WO2008059784A1

WO2008059784A1 - Compressor

Info

Publication number: WO2008059784A1
Application number: PCT/JP2007/071896
Authority: WO
Inventors: Iwao Uchikado
Original assignee: Sanden Corporation
Priority date: 2006-11-15
Filing date: 2007-11-12
Publication date: 2008-05-22
Also published as: JP2008121633A

Abstract

A compressor characterized in that the connection part between a chamfered part on the piston top side and a piston cylindrical surface and the connection part between a chamfered part or a recess on the cylinder bore top side and a cylinder bore cylindrical surface are set in such a positional relation that they don't slidingly contact with each other in the axial and/or circumferential directions of a cylinder bore. Consequently, a piston coating can be prevented at a low cost from being peeled off without increasing the size of the compressor, whereby the durability of the compressor can be enhanced.

Description

Specification

Compressor

Technical field

[0001] The present invention relates to a compressor in which a piston is reciprocally inserted into a cylinder bore.

The present invention relates to a compressor capable of preventing peeling of a coating applied to a piston. Background art

For example, in a piston type compressor used for a vehicle air conditioner, in order to smoothly reciprocate a piston in a cylinder bore with little sliding resistance, for example, a “Teflon” (registered trademark) system is provided on the piston cylindrical surface. Apply coating, or apply Teflon coating to the cylindrical surface, and apply groove processing to one or more parts of the cylindrical surface to mount one or more Teflon piston rings for each piston. The structure to be known is known. Also, it has the same number of cylinder bores for reciprocating multiple pistons, and a semicircular recess (below chamfered part or suction valve stopper) at the top dead center side (top side) opening edge of each cylinder bore (below) A general structure in which a recess is formed is known.

[0003] In such a conventional ordinary structure, there is a problem that when the compressor is used under high pressure conditions, the coating on the piston cylindrical surface is easily peeled off. In particular, in the system using carbon dioxide refrigerant, the operating pressure is about 7 to 10 times higher than that of R134a refrigerant. Therefore, there is a problem that the coating on the piston cylindrical surface is easily peeled off due to sliding of the piston and cylinder bore. Since the piston and the cylinder bore are fitted with a predetermined talalas, and the piston slides in the cylinder bore while receiving side force during the refrigerant suction and compression process, the piston cylindrical surface is inclined with respect to the cylinder bore. In particular, the contact surface pressure increases at the chamfered corner on the top side, which is the end of the piston cylindrical surface, and the coating tends to peel off from this point. The peeling of the coating leads to a decrease in the durability of the entire compressor.

[0004] In addition, since the chamfered portion and the recess are provided at the top dead center side opening edge also on the cylinder bore side, the connecting portion between the chamfered portion and the recess and the cylindrical surface of the cylinder bore has an edge shape. There are many cases. Therefore, the piston chamfered portion slides on this part with high surface pressure. In addition, there is a problem that the coating is more easily peeled off.

[0005] In order to prevent such coating peeling, there are methods of increasing the coating film strength of the coating and increasing the oil film strength of the lubricating oil interposed between the coating and the cylinder bore. In addition, the cost of coating agents and lubricants increases. In addition, there is a method of increasing the fitting length between the piston and the cylinder bore, or a method of reducing the side force by reducing the swash plate inclination angle in the case of a swash plate compressor, for example. The direction causes a problem that the size is increased in the radial direction.

Disclosure of the invention

Problems to be solved by the invention

[0006] Accordingly, an object of the present invention is to prevent the peeling of the piston coating without increasing the size of the compressor by an inexpensive method, and to improve the durability of the compressor.

Means for solving the problem

[0007] In order to solve the above-described problem, a compressor according to the present invention includes a piston with respect to an axial direction and / or a circumferential direction of a cylinder bore of a compression mechanism in which a piston is inserted in a reciprocating motion within the cylinder bore. The top side chamfered portion and the piston cylindrical surface are connected to the top side chamfered portion of the cylinder bore or the connecting portion between the recess and the cylinder bore cylindrical surface. Consists of.

