Injector, compensation assembly for the injector, and relieving device for the compensation assembly and method of assembling and calibrating the injector

Abstract

 A Relieving device for a compensation device (31) of an injector comprises a relieving body (32), a relieving spring (48), and a relieving spring washer (50). The relieving body (32) comprises a ground plate (36), a first relieving spring rest, and an at least one transferring element (34) which extends rectangular from the ground plate (36) to the first relieving spring rest. The relieving spring (48) is axially coupled to the first relieving spring rest at a first axial end of the relieving spring (48). The relieving spring (48) is axially coupled to the relieving spring washer (50) at a second axial end of the relieving spring (48).

Description

[0001] The invention relates to an injector, to a compensation assembly for the injector, and to a relieving device for the compensation assembly. The injector comprises the compensation assembly, a housing which has a recess of the housing, an actor which is arranged in the recess of the housing, and a valve group which is coupled to the housing at a first axial end of the housing of the injector. The actor is coupled to the compensation assembly at a first axial end of the actor and the actor is coupled to the valve group at a second axial end of the compensation assembly. The compensation assembly comprises the relieving device and a compensation device which comprises a first and a second compensation body which are axially movable relative to each other. The first compensation body comprises a first axial end of the compensation device and the second compensation body comprises a second axial end of the compensation device. The compensation device is coupled to the relieving device. Further, the invention relates to a method of assembling and calibrating the injector.

[0002] DE 103 44 061 A1 discloses an injector with a hydraulic compensation element. The compensation element enables the compensation of a clearance in the injector during an operation of the injector. The compensation of the clearance may be achieved by a sealed hydraulic system and by a piston which separates the hydraulic system in an upper and a lower volume. A difference of the pressure of the upper and the lower volume may be compensated by a clearance fit of a piston head of the piston to an inner wall of the hydraulic system.

[0003] The object of the invention is to create an injector, a compensation assembly for the injector, a relieving device for the compensation assembly, and a method of assembling and calibrating the injector which enable a precise dosing of fluid by the injector and a long lifetime of the injector, especially of the compensation assembly.

[0004] The object of the invention is achieved by the features of the independent claims 1, 11, 13, and 17. Advantageous embodiments of the invention are given in the sub-claims.

[0005] The invention is distinguished concerning a first aspect of the invention by an injector, a compensation assembly for the injector, and by a relieving device for the compensation assembly. The relieving device comprises a relieving body, a relieving spring, and relieving spring washer. The relieving body comprises a ground plate, a first relieving spring rest, and at least one transferring element. The transferring element extends rectangular from the ground plate to the first relieving spring rest. The relieving spring is axially coupled to the first relieving spring rest at a first axial end of the relieving spring. The relieving spring is axially coupled to the relieving spring washer at the second axial end of the relieving spring.

[0006] If the compensation device is arranged in the relieving device with a first axial end of the compensation device being axially coupled to the ground plate and with the second axial end of the compensation device being rigidly coupled to the relieving spring washer, the relieving device enables to relieve the compensation device, if a force acts on the second axial end of the compensation device and/or on the relieving device. The force on the second axial end of the compensation device and/or, respectively, on the relieving device, is transferred only partially to the compensation device. This enables to apply a higher force on the compensation assembly and/or on a needle of the injector by an actor of the injector and/or by a machine for calibrating the injector than it would be possible without the relieving device. This may contribute to a precise dosing of fluid by the injector.

[0007] If there is nearly the same force applied on the compensation assembly than without the relieving device, the compensation device is relieved relative to the compensation assembly without the relieving device. In that way the relieving device contributes to a long lifetime of the injector, especially of the compensation device. The decrease of the force on the compensation device is especially advantageous if the compensation device comprises a membrane which is strained by the force on the compensation device.

[0008] In an advantageous embodiment of the relieving device, the relieving body comprises a relieving rod. The relieving rod extends in axial direction from the ground plate in opposite direction relative to the transferring element. This may contribute to a proper calibration of the injector.

[0009] In a further advantageous embodiment of the relieving device, the relieving rod has at least one groove which extends circumferentially the relieving rod. This may contribute to a proper rigid coupling of the relieving body to a housing of the actor and/or this enables to arrange a sealing ring in the groove of the relieving rod.

