Compressor

The present invention relates to, for example, a compressor which is used in an air conditioning system for vehicles, etc., and specifically, to a structure for providing a muffler device on a suction passageway or a discharge passageway.

A multi-cylinder reciprocating compressor is known, for example, as a conventional compressor used in an air conditioning system for vehicles. Inside of a cylinder head of this compressor, for example, a discharge chamber at the central part and a schematic hollow ring-like suction chamber at the periphery part are provided by dividing the inside. The discharge chamber is communicated with a cylinder head discharge port and the suction chamber is communicated with a cylinder head suction port, respectively. After the compressor is driven, refrigerant gas, which is introduced from a circuit pipe connected with an evaporator into the suction chamber through the cylinder head suction port, pushes to open a suction valve (reed valve) when a piston present in a cylinder bore is in a suction stroke, and is sucked through each suction hole of a valve plate into the cylinder bore during the suction stroke, sequentially. Further, the suction valve is closed when a piston is in a compression stroke, and a discharge valve is pushed to be opened, the compressed refrigerant gas is discharged from each discharge hole of the valve plate into the discharge chamber sequentially, and the gas in the discharge chamber is finally discharged through the cylinder head discharge port into a circuit of an air conditioning system connected to a condenser.

Near the above-described cylinder head suction port or discharge port, in particular, near the suction port, a muffler device may be provided for reducing noises and vibrations. The muffler device is provided, for example, on the side of a cylinder block or a cylinder head (around the cylinder block or the cylinder head) so as to be formed integrally with the cylinder block and the cylinder head, and structured usually so that the muffler space is closed by an adaptor, etc. Alternatively, the muffler device is provided on the side of the cylinder block or the cylinder head to be formed integrally with the cylinder block or the cylinder head, the muffler space may be formed by assembling this cylinder block or cylinder head (Patent document 1 for example). A passageway for suction gas at the part where the muffler device is provided usually extends from the muffler device to an inlet of the cylinder head suction chamber in an axial direction of the compressor.

Patent document 1: JP-A-8-254181

A multi-cylinder reciprocating compressor often has a problem that a pulsation, which is caused specifically when the compressor sucks refrigerant gas, is transmitted to suction pipes of an air conditioning system via the suction port and vibrates them to make a noise. To prevent it, the muffler device may be provided near the suction port as described above. The suction gas passageway including this muffler device extends in an axial direction of the compressor.

In order to reduce the pulsation of the suction gas, it is necessary to design a muffler device in correspondence with the frequency of the pulsation being generated. However, in order to deal with a relatively low frequency suction pulsation, generally the overall length of the muffler device becomes relatively long. Further, the sectional area of the muffler space (inner space of the muffler device) generally has to be designed at a large size to enhance the effect for reducing the pulsation by the muffler device.

In a case where the muffler device is provided on the side of (around) the compressor, however, a muffler device having a high pulsation reduction performance often cannot be provided, because the axial length of the compressor enough to deal with this condition often cannot be employed. Further, when an adaptor is used for the muffler device, the number of parts and the cost may be increased.

Accordingly, an object of the present invention is to provide a compressor with a low-cost muffler device which can effectively attenuate and reduce the pulsation (in particular, suction pulsation) generated from the reciprocating compressor.

To achieve the above-described object, a compressor according to the present invention is a reciprocating compressor in which a plurality of cylinder bores are formed and a muffler device is provided, wherein an internal space of the muffler device is divided into at least two compartments by a partition wall, and to the partition wall, a cylindrical body which allows the two compartments to communicate with each other and has a length of 16 to 50% relative to the overall length of the internal space is provided (the first embodiment). In the first embodiment, although the partition wall typically divides the internal space into two compartments, division into three or more compartments is possible. Further, although the shape of the cylindrical body is typically a circular cylinder with a circular cross section, a cylinder with another cross section can be employed.

The muffler device in the first embodiment is applicable not only to a suction pulsation reduction but also to a discharge pulsation reduction, or to both of them.

In the first embodiment, the pulsation reduction is particularly effective in a condition where the length of the internal space of the muffler device and the length of the cylindrical body are both in specified ranges. Namely, it is preferable that the overall length of the internal space of the muffler device is in a range of 100 to 120 mm and the length of the cylindrical body is in a range of 20 to 50 mm.

Further, it is preferable that a wall of the muffler device is formed integrally with a cylinder head or a cylinder block, or both of the cylinder head and the cylinder block. Whereby, the number of parts can be reduced, the assembly can be simplified, and the cost can be reduced.

Further, it is preferable that the partition wall is formed by an elongated section of a valve plate interposed between a cylinder head and a cylinder block. Whereby, the number of parts can be more reduced by omitting an adaptor, etc. in the conventional structure, the assembly can be more simplified, and the cost can be more reduced.

Further, a compressor according to the present invention is a reciprocating compressor in which a plurality of cylinder bores are formed and a muffler device is provided, wherein a direction of gas flow in the muffler device is set at a circumferential direction of the compressor (the second embodiment). The purpose of the second embodiment is to ensure a length in the direction of gas flow required to perform a muffling function, in the circumferential direction of the compressor, and this embodiment is specifically effective in case where an enough length for the muffler device cannot be set in an axial direction of the compressor. Because the required length can be ensured relatively easily in the circumferential direction of the compressor, the muffler device with a target performance can be easily provided.

In the second embodiment, the muffler device may be provided around either a cylinder block or a cylinder head. It is preferably provided near the suction port in particular for reducing suction pulsation. Where, the muffler device in the second embodiment is applicable not only to the suction pulsation reduction but also the discharge pulsation reduction, or both of them.

In the second embodiment, an internal space of the muffler device can be formed by a wall which is formed integrally with a cylinder block and has an opening section at a cylinder head side and an elongated section of a valve plate interposed between the cylinder head and the cylinder block, the elongated section closing the opening section of the wall.

Alternatively, the internal space of the muffler device can be formed by a wall which is formed integrally with a cylinder head and has an opening section at a cylinder block side and an elongated section of a valve plate interposed between the cylinder head and the cylinder block, the elongated section closing the opening section of the wall. In any of the structures, the number of parts can be reduced by the integrated structure, the assembly can be simplified, and the cost can be reduced. Further, an adaptor, etc. in the conventional structure can be omitted by applying the structure where the elongated section of the valve plate closes the opening section, so that the number of parts can be more reduced, the assembly can be more simplified, and the cost can be more reduced.

Further in the second embodiment, the technical concept in the first embodiment can be developed in the second embodiment to improve a muffling function. Namely, a structure can be employed wherein the overall length in a direction of gas flow of an internal space of a muffler device is in a range of 100-120 mm, and the internal space can be divided into at least two compartments by a partition wall, and to the partition wall, a communication path communicating the two compartments with each other is provided. Also in the second embodiment, the partition wall typically divides the internal space into two compartments, but division into three or more compartments is possible.