Patent Application
20140196683
1. Field
The described technology generally relates to a compressor with a pressure chamber which is separated by at least two housing parts, more particularly, a compressor for use in an air conditioning of a motor vehicle.
2. Description of the Related Technology
Compressors of this type are known. Its pressure chamber is delimited by at least two housing parts, which are connected by a connection device which applies a contact pressure force between the sealing surfaces.
DE 102 31 211 A1 discloses such a compressor, where several housing parts forming the pressure chamber are screwed together. Screwing of the housing parts is a simple and cost effective way of connecting the housing parts on which the pressure is applied on. However, the above compressors are often constructed in such a way that high internal pressures are applied on in operation or in the case of a malfunction requiring an extensive and a space consuming configuration of the screw connections for connecting the housing parts to exclude a potential unwanted detachment of a housing part.
EP 1 297 256 B1 discloses a safety device for compressor, which can avoid pressures overstraining the strength of the connection between the housing parts. However, this safety device requires the installation of additional components in the compressor and thus entails an increase of the required installation space and weight.
In the DE 198 07 691 A1 a compressor with an at least two part housing for an air conditioning of a motor vehicle is disclosed, which has a sealing device that is inserted into the face of a second housing part.
One inventive aspect is an improved compressor.
Another aspect is a compressor comprising a pressure chamber which is delimited by at least two housing parts and, for example, it is intended for or suitable for use in an air conditioning of a motor vehicle. The housing parts have sealing surfaces, which are connected by a connecting device which applies a contact pressure force between the sealing surfaces. On at least one sealing surface of the at least one housing part is arranged a groove extending in the circumferential direction. In addition, at least one vent opening is arranged on the at least one housing part, which connects this groove with the environment of the housing, wherein the at least one vent opening extends from the groove extending in circumferential direction, and wherein the groove is arranged in such a way that on exceeding a predetermined pressure in the pressure chamber the pressurization medium, for example, a refrigerant, accumulates in the groove and can at least partly escape through the vent opening.
Another aspect is a compressor for use in an air conditioning of a motor vehicle, for example, an electric or hybrid powered vehicle. The compressor can also be applied for air conditioning in a vehicle with an internal combustion engine. Furthermore, the compressor can also be applied for air conditioning systems for stationary applications, for example, buildings, or for pressurized casings used for other applications.
To avoid pressure forces acting radially outward on a thinner walled area, this sealing device has a groove into which a seal ring is inserted. By the safety device it is ensured that the pressure in the pressure chamber cannot reach the thinner walled area. For safety, a relief opening is provided in this wall area, via which the refrigerant being at the second wall area can be discharged into the environment.
A typical compressor has no vent opening arranged in the groove extending in the circumferential direction, but it has only a vent opening, which is spaced apart from the groove. For the compressor according to some embodiments, the vent opening extends directly from the groove extending in the circumferential direction, so that in the whole groove extending in the circumferential direction there the pressure is substantially the pressure of the environment of the compressor.
The compressor can include a device by which a refrigerant for an air conditioning system, for example, a motor vehicle can be compressed—thus can be condensed. Such a compressor, also called half hermetic, can have a rotor device, which is driven by a shaft to compress the refrigerant. The shaft can be arranged completely inside the housing of the compressor. The rotor device is arranged in the housing of the compressor, which has several housing parts, for example, at least a housing pot and a housing cover. These housing parts delimit the pressure chamber of the compressor. For that purpose, the sealing surfaces are arranged on those areas of the housing parts, which are in contact to each other and which by a connection device apply a sufficiently high pressure to each other to delimit at normal operating pressure the pressure chamber against the environment of the compressor. The sealing surfaces can be planar.
The pressure chamber can have a volume delimited by the housing parts within which a rotor device of the compressor is arranged. The pressurization in the pressure chamber is done by compression of a pressurization medium, for example, of the refrigerant of the compressor, by the rotor device of the compressor.
The housing parts can include parts, which form in its entirety the housing of the compressor, which delimits the pressure chamber against the environment, for example, in regard to a transmission of a refrigerant. In some embodiments, the compressor housing comprises two or more housing parts. The boundary surfaces of the separate housing parts have sealing surfaces against each other.
The sealing surface of a housing part can include a surface of the housing part, which is adjacent to a corresponding sealing surface of another housing part in such a way that a sufficiently high contact pressure force between the two sealing surfaces can be applied when connecting the two sealing surfaces by a connecting device, and that up to reaching a predetermined maximum pressure due to, for example, the construction of the compressor it is prevented that the pressurization medium in the pressure chamber, for example, the refrigerant escapes.
The connecting device can include a device by which a contact pressure force between the sealing surfaces of the housing parts of the compressor can be applied. In some embodiments, a connecting device has several connecting elements, which apply the contact pressure force between the sealing surfaces. A pressurization housing having housing parts, which are connected by detachable connection elements is referred to as a half-hermetic housing.