[0010] In a further advantageous embodiment, the relieving device comprises a sealing ring which is arranged in the groove of the relieving rod. Together with a tube-section of an end piece of the injector which takes in the relieving rod, this contributes to a proper sealing of a recess of the housing by the end piece and the relieving rod.

[0011] In a further advantageous embodiment of the relieving device, the relieving device comprises at least two transferring elements which are arranged symmetrically to an axis of the relieving body in an outer area of the ground plate. This enables a light compensation body and less friction of the compensation device to the relieving body.

[0012] In a further advantageous embodiment of the relieving device, the transferring elements are tube segment shaped. This may contribute to a proper coupling of the compensation device and the relieving body.

[0013] In a further advantageous embodiment of the relieving device, the transferring element is tube shaped. This contributes to a proper load capacity of the transferring element and this may contribute to a centering of the compensation device.

[0014] In a further advantageous embodiment of the relieving device, the relieving body comprises a relieving ring which comprises the first relieving spring rest. The relieving ring forms in a simple way a proper first relieving spring rest.

[0015] In a further advantageous embodiment of the relieving device, the relieving spring washer has a first and a second axial section separated by a first step of the relieving spring washer. The first step of the relieving spring washer comprises the second relieving spring rest. The second axial section of the relieving spring washer is radially surrounded by an axial section of the relieving spring. This contributes to a proper centering of the relieving spring.

[0016] In a further advantageous embodiment of the relieving device, the relieving spring washer has a third axial section which is separated from the second axial section of the spring washer by a second step of the relieving spring washer. The second step of the relieving spring washer forms a first compensation spring rest for a first compensation spring of the compensation device. This contributes to a proper centering of the first compensation spring and in this way, the relieving spring washer forms the second relieving spring rest and the first compensation spring rest.

[0017] The compensation assembly comprises the relieving device and the compensation device. The compensation device comprises a first and a second compensation body which are axially movable relative to each other. The first compensation body comprises a first axial end of the compensation device. The second compensation body comprises a second axial end of the compensation device. The first axial end of the compensation device is coupled in axial direction with the ground plate of the relieving body. The second compensation body is rigidly coupled to the relieving spring washer. This contributes in a simple way to a relieving of the compensation device by the relieving device.

[0018] In an advantageous embodiment of the compensation assembly, the first and/or the second compensation body have at least two grooves at an outer shell of the first and/or, respectively, the second compensation body which at least partially take in the transferring elements. This contributes to a proper positioning of the compensation device in the relieving device.

[0019] The injector comprises the compensation assembly and a housing which has a recess of the housing and an actor which is arranged in the recess of the housing and which is coupled to the compensation assembly at a first axial end of the actor. The injector further comprises a valve group which is coupled to the housing at a first axial end of the recess of the housing and which is coupled to the actor at a second axial end of the actor. The compensation assembly enables the compensation of an expansion of the injector housing. This contributes to a precise dosing of fluid by the injector. The expansion of the housing may occur because of an increasing temperature of the housing of the injector.

[0020] In an advantageous embodiment of the injector, the injector comprises an end piece. The end piece is coupled to the relieving body and has a recess of the end piece axially extending through the end piece from that side of the end piece facing towards the ground plate of the relieving body. The relieving body and the end piece close the recess of the housing in axial direction. The end piece contributes to a proper calibration of the injector.

[0021] In a further advantageous embodiment of the injector, the end piece comprises a first tube-section. The first tube-section axially extends from the recess of the end piece. Further, the first tube-section takes in the relieving rod. The relieving rod protrudes from the first tube-section of the end piece. This may contribute to a proper fixing of the relieving rod to the end piece and to a proper calibration of the injector.

[0022] In a further advantageous embodiment of the injector, the end piece comprises a second tube-section which at least partially takes in the ground plate of the relieving body. This contributes to a proper positioning of the relieving body in the recess of the housing of the injector.

[0023] The invention is distinguished concerning a second aspect of the invention by a method of assembling and calibrating the injector. The valve group of the injector is coupled to the first axial end of the recess of the housing of the injector. The actor is inserted into the recess of the housing. The compensation assembly is inserted into the recess of the housing of the injector. The second compensation body of the compensation device is coupled to the actor. A given force is applied on the relieving body. Fluid is dosed with the injector. The fluid dosed by the injector is detected. The force on the relieving body is varied dependent on the detection of the dosing of the fluid. The relieving body is rigidly coupled to the housing of the injector, if the fluid is dosed by the injector in a given way. This enables to calibrate the injector with a relative high force. This may contribute to a precise dosing of fluid by the injector. The relative high force means in this context that the high force is relatively high in respect to the force which may by applied on the compensation assembly by the actor of the injector.

[0024] In an advantageous embodiment of the second aspect of the invention, the end piece is inserted into the recess of the housing and the end piece is fixed to the relieving body before the given force is applied on the relieving body. The relieving body is rigidly coupled to the housing of the injector via the end piece, if the fluid is dosed by the injector in a given way. This enables a proper calibration of the injector without the relieving rod and without the first tube-section of the end piece.

[0025] In a further advantageous embodiment of the second aspect of the invention, the end piece is inserted into the recess of the housing. The end piece is fixed to the housing before the given force is applied on the relieving body. The first tube-section of the end piece is rigidly coupled to the relieving rod if the fluid is dosed by the injector in a given way. This enables a proper calibration of the injector without welding the relieving body to the end piece, if the fluid is dosed by the injector in a given way.

[0026] Advantageous embodiments of the invention are explained in the following with the aid of schematic drawings.

[0027] These are as follows:

Figure 1

an injector,

Figure 2

a compensation assembly for the injector comprising a first embodiment of a relieving device and a first embodiment of a compensation device,

Figure 3

a second embodiment of the relieving device,

Figure 4

a third embodiment of the relieving device and a second embodiment of the compensation device,

Figure 5

a cut through the third embodiment of the relieving device and the second embodiment of the compensation device according to Figure 4,

Figure 6

a flow chart for assembling and calibrating the injector.

[0028] Elements with the same design and function that appear in the different illustrations are identified by the same reference character.

[0029] An injector (figure 1) comprises a double tube shaped housing 1, a valve group 2, an actor 14, and a compensation assembly 30. The injector is preferably used for dosing fluid into a combustion chamber of an internal combustion engine. In this case, the fluid is preferably fuel. In this embodiment, the injector is of an outward opening type. In an alternative embodiment, the injector may be of an inward opening type.

[0030] The valve group 2 comprises a nozzle body 4, a needle 6, a needle spring 10, and a needle spring washer 12. The nozzle body 4 has a nozzle body recess 8. The nozzle body recess 8 takes in the needle 6 movable in axial direction. The needle spring 10 is arranged circumferential an axial section of the needle 8. In axial direction, the needle spring 10 is arranged intermediate the nozzle body 4 and the needle spring washer 12. The nozzle body 4 forms a first needle spring rest and the needle spring washer 12 forms a second needle spring rest for the needle 6. The needle spring 10 is formed and arranged in such a way that the needle spring 10 is preloaded and in that way the needle 6 is pressed from the outside against the nozzle body 4 via the spring washer 12 and so the needle 6 is in its closed position.

[0031] The spring washer 12 is coupled to an actor 14 via a ground plate 16 of the actor 14. The actor 14 is coupled via a top plate 18 of the actor 14 to the compensation assembly 30.

[0032] The injector further comprises a connection 20 for connecting the injector to an external fluid line. A fluid line 22 of the injector is formed in the double tube shaped housing 1 of the injector.

[0033] If the actor 14 gets energized, it may change its axial length in a time range of about some microseconds. If a force acts on the compensation assembly 30 that fast, the compensation assembly 30 reacts like a stiff body. In that way, the force applied by the actor 14 is transferred to the needle spring washer 12 and/or the needle 6. In that way, the actor 14 is able to force the needle 6 away from the connection 20 and away from the closed position of the needle 6. If the needle 6 is not in its closed position, there is an opening formed between the needle 6 and the nozzle body 4 at an axial end of the nozzle body 4 facing away from the actor 14. This opening forms a nozzle of the injector.

[0034] Whether the needle 6 is in its closed position or not depends on a force balance. A first force on the needle 6 in closing direction of the needle 6 is applied by the needle spring 12. A second force on the needle 6 against the closing direction of the needle 6 may be applied on the needle 6 by the actor 14. A third force on the needle 6 may be applied on the needle 6 by the fluid in the recess 8 of the nozzle body 4.

[0035] If the housing 1 of the injector changes its axial length for example because of an increasing temperature of the housing 1, there is a slowly changing force applied on the compensation assembly 30 relative to the time range in which the actor 14 may change its axial length if the actor 14 gets energized. If the slowly changing force is applied on the compensation assembly 30, the compensation assembly 30 is able to change its axial length and in that way is able to compensate the expansion of the housing 1 of the injector.

[0036] The compensation assembly 30 comprises a relieving device and a compensation device 31 (figure 2). The relieving device comprises a relieving body 32. The relieving body 32 comprises a ground plate 36, at least one transferring element 34, and a relieving rod 38. The relieving device further comprises a relieving ring 46, a relieving spring 48, and a relieving spring washer 50.

[0037] Preferably, the ground plate 36 has a spherical shape. The transferring element 34 extends from an outer area of the ground plate 36 parallel to an axis of the compensation assembly 30 towards the relieving ring 46. The relieving ring 46 comprises a first relieving spring rest for the relieving spring 48. Alternatively, the first relieving spring rest may be of an other type which enables a proper support for the relieving spring 48. The relieving spring washer 50 forms a second relieving spring rest for the relieving spring 48.

[0038] The relieving rod 38 preferably extends from the center of the ground plate 36 in axial direction away from the compensation device 31. The transferring element 34 may be tube shaped. The tube shaped transferring element 34 is very robust against a force acting on the transferring element 34 in axial direction of the tube shaped transferring element 34. An inner diameter of the tube-shaped transferring element 34 is preferably formed with a slight clearance to the outside of the compensation device 31. This contributes to a proper positioning of the compensation device 31 in the relieving device. Further, the relieving rod 38 preferably comprises some grooves 58 of the relieving rod 38 which extend circumferentially the relieving rod 38. One of the grooves 58 may be used for taking in a sealing ring 60. In combination with an end piece 66 of the injector, the groove 58 with the sealing ring 60 contributes to a proper sealed coupling of the end piece 66 to the relieving rod 38.

[0039] Alternatively or additionally, the grooves 58 may contribute to a proper rigid coupling of the end piece 66 to the relieving rod 38. For the proper rigid coupling of the end piece 62 to the relieving body 32, a first tube-section 64 of the end piece 62 may be crimped to the relieving rod 38 in the area of the grooves 58 of the relieving rod 38. A second tube-section 66 of the end piece 62 preferably takes in the ground plate 36 of the relieving body 32.

[0040] The relieving spring washer 50 preferably is formed and arranged in such a way that a first axial section 52 of the relieving spring washer 50 has a larger diameter than a second axial section 54 of the relieving spring washer 50. The first and the second axial section 52, 54 of the relieving spring washer 50 are separated by a first step 56 of the relieving spring washer 50. The first step 56 of the relieving spring washer 50 preferably forms a second spring rest for the relieving spring 48. The second axial section 54 of the relieving spring washer 50 is preferably formed in such a way that the second axial section 54 of the relieving spring washer 50 is surrounded in axial direction by the relieving spring 48 and in this way the second axial section 54 contributes to a centering of the relieving spring 48.

[0041] The compensation device 31 comprises a first compensation body 40 and a second compensation body 41. The first and the second compensation bodies 40, 41 are arranged axially movable relative to each other. The second compensation body 41 is coupled to the first compensation body 40 in such a way that the fluid in the compensation device 31 is not able to leak out from the compensation device 31. The first compensation body 40 comprises a first axial end 42 of the compensation device 31 and the second compensation body 41 comprises a second axial end of the compensation device 44. The second axial end of the compensation device 31 is coupled to the actor 40.

[0042] The first compensation body 40 comprises, for example, a first and a second volume 402, 403 which hydraulically communicate with each other via a fluid line 401 of the first compensation body 40. The fluid line 401 of the first compensation body 40 comprises a throttle, and/or a check valve, and/or a control valve. The second volume 403 is sealed in axial direction away from the first compensation body 41 by a membrane 406. The membrane 406 is coupled to the ground plate 36 via a pusher 404. The pusher 404 is coupled to the ground plate 36 via a pusher spring 405. The throttle, the check valve, and/or, respectively, the control valve are formed and arranged in such a way that if there is the slowly changing force applied on the first compensation body 41, the first compensation body 41 is able to move towards the ground plate 36. A fluid in the first volume 404 in that way is slowly pressed through the fluid line 401 of the first compensation body 40 towards the second volume 403. This leads to a stress on the first membrane 406 and loads the pusher spring 405.

[0043] If there is the fast changing force applied on the first compensation body 41, the fluid is not able to pass the fluid line 401 of the first compensation body 40 fast enough because of the throttle, the check valve, and/or, respectively, the control valve and the first compensation body 40 and the second compensation body 41 are not able to move relative to each other. In that way, the compensation device 31 acts like the stiff body.

[0044] If a force is applied on the relieving rod 38 in axial direction towards the compensation device 31 the force is divided in two parts. A first part of the force is transferred via the relieving body 32 to the relieving spring 48 and via the relieving spring 48 and the relieving spring washer 50 to the actor 14. A second part of the force is applied on the compensation device 31. The second part of the force, which is applied on the compensation device 31, is transferred to the actor 14 via the pusher 404, the pusher spring 405, the membrane 406, the fluid in the first and the second volume 404, 403, and via the second compensation body 41. Preferably, the second compensation body 41 comprises a compensation body rod 411. In this way, the whole force on the compensation assembly 30 is transferred to the actor 14 but only the second part of the force is transferred by the compensation device 31. The second part of the force depends on the force which is applied on the compensation assembly 30 by the relieving spring 48.

[0045] The separation of the force in two parts enables to act on the whole compensation assembly 30 with a force which is much higher than it would be possible without the relieving device. So, the relieving device enables to use an actor 14 which acts on the needle 6 and the compensation assembly 30 with a higher force than it would be possible without the relieving device. Further, there may be applied a higher force on the compensation assembly 30 by calibrating the injector. This may contribute to a short reaction duration of the injector on a signal for opening or closing the injector and/or, respectively, this may contribute to a proper calibration of the injector. The short reaction duration and/or, respectively, the proper calibration contribute to a precise dosing of fluid by the injector.

[0046] If the same force is applied on the compensation assembly 30 than it would be applied on the compensation assembly 30 without the relieving device, the separation of the force diminishes the stress on the whole compensation device 31, especially on the first membrane 406. This is especially advantageous for the calibration of the injector because the force on the compensation assembly 30 needed for calibrating the injector is relatively high and without the relieving device, this high force may lead to a plastic deformation of the membrane 406. In this context the relative high force means that the high force is relative high according to the force which may be applied to the compensation assembly by the actor 14 of the injector.

[0047] In an alternative embodiment (figure 3), the relieving body 32 comprises at least two, preferably three, transferring elements 34. Preferably, the transferring elements 34 are tube segment shaped. The tube segment shape of the transferring elements 34 contributes to a decrease of a friction between the compensation device 31 and the transferring elements 34. Further, the tube segment shape of the transferring elements 34 contributes to a light relieving body 32. The transferring elements 34 have a clearance to each other which is formed in such a way that the compensation device 31 may be arranged intermediate the transferring elements 34 with a light clearance between the transferring elements 34 and the compensation device 31.

[0048] Alternatively, the compensation device 31 is made of a different type (figure 4). For example, the first compensation body 40 has a cup shape. The second compensation body 41 is piston shaped comprising a piston head and a piston rod 411. The cup shaped first compensation body 40 is preferably sealed by a second membrane 409 of the compensation device 31. The first compensation body 41 separates a third volume 407 from a fourth volume 408. The third volume 407 communicates hydraulically with the fourth volume 408 preferably via a clearance between the second compensation body 41 and an inner wall of the cup shaped first compensation body 40 and/or the third volume 407 communicates hydraulically via a fluid line 412 of the second compensation body 41. The fluid line 412 of the second compensation body 41 may comprise, for example, the throttle, the check valve, and/or the control valve. The clearance, the fluid line 412 of the second compensation body 41, the throttle, the check valve, and/or the control valve are formed and arranged in such a way that, if there is the slowly changing force applied on the second compensation body 41 in axial direction, for example because of the thermal expansion of the housing 1, the first compensation body 41 is moved towards the ground plate 36. A fluid in the third volume 407 in that way is pressed through the clearance and/or, respectively, through the fluid line 412 of the second compensation body 41 to the fourth volume 408. In this way, the compensation device 31 is able to compensate the thermal expansion of the housing 1 of the injector.

[0049] If there is the fast changing force applied on the second compensation body 41, the fluid in the third volume 407 is not able to flow through the fourth volume 408 and the first compensation body 40 and the second compensation body 41 are not able to move relative to each other. In this way, the whole compensation device acts like the stiff body.

[0050] Preferably, in this embodiment there is a compensation device spring 72 arranged intermediate the relieving spring washer 50 and the second membrane 409. The compensation device spring 72 is preloaded and in this way the second membrane 409 is deformed. In this embodiment, the relieving spring washer 50 preferably comprises a third axial section 70 which is separated from the second axial section 45 by a second step 76 of the relieving spring washer 50. The second step 76 of the relieving spring washer 50 in this way forms a spring rest for the compensation device spring 72. The third axial section 70 of the relieving spring washer 50 is preferably formed in such a way that it contributes to a proper centering of the compensation device spring 72. A stress on the second membrane 409 because of the deformation of the second membrane 409 is diminished by the relieving device.

[0051] In order to have a proper positioning of the compensation device 31 in the relieving device, the compensation device 31 comprises as many grooves 74 (figure 5) as there are transferring elements 34. The grooves 74 of the compensation device 31 are formed in such a way that the grooves 74 of the compensation device 31 at least partly take in the transferring elements 34.

[0052] Preferably, the injector is assembled and calibrated as explained in the following.

[0053] In a step S1, all parts which are needed for the injector are arranged in a machine which assembles and calibrates the injector.

[0054] In a step S2, the valve group 2 is rigidly coupled to the injector housing 1 at the first axial end of the recess of the housing 1.

[0055] In a step S3, the actor 14 is inserted into the recess of the housing 1.

[0056] In a step S4, the compensation assembly 30 and the end piece 62 are inserted into the recess of the housing 1 with the first compensation body 41 being coupled to the actor 14 and with the end piece 62 facing away from the actor 14.

[0057] In a step S5, a force F is applied on the compensation assembly 30 preferably via the relieving rod 38.

[0058] In a step S6, the end piece 62 is preferably rigidly coupled to the housing 1. Alternatively, the end piece is rigidly coupled to the relieving body 32.

[0059] In a step S7, fluid is dosed by the injector and the dosed fluid is detected.

[0060] In a step S8 the force F is varied from a force F1 to a force FN dependent on the detected fluid. If the injector doses the fluid in a given way, preferably the first tube-section 64 of the end piece 62 is crimped to the relieving rod 38, preferably in the area of the grooves 58 of the relieving rod 38. Alternatively, the second tube-section 66 of the end piece 62 is rigidly coupled to the housing 1, if in step S6 the end piece 62 has been rigidly coupled to the relieving body 32.

[0061] In a step S10, the assembled and calibrated injector may be taken out the assembling and calibrating machine.

[0062] The invention is not restricted on the explained embodiments. For example, the different embodiments may be combined. For example, the compensation device 31 may be of any type which enables the compensation of the expansion of the axial length of the housing 1 of the injector. Further, for example, the compensation device 31 may comprise the first membrane 406 and the second membrane 409 and/or the compensation device spring 72. Further, there may be more or less transferring elements 34.

Claims

1. Relieving device for a compensation device (31) of an injector with

- the relieving device comprising a relieving body (32), a relieving spring (48), and a relieving spring washer (50),

- the relieving body (32) comprising a ground plate (36), a first relieving spring rest, and a at least one transferring element (34) which extends rectangular from the ground plate (36) to the first relieving spring rest,

- the relieving spring (48) being axially coupled to the first relieving spring rest at a first axial end of the relieving spring (48) and with the relieving spring (48) being axially coupled to the relieving spring washer (50) at a second axial end of the relieving spring (48).

2. Relieving device in accordance with claim 1 with the relieving body (32) comprising a relieving rod (38) extending in axial direction from the ground plate (36) in opposite direction than the transferring element (34).

3. Relieving device in accordance with claim 2 with the relieving rod (38) having at least one groove (58) which extends circumferentially the relieving rod (38).

4. Relieving device in accordance with claim 3 comprising a sealing ring which is arranged in the groove (58) of the relieving rod (38).

5. Relieving device in accordance with one of the preceding claims comprising at least two transferring elements (34) which are arranged symmetrically to an axis of the relieving body (32) in an outer area of the ground plate (36).

6. Relieving device in accordance with claim 5 with the transferring elements (34) being tube-segment shaped.

7. Relieving device in accordance with one of the claims 1 to 4 with the transferring element (34) being tube shaped.

8. Relieving device in accordance with one of the preceding claims with the relieving body (32) comprising a relieving ring (46) which comprises the first relieving spring rest.

9. Relieving device in accordance with one of the preceding claims with the relieving spring washer (50) having a first and a second axial section (52, 54) separated by a first step (56) of the relieving spring washer (50) and with the first step (56) of the relieving spring washer (50) comprising the second relieving spring rest and with the second axial section (54) of the relieving spring washer (50) being radially surrounded by an axial section of the relieving spring (48).

10. Relieving device in accordance with claim 9 with the relieving spring washer (50) having a third axial section (70) which is separated from the second axial section (54) of the spring washer by a second step (76) of the relieving spring washer (50) and with the second step (76) of the relieving spring washer (50) forming a first compensation spring rest for a first compensation spring (72) of the compensation device (31).

11. Compensation assembly (30) for an injector comprising the relieving device in accordance with one of the preceding claims and comprising the compensation device (31), with

- the compensation device (31) comprising a first and a second compensation body (40, 41) which are axially movable relative to each other,

- the first compensation body (40) comprising a first axial end (42) of the compensation device (31) and with the second compensation body (41) comprising a second axial end (44) of the compensation device (31),

- the first axial end (42) of the compensation device (31) being coupled in axial direction with the ground plate (36) of the relieving body (32) and with the second compensation body (41) being rigidly coupled to the relieving spring washer (50).

12. Compensation assembly in accordance with claim 11 and with one of the claims 5 or 6 with the first and/or the second compensation body (41) having at least two grooves (74) at an outer shell of the first and/or respectively the second compensation body (41) which at least partly take in the transferring elements (34).

13. Injector comprising the compensation assembly in accordance with one of the claims 11 or 12 and comprising a housing (1) which has a recess of the housing (1) and comprising an actor (14) which is arranged in the recess of the housing (1) and which is coupled to the compensation assembly (30) at a first axial end of the actor (14) and comprising a valve group (2) which is coupled to the housing (1) at a first axial end of the recess of the housing (1) and which is coupled to the actor (14) at a second axial end of the actor (14).

14. Injector in accordance with claim 13 comprising an end piece (62) which is coupled to the relieving body (32) and which has a recess (68) of the end piece (62) axially extending through the end piece (62) from that side of the end piece (62) facing towards the ground plate (36) of the relieving body (32), with the relieving body (32) and the end piece (62) closing the recess of the housing (1) in axial direction.

15. Injector in accordance with claim 14 with the end piece (62) comprising a first tube-section (64) which axially extends from the recess (68) of the end piece (62) and which takes in the relieving rod (38), the relieving rod (38) protruding from the first tube-section (64) of the end piece (62).

16. Injector in accordance with one of the claims 14 or 15 with the end piece (62) comprising a second tube-section (66) which at least partly takes in the ground plate (36) of the relieving body (32).

17. Method of assembling and calibrating an injector in accordance with one of the claims 13 to 16, the method comprising the steps of

- coupling the valve group (2) of the injector to the first axial end of the recess of the housing (1) of the injector,

- inserting the actor (14) into the recess of the housing (1),

- inserting the compensation assembly (30) into the recess of the housing (1) of the injector, the second compensation body (41) of the compensation device (31) being coupled to the actor (14),

- applying a given pressure on the relieving body (32),

- dosing fluid with the injector,

- detecting the fluid dosed by the injector,

- varying the pressure on the relieving body (32) dependent on the detection of the dosing of the fluid,

- coupling the relieving body (32) rigidly to the housing (1) if the fluid is dosed by the injector in a given way.

18. Method in accordance with claim 16 with the end piece (62) being inserted into the recess of the housing (1) and with the end piece (62) being fixed to the relieving body (32) before the given pressure is applied on the relieving body (32) and with the relieving body (32) being rigidly coupled to the housing (1) of the injector via the end piece (62), if the fluid is dosed by the injector in a given way.

19. Method in accordance with claim 16 with the end piece (62) being inserted into the recess of the housing (1) and with the end piece (62) being fixed to the housing (1) before the given pressure is applied on the relieving body (32) and with the tube-section of the end piece (62) being rigidly coupled to the relieving rod (38), if the fluid is dosed by the injector in a given way.

Drawing