Patent Description:
Encapsulated, especially hermetically sealed, refrigerant compressors have been known for a long time and are mainly used in refrigeration cabinets, such as refrigerators or refrigerated shelves, but can also be used in mobile appliances. The refrigerant process as such has also been known for a long time. Refrigerant is thereby heated by energy absorption from the space to be cooled in an evaporator and finally superheated and pumped to a higher pressure level using the refrigerant compressor having a cylinder and a reciprocating piston. At this higher pressure level the refrigerant is cooled via a condenser and is conveyed back into the evaporator via a throttle, via which throttle the pressure is reduced and the refrigerant is further cooled down, before the cycle starts anew.

The path of the (usually gaseous) refrigerant through the compressor can be described as follows:
The refrigerant enters a compressor shell of the refrigerant compressor, which compressor shell encapsulates a pump unit of the refrigerant compressor, through a suction pipe, which is in the operating state connected to the evaporator of the refrigerant appliance. During a suction cycle, the refrigerant is sucked through a suction muffler, a suction opening of a valve plate, which suction opening is released by a suction valve spring, into a cylinder of the pump unit of the refrigerant compressor. The suction is caused by linear movement of a piston inside the cylinder. During a compression part of a compression and discharge cycle, the refrigerant is compressed within the cylinder by the linear movement of the piston until a discharge valve spring releases a discharge opening of the valve plate. During a discharge part of the compression and discharge cycle, the so compressed refrigerant then flows through the discharge opening of the valve plate into a discharge muffler and leaves the compressor shell through a discharge pipe, which is connected to the discharge muffler by a discharge connection tube. The discharge tube is in the operating state connected to the condenser of the refrigerant appliance.

The pump unit comprises a cranktrain, which includes the piston and is causing the linear movement of the piston inside the cylinder, a crankcase, in which a crankshaft of the cranktrain is mounted, the crankcase also having a cylinder housing, an electric drive unit, which comprises a rotor and a stator, and a cylinder head assembly. The cylinder head assembly includes the valve plate, the suction valve spring, the discharge valve spring, the suction muffler and the discharge muffler. The pump unit is supported within the compressor shell on a plurality of support spring assemblies, preferably on four support spring assemblies.

The shell usually comprises a lower shell part and an upper shell part, which are welded together. The discharge pipe and the suction pipe as well as a maintenance pipe (also known as service pipe) are hermetically connected to the shell. As the refrigerant compressor is a stand-alone product, which is integrated into a refrigerant appliance at some stage of the assembly process, the discharge pipe, the suction pipe and the maintenance pipe are also called discharge connector, suction connector and maintenance connector as they are configured to be connected with respective elements with the refrigerant appliance during assembly and/or in the operation state.

The movement of the piston is caused by rotation of the crankshaft, wherein the piston is connected to a crank-pin of the crankshaft via a connecting rod. The electric drive unit is required to facilitate the rotation of the crankshaft, wherein the rotor is fixed to the crankshaft.

Usually an electronic control unit is mounted to an outside surface of the compressor shell, wherein the stator is connected to an electric pass through element (also known as "fusite") via an inner harness and the electronic control unit is connected to the electric pass through element via an outer harness. The electronic control unit powers the stator and thereby controls the rotational speed of the pump unit of the refrigerant compressor.

All members of the cylinder head assembly, in particular the valve plate, the suction valve spring and the discharge valve spring, have to withstand high levels of pulsation due to refrigerant pumping. These pulsations can propagate and excite other structural components of the refrigerant compressor, ultimately being translated to unwanted noise. Furthermore, the discharge side of the refrigerant compressor has to withstand high temperature and pressure levels. Therefore, the fixation of these members has to endure these conditions, wherein particular importance is attributed to the fixation of the suction valve spring and the discharge valve spring. It is known from prior art that both the suction valve spring and the discharge valve spring are attached to the valve plate by means of a plug-in connection. A disadvantage of this type of connection is that it is difficult to assemble since both springs tend to slip during assembly. However, a cylinder head assembly that is not assembled to fit accurately results in a lower efficiency of the refrigerant compressor.

<CIT> discloses a cylinder head assembly for a refrigerant compressor having a suction valve and a discharge valve, which are fixed to a valve plate. It further comprises a gasket, a muffler assembly with a suction/discharge part as well as a clamp and an elastic element, which press the cylinder head assembly against the cylinder. The suction valve and the discharge valve are configured as flat spring reed valves.

