assembled state. FIG. 16 is a longitudinal sectional view showing the assembled state, FIG. 17 is a plan sectional view of the a part in FIG. 16 (cross sectional view seen from above), and FIG. 18 is a sectional plan view of the d part in FIG. FIG. 19 is a cross-sectional view of the bottom of the part c in FIG. 16 (a cross-sectional view seen from below). In these drawings, the same members as those in FIGS. 1 to 4 and FIGS. 6 to 11 are denoted by the same reference numerals.

  The present embodiment differs from the embodiments of FIGS. 1 to 4 and FIGS. 6 to 11 in the configuration of the cam mechanism. The cylinder is formed by two members 2 and 2 '.

  That is, in the present embodiment, the cam mechanism includes an inward cam groove (that is, a cam groove formed on the inner surface) 26 that is formed on the inner peripheral portion of the cylinder 2, 2 ′ and rotates around the central axis X, and the piston 4. And an outward engagement portion 68 that engages with the inward cam groove 26 (that is, an engagement portion that protrudes outward).

  The inward cam groove 26 travels around the central axis X at an increased angle with respect to the spatially fixed angular coordinate of the direction of rotational movement of the piston 4 about the central axis X (i.e., around the central axis X). The distance from the inner end surface 21 of the cylinder 2 in the direction of the central axis X gradually increases from the minimum value to the maximum value while making a round around the central axis X in the direction of the piston rotational movement along the cam groove 26. It is formed so as to gradually decrease from the maximum value to the minimum value. Here, the cam groove portion where the distance from the inner end surface 22 of the cylinder 2 gradually increases from the minimum value to the maximum value is called a distance increasing portion, and the distance from the inner end surface 22 of the cylinder 2 gradually decreases from the maximum value. The cam groove portion that reaches the minimum value is called the distance reduction portion. The cam groove 26 is formed such that the distance decreasing portion exists around the central axis X over the same angular range (180 degrees) as the distance increasing portion.

  The outward engagement portion 68 includes a screw screwed into a screw hole formed in the piston 4 in the radial direction and a roller supported by the screw. The rollers engage with the side surfaces of the inward cam groove 26, that is, the surfaces facing each other in the direction of the central axis X.

  The notch 44 is positioned corresponding to a part of the distance increasing portion of the cam groove 26.

  The operation and effects of the pump of this embodiment are essentially the same as those of the embodiment described with reference to FIGS.

It is a typical exploded perspective view showing an embodiment of a pump by the present invention. It is a longitudinal cross-sectional view which shows the assembly state of the pump of FIG. It is sectional drawing seen from the upper side of the pump of FIG. It is sectional drawing seen from the lower side of the pump of FIG. It is operation | movement explanatory drawing of the pump of FIG. It is a typical perspective view which shows embodiment of the pump by this invention. It is a disassembled perspective view of the pump of FIG. It is a longitudinal cross-sectional view which shows the assembly state of the pump of FIG. It is A section top sectional drawing of the pump of FIG. It is a B section top sectional view of the pump of Drawing 6. It is C section bottom sectional drawing of the pump of FIG. It is operation | movement explanatory drawing of the compressor by this invention. It is a typical fragmentary sectional view showing an embodiment of a pump by the present invention. It is a typical exploded perspective view showing an embodiment of a pump by the present invention. It is a typical perspective view which shows the assembly state of the pump of FIG. It is a longitudinal cross-sectional view which shows the assembly state of the pump of FIG. It is a section plane sectional view of the pump of FIG. It is d section top sectional drawing of the pump of FIG. It is c section bottom sectional drawing of the pump of FIG.

Explanation of symbols

2, 2 'Cylinder 21 Inner peripheral surface 22 Inner end surface 23 Suction port 24 Discharge port 26 Inward cam groove 4 Piston 41 Front end surface 42, 43 Outward cam groove 42a, 43a Distance increasing portion 42b, 43b Distance decreasing portion 44 Notch 45, 46 Sliding groove 48 Communication hole 5 Piston rings 61, 62, 65 Inward engagement pins 63, 64, 66 Adjustment screw 67 Inward engagement ball 68 Outward engagement portion 8 Rotation drive means 81 Rotating shaft 82, 83 Driving force transmission protrusion 10 Electric motor 101 Output rotation axis X Center axis C Compartment

Claims (8)

A cylinder having an inner peripheral surface with rotational symmetry about the central axis;
A piston arranged to allow both reciprocation in the direction of the central axis and rotational movement about the central axis in the cylinder;
Rotational drive means for driving the rotational movement of the piston while allowing reciprocal movement of the piston; and communication with a compartment formed by the front end surface of the piston and the inner peripheral surface and inner end surface of the cylinder; A suction port and a discharge port formed in the cylinder so as to be positioned on opposite sides of the central axis,
Between the piston and the cylinder is interposed a cam mechanism for converting the rotational movement of the piston into the reciprocating movement,
A notch portion that communicates with the compartment is formed in the outer peripheral portion of the piston, and the notch portion communicates with the suction port and the discharge port during the reciprocating motion of the piston with respect to the direction of the central axis. And with respect to the circumferential direction around the central axis, the piston is formed so as to be able to selectively communicate with the suction port and the discharge port during the rotational movement of the piston. Fluid suction and discharge device.   The cam mechanism includes an outward cam groove formed on an outer peripheral portion of the piston and circling around the central axis, and an inward engagement portion held by the cylinder and engaged with the outward cam groove. As the outward cam groove advances around the central axis in the direction of the rotational movement along the outer cam groove, the distance from the inner end surface of the cylinder in the direction of the central axis gradually increases from the minimum value. The fluid suction / discharge device according to claim 1, wherein the fluid suction / discharge device is configured to reach a maximum value and gradually decrease from the maximum value to reach the minimum value.   The cam mechanism includes an inward cam groove formed on an inner peripheral portion of the cylinder and circling around the central axis, and an outward engagement portion held by the piston and engaged with the inward cam groove. As the inward cam groove advances around the central axis in the direction of the rotational movement along the inward cam groove, the distance from the inner end surface of the cylinder in the direction of the central axis gradually increases from the minimum value. The fluid suction / discharge device according to claim 1, wherein the fluid suction / discharge device is configured to reach a maximum value and gradually decrease from the maximum value to reach the minimum value.   The fluid suction / discharge device according to any one of claims 1 to 3, wherein the notch of the piston is continuous with the tip surface.   The fluid suction / discharge device according to any one of claims 1 to 3, wherein a communication hole is formed in the piston so as to communicate the notch with the compartment.   The fluid suction / discharge device according to claim 5, wherein piston rings are attached to both sides of the notch in the outer peripheral portion of the piston in the direction of the central axis.   The fluid suction / discharge device is a pump, and the cam mechanism is configured such that the volume of the compartment gradually decreases from a maximum value to a minimum value when the piston rotates. The rotation angle range is equivalent to the rotation angle range of the piston around the central axis where the volume of the compartment gradually increases from the minimum value to the maximum value during the rotational movement of the piston. The fluid suction / discharge device according to any one of claims 1 to 6, wherein the fluid suction / discharge device is formed.   The fluid suction / discharge device is a compressor, and the cam mechanism is configured such that the volume of the compartment gradually decreases from a maximum value to a minimum value during the rotational movement of the piston, and the piston around the central axis reaches a minimum value. The rotation angle range is larger than the rotation angle range of the piston around the central axis where the volume of the compartment gradually increases from the minimum value to the maximum value during the rotational movement of the piston. The fluid suction / discharge device according to any one of claims 1 to 6, wherein the fluid suction / discharge device is provided.

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