[0008] That is, in the conventional structure, as will be described later, a connecting portion (corner portion) between the chamfered portion on the piston top and the piston cylindrical surface, a top side chamfered portion or recess of the cylinder bore, and a cylinder bore cylindrical surface. The connecting portion (corner portion) is basically set to a positional relationship in which the piston reciprocates as the piston reciprocates. Therefore, especially when high pressure acts on the piston or when the piston is reciprocated with the piston tilted, a high surface pressure may be applied locally to the coating surface of the piston, and the coating may peel off from this portion. It was easy. On the other hand, in the present invention, since the sliding relationship between the connecting portions composed of such corners is set so as not to occur, high surface pressure at the corners at which the coating peeling starts is not generated. . When the starting point disappears, inevitably, the coating will not easily peel off, and the occurrence of this will be prevented, thereby improving the durability of the compressor.

Yes [0009] The positional relationship can be set with respect to the axial direction or the circumferential direction of the cylinder bore, or with respect to both the axial direction and the circumferential direction. As for the axial direction of the cylinder bore, for example, at the position where the piston is at the top dead center, the connection force between the chamfered portion on the piston top side and the piston cylindrical surface, and the connection between the top side chamfered portion of the cylinder bore and the cylinder bore cylindrical surface It can comprise so that it may be located in the bottom dead center side rather than a part. Alternatively, at the position where the piston is at the top dead center, the connecting portion between the chamfered portion on the piston top side and the piston cylindrical surface is provided with a recess and a cylinder bore cylinder provided on the top side of the cylinder bore to regulate the stroke of the intake valve. Can be configured to be located on the bottom dead center side of the connection with the surface

[0010] With this configuration, the two connecting portions do not come into a position where they are in sliding contact with each other in the axial direction of the cylinder bore. That is, even if the piston reaches top dead center, the chamfered portion on the piston top side and the piston cylinder The connection part with the surface does not reach the connection part between the top side chamfered part of the cylinder bore and the cylinder bore cylindrical surface, or the connection part between the recess and the cylinder bore cylindrical surface. What happens is that the starting point of the coating peeling due to the sliding contact between the corners does not occur, and the coating peeling is surely prevented.

Further, regarding the circumferential direction of the cylinder bore, for example, with respect to a piston inclined with respect to the cylinder bore by a side force acting on the piston, the connecting portion between the chamfered portion on the piston top side and the piston cylindrical surface is connected to the cylinder bore by the inclination of the piston. Cylindrical bore circumferential position that is in strong sliding contact with the cylinder bore (for example, in the case of a swash plate compressor, if it has a piston with a bridge portion that straddles the outer periphery of the swash plate, the cylinder bore circumferential position in the same direction as the bridge portion) Is provided with a recess formed on the top side of the cylinder bore to restrict the stroke of the intake valve at a circumferential position approximately opposite to the axial center of the cylinder bore. A connecting portion of the cylindrical surface, a recess of the cylinder bore, and a connecting portion of the cylinder bore cylindrical surface, It can be configured to be set in a positional relationship not in sliding contact with one another by streams Aransu set between the piston and the cylinder bore. Alternatively, with respect to the piston tilted with respect to the cylinder bore by the side force acting on the piston, the cylinder bore circumferential position where the connection portion between the chamfered portion on the piston top side and the piston cylindrical surface strongly contacts the cylinder bore due to the tilt of the piston is the cylinder bore circumferential position. In the axis By providing a passage for the compressed fluid that can communicate with the inside of the cylinder bore at a circumferential position approximately opposite to the center, the chamfered portion on the piston top side, the connecting portion of the piston cylindrical surface, and the compressed fluid The connection portion between the passage and the cylinder bore cylindrical surface is set between the piston and the cylinder bore! In this structure, a part of the inner peripheral surface of the compressed fluid passage may be formed at the same position as the cylinder bore forming surface, and in this case, the inner periphery of the compressed fluid passage having different curvatures may be used. In many cases, a step is formed at a site where the surface and the cylinder bore forming surface are separated from each other!

[0012] With this configuration, the two connecting portions are prevented from sliding against each other in the circumferential direction of the cylinder bore, and a clearance exists between the two connecting portions due to the inclination of the piston. Therefore, at this circumferential position, the connecting portion between the chamfered portion on the piston top side and the piston cylindrical surface is connected to the connecting portion between the recess on the cylinder bore side and the cylinder bore cylindrical surface, or the passage installation portion of the fluid to be compressed. There is no sliding contact with the step that may be formed, and the starting point of the coating peeling due to the sliding contact between the corner portions does not occur, and the coating peeling is surely prevented.

