Oil distribution disc and plunger pump

Abstract

An oil distribution disc of a plunger pump and the plunger pump relate to the technical field of plunger pumps, and comprise an oil distribution disc body with a first end and a second end; the oil suction port penetrates through the first end and the second end of the oil distribution disc body and is provided with an oil suction end and an oil outlet end corresponding to the first end and the second end of the oil distribution disc body; the oil discharge port penetrates through the first end and the second end of the oil distribution disc body and is provided with an oil discharge end and an oil inlet end corresponding to the first end and the second end of the oil distribution disc body, and the size of the oil discharge port is smaller than that of the oil suction port; the abutting ring is fixedly arranged in the oil storage area, one side of the abutting ring covers the oil discharge port, the other side of the abutting ring is provided with a notch corresponding to the oil suction port, and the abutting ring is provided with an oil storage groove communicated with the oil discharge port; and oil sucked into the oil storage area through the oil suction port can flow into the oil storage tank under the action of the pump body and is discharged from the oil discharge port. By the adoption of the technical scheme, the effects of low noise, stable operation, production cost reduction and the like are achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of plunger pumps, in particular to an oil distribution plate of a plunger pump and a plunger pump. Background Art

[0002] The plunger pump is an important device in the hydraulic system. It relies on the reciprocating motion of the plunger in the cylinder to change the volume of the sealed working chamber to achieve oil suction and oil pressure. The oil distribution plate in the hydraulic motor or pump plays the role of high and low oil circuit distribution, so that when the high-pressure oil in the motor or pump acts, the torque is output, and when the low-pressure oil (return oil) is used, the high-pressure oil in the plunger chamber that stops outputting torque is discharged.

[0003] In the related art, CN113653636A discloses a hydraulic plunger pump oil distribution plate, which includes an oil distribution plate body, an oil suction window, an oil discharge window, and a sealing portion. The sealing portion divides the surface of the oil distribution plate body into an oil suction area, an oil discharge area, and an oil leakage area. The oil suction area is connected to the oil suction window, and the oil discharge area is connected to the oil discharge window. The sealing portion is provided with a connecting portion connecting the oil suction area and the oil leakage area.

[0004] However, according to the attached drawings of CN113653636A, the oil suction window and the oil discharge window of the oil distribution plate disclosed therein are equal in size, which will cause the oil suction flow rate and the oil discharge flow rate of the plunger pump to be mismatched. Excessive oil discharge flow rate may cause the oil to be discharged quickly, causing hydraulic shock and system vibration, affecting the smooth operation of the system. Although some oil distribution plates with suction windows larger than the oil discharge windows have appeared on the market, they are usually a larger suction window with multiple small oil discharge windows, and multiple small oil discharge windows need to be punched out, which increases the production cost.

[0005] Therefore, the present application proposes an oil distribution plate and a plunger pump to solve the above problems. Utility Model Content

[0006] The utility model aims to solve the defects and shortcomings in the prior art and provides an oil distribution plate and a plunger pump.

[0007] The utility model provides an oil distribution plate adopting a technical solution: an oil distribution plate, comprising:

[0008] An oil distribution plate body, which has a first end and a second end, wherein the second end has a plurality of abutting portions for abutting against a pump body of a plunger pump, wherein the plurality of abutting portions are distributed along a circumferential direction of the oil distribution plate body, and the plurality of abutting portions cooperate with the pump body to form an oil storage area;

[0009] an oil suction port, which passes through the first end and the second end of the oil distribution plate body, and has an oil suction end and an oil outlet end corresponding to the first end and the second end of the oil distribution plate body, the oil outlet end of the oil suction port is communicated with the oil storage area, and the oil outlet end of the oil suction port is located on one side of the center of the oil storage area;

[0010] an oil discharge port, which passes through the first end and the second end of the oil distribution plate body, and has an oil discharge end and an oil inlet end corresponding to the first end and the second end of the oil distribution plate body, the oil inlet end of the oil discharge port is communicated with the oil storage area, the oil discharge end of the oil discharge port is located on the other side of the center of the oil storage area, and the size of the oil discharge port is smaller than the oil suction port; and

[0011] An abutment ring is fixedly arranged in the oil storage area, with one side covering the oil discharge port and the other side being provided with a notch corresponding to the oil suction port, and an oil storage groove connected to the oil discharge port is arranged on the abutment ring, so that the low-pressure oil sucked into the oil storage area through the oil suction port can flow into the oil storage groove and be discharged from the oil discharge port after being converted into high-pressure oil by the action of the pump body.