<CIT> discloses a cylinder head assembly for a refrigerant compressor with a muffler, two gaskets and a valve plate, on which valve plate a suction valve plate and an exhaust valve plate are welded. The suction valve plate and the exhaust valve are configured as flat spring reed valves.

<CIT> discloses cylinder head assembly with a valve seat, a gasket, a discharge reed valve configured as a flat spring reed valve and a suction valve plate. The suction valve plate is a rectangular piece of flat metal, which has a cut-out defining the reed valve section of the suction valve plate. The suction valve plate, the valve seat and the gasket are sandwiched between a front surface of a compressor cylinder block and a base plate of a cylinder head cover, which base plate clamps the cylinder head assembly against the cylinder block via four screws- The screws pass through holes in the base plate, the gasket, the valve seat and the suction valve plate.

It is therefore an object of the invention to provide a cylinder head assembly which overcomes the disadvantages of the prior art. In particular, the cylinder head assembly shall ensure a simple and safe installation and be economical to manufacture. Furthermore, the compressor should perform efficiently over long operation periods. Also the noise level of the compressor, caused by the cylinder head assembly, shall be as low as possible.

In order to achieve at least one of the objects set out above in a cylinder head assembly for an encapsulated refrigerant compressor comprising.

it is provided according to a first aspect of the invention that the suction valve spring is welded onto the suction side of the valve plate and the discharge valve spring is welded onto the discharge side of the valve plate.

The welded joint between the suction valve spring and the valve plate as well as between the discharge valve spring and the valve plate leads to a simple, yet robust, way to assemble these parts of the cylinder head assembly. Due to the welded joint, the suction valve spring and the discharge valve spring always cover the corresponding suction and discharge opening of the valve plate with a perfect fit, even after operations over a long period of time. even after a long period of operation, the compressor still works efficiently. Furthermore, in reducing the assembly-steps and assembly-time on the production line due to welding (the creation of the rather time-consuming plug-in connection is no longer necessary) costs can be avoided. In addition, weight savings due to the elimination of overlapping lugs, as well as no weakening of the springs due to connecting holes are also achieved by the arrangement according to the invention.

The valve plate can have corresponding indentations and / or grooves located below the suction valve spring and /or the discharge valve spring, which are configured such that a surface of both springs facing away from the valve plate lies in substantially the same plane as a surface of the valve plate. The indentations and / or grooves thus ensure.

In order to be able to position the suction valve spring better on the valve plate, in particular above the suction opening of the valve plate, it is provided according to the first aspect of the invention that the suction valve spring has a suction spring body,.

The suction spring body thus comprises three sections, namely.

As the suction spring body is a flexible metal disk, the different sections of the suction valve plate can be defined by a linear cut-out, i.e. a cut out that follows a straight and / or curved line. Due to the inherent flexibility of the metal disk, because of its material properties (e.g. its spring constant) and the thickness, the valve reed section is flexible in such a way that it opens and closes the suction opening of the valve plate while being hinged against the hinge section.

This design of the suction spring body provides a robust element that allows on the one hand an easy connection to the valve plate, while ensuring optimum opening and closing of the suction opening on the other hand.

In order to be able to arrange the suction spring body easily and precisely on the valve plate, it is provided in a further embodiment variant of the invention that an outer shape of the suction spring body corresponds to an outer shape of the valve plate at least in sections. the suction spring body and the valve plate can be arranged congruently at least in sections. Preferably all circular sections of the valve plate contour correspond with matching circular sections of the suction spring body.

In a further embodiment variant of the invention, it is provided that the suction reed valve section has a second cut-out, which second cut-out is located between a segment of the suction reed valve section positioned above the suction opening and the hinge section.

The use of the second cut-out results in a better flow pattern of the refrigerant in the area of the suction opening with significantly less turbulence, since in addition to the gap between the valve plate and the suction valve spring, which gap is created when the suction valve spring opens, there is another opening, namely the second cut-out, through which refrigerant can flow from the suction muffler into the cylinder.

To be able to easily arrange the valve plate and the suction valve spring relative to each other as well as to align them against each other, it is provided in a further embodiment variant of the invention that the valve plate has a first positioning protrusion, which first positioning protrusion protrudes from a circumferential surface of the valve plate and that the static mounting section has a second positioning protrusion, which second positioning protrusion of the suction valve spring is matching the first protrusion of the valve plate.

In order to be able to design the suction spring body in such a way that it can be easily aligned with the valve plate, while not hindering the flow of compressed refrigerant through the discharge opening of the valve plate, it is provided in a further embodiment variant of the invention that the suction spring body has a third cut-out for the discharge opening. This design of the suction spring body ensures that, despite the suction spring body being a flexible metal disk, it has a certain stability and allows a firm connection between the suction spring body and the valve plate as well as precise positioning.

In a further embodiment variant of the invention, it is provided that the first cut-out and the third cut-out are overlapping, which allows a cost-effective and simple production of the suction valve spring.

To be able to easily arrange the valve plate with respect to the cylinder as well as to align them against each other and at the same time to ensure a non-rotating mounting of the valve plate in a recess of the cylinder housing, it is provided in a further embodiment variant of the invention that the valve plate has at least one first positioning protrusion for aligning the valve plate with respect to a cylinder of the refrigerant compressor, wherein the at least one first positioning protrusion is configured to interact with a matching positioning recess of a valve plate seat of a cylinder housing of the refrigerant compressor.

Thus, it is conceivable that the first positioning protrusion of the valve plate interacts with two further elements of the cylinder head assembly of this invention, namely with the second positioning protrusion of the suction valve spring and with the recess of the cylinder housing, and, thereby, allows an easy assembly and relative positioning of these elements. To easily align the valve plate relative to the cylinder and ensure a centered position of the valve plate in a valve plate seat of the cylinder housing, it is provided in a further embodiment variant of the invention that
the valve plate has at least two centring protrusions for centring the valve plate in a valve plate seat of a cylinder housing of the refrigerant compressor, which at least two centring protrusions are located at a circumferential surface of the valve plate. the centring protrusions contact an inner circumferential surface of the valve plate seat located in the cylinder housing.

To ensure easy manufacturing of the valve plate and an increased centring effect, it is provided in a further embodiment variant of the invention that the valve plate has three centring protrusions, which are preferably evenly distributed around the circumference of the valve plate.

In a further embodiment variant of the invention, it is provided that the discharge valve spring is configured as a flat spring,.

In contrast to the suction valve spring, which consists of a disk shaped flexible metal disk, having an approximately circular outer contour, the discharge valve spring is smaller and has less material compared to the suction valve spring.

The discharge valve spring thus comprises two sections, namely.

This design of the discharge valve spring provides a robust element that allows on the one hand an easy connection to the valve plate while ensuring optimum opening and closing of the discharge opening.

To ensure safe operation of the discharge valve spring, it is provided in a further embodiment variant of the invention that the valve plate has a first recess located on the discharge side,
wherein the first recess is positioned between the discharge opening and the mounting section of the discharge valve spring.

In particular, the recess ensures that particles, such as chips which may be formed in or transported into the cylinder during operation, can collect therein, whereby the closing of the discharge opening by means of the discharge valve spring is not hindered. This ensures an efficient operation and an increased lifecycle time.

To press the valve plate against the cylinder housing on the one hand and to press the suction connector head as well as the discharge connector head against the valve plate on the other hand, it is provided in a further embodiment variant of the invention that the mounting assembly comprises a clamping element for clamping the valve plate to the cylinder housing of the refrigerant compressor and a fixing element for pressing the suction connector head and the discharge connector head to the valve plate,
wherein the fixing element is mounted on the clamping element.

As a result, the clamping element known from the prior art, which is fixed to the cylinder by means of screws, can be replaced by lighter and easier-to-install components with a higher clamping force.

In addition, the fixing element can have a preload and, therefore, acts like a spring in operation keeping the force to fix the other elements of the cylinder head assembly of the invention over a long time, even when slight creeping effects may occur.

In order to attach the valve plate particularly securely and firmly to the cylinder housing, it is provided in a further embodiment variant of the invention that the clamping element has an annular clamping section and a plurality of first clamping protrusions, which first clamping protrusions are configured to latch with a circumferential clamping groove of the cylinder housing.

To be able to arrange both the suction muffler and the discharge muffler easily and safely with respect to the valve plate, it is provided in a further embodiment variant of the invention that the clamping element has two positioning pins for aligning the suction connector head of the suction muffler and the discharge connector head of the discharge muffler with respect to the valve plate,
wherein the positioning pins extend to an opposite side of the annular clamping section than the first clamping protrusions. Preferably both the suction connector head and the discharge connector head have positioning openings matching the cross section of the positioning pins.

To be able to connect the fixing element securely and firmly to the clamping element, which itself is firmly attached to the cylinder housing, it is provided in a further embodiment variant of the invention that the clamping element has at least three second clamping protrusions which second are clamping protrusions are configured to latch with a circumferential clamping groove of the cylinder housing, wherein each second clamping protrusion has a fixing recess, wherein the fixing element has at least three fixing legs, wherein each fixing leg is configured to latch with a fixing recess of the clamping element.

The contours of the fixing recesses of the second protrusions correspond to at least a section of the contours of the fixing legs. On the one hand, this prevents the clamping element from slipping off and, on the other hand, ensures that the clamping force is constantly maintained.

The invention further relates to an encapsulated refrigerant compressor having.

wherein the pump unit further comprises a cylinder head assembly according to the invention described above.

The invention will now be explained in more detail below with reference to one exemplary embodiment. The drawings are provided by way of example and are intended to explain the concept of the invention, but shall in no way restrict it or even render it conclusively, wherein:.

<FIG> shows an outside view of an, in particular hermetically, encapsulated refrigerant compressor <NUM> which extends along a length direction x, a width direction y and a height direction z. Length direction x, width direction y and height direction z form an orthogonal reference system. In general the length dimension of the refrigerant compressor measured along the length direction x is greater than the width dimension measured along the width direction y.

In the following reference will occasionally be made to (usually gaseous) refrigerant, which flows through the refrigerant compressor <NUM>. It is self evident that these remarks refer to an operating state of the refrigerant compressor <NUM>, but that usually no refrigerant is present in the refrigerant compressor <NUM> when the refrigerant compressor <NUM> is produced or sold as a stand-alone product.

The refrigerant compressor <NUM> comprises a compressor shell <NUM>, which in this embodiment consists of a lower shell part <NUM> and an upper shell part <NUM>. The upper shell part <NUM> and the lower shell part <NUM> are welded together. On both sides of the lower shell part <NUM>, which extend mainly in the length direction x, a supporting base plate <NUM> is fixed to the compressor shell <NUM>. Each supporting base plate <NUM> has two openings <NUM> for mounting support damper assemblies <NUM> (see <FIG>).

A suction pipe <NUM>, which is connectable to a low pressure side of a refrigerant appliance, enters the upper shell part <NUM> on a lateral side of the refrigerant compressor <NUM>. During operation refrigerant is sucked into the refrigerant compressor <NUM> through the suction pipe <NUM>, mainly during a suction cycle of a pump unit <NUM> (see <FIG>) of the refrigerant compressor <NUM>. Therefore, in an operating state, the suction pipe <NUM> is connected directly or indirectly, e.g. through piping of the low pressure side of the refrigerant appliance, to an evaporator of the refrigerant appliance. With regard to the compressor shell <NUM>, the suction pipe <NUM> is entering the upper shell part <NUM> through a second connector element <NUM>, which second connector element <NUM> is hermetically connected to the upper shell part <NUM> on the one hand and to the suction pipe <NUM> on the other hand, for example by welding and/or soldering.

A discharge pipe <NUM> as well as a maintenance pipe <NUM> enters the lower shell part <NUM> on a front side of the refrigerant compressor <NUM>. The discharge pipe <NUM> enters the lower shell part <NUM> through a first connector element <NUM>, which first connector element <NUM> is hermetically connected to the lower shell part <NUM> on the one hand and to the discharge pipe <NUM> or maintenance pipe <NUM> respectively on the other hand, for example by welding and/or soldering. During operation, refrigerant compressed by the pump unit <NUM> can escape the refrigerant compressor <NUM> through the discharge pipe <NUM>, mainly during a compression and discharge cycle of the pump unit <NUM>. Therefore, the discharge pipe <NUM> is connectable to a high pressure side of the refrigerant appliance to allow compressed refrigerant to be fed to a high pressure side of the refrigerant appliance. In the operation state the discharge pipe <NUM> is connected directly or indirectly, e.g. through piping of the high pressure side of the refrigerant appliance, to a condenser of the refrigerant appliance.

The maintenance pipe <NUM> can be used to insert lubrication oil and/or refrigerant into the refrigerant compressor <NUM> during assembly of the refrigerant application or during maintenance operations. The maintenance pipe <NUM> is, similar to the suction pipe <NUM>, connected to the lower shell part <NUM> by a second connector element <NUM>, which is hermetically connected to the lower shell part <NUM> on the one hand and to the maintenance pipe <NUM> on the other hand, for example by welding and/or soldering.

With regard to <FIG> all main components of the refrigerant compressor <NUM> as well as their functions will be briefly described. The refrigerant compressor <NUM> comprises the shell <NUM>, an electronic control unit <NUM>, which is detachably mounted to the compressor shell <NUM>, and the pump unit <NUM> (see <FIG>), which is located inside the compressor shell <NUM> and supported by four support spring assemblies <NUM>. The refrigerant compressor <NUM> is mounted on four support damper assemblies <NUM>, which are connected to the respective openings of the two supporting base plates <NUM>. Each support damper assembly <NUM> includes a damper pin <NUM>, an outer dampening element <NUM>, a lining disk <NUM> and a securing element <NUM>.

As can be seen in <FIG>, the suction pipe <NUM> enters the upper shell part <NUM> through a second connection opening <NUM>, whereas the maintenance pipe <NUM> enters the lower shell part <NUM> through a third connection opening <NUM>. Even though not visible in <FIG>, the discharge pipe <NUM> enters the lower shell part <NUM> through a first connection opening.

The pump unit <NUM> comprises an electric drive unit <NUM>, a cranktrain <NUM>, a crankcase <NUM> and a cylinder head assembly <NUM>, which includes a suction muffler <NUM> and a discharge muffler <NUM>.

Each support spring assembly <NUM> comprises a mounting pin <NUM>, which is fixed, preferably welded, to the lower shell part <NUM>, a lower spring pin <NUM>, which is mounted on the respective mounting pin <NUM>, and a support spring <NUM>, which is supported on the lower spring pin <NUM>.

The electric drive unit <NUM> comprises a stator <NUM>, a rotor <NUM> and an inner harness <NUM>. The stator <NUM> has a lower end element <NUM> made of plastic, which lower end element <NUM> comprises four upper spring holders <NUM> for the respective support springs <NUM>. The stator <NUM> is fixed to the crankcase <NUM> via two stator mounting screws <NUM>. The inner harness <NUM> connects the stator <NUM> with an electric pass through element <NUM>, which is located in the compressor shell <NUM>. On the outside of the compressor <NUM> the electronic control unit <NUM> is connected to the electric pass through element <NUM> via an outer harness <NUM>, in order to control the rotation speed of the pump unit <NUM>.

The cranktrain <NUM> comprises a piston <NUM> and a crankshaft <NUM>, which is rotatably mounted inside a main bearing <NUM> of the crankcase <NUM> on the one hand and axially supported on the crankcase <NUM> by a ball bearing <NUM>. The crankshaft <NUM> has a crank pin <NUM> on which a connecting rod <NUM> is mounted, which connecting rod <NUM> connects the crank pin <NUM> with a piston pin <NUM> of the piston <NUM>. The piston pin <NUM> is fixed to the piston <NUM> via a clamping sleeve <NUM> that is inserted into a matching axial opening in the piston <NUM> and the piston pin <NUM>. On a lower end of the crankshaft <NUM>, opposite the end with the crankpin <NUM>, the rotor <NUM> is mounted to the crankshaft <NUM>, preferably via press fitting. Further an oil pickup <NUM> for conveying lubricant from a lubricant sump formed in the lower shell part <NUM> during operation into a lubricant conveying system of the cranktrain <NUM> is mounted to the rotor <NUM> via three mounting rivets <NUM>.

The crankcase <NUM> includes a cylinder housing <NUM>, in which a cylinder <NUM> is formed. The piston <NUM> reciprocates within the cylinder <NUM> during operation of the refrigerant compressor <NUM> in order to suck refrigerant into the cylinder <NUM> during a suction cycle and to compress and discharge the compressed refrigerant during a compression and discharge cycle. On the crankcase <NUM> a set of two first protrusions <NUM> is located on the side opposite of the cylinder housing <NUM> and a set of two second protrusions <NUM> is located on the cylinder housing <NUM> itself. Inner dampening elements <NUM> are attached to each of the first protrusions <NUM> and second protrusions <NUM>, which inner dampening elements <NUM> interact with respective regions of an inner surface of the upper housing part <NUM> in order to dampen vibrations of the pump unit <NUM> during operation and to prevent damages during transport.

In order to establish a suction path and a discharge path for the refrigerant from the suction pipe <NUM> via the cylinder <NUM> to the discharge pipe <NUM>, the cylinder head assembly <NUM> is mounted onto a cylinder head section of the cylinder housing <NUM>. The cylinder head assembly <NUM> comprises a cylinder gasket <NUM>, a suction valve spring <NUM>, a valve plate <NUM> and a discharge valve spring <NUM>, wherein the valve plate <NUM> has a suction opening <NUM> and a discharge opening <NUM>. The cylinder gasket <NUM> and the suction valve spring <NUM> are located on a suction side 530a of the valve plate <NUM>, which suction side faces towards the piston <NUM>. The discharge valve spring <NUM> is located on a discharge side 530b of the valve plate <NUM>, which faces in the opposite direction of the piston <NUM>. When assembled, the valve plate <NUM>, the suction valve spring <NUM> and the cylinder gasket <NUM> are pressed into a valve plate seat <NUM> of the cylinder housing <NUM>, as will be described below in detail.

A suction connector head <NUM> of the suction muffler <NUM> and a discharge connector head <NUM> of the discharge muffler <NUM> are pressed onto the discharge side 530b of the valve plate <NUM>, wherein a first sealing element <NUM> is placed between the valve plate <NUM> and the suction connector head <NUM> as well as the discharge connector head <NUM> respectively.

During the suction cycle of the pump unit <NUM>, the piston <NUM> inside the cylinder <NUM> moves away from the valve plate <NUM>, so that a negative pressure builds up in the cylinder <NUM>, because the suction valve spring <NUM> keeps the suction opening <NUM> of the valve plate <NUM> closed due to its spring force, while the discharge valve spring <NUM> closes the discharge opening <NUM> of the valve plate <NUM>. When the negative pressure exceeds a certain threshold, the suction valve spring <NUM>, which at least has a section configured as a reed valve, opens the suction opening <NUM> to allow refrigerant to flow from the suction pipe <NUM> through the suction muffler <NUM> into the cylinder <NUM>.

During the compression cycle of the pump unit <NUM>, the piston <NUM> inside the cylinder <NUM> moves in the direction of the valve plate <NUM>, so that the refrigerant in the cylinder <NUM> is compressed, because the discharge valve spring <NUM> keeps the discharge opening <NUM> of the valve plate <NUM> closed due to its spring force, while the suction valve spring <NUM> keeps the suction opening <NUM> of the valve plate <NUM> closed. Once the pressure of the compressed refrigerant exceeds a predefined threshold, the discharge valve spring <NUM>, which is configured as a reed valve, opens the discharge opening <NUM> of the valve plate <NUM> to allow refrigerant to flow from the cylinder <NUM> through the discharge muffler <NUM> to the discharge tube <NUM>.

The suction muffler <NUM> includes a lower housing part <NUM>, an upper housing part <NUM> and an inner housing element <NUM>, which is inserted into a suction muffler volume <NUM> defined by the lower housing part <NUM> and the upper housing part <NUM> of the suction muffler <NUM>. Refrigerant is sucked into the suction muffler <NUM> via an inlet opening <NUM> located in the upper housing part <NUM> mainly during the suction cycle of the pump unit <NUM>. The suction muffler <NUM> dampens sound based on the well-known Helmholtz principle when refrigerant flows through it, i.e. by chambers formed within the suction muffler <NUM> which act as resonators that absorb sound. The refrigerant escapes the suction muffler <NUM> through the suction connector head <NUM>, which is placed above the suction opening <NUM> of the valve plate <NUM> and is located on the upper housing part <NUM> of the suction muffler <NUM>.

The discharge muffler <NUM> includes a lower housing part <NUM>, an upper housing part <NUM> and the discharge connector head <NUM>, which is connected to the upper housing part <NUM> of the discharge muffler <NUM>. During the discharge cycle of the pump unit <NUM>, compressed refrigerant coming from the discharge opening <NUM> of the valve plate <NUM> enters the discharge muffler <NUM> though the discharge connector head <NUM>. The discharge muffler <NUM> dampens sound based on the well-known Helmholtz principle when refrigerant flows through it, i.e. by chambers formed within the discharge muffler <NUM> which chambers act as resonators that absorb sound and or by pulsation filtering. The compressed refrigerant escapes the discharge muffler <NUM> through a discharge connection tube <NUM>, which is connected to the discharge tube <NUM> via connection sleeve <NUM> and an O-ring seal <NUM>.

The mounting of the cylinder head assembly <NUM> to the cylinder housing <NUM> is facilitated by a mounting assembly <NUM> (see <FIG>), which comprises a clamping element <NUM> for clamping the valve plate <NUM> to the valve plate seat <NUM> and a fixing element <NUM>, which presses the suction connector head <NUM> and the discharge connector head <NUM> onto the valve plate <NUM>. The fixing element <NUM> is latched onto the clamping element <NUM>. The clamping element <NUM> further comprises two positioning pins <NUM> (see <FIG>), which are used for aligning the discharge connector head <NUM> with the discharge opening <NUM> and the suction connector head <NUM> with the suction opening <NUM> respectively.

<FIG> shows the pump unit <NUM> of the refrigerant compressor <NUM> in an assembled state. The suction muffler <NUM> and the discharge muffler <NUM> are fixed to the cylinder housing <NUM> via the clamping element <NUM> and the fixing element <NUM> of the mounting assembly <NUM>, while the crankshaft <NUM> is inserted into the crankcase <NUM> and the stator <NUM> is surrounding the rotor <NUM>.

<FIG> shows an exploded view of the cylinder head assembly <NUM> of the refrigerant compressor <NUM>, in which a detailed arrangement of the various members of the cylinder head assembly <NUM> is visible. Seen from the fixing element <NUM> in the direction of the cylinder housing <NUM>, the following members are arranged between the fixing element <NUM> and cylinder housing <NUM>: the suction connector head <NUM>, the discharge connector head <NUM>, the first sealing element <NUM>, the discharge valve spring <NUM>, the clamping element <NUM>, the valve plate <NUM>, the suction valve spring <NUM> and the cylinder gasket <NUM>. Both the suction valve spring <NUM> and the discharge valve spring <NUM> are welded onto the valve plate. The welded joint between the suction valve spring <NUM> and the valve plate <NUM> as well as the discharge valve spring <NUM> and the valve plate <NUM> leads to a simple, yet robust, way to combine these parts of the cylinder head assembly <NUM> together.

Both from <FIG> as well as from <FIG>, which shows a top view of the suction side 530a of the valve plate <NUM> of the cylinder head assembly <NUM>, is visible that the suction valve spring <NUM> comprises a suction spring body <NUM>, which is a flexible metal disk and which outer shape corresponds to an outer shape of the valve plate <NUM>. The suction spring body <NUM> has a linear first cut-out <NUM>, which separates a suction reed valve section 521a for opening and closing the suction opening <NUM> from a surrounding static positioning section 521b. The suction reed valve section 521a and the static positioning section 521b are connected by a hinge section 521c, wherein the suction spring body <NUM> is welded to the valve plate <NUM> in the positioning section 521b.

To improve the flow behavior of the refrigerant, the suction reed valve section 521a comprises a second cut-out <NUM>, which is located between a segment of the suction reed valve section 521a positioned above the suction opening <NUM> and the hinge section 521c.

The suction spring body <NUM> has a third cut-out <NUM> for the discharge opening <NUM>, which third cut-out <NUM> overlaps with the first cut-out <NUM>.

In <FIG>, which shows a top view of a discharge side 530b of the valve plate <NUM> of the cylinder head assembly <NUM>, as well as in <FIG>, which shows a three dimensional view of the valve plate <NUM> of the cylinder head assembly <NUM>, it can be seen that the discharge valve spring <NUM> is configured as a flat spring, which comprises a discharge reed valve section 540a for opening an closing of the discharge opening <NUM> of the valve plate <NUM> and a mounting section 540b, wherein the discharge valve spring <NUM> is welded to the valve plate <NUM> in the mounting section 540b.

Furthermore <FIG> and <FIG> show that the valve plate <NUM> has a first positioning protrusion <NUM>, which protrudes from a circumferential surface 530c of the valve plate <NUM>. The static mounting section 521b of the suction spring body <NUM> comprises a second positioning protrusion 521d, which is matching the first positioning protrusion <NUM>. Both positioning protrusions <NUM>, 521d allow an easy arrangement of the valve plate <NUM> and the suction valve spring <NUM> one above the other.

In addition, the first positioning protrusion <NUM> serves also for aligning the valve plate <NUM> with respect to the cylinder <NUM>. Namely, the first positioning protrusion <NUM> is configured to interact with a matching positioning recess 312a of a valve plate seat <NUM> of the cylinder housing <NUM>.

To easy align the valve plate <NUM> to the cylinder <NUM>, the valve plate <NUM> has three centring protrusions <NUM> for centring the valve plate <NUM> in a valve plate seat <NUM> of the cylinder housing <NUM>, which centring protrusions <NUM> are located at the circumferential surface 530c of the valve plate <NUM> (see <FIG>, <FIG> and <FIG>). In <FIG> it can be seen that the centring protrusions <NUM> extend circumferentially over the entire thickness of the valve plate <NUM>.

A first recess <NUM> is located on the discharge side 530b of the valve plate <NUM>, which first recess <NUM> ensures that particles, such as chips, can collect therein, whereby the closing of the discharge opening <NUM> by means of the discharge valve spring <NUM> is not hindered. The first recess <NUM> is positioned between the discharge opening <NUM> and the mounting section 540b of the discharge valve spring <NUM>.

For clamping the valve plate <NUM> to the cylinder housing <NUM> and for pressing the suction connector head <NUM> as well as the discharge connector head <NUM> to the valve plate <NUM>, the cylinder head assembly <NUM> comprises the mounting assembly <NUM> (see <FIG>), which comprises the clamping element <NUM> for the first purpose mentioned above and the fixing element <NUM> for the second purpose mentioned above.

In <FIG> and <FIG> it can be seen that the clamping element <NUM> has an annular clamping section <NUM> and a plurality of first clamping protrusions <NUM>, which are configured to latch with a circumferential clamping groove <NUM> of the cylinder housing <NUM>. In addition, the clamping element <NUM> has six second clamping protrusions <NUM>, which are configured to latch with the circumferential clamping groove <NUM>, wherein each second clamping protrusion <NUM> has a fixing recess <NUM>. The fixing element <NUM> on the contrary has three fixing legs <NUM>, wherein each fixing leg <NUM> is configured to latch with a fixing recess <NUM> of the clamping element <NUM>. the fixing element <NUM> is mounted on the clamping element <NUM>.

Claim 1:
A cylinder head assembly (<NUM>) for an encapsulated refrigerant compressor (<NUM>) comprising
- a valve plate (<NUM>) having a suction opening (<NUM>) and a discharge opening (<NUM>);
- a suction valve spring (<NUM>) being mounted to a suction side (530a) of the valve plate (<NUM>);
- a discharge valve spring (<NUM>) being mounted to a discharge side (530b) of the valve plate(<NUM>);
- a suction muffler (<NUM>) having a suction connector head (<NUM>) which is connecting an outlet section (<NUM>) of the suction muffler (<NUM>) with the suction opening (<NUM>) and the suction valve spring (<NUM>);
- a discharge muffler (<NUM>) having a discharge connector head (<NUM>) which is connecting an inlet section (<NUM>) of the discharge muffler (<NUM>) with the discharge valve spring (<NUM>) and the discharge opening (<NUM>) ;
- a mounting assembly (<NUM>) for fixing the cylinder head assembly (<NUM>) to a cylinder housing (<NUM>) of the refrigerant compressor (<NUM>);
- a first sealing element (<NUM>) which is located between the discharge connector head (<NUM>) as well as the suction connector head (<NUM>) and the discharge side (530b) of the valve plate (<NUM>),
characterized in that
the suction valve spring (<NUM>) is welded onto the suction side (530a) of the valve plate (<NUM>) and the discharge valve spring (<NUM>) is welded onto the discharge side (530b) of the valve plate (<NUM>),
wherein the suction valve spring (<NUM>) has a suction spring body (<NUM>),
wherein the suction spring body (<NUM>) is a flexible metal disk,
wherein the suction spring body (<NUM>) has a linear first cut-out (<NUM>), which first cut-out (<NUM>) separates a suction reed valve section (521a) for opening and closing the suction opening (<NUM>) of the valve plate (<NUM>) from a surrounding static positioning section (521b),
wherein the suction valve spring (<NUM>) is welded to the valve plate (<NUM>) in the positioning section (521b), wherein the movable reed valve section (521a) and the positioning section (521b) are connected by a hinge section (521c) of the suction spring body (<NUM>).