The contact pressure force between the sealing surfaces of the housing parts can include a force which counteracts the mutual removal of separate housing parts from each other under the influence of the pressurization medium in the pressure chamber. The surface pressure resulting from the contact pressure force applied by the connecting device in a sealing surface of the compressor can be more than twice as large as the force acting against this surface pressure, wherein that force is generated by applying the maximum operating pressure between the connected housing parts. The contact pressure force also causes that the pressurization medium, for example, the refrigerant cannot escape between the housing parts.
The maximum pressure in the pressure chamber of the compressor can be the pressure for which, on its application in the pressure chamber, the connecting device can barely secure a sufficient contact pressure force between the sealing surfaces of the housing parts, with a predetermined safety, for example, a reserve of the contact pressure force. This can counteract the forces acting to release the connection between the sealing surfaces and which are transmitted by the maximum pressure and in this way to prevent the pressurization medium, for example, the refrigerant from escaping upon reaching the maximum pressure.
The groove extending in the circumferential direction in the sealing surface of the housing part can include a groove excluding a volume which extends from the sealing surface, for example, from the level of the sealing surface into the housing part allocated with the sealing surface, wherein the surface area the groove extending into extends in the circumferential direction between an inner edge contour closing the sealing surface and an outer edge contour closing the sealing surface. The groove is constructed in such a way that the pressurization medium can be collected in the groove when on exceeding the maximum pressure the pressurization medium escapes from the pressure chamber and that at least partially it can escape through a vent opening. The diameter of the groove can be constructed in such a way that at the maximum operating pressure the housing parts are not diverged up to the groove.
The vent opening can include an opening which connects the groove extending in the circumferential direction to the environment of the compressor. The vent opening is constructed as a channel which can guide the pressurization medium and which has been excluded for relieving pressure from the housing parts or connecting device or it is constructed as a volume which has been already arranged in recesses for passing through of elements of the connecting device. The vent opening, for example, the radial inner end thereof extends from the groove extending in the circumferential direction. The term “extends” can mean that the vent opening is not spaced apart from the groove, for example, one of the channel or recesses of the vent opening.
The environment of the housing can include an area on which is applied substantially atmospheric pressure, for example, an area which is characterized by the normal ambient conditions in the installation room of air conditioning, especially in a motor vehicle.
Under application of a pressure, for example, under an application of a pressure close to the maximum pressure, the connecting elements of the connecting device of the compressor may expand, whereupon a gap may arise at the sealing surfaces facing the pressure chamber. As long as the pressure does not exceed the maximum pressure, the whole pressurization medium will remain in the pressure chamber. On reaching the maximum pressure, the pressurized parts of the housing parts of the sealing surfaces will become larger by the diverging of the housing parts and therefore the force counteracting to the contact pressure force of the connecting device rises.
In some embodiments, in order to limit the pressurized area to a defined extent, the groove extending in the circumferential direction is arranged in at least one sealing surface of one housing part and be brought into contact with the environment of the compressor through a vent opening, so that a pressure relief can take place, once the housing parts at their sealing surfaces diverge to the position of the groove.
In some embodiments, the connecting device has several connecting elements. These connecting elements can protrude through recesses in the sealing surfaces of the housing parts to be connected. The center points of these recesses can be arranged in substantially equidistant from the edge contour of the sealing surface, which is facing the pressure chamber.
The connection elements can include elements by which a contact pressure force between the sealing surfaces of different housing parts can be applied. In some embodiments, the connection elements are constructed as screws or bolts and protrude through recesses, which are arranged in the sealing surfaces of the housing parts to be connected. In some embodiments, the connection elements are constructed as brackets, which are attached to designated and, for example, constructed coupling areas of the housing parts to be connected on the side facing the environment. To apply the necessary contact pressure force, these brackets can be constructed with corresponding spring properties.
The recesses in the sealing surfaces of the housing parts to be connected can include recesses, which extend from the surface of the sealing surface or through the housing part. In some embodiments, these recesses are constructed as grooves or holes are, for example, through-holes or blind holes. In the case of using screws as connecting elements, the recesses may exhibit also an internal thread, which is suitable for screwing with a screw. In the case of using of bolts as connecting elements, the recesses may exhibit also fits, which are suitable to dowel the recess with the bolt used.
In some embodiments, the groove extending in the circumferential direction has a constantly larger distance or a constantly smaller distance or a constantly substantially identical distance or a variable distance to the inside of the housing in regard the recesses and, for example, in regard to the center points.
In some embodiments, the vent opening is formed by at least a relieving channel in at least one of the sealing surfaces, wherein relieving channel extends from the groove extending in the circumferential direction to the environment of the compressor.
The relieving channel can include a channel which extends from the groove extending in the circumferential direction in a sealing surface and which can discharge a medium from the pressure chamber, for example, a refrigerant from the groove extending in the circumferential direction directly or indirectly on the environment. For example, a discharge is provided from the groove extending in the circumferential direction through the relieving channel to one or more further relieving channels, to a recess for the connecting element, or to further volumes connected with the environment or directly into the environment of the compressor.
In some embodiments, the vent opening is formed by a relieving channel in at least one of the sealing surfaces, wherein the relieving channel extends from the groove extending in the circumferential direction to the recess for the connecting element.
In some embodiments, at least one of the connection elements is constructed and arranged in such a way that the medium which has been accumulated in the groove extending in the circumferential direction can escape into the environment of the compressor. For a configuration of the connecting device as a screwing connection, the medium can escape through a connecting passage recess in at least one housing part and that a groove is provided, for example, in the direction of the screw head. When using a pass connection, however, the medium escapes through the groove in at least one of the bolts used for doweling or in at least one of the recesses of the housing part which has been doweled with bolts.
In some embodiments, the vent opening has at least one relieving channel, which extends from least one of the recesses for the connecting elements, for example, through holes of at least one of the housing parts to the environment of the compressor. For example, such a relieving channel is provided if the groove extending in the circumferential direction is spaced substantially identical to the inside of the housing as to the corresponding through hole wherein the groove leads to at least one through hole.
In some embodiments, at least one sealing element is arranged in the groove extending in the circumferential direction. The groove can be arranged near to the pressure chamber of the compressor.
The sealing element can include an element, which is provided in the case of entering of the pressurization medium in the groove extending in the circumferential direction up to a predetermined maximum pressure for preventing a discharge of the pressurization medium, for example, a refrigerant, a CO2 containing refrigerant or CO2.
Exemplary embodiments can be seen from the following description in connection with the figures.
a illustrates the radial pressure gradient in the sealing surface between two housing parts of the typical compressor at operating pressure.
b illustrates the radial pressure gradient in the sealing surface between two housing parts of the typical compressor at maximum pressure.
c illustrates the radial pressure gradients in the sealing surface between two housing parts of the compressor at the operating pressure and at the maximum pressure according to some embodiments.
a shows a radial pressure gradient in the sealing surface between the two housing parts of the typical compressor 10 at operating pressure. The sealing surface 135 of the housing cover 30 and the sealing surface 125 of the housing 20 rest on one another at the operating pressure. The radial pressure gradient in the sealing surface at the operating pressure GBS decreases over the entire sealing surface radially from the inside to the outside, wherein on the radially inner edge of the sealing surfaces of the full operating pressure is applied in the pressure chamber 12, and on the outer radial edge of the sealing surfaces the ambient pressure of the environment 11 is applied.
b shows the radial pressure gradient in the sealing surface between two housing parts of the typical compressor 10 for maximum pressure. When the maximum pressure is applied on the pressure chamber 13 of the compressor 10, the sealing surface 135 of the housing cover 30 and the sealing surface 125 of the housing 20 diverge with an acute angle, whereby the gap 31 is formed. As a result, in a radial area of the sealing surfaces from the inner edge of the radial sealing surface 125 and 135 near to the outer edge of the sealing surfaces, the full maximum pressure is applied on pressure chamber 13 at the sealing surfaces. Only in the outer radial edge of the sealing surfaces up to the outer edge of the sealing surfaces, the radial pressure gradient GHS in the sealing surface at the maximum pressure shows an idealized linearly decreasing curve up to the environment 11 of the compressor 10 under ambient pressure.
c shows the radial pressure gradients in the sealing surfaces 25 and 35 between two housing parts 20 and 30 of the compressor according to some embodiments for the operating pressure and for the maximum pressure 10. In the configuration shown here, the sealing surface 25 of the housing 20 and the sealing surface 35 of the housing cover have each a groove 40a and 40b, respectively extending in circumferential direction. The radial pressure gradients in the sealing surface at the operating pressure GBE and at the maximum pressure GHE are in contrast to the corresponding pressure gradients for the typical compressor limited radially on the range between the inner edge radial of the sealing surfaces and the radial position of the grooves 40a and 40b. Concerning the radial extension of the sealing surfaces, the ambient pressure of the environment 11 is applied to from the radial position of the grooves 40a and 40b.
According to at least one of the disclosed embodiments, the maximum pressure can be predetermined by a relatively simple safety device, against which the connecting device applies a contact pressure force between the housing parts. Thus, under the same conditions, it is possible to have a connecting device with smaller dimension compared to the conventional compressors resulting in cost and space benefits.
Furthermore, the axial compression force between two housing parts can be limited, the axial compression force being in relation to the longitudinal axis of the compressor, compared to conventional technology such as in DE 198 07 691 A1 where only a radial force can be avoided. This limitation of the axial compression force allows, for example, a smaller dimensioning of the connecting device between the housing parts without that inside of the compressor the contact force falls below the minimum contact pressure between the housing parts necessary to maintain the pressure chamber.
In addition, the groove extending in the circumferential direction, for example, does not need to have a sealing function and that it therefore can be configured in regard to its function of a pressure reduction.
While the above description has pointed out features of various embodiments, the skilled person will understand that various omissions, substitutions, and changes in the form and details of the device or process illustrated may be made without departing from the scope of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2011 114 904.3 | Oct 2011 | DE | national |
This application is a continuation application, and claims the benefit under 35 U.S.C. §§120 and 365 of PCT Application No. PCT/EP2012/004039, filed on Sep. 26, 2012, which is hereby incorporated by reference. PCT/EP2012/004039 also claimed priority from German Patent Application No. DE 10 2011 114 904.3 filed on Oct. 5, 2011, which is hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/EP2012/004039 | Sep 2012 | US |
| Child | 14216781 | US |