[0012] Preferably, the oil storage tank is arranged in a semicircular waist-shaped hole shape, the size of the oil discharge port is smaller than the size of the oil storage tank, and the oil discharge port corresponds to the middle part of the oil storage tank.

[0013] Preferably, the cross section of the oil suction port is circular, and the cross section of the oil discharge port is an arc rectangle.

[0014] Preferably, the number of the abutting portions is four, the four abutting portions are evenly distributed along the circumferential direction of the oil distribution plate body, and the four abutting portions cooperate to form four oil drain ports connected to the oil storage area.

[0015] Preferably, a groove is provided on the first end of the oil distribution plate body, the oil discharge end of the oil discharge port is communicated with the groove, and a sealing rubber ring is provided in the groove.

[0016] The utility model also provides a plunger pump, comprising a housing, the oil distribution plate as described above, a pump body, a plunger, a swash plate and a rear cover, the housing having an installation cavity, and two ends of the housing respectively having a first opening and a second opening connected to the installation cavity, the oil distribution plate body, the pump body, the plunger and the swash plate are sequentially arranged in the installation cavity from the first opening toward the second opening.

[0017] Preferably, a guide groove is provided at the first opening of the shell, and the guide groove is arranged along the axial direction of the shell, one end of the guide groove is located at the first opening of the shell, and the other end of the guide groove extends toward the inside of the shell along the axial direction of the shell, and the side wall of the oil distribution plate body is provided with a guide block that slides with the guide groove.

[0018] Preferably, a plunger cavity corresponding to the plunger is provided on the pump body, one end of the plunger is elastically connected to the plunger cavity, and the other end of the plunger extends out of the plunger cavity and is rotatably connected to the swash plate. A connecting groove is also provided on the pump body, so that the oil in the oil storage area can flow into the plunger cavity through the connecting groove.

[0019] Preferably, a sliding shoe rotatably matched with the plunger is provided on the swash plate, and an oil groove is provided on one side surface of the sliding shoe matched with the plunger.

[0020] Preferably, an external drive shaft is connected to the second opening of the shell, one end of the external drive shaft extends into the shell through the second opening and is fixedly connected to the pump body, and an oil seal is provided on the shell for sealing the gap between the drive shaft and the second opening.

[0021] After adopting the above technical solution, the beneficial effects of the utility model are:

[0022] The present application sets the size of the oil discharge port on the oil distribution plate body to be smaller than the size of the oil suction port, and at the same time, through the cooperation between the oil storage groove on the abutment ring and the oil discharge port, the low-pressure oil is sucked into the oil storage area through the oil suction port during operation, and the low-pressure oil in the oil storage area is compressed into high-pressure oil through the movement of the pump body, and then flows into the oil discharge port through the oil storage groove, thereby completing the oil supply to the external system. The mismatch between the oil suction flow rate and the oil discharge flow rate will not cause the oil to be discharged quickly, causing hydraulic shock and system vibration, and affecting the smooth operation of the system. That is, the vibration noise generated during operation is reduced, and the smooth operation of the entire plunger pump is ensured. Only one oil discharge port is required, which reduces the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0024] Figure 1 It is a display diagram of the oil distribution plate body in this embodiment;

[0025] Figure 2 yes Figure 1 Another perspective of the display diagram;

[0026] Figure 3 is a display diagram of the plunger pump in this embodiment;

[0027] Figure 4 is a cross-sectional view of the plunger pump in this embodiment;

[0028] Figure 5 2 is an exploded view of the plunger pump in this embodiment.

[0029] Explanation of the reference numerals in the accompanying drawings: 10, oil distribution plate body; 101, first end; 102, second end; 11, oil suction port; 12, oil discharge port; 13, abutment portion; 131, oil storage area; 132, oil drain groove; 14, abutment ring; 141, oil storage groove; 15, groove; 151, sealing rubber ring; 16, guide block; 20, housing; 21, mounting cavity; 22, first opening; 23, second opening; 24, guide groove; 30, pump body; 31, plunger cavity; 32, connecting groove; 40, plunger; 50, inclined plate; 51, sliding shoe; 60, oil seal. DETAILED DESCRIPTION

[0030] The following will be combined with the attached embodiment of the utility model Figure 1-5 , clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of them. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0031] It should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", "back", "side", "circumferential" and the like in the present invention indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation on the present invention. In addition, the words "first", "second" and the like are only used to distinguish multiple components or structures with the same or similar structures, and do not represent any special limitation on the setting order or connection relationship.

