JP2017066913A - Swash plate type compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrict a steep edge formation at a location where a circular arc inner peripheral surface of a piston guide part and an inner wall surface of a cylinder block are crossed to each other when a piston guide part restricting inclination of a single head piston is formed at the cylinder block.SOLUTION: When a cylinder block is formed with a piston guide part extending from a cylinder bore so as to restrict inclination of a single head piston, an expected location crossing with an inner wall surface 52 of the cylinder block of a raw material surface of the cylinder block before machining the piston guide part 51 when a piston guide part 51 is machined is provided with edge relaxation means [a curved surface A or a tapered surface with a negative curvature factor] for increasing an angle of an edge 53 formed at the expected location.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for forming a piston guide portion extending from a cylinder bore to an inner wall surface of a crank chamber and in which a mooring portion of a single-head piston slides in a single-head piston swash plate compressor.

  In a fixed-capacity single-head swash plate compressor used in a vehicle air-conditioning compressor, a cylinder block having a cylinder bore that houses a head of a single-head piston and forms a compression chamber, and a cylinder head that forms a suction chamber and a discharge chamber Is disposed only at one end in the axial direction of the compressor. Therefore, a simple housing structure can be adopted as compared with a double-headed swash plate type compressor in which a cylinder block and a cylinder head are arranged at both end portions in the axial direction of the compressor. Furthermore, unlike a variable capacity single-head swash plate compressor, the fixed-capacity single-head swash plate compressor does not require (i) a pressure control valve for discharge capacity control, and (ii) ensures stable control during high-speed operation. There is an advantage that it is not necessary to adopt an expensive hollow piston structure which is an essential technology. On the other hand, there may be a case where a relatively heavy piston is cantilevered by the cylinder bore and is operated at a high speed with the maximum stroke inside the cylinder bore.

  When such a relatively heavy piston reciprocates at a maximum stroke with the cylinder bore being cantilevered, a large inertial force is generated in the piston. In particular, when the swash plate presses the piston toward the top dead center via the shoe in the phase where the piston movement is switched from the bottom dead center position to the top dead center side, the piston mooring portion is moved radially outward of the cylinder block. The component force which pushes toward For this reason, there is a possibility that the piston tilts with respect to the cylinder bore and abnormal wear occurs at the end of the piston, or the mooring portion of the piston is deformed to cause damage to the mooring portion or drop off of the shoe.

  Therefore, conventionally, the outer peripheral arc surface of the anchoring portion of the piston that slidably holds the peripheral portion of the swash plate via the pair of shoes is formed so as to be concentric with the piston head and have the same radius of curvature. Further, as shown in FIG. 5, an arc inner peripheral surface 51 a that is concentric with the cylinder bore 14 and has the same radius of curvature is formed on the inner wall surface of the cylinder block 1 (the shell forming portion 50 formed following the cylinder bore forming portion 11). The piston guide portion 51 is provided so as to extend from the cylinder bore, and the piston head and the mooring portion can slide along the cylinder bore 14 and the piston guide portion 51 even if the piston moves from the bottom dead center to the top dead center. A configuration has been proposed in which the substantial fitting length of the piston is increased to suppress the tilt of the piston (see Patent Documents 1 and 2).

JP-A-4-308371 JP 2002-180963 A

  However, since the circular arc inner peripheral surface 51a of the piston guide portion 51 formed on the inner wall surface of the cylinder block 1 has an arc shape that is concentric with the cylinder bore 14 and has the same curvature radius, the piston guide portion 51 is processed when the piston guide portion 51 is processed. As shown in FIG. 6, a relatively edge extending in the axial direction of the cylinder bore 14 at a location where the inner circumferential surface 51a of the arc 51 intersects with the inner wall surface of the cylinder block (the inner wall surface of the housing defining the crank chamber). Edge 53 having a small angle (this edge angle is defined as θ0) is formed, and when the piston is assembled to the cylinder block 1, the piston abuts on the edge 53 to damage the surface of the piston, or the edge piece that is missing and dropped off. May be trapped between the piston and cylinder bore, causing inconveniences such as obstructing the smooth sliding of the piston.

  The present invention has been made in view of such circumstances, and in forming the piston guide portion extending from the cylinder bore in the cylinder block in order to suppress the inclination of the single-headed piston, there is an obstacle when the piston is assembled to the cylinder block. It is a main object to provide a swash plate type compressor that can suppress the formation of a sharp edge.

  In order to achieve the above object, a swash plate compressor according to the present invention includes a cylinder bore forming portion in which a plurality of cylinder bores are formed, and a cylinder provided so as to extend from one end side in the axial direction of the cylinder bore forming portion. A cylinder block having a cylindrical shell forming portion, a shaft rotatably supported at the center of the cylinder bore forming portion, a swash plate that rotates with the rotation of the shaft, and a pair of shoes through the inclined block. A piston connected to a plate and reciprocally sliding in the cylinder bore as the swash plate rotates, and the piston supports a head that slides in the cylinder bore and the pair of shoes in a rollable manner. And the anchoring portion is configured to have an arc outer peripheral surface that is concentric with the head and has the same radius of curvature, and the shell forming portion. A piston guide portion having an arc inner peripheral surface that is concentric with the cylinder bore and has the same radius of curvature is formed on the inner peripheral surface so as to extend from an end of the cylinder bore. A swash plate compressor in which an arc outer peripheral surface is in sliding contact with an arc inner peripheral surface of the piston guide portion, and the arc inner peripheral surface of the piston guide portion and an inner wall surface of the shell forming portion intersect each other. An edge relaxation means for increasing the angle of the edge formed here is formed at a location.

  Therefore, edge mitigation means for increasing the angle of the edge formed here is provided at a location where the inner circumferential surface of the arc of the piston guide portion intersects with the inner wall surface of the shell forming portion. A sharp edge is no longer formed where the peripheral surface intersects the inner wall surface of the shell forming part, and when the piston is assembled to the cylinder block, the piston abuts against the edge and is damaged, or a part of the edge is missing. Thus, it is possible to reduce the possibility that the edge piece that has fallen off is caught between the piston and the cylinder bore.

  Preferably, the cylinder block material is formed by casting, the arc inner peripheral surface of the piston guide portion is formed by cutting the cast material, and the edge relaxation means is formed by the cast material surface.

  Here, as an edge mitigation means, among the cast material surface of the cylinder block before cutting the piston guide part, when the piston guide part is machined, at an expected place that intersects the inner wall surface of the shell forming part A curved surface having a negative curvature with respect to the inner circumferential surface of the arc of the piston guide portion may be formed.

  Also, as an edge relaxation means, out of the casting material surface of the cylinder block before cutting the piston guide portion, when processing the piston guide portion, in the prospective location that intersects the inner wall surface of the shell forming portion, A tapered surface may be formed.

  The swash plate compressor may be a fixed capacity single-head swash plate type in which the swash plate is fixed to the shaft at a predetermined inclination angle.

  As described above, according to the present invention, when the piston guide portion having the arc inner peripheral surface having the same radius of curvature as the cylinder bore is formed in the shell forming portion of the cylinder block, Edge mitigation means for increasing the edge angle of the edge formed here is formed at a location where the circumferential surface and the inner wall surface of the shell forming portion intersect, so the arc inner circumferential surface of the piston guide portion and the shell forming portion It becomes possible to make the edge angle of the edge formed at the location intersecting with the inner wall surface larger than the conventional one, and to suppress the formation of a steep edge.

  In addition, by forming the cylinder block on the casting material surface as the edge relaxation means, it is not necessary to perform another process after casting the cylinder block, and an increase in the manufacturing process can be avoided.

FIG. 1 is a view showing an example of a swash plate type compressor having a piston guide portion according to the present invention, wherein (a) is a cross-sectional view thereof, and (b) is a piston block and a piston guide portion accommodated in a cylinder bore. It is the figure seen from the axial direction. FIG. 2A shows a cylinder block of a swash plate compressor, and is a perspective view seen from above obliquely so as to face the piston guide portion. FIG. 2B shows the cylinder bore and piston guide portion of the cylinder block. It is the figure seen from the axial direction. FIG. 3 is a view showing a first embodiment of a method for forming a piston guide portion in a shell forming portion of a cylinder block, and (a) is an inner peripheral surface of the shell forming portion before forming the piston guide portion. It is a figure which shows the state by which edge relaxation means (the curved surface A in which the code | symbol of curvature is opposite to a cylinder block) is shape | molded by the casting raw material surface. (B) is a figure which shows the state which formed the piston guide part in the casting raw material surface of the shell formation part of (a). FIG. 4 is a view showing a second embodiment of the method for forming the piston guide portion in the shell forming portion of the cylinder block, and (a) is an inner peripheral surface of the shell forming portion before forming the piston guide portion. And it is a figure which shows the state by which the other edge relaxation means (taper surface B) is shape | molded by the casting raw material surface. (B) is a figure which shows the state which formed the piston guide part in the casting raw material surface of the shell formation part of (a). FIG. 5 is a view showing a piston guide portion formed in a shell forming portion of a cylinder block of a conventional swash plate compressor, (a) is a perspective view seen obliquely from above, and (b) is It is the figure which looked at the cylinder bore and the piston guide part from the axial direction of the cylinder block. FIG. 6 is a view showing a conventional state in which a piston guide portion is formed in the shell forming portion.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 shows a fixed capacity single-head swash plate compressor according to the present invention. The swash plate compressor is assembled so as to cover a cylinder block 1 and a shell forming portion 50 integrally formed so as to extend to the front side of the cylinder block 1. A front housing 3 that defines the chamber 2 and a cylinder head 5 that is assembled to the rear side of the cylinder block 1 via a valve plate 4 are configured. The front housing 3, the cylinder block 1, the valve plate 4, and the cylinder head 5 are fastened in the axial direction by fastening bolts (not shown).

  A crank chamber 2 defined by the front housing 3 and the cylinder block 1 accommodates a shaft 6 whose front end protrudes from the front housing 3. A drive pulley (not shown) is provided at a portion of the shaft 6 protruding from the front housing 3 so that the rotational power applied to the drive pulley is transmitted to the shaft 6 via the clutch plate.

  Further, the front end side of the shaft 6 is hermetically sealed with the front housing 3 through a seal member 7 provided between the shaft 6 and is rotatably supported by a radial bearing 8. The rear end side of the shaft 6 is rotatably supported via a radial bearing 13 that is accommodated in an accommodation hole 12 formed substantially at the center of the cylinder block 1. Here, the radial bearings 8 and 13 may be rolling bearings or plain bearings.

  The cylinder block 1 includes a cylinder bore forming portion in which the accommodation hole 12 in which the radial bearing 13 and the like are accommodated and a plurality of cylinder bores 14 arranged at equal intervals on a circumference around the accommodation hole 12 are formed. 11 and a cylindrical shell forming portion 50 that is connected to the outer peripheral surface of the cylinder bore forming portion 11 and extends from the front end surface. A piston 15 is inserted into each cylinder bore 14 so as to be slidable back and forth. The material of the cylinder block 1 is formed by casting, for example, aluminum die casting.

A swash plate 16 that rotates integrally with the shaft 6 is fixed to the shaft 6 in the crank chamber 2. The swash plate 16 is rotatably supported via a thrust bearing 18 on an end surface of a boss portion 17 projecting from an inner wall of the front housing 3.
And the mooring part 40 of the piston 15 is moored by the peripheral part of the swash plate 16 via a pair of shoes 19 provided in the front and back.

  Accordingly, when the shaft 6 rotates, the swash plate 16 rotates with a predetermined inclination angle accordingly, so that the peripheral portion of the swash plate 16 swings with a predetermined width in the axial direction of the shaft 6. As a result, the piston 15 engaged with the peripheral portion of the swash plate 16 via the shoe 19 reciprocates in the axial direction of the shaft 6 (the rotational movement of the swash plate 16 is caused by the rotation of the piston 15 via the shoe 19). The volume of the compression chamber 20 defined between the piston 15 and the valve plate 4 in the cylinder bore 14 is changed.

The cylinder head 5 is formed in a bottomed cylindrical shape, and an annular partition wall 21 standing from the bottom 5 a is formed inside. The partition wall 21 divides the inside into a suction chamber 22 and a discharge chamber 23. It has been.
The discharge chamber 23 is formed on the center side of the cylinder head 5 on the inner side of the partition wall 21 and communicates with a high-pressure line of the refrigeration cycle via a discharge port (not shown). The suction chamber 22 is defined outside the partition wall 21 and the refrigerant from the low-pressure line of the refrigeration cycle is guided through the suction port 24.

  In addition, a cylindrical portion 28 formed independently of the partition wall 21 is erected from the bottom portion 5 a inside the partition wall 21 of the cylinder head 5. The cylindrical portion 28 is formed at a height approximately equal to the partition wall 21 at the approximate center (on the axis of the cylinder head 5) of the discharge chamber 23 defined by the partition wall 21. For this reason, when the cylinder head 5 is pressed to the cylinder block 1 side via the valve plate 4 by the axial force of a fastening bolt (not shown), the discharge chambers located inside the tubular portion 28 and outside the tubular portion 28 are disposed. Airtightness between the two is secured.

The valve plate 4 communicates with the suction chamber 22 and the cylinder bore 14 (compression chamber 20), and communicates the suction hole 25 opened and closed by a suction valve (not shown), the discharge chamber 23, and the cylinder bore 14 (compression chamber 20). A discharge hole 27 opened and closed by the discharge valve 26 is formed at a predetermined position in the circumferential direction.
Therefore, during the suction process in which the piston 15 increases the volume of the compression chamber 20, the working fluid is sucked into the compression chamber 20 from the suction chamber 22 through the suction hole 25, and the piston 15 reduces the volume of the compression chamber 20. During the compression process, the refrigerant compressed in the compression chamber 20 is discharged to the discharge chamber 23 through the discharge hole 27.

  In addition, a through hole 4a is formed substantially at the center of the valve plate 4, and the inside of the cylindrical portion 28 accommodates the through hole 4a, the oil separation passage 70 formed in the shaft 6, and the seal member. The seal chamber 73 communicates with the crank chamber 2 through a communication hole 74 formed in the front housing 3, and communicates with the suction chamber 22 through a communication hole 29 (not shown) formed in the cylinder head 5. ing.

An oil separation passage 70 formed in the shaft 6 communicates with an axial through hole 71 formed on the axial center of the shaft 6 from the rear end toward the front end to the vicinity of the front end, and the axial through hole 71. The shaft 6 is formed by a radial through hole 72 that is formed in the radial direction of the shaft 6 and opens into a seal chamber 73 that accommodates the seal member 7 provided between the shaft 6 and the front housing 3. The oil has a function of separating the oil from the working fluid flowing in from the radial through hole 72 by the centrifugal force generated by the rotation.
The seal chamber 73 communicates with the crank chamber 2 through a communication hole 74 formed in the front housing 3.

  Therefore, the communication hole 74 formed in the front housing 3, the seal chamber 73, the oil separation passage 70 formed in the shaft 6 (the axial direction hole 71 and the radial direction hole 72), and the through hole formed in the valve plate 4. 4a, a bleed passage for allowing blow-by gas in the crank chamber 2 to escape to the suction chamber 22 is formed through the inside of the cylindrical portion 28.

  By the way, the piston 15 is formed following the head 30 slidably inserted into the cylinder bore 14, and holds the hemispherical shoe 19 slidably through the shoe 19. And a mooring portion 40 moored to the swash plate 16.

  In this example, the head part 30 and the mooring part 40 are integrally formed, for example, are formed solid by forging, die casting, or the like using an aluminum-based metal material. In addition, an elastic deformation portion 31 that allows elastic deformation in the radial direction is integrated with an end portion of the mooring portion 40 on the side opposite to a later-described bridge portion 43 with respect to the axis of the head portion 30. Is formed.

  The mooring portion 40 includes a pair of shoe receiving portions 41 and 42 that are engaged with both side surfaces of the outer peripheral portion of the swash plate 16 via the shoe 19, and the pair of shoe receiving portions 41 and 42 are radially outward of the swash plate 16. And a bridging portion 43 to be coupled with each other. The bridging portion 43 has an arc outer peripheral surface 40a that is concentric with the head 30 and has the same radius of curvature.

  Here, the shoe 19 is formed in a hemispherical shape, and is slidably held by the shoe receiving portions 61 and 62 at the spherical portion, and slidably abuts against the side surface of the swash plate 16 at the flat portion. The swash plate 16 is sandwiched between the pair of shoes 19.

  As shown in FIG. 2, a piston guide portion having an arc inner peripheral surface 51a that is concentric with the cylinder bore 14 and has the same radius of curvature is formed on the inner peripheral surface of the shell forming portion 50 of the cylinder block 1. 51 is formed to be continuous with the cylinder bore 14. When the piston 15 moves from the top dead center to the bottom dead center, the piston outer peripheral surface 40a of the anchoring portion 40 of the piston 15 makes the circular inner peripheral surface 51a of the piston guide portion 51 the axis of the cylinder bore 14 when the piston 15 moves. It is formed over a range that can be slid along the center. The piston guide portion 51 needs to be in contact with the entire circular arc outer peripheral surface 40a of the mooring portion 40 of the piston 15 when the piston 15 is at the bottom dead center position. Instead, it may be formed over a range in which a part of the arc outer peripheral surface 40a of the anchoring portion 40 of the piston 15 can abut against the arc inner peripheral surface 51a of the piston guide portion 51 to prevent the piston 15 from being inclined.

In such a configuration, a method as shown in FIG. 3 is adopted in forming the piston guide portion 51.
First, when the cylinder block 1 is molded by casting, the inner surface of the shell forming portion 50 when the piston guide portion 51 is machined out of the cast material surface of the shell forming portion 50 before the piston guide portion 51 is cut. Edge mitigation means for increasing the angle of the edge formed at the time of cutting of the piston guide portion 51 is formed at a prospective location intersecting the peripheral surface.

  The edge mitigating means includes a portion of the cast material surface of the shell forming portion 50 before the piston guide portion 51 is machined and a portion where the piston guide portion 51 is to be formed by cutting and a shell forming portion 50 subsequent thereto. Casting is performed so that the wall surface 52 (the inner wall surface 52 of the housing (cylinder block) defining the crank chamber 2) is smoothly connected to the circular arc surface A having a predetermined curvature.

  That is, when casting the material of the cylinder block 1, the radius of curvature is larger than that of the circular arc inner peripheral surface 51 a of the piston guide portion 51 after processing at a place where the piston guide portion 51 of the inner wall surface 52 of the shell forming portion 50 is to be processed. Is formed so that the portion that becomes the peripheral edge of the arc inner peripheral surface 51a is included in the portion that transitions from the inner wall surface 52 of the shell forming portion 50 to the piston guide processing scheduled recess 55. The front and rear points P1 and P2 are connected to a circular arc inner peripheral surface 51a of the piston guide portion 51 by a curved surface (curved surface having a negative curvature) A having the opposite sign of curvature. In other words, the portions P1 and P2 where the sign of the curvature changes are located between the portions intersecting the inner wall surface 52 of the shell forming portion 50 of the piston guide portion 51 formed by processing the piston guide processing scheduled recess 55. Set to do. Also, a cylinder bore machining planned hole which is a cylindrical surface having a curvature radius that is concentric and the same as that of the piston guide machining planned recess 55 at a place where the cylinder bore 14 is to be formed, and is smaller than the cylinder bore 14 after machining. A portion (not shown) is formed.

  The material of the cylinder block 1 having such a material surface is molded by casting, and the piston guide processing scheduled recess 55 in FIG. 3A is machined to the portion indicated by the wavy line, and FIG. As shown, an arc inner peripheral surface 51a of the piston guide portion 51 is formed. At this time, since the cylinder bore machining scheduled hole is also machined by the same machining process, the cylinder bore 14 after machining and the arc inner circumferential surface 51a of the piston guide part 51 are formed so as to have concentric and the same curvature radius. The

  Then, the portion where the piston guide portion 51 is connected to the inner wall surface 52 of the shell forming portion 50 is connected by a curved surface having the opposite sign of the curvature, so that when the piston guide portion 51 is formed, this portion is formed. An edge 53 formed at an intersecting portion of the arc inner peripheral surface 51a of the piston guide portion 51 and the inner wall surface 52 of the shell forming portion 50 (portion surrounded by an alternate long and short dash line in FIG. 3B) has an edge angle θ1. It becomes larger than the edge angle θ0 of the conventional edge (Q1> Q0).

  Therefore, an edge having a small edge angle (a steep edge) is not formed at the intersection of the piston guide portion 51 and the shell forming portion 50, and the piston 15 moves to the edge 53 when the piston 15 is assembled to the cylinder block 1. Even in the case of contact, the inconvenience of scratching the piston is reduced.

  In the above-described configuration, the edge mitigation means that suppresses the generation of the steep edge 53 has a sign of curvature between the piston guide processing scheduled recess 55 and the inner wall surface 52 of the shell forming portion 50 (the inner surface of the crank chamber 2). Although an example of connecting with different curved surfaces (connecting points P1 and P2 whose curvature changes with curved surfaces) has been shown, P1 and P2 are connected with a plane (tapered surface) B as shown in FIG. When the piston guide portion 51 is formed by processing the guide processing scheduled recess 55, the angle (edge angle) connecting the piston guide portion 51 and the inner wall surface 52 of the shell forming portion 50 may be increased. .

  By providing such a flat surface (tapered surface) in advance, compared to the case where P1 and P2 are connected by a curve, the intersection of the piston guide portion 51 and the inner wall surface 52 of the shell forming portion 50 (FIG. 4). (B) It is possible to further increase the edge angle (Q2) of the edge 53 formed at the portion surrounded by the alternate long and short dash line (Q2> Q1> Q0), and further suppress the formation of the steep edge 53. Is possible.

DESCRIPTION OF SYMBOLS 1 Cylinder block 2 Crank chamber 6 Shaft 11 Cylinder bore formation part 14 Cylinder bore 15 Piston 16 Swash plate 19 Shoe 30 Head 40 Anchoring part 50 Shell formation part 51 Piston guide part 51a Circular-arc internal peripheral surface 55 Piston guide process scheduled recessed part A Sign of curvature Curved surface with negative curvature (curved surface with negative curvature)
B plane (tapered surface)

Claims (5)

A cylinder bore forming portion formed with a plurality of cylinder bores;
A cylinder block having a cylindrical shell forming portion provided so as to extend from one end side in the axial direction of the cylinder bore forming portion;
A shaft rotatably supported at the center of the cylinder bore forming portion;
A swash plate that rotates as the shaft rotates;
A piston coupled to the swash plate via a pair of shoes and reciprocally sliding in the cylinder bore as the swash plate rotates,
The piston has a head portion that slides in the cylinder bore and an anchoring portion that supports the pair of shoes so as to be capable of rolling, and the anchoring portion has the same core and the same radius of curvature as the head portion. It is configured to have an arc outer peripheral surface,
On the inner peripheral surface of the shell forming portion, a piston guide portion having an arc inner peripheral surface that is concentric with and has the same radius of curvature as the cylinder bore is formed so as to extend from the end of the cylinder bore,
A swash plate compressor in which an arc outer peripheral surface of the mooring portion of the piston is in sliding contact with an arc inner peripheral surface of the piston guide portion,
A swash plate compressor characterized in that edge relaxation means for increasing the angle of an edge formed here is formed at a location where the inner circumferential surface of the arc of the piston guide portion intersects with the inner wall surface of the shell forming portion. . The cylinder block material is molded by casting,
The inner circumferential surface of the arc of the piston guide part is formed by cutting the casting material of the cylinder block,
2. The swash plate compressor according to claim 1, wherein the edge relaxation means is formed of a casting material surface.   The edge mitigating means, in the casting material surface of the shell forming part before cutting the piston guide part, in the prospective location that intersects the inner wall surface of the shell forming part when processing the piston guide part, The swash plate compressor according to claim 2, wherein a curved surface having a negative curvature is formed with respect to an inner circumferential surface of the arc of the piston guide portion.   The edge mitigating means, in the casting material surface of the shell forming part before cutting the piston guide part, in the prospective location that intersects the inner wall surface of the shell forming part when processing the piston guide part, 3. A swash plate compressor according to claim 2, wherein the swash plate compressor has a tapered surface.   5. The swash plate compressor is a fixed capacity single-head swash plate compressor in which the swash plate is fixed to the shaft at a predetermined inclination angle. The swash plate type compressor described in the above.

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