[0013] The structure of the compressor according to the present invention is suitable for a compressor for a vehicle air conditioner that requires high durability. In particular, the compressed fluid is a carbon dioxide refrigerant. In this case, it is suitable. The type of the compressor is not particularly limited, and the present invention can be applied to any compressor having a piston and a cylinder bore. The invention's effect

As described above, according to the compressor of the present invention, the connecting portion between the piston top side chamfered portion and the cylindrical surface, and the chamfered portion of the cylinder bore and the connecting portion between the recess and the cylinder bore cylindrical surface are slid. Since there is no contact, coating peeling can be reliably prevented. In addition, since the piston itself can be manufactured by the same process as before, it is possible to improve the durability of the piston and thus the compressor at low cost.

[0015] Further, since the peeling can be prevented without reinforcing the coating agent or the lubricating oil, the durability can be improved at a low cost. Furthermore, there is no need to increase the piston fitting length (in the axial direction) or decrease the swash plate inclination angle (increase in radial direction). An increase in size of the compressor can be prevented while preventing peeling.

Brief Description of Drawings

FIG. 1 is a longitudinal sectional view of a conventional compressor.

2 is a schematic cross-sectional view of the compressor in FIG. 1 as viewed from the cylinder head side.

3 is an enlarged partial sectional view of the compressor of FIG.

FIG. 4 is a partial cross-sectional view of the compressor according to Embodiment 1 of the present invention.

FIG. 5 is a longitudinal sectional view of a compressor according to Embodiment 2 of the present invention.

6 is a schematic cross-sectional view of the compressor of FIG. 5 as viewed from the cylinder head side.

FIG. 7 is an enlarged partial cross-sectional view of the compressor of FIG.

FIG. 8 is an enlarged partial cross-sectional view showing another part of the compressor of FIG.

Explanation of symbols

[0017] 1 Compressor

2 Drive shaft

5 Swash plate

6 Piston

7 Cylinder block

8 Cylinder bore

9 No, ~ '

10 Bridge section

11 To cylinder

12 Suction chamber

13 Valve plate

14 Suction hole

15 Discharge hole

16 Discharge chamber

17 Suction valve

18 Recess

19 Discharge valve Discharge valve retainer

Piston phosphorus

Piston tos

Connection

Cylinder bore 'top side chamfer Cylinder bore cylindrical surface

28 connections

Piston

Piston top '° side chamfer Piston cylindrical surface

Connection

Compressor

Cylinder head K

Suction chamber

Discharge chamber

Valve plate

Suction hole

Discharge hole

Intake valve

Discharge valve

Recess

Discharge valve retainer

Piston

Piston tough '° side chamfer

Piston cylindrical surface

Connection

Recess and connection between the cylinder and the cylindrical surface of the dowel bore BEST MODE FOR CARRYING OUT THE INVENTION

[0018] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

First, in order to clarify the effects of the present invention, the conventional structure and its problems will be specifically described. 1 to 3 show a conventional structure, and FIG. 1 illustrates the case of a swash plate compressor. In FIG. 1, 1 indicates the entire swash plate compressor. The compressor 1 is integrated with the drive shaft 2 so that the tilt angle can be varied by the drive shaft 2 via the rotor 3 and the hinge mechanism 4. It has a swash plate 5 that is rotated. Each piston 6 is inserted into a corresponding cylinder bore 8 formed in the cylinder block 7 so as to be reciprocally movable, and the rotational movement of the swash plate 5 is slidably contacted with the swash plate 5. It is converted into the reciprocating motion of the piston 6 through 9 and the bridge portion 10 of the piston 6 holding it. As the piston 6 reciprocates, a fluid to be compressed (for example, carbon dioxide refrigerant) from the suction chamber 12 formed in the cylinder head 11 passes through the suction hole 14 formed in the valve plate 13 and enters the cylinder bore 8. Compressed fluid (for example, high-pressure compressed gas) compressed in the cylinder bore 8 is discharged into a discharge chamber 16 formed in the cylinder head 11 through a discharge hole 15 formed in the valve plate 13, It is discharged from there. A suction valve 17 is provided on the cylinder bore 8 side of the suction hole 14, and a recess 18 is formed on the top side (piston top dead center side) of the cylinder bore 8 to restrict the stroke of the suction valve 17. A discharge valve 19 is provided on the discharge chamber 16 side of the discharge hole 15, and the stroke of the discharge valve 19 is regulated by a discharge valve retainer 20. In this example, the piston 6 is provided with a plurality of piston rings 21. The arrangement of each part viewed from the cylinder head 11 side of the compressor 1 is as shown in FIG.

In the conventional compressor 1 having such a configuration, the positional relationship of the respective parts at the top dead center position of the piston 6 is as shown in FIG. A chamfered portion 22 is formed on the top side of the piston 6, and a connecting portion 24 is formed between the chamfered portion 22 and the piston cylindrical surface 23. A chamfered portion 25 is also formed on the top side (piston top dead center side) of the cylinder bore 8, and a connecting portion 27 is formed between the chamfered portion 25 and the cylinder bore cylindrical surface 26. Further, a connecting portion 28 between the recess 18 and the cylinder bore cylindrical surface 26 is formed. These connecting portions 27 and 28, particularly the connecting portion 28 in the illustrated example, form a relatively sharp corner. [0020] When the piston 6 is reciprocated so that the connecting portion 24 on the piston 6 side and the connecting portion on the cylinder bore 8 side (the connecting portion 28 in the illustrated example) are in sliding contact with each other, the connection is established. The sliding contact between the parts (that is, the corners) forms the starting point of the coating peeling as described above, and the coating peeling easily occurs. In particular, the top side of the piston 6 receives a side force, and as shown in FIG. When the piston 6 is reciprocated in such a state, the connecting portion 24 of the piston 6 crosses the connecting portion 28 of the cylinder bore 8 until the piston 6 reaches the top dead center. The edges of the slidably contact each other, and the coating on the piston 6 side is easily peeled off.

Therefore, the following configuration is adopted in the present invention. FIG. 4 shows a configuration according to Embodiment 1 of the present invention. In the present invention, the piston is inserted into the cylinder bore so as to be reciprocally movable! /, The connection between the chamfered portion on the piston top side and the piston cylindrical surface in the axial direction and / or circumferential direction of the cylinder bore of the compression mechanism. 4 and the top side chamfer of the cylinder bore or the connection portion between the recess and the cylinder bore cylindrical surface are set in a positional relationship in which they do not slide on each other. It is set in a positional relationship where the chamfered portion 32 and the piston cylindrical surface 33 are connected to the connecting portion 34 and the top side chamfered portion 25 of the cylinder bore 8 or the connecting portions 27 and 28 of the recess 18 and the cylinder bore cylindrical surface 26 are not in sliding contact with each other. ing. In particular, in this embodiment, at the top dead center position of the piston 31, the connecting portion 34 on the piston 31 side is arranged closer to the piston bottom dead center side than the connecting portion 28 between the recess 18 and the cylinder bore cylindrical surface 26. The positional relationship between the two is set. Such a positional relationship can be easily set by forming the chamfered portion 32 on the top side of the piston 31 longer in the axial direction than in the structure shown in FIG.

[0022] In the structure according to the first embodiment, the chamfered portion 32 on the top side of the piston 31 and the piston cylindrical surface

The connecting part 34 to 33 is a piston more than the connecting part 28 of the top side chamfer 25 or recess 18 of the cylinder bore 8 and the connecting part 27 and 28 of the cylinder bore cylindrical surface 26, in particular the recess 18 and the cylindrical bore cylindrical surface 26. Because it is provided on the bottom dead center side, even if the piston 31 is reciprocated to its top dead center, the edges of these connection parts 34 and 28 do not slide against each other. Is prevented. By preventing the coating from peeling off, the durability of the piston 31, and thus the compressor, is improved. In this embodiment, the piston 31 The present invention can be implemented simply by forming the chamfered portion 32 on the top side of the shaft longer in the axial direction, and the piston can be manufactured by substantially the same process as the conventional one, making the present invention extremely inexpensive. It can be implemented. In addition, as described above, the present invention can be implemented at low cost from the viewpoint of preventing peeling without strengthening the coating agent or lubricating oil. Furthermore, since it is not necessary to substantially change the size of the piston, it is possible to prevent the coating from peeling off and to increase the size of the compressor.

5 and 6 show the structure of the compressor according to Embodiment 2 of the present invention. In this embodiment, the avoidance of sliding contact between the connecting portions is mainly arranged in the circumferential direction of the cylinder bore. It has been achieved. As shown in FIGS. 5 and 6, compared to the conventional configuration shown in FIGS. 1 and 2, a suction chamber 43 is formed in the center of the cylinder head 42 of the compressor 41, and a discharge chamber 44 is formed on the outer peripheral side. Correspondingly, a suction hole 46, a discharge hole 47, and a suction valve 48, a discharge valve 49, a recess 50, and a discharge valve retainer 51 are arranged in the valve plate 45 so as to correspond to the suction hole 46 and the discharge hole 47. . In particular, the position of the recess 50 is set at a position opposite to the axial center of the cylinder bore as compared with the conventional configuration shown in FIGS. Parts having the same configurations as those in FIGS. 1 and 2 are denoted by the same reference numerals as those in FIGS. 1 and 2, and description thereof is omitted.

Also in the structure according to the second embodiment configured in this way, as shown in FIG. 7, at the top dead center position of the piston 61, the chamfered portion 62 on the top side of the piston 61 and the piston cylindrical surface 63 The connecting portion 64 is provided closer to the piston bottom dead center than the connecting portion 27 between the top side chamfer 25 of the cylinder bore 8 and the cylinder bore cylindrical surface 26. Therefore, even if the piston 61 is reciprocated to the top dead center, the peeling of the coating on the piston 61 side that prevents the edges of these connecting portions 64 and 27 from slidingly contacting each other is appropriately prevented. Further, as shown in FIG. 8, the recess 50 is provided on the side opposite to the direction in contact with the cylinder bore 8 when the piston 61 is tilted by the side force, so that the recess 50 is provided between the piston 61 and the cylinder bore 8. Because of this clearance, the connecting portion 64 on the piston 61 side does not slide on the connecting portion 65 between the recess 50 and the cylinder bore cylindrical surface 26 even on this side. Therefore, peeling of the coating on the piston 61 side due to sliding contact between the edges of these connection portions 64 and 65 is also appropriately prevented. By preventing the coating from peeling off, the durability of the piston 61 and thus the compressor is improved. Industrial applicability

The structure of the compressor according to the present invention can be applied to any compressor having a piston and a cylinder bore, and is a compressor for a vehicle air conditioner that requires particularly high durability, particularly, a dioxide used at high pressure. This is suitable for a compressor using a carbon refrigerant.

Claims

The scope of the claims

[1] With respect to the axial direction and / or circumferential direction of the cylinder bore of the compression mechanism in which the piston is reciprocally inserted into the cylinder bore, the connecting portion between the chamfered portion on the piston top side and the piston cylindrical surface, and the top of the cylinder bore The compressor is characterized in that the side chamfered portion or the connecting portion between the recess and the cylinder bore cylindrical surface is not in sliding contact with each other!

[2] At the position where the piston is at the top dead center, the connecting portion between the chamfered portion on the piston top side and the piston cylindrical surface is closer to the bottom dead center side than the connecting portion between the top side chamfered portion of the cylinder bore and the cylinder bore cylindrical surface. The compressor of claim 1, wherein the compressor is located.

[3] At the position where the piston is at the top dead center, the connecting portion between the chamfered portion on the piston top side and the piston cylindrical surface is provided with a recess and a cylinder bore provided on the top side of the cylinder bore to restrict the stroke of the intake valve. The compressor according to claim 1, wherein the compressor is located on a bottom dead center side with respect to a connection portion with the cylindrical surface.

[4] With regard to the piston tilted with respect to the cylinder bore by the side force acting on the piston, the cylinder bore circumferential position where the connecting portion between the chamfered portion on the piston top side and the piston cylindrical surface strongly contacts the cylinder bore due to the tilt of the piston is the cylinder bore A recess formed on the top side of the cylinder bore to restrict the stroke of the intake valve is provided at a circumferential position approximately opposite to the axial center of the piston, so that the chamfered portion on the piston top side and the piston cylindrical surface The connecting portion of the cylinder bore and the connecting portion of the cylinder bore recess and the cylinder bore cylindrical surface are set to a positional relationship that does not slide against each other by a clearance set between the piston and the cylinder bore. The compressor according to 1.

[5] With regard to the piston tilted with respect to the cylinder bore by the side force acting on the piston, the cylinder bore circumferential position where the connecting portion between the chamfered portion on the piston top side and the cylindrical surface of the piston strongly slides on the cylinder bore due to the tilt of the piston is the cylinder bore By providing a passage for the compressed fluid that can communicate with the inside of the cylinder bore at a circumferential position substantially opposite to the center of the shaft, the chamfered portion on the piston top side, the connecting portion of the piston cylindrical surface, and the compressed portion The connection between the fluid passage and the cylindrical surface of the cylinder bore is set between the piston and the cylinder bore! In item 1 The compressor described.

The compressor according to claim 1, comprising a compressor for a vehicle air conditioner.

The compressor according to claim 1, wherein the fluid to be compressed is made of a carbon dioxide refrigerant.