[0032] This embodiment relates to an oil distribution plate, which is used in conjunction with a pump body 30 of a plunger pump to distribute high and low oil circuits in a hydraulic motor or pump. Figure 1 and Figure 2 It includes an oil distribution plate body 10, the oil distribution plate body 10 has a first end 101 and a second end 102, and the second end 102 is provided with a plurality of abutting portions 13 abutting against a pump body 30 of a plunger pump, the plurality of abutting portions 13 are distributed along the circumferential direction of the oil distribution plate body 10, and the plurality of abutting portions 13 cooperate with the pump body 30 to form an oil storage area 131.

[0033] The oil distribution plate body 10 is provided with an oil suction port 11 and an oil discharge port 12, both of which penetrate the first end 101 and the second end 102 of the oil distribution plate body 10. The oil suction port 11 has an oil suction end and an oil discharge end corresponding to the first end 101 and the second end of the oil distribution plate body 10. The oil discharge end of the oil suction port 11 is connected with the oil storage area 131, and the oil discharge end of the oil suction port 11 is located on one side of the center of the oil storage area 131. The oil discharge port 12 has an oil discharge end and an oil inlet end corresponding to the first end 101 and the second end 102 of the oil distribution plate body 10. The oil inlet end of the oil discharge port 12 is connected with the oil storage area 131, and the oil discharge end of the oil discharge port 12 is located on the other side of the center of the oil storage area 131, and the size of the oil discharge port 12 is smaller than the oil suction port 11.

[0034] A butt ring 14 is also provided on the second end 102 of the oil distribution plate body 10. The butt ring 14 is located in the oil storage area 131 and is used to butt against one end of the pump body 30. One side of the butt ring 14 covers the oil discharge port 12, and the other side of the butt ring 14 is provided with a notch corresponding to the oil suction port 11, so that the external low-pressure oil can enter the oil storage area 131 through the oil suction port 11, and the butt ring 14 is provided with an oil storage groove 141 connected to the oil discharge port 12, so that the oil sucked into the oil storage area 131 through the oil suction port 11 can flow into the oil storage groove 141 and be discharged from the oil discharge port 12 under the action of the pump body 30.

[0035] Furthermore, the oil storage tank 141 is arranged in a semicircular waist hole shape, the size of the oil discharge port 12 is smaller than the size of the oil storage tank 141, and the oil discharge port 12 corresponds to the middle of the oil storage tank 141. During operation, the oil with lower pressure in the oil storage area 131 is converted into oil with higher pressure after the pump body 30 is actuated and flows into the oil storage tank 141 for transfer and then flows into the oil inlet end of the oil discharge port 12, thereby controlling the discharge flow of the oil discharge port 12, avoiding the situation of hydraulic shock and vibration of the plunger pump system caused by excessive discharge flow, and ensuring the smooth operation of the entire plunger pump system.

[0036] Furthermore, the cross section of the oil suction port 11 is circular, and the cross section of the oil discharge port 12 is an arc rectangle.

[0037] Through the above arrangement, the circular oil suction port 11 can ensure the oil inlet flow rate of the oil suction port 11, and the arc rectangular oil discharge port 12 can further reduce the oil discharge flow rate of the oil discharge port 12, thereby ensuring the stable operation of the plunger pump.

[0038] Furthermore, the number of the abutment portions 13 is four, and the four abutment portions 13 are evenly distributed along the circumferential direction of the body of the oil distribution plate, and the four abutment portions 13 cooperate to form four oil drain ports that are connected to the oil storage area 131. In other embodiments, the abutment portions 13 may also be set to three or other numbers, which may be increased or decreased accordingly according to actual conditions, and are not limited here.

[0039] During operation, the oil in the oil storage area 131 is discharged to between the oil distribution plate body 10 and the pump body 30 through the oil drain port, so that during operation, the low-pressure oil in the oil storage area 131 can be sucked into the pump body 30, and the low-pressure oil in the pump body 30 can also be discharged to the oil storage area 131 or the oil drain port 12, thereby forming an oil circulation system to ensure the stable operation of the plunger pump.

[0040] Furthermore, a groove 15 is provided on the first end 101 of the oil distribution plate body 10, the oil discharge end of the oil discharge port 12 is connected to the groove 15, and a sealing rubber ring 151 is provided in the groove 15. That is, by providing the sealing rubber ring 151, the oil pipe at the oil discharge end of the oil discharge port 12 and the oil discharge end of the oil discharge port 12 are better sealed to avoid oil leakage.

[0041] In addition, refer to Figure 3 , Figure 4 and Figure 5 The present embodiment further provides a plunger pump, comprising a housing 20, the oil distribution plate as described above, a pump body 30, a plunger 40, a swash plate 50 and a rear cover, wherein the housing 20 is roughly cylindrical, has a mounting cavity 21, and has a first opening 22 and a second opening 23 connected to the mounting cavity 21 at both ends of the housing 20, respectively, and the oil distribution plate body 10, the pump body 30, the plunger 40, the swash plate 50 and the rear cover are sequentially arranged in the mounting cavity 21 from the first opening 22 toward the second opening 23.

[0042] In addition, it should be noted that the abutment portion 13 and the abutment ring 14 on the oil distribution plate body 10 are both abutted against the end surface of the pump body 30, and the oil suction port 11 and the oil discharge port 12 of the oil distribution plate body 10 are provided with a suction valve and a discharge valve, the pump body 30 is rotatably arranged in the mounting cavity 21 of the housing 20, the central axis of the swash plate 50 and the central axis of the pump body 30 have an inclination angle, and in this embodiment, a driving mechanism for driving the pump body 30 to rotate is also provided.

[0043] Furthermore, in order to realize the rapid positioning between the oil distribution plate body 10 and the housing 20 and improve the assembly efficiency, a guide groove 24 is provided at the first opening 22 of the housing 20, and the guide groove 24 is arranged along the axial direction of the housing 20, one end of the guide groove 24 is located at the first opening 22 of the housing 20, and the other end of the guide groove 24 extends toward the inside of the housing 20 along the axial direction of the housing 20, and the side wall of the oil distribution plate body 10 is provided with a guide block 16 that slides with the guide groove 24.

[0044] It can be understood that through the cooperation between the guide block 16 on the oil distribution plate body 10 and the guide groove 24 on the shell 20, the oil distribution plate body 10 and the shell 20 can be quickly positioned, the operation is simple and convenient, the assembly efficiency is improved, and the oil distribution plate body 10 is not easy to shift.

[0045] Furthermore, a plunger cavity 31 corresponding to the plunger 40 is provided on the pump body 30. In the present embodiment, the number of the plunger cavity 31 and the number of the plunger 40 are both three, and the three plunger cavities 31 are evenly arranged along the circumferential direction of the pump body 30. One end of the plunger 40 is elastically connected to the plunger cavity 31 through a spring, and the other end of the plunger 40 extends out of the plunger cavity 31 and is rotatably connected to the swash plate 50. The pump body 30 is also provided with connecting grooves 32, and the number of the connecting grooves 32 corresponds to that of the plunger cavity 31, so that the oil in the oil storage area 131 can flow into the plunger cavity 31 through the connecting grooves 32.

[0046] When working, the pump body 30 is driven to rotate, which drives the plunger 40 and the swash plate 50 to rotate. Since the central axis of the swash plate 50 is inclined at an angle to the central axis of the pump body 30, the swash plate 50 can drive the plunger 40 to reciprocate in the plunger cavity 31 when rotating. The working process of the plunger pump is divided into the suction stage, the closing and compression stage, and the discharge stage for detailed description.

[0047] Suction stage: When the swash plate 50 starts to rotate, the plunger 40 moves outward under the action of centrifugal force, that is, the plunger 40 moves relative to the plunger chamber 31 toward the swash plate 50. At this time, negative pressure is generated in the plunger chamber 31, and the suction valve is opened, so that the oil flows into the oil storage area 131 through the oil suction port 11 and then enters the plunger chamber 31 through the connecting groove 32 (the oil at this time is low-pressure oil). At this time, the oil is sucked into the pump body 30.

[0048] Closing and compression stage: When the plunger 40 reaches the outermost end of the swash plate 50 and starts to move toward the center of the swash plate 50, the suction valve is closed, the liquid in the plunger chamber 31 is closed, and the plunger 40 moves relative to the plunger chamber 31 in a direction away from the swash plate 50, thereby compressing the oil in the plunger chamber 31, that is, converting the low-pressure oil into high-pressure oil.

[0049] Discharge stage: When the plunger 40 moves to a certain position toward the center of the swash plate 50, the discharge valve opens, and the high-pressure oil in the plunger chamber 31 enters the oil storage area 131 through the connecting groove 32 and then flows into the oil discharge port 12 for discharge. When the plunger 40 moves to the innermost end, that is, the plunger 40 moves to the maximum stroke position, the discharge valve closes and the oil is completely discharged.

[0050] Furthermore, in order to enable the plunger 40 to be stably rotatably connected to the swash plate 50, a slipper 51 rotatably matched with the plunger 40 is provided on the swash plate 50, and one end of the plunger 40 away from the pump body 30 is accommodated in the slipper 51 and can rotate relative to the slipper 51, and an oil groove is provided on the surface of the side where the slipper 51 cooperates with the plunger 40. By adding lubricating oil to the oil groove, the mechanical friction between the slipper 51 and the plunger 40 can be reduced, so that the plunger 40 can be stably rotatably connected to the swash plate 50, and the service life of the slipper 51 and the plunger 40 is extended.

[0051] Furthermore, an external drive shaft is connected to the second opening 23 of the shell 20, one end of the external drive shaft is connected to the driving mechanism, and the other end of the external drive shaft extends into the shell 20 through the second opening 23 and is fixedly connected to the pump body 30. An oil seal 60 is provided on the shell 20 for sealing the gap between the external drive shaft and the second opening 23.

[0052] It can be understood that, through the cooperation between the second opening 23 of the housing 20 and the external drive shaft, the external drive shaft can be extended into the installation cavity 21 of the housing 20 and fixedly connected to the pump body 30, thereby driving the pump body 30 to rotate, and then the plunger 40 can reciprocate in the plunger cavity 31 of the pump body 30. At the same time, the gap between the external drive shaft and the through hole is sealed by the oil seal 60, thereby preventing the oil (generally lubricating oil, the oil in the plunger cavity 31 will not enter the installation cavity 21) in the installation cavity 21 from flowing out of the gap between the through hole and the external drive shaft.

[0053] The above is only used to illustrate the technical solution of the utility model rather than to limit it. Other modifications or equivalent substitutions made to the technical solution of the utility model by ordinary technicians in this field should be included in the scope of the claims of the utility model as long as they do not depart from the spirit and scope of the technical solution of the utility model.

Claims

1. An oil distribution plate, characterized in that: include: An oil distribution plate body (10) having a first end (101) and a second end (102), wherein the second end (102) has a plurality of abutment portions (13) for abutting against a pump body (30) of a plunger pump, wherein the plurality of abutment portions (13) are distributed along a circumferential direction of the oil distribution plate body (10), and the plurality of abutment portions (13) cooperate with the pump body (30) to form an oil storage area (131); An oil suction port (11) passes through the first end (101) and the second end (102) of the oil distribution plate body (10), and has an oil suction end and an oil discharge end corresponding to the first end (101) and the second end (102) of the oil distribution plate body (10), the oil discharge end of the oil suction port (11) being in communication with the oil storage area (131), and the oil discharge end of the oil suction port (11) being located on one side of the center of the oil storage area (131); an oil discharge port (12) penetrating the first end (101) and the second end (102) of the oil distribution plate body (10), and having an oil discharge end and an oil inlet end corresponding to the first end (101) and the second end (102) of the oil distribution plate body (10), the oil inlet end of the oil discharge port (12) being in communication with the oil storage area (131), the oil discharge end of the oil discharge port (12) being located on the other side of the center of the oil storage area (131), and the size of the oil discharge port (12) being smaller than the oil suction port (11); and The abutment ring (14) is fixedly arranged in the oil storage area (131), with one side covering the oil discharge port (12) and the other side being provided with a notch corresponding to the oil suction port (11), and the abutment ring (14) is provided with an oil storage groove (141) connected with the oil discharge port (12), so that the oil sucked into the oil storage area (131) through the oil suction port (11) can flow into the oil storage groove (141) and be discharged from the oil discharge port (12) under the action of the pump body (30).

2. An oil distribution plate according to claim 1, characterized in that: The oil storage tank (141) is arranged in the shape of a semicircular waist hole, the size of the oil discharge port (12) is smaller than the size of the oil storage tank (141), and the oil discharge port (12) corresponds to the middle part of the oil storage tank (141).

3. An oil distribution plate according to claim 2, characterized in that: The cross section of the oil suction port (11) is circular, and the cross section of the oil discharge port (12) is an arc rectangle.

4. The oil distribution plate according to claim 1, characterized in that: The number of the abutment portions (13) is four, the four abutment portions (13) are evenly distributed along the circumferential direction of the oil distribution plate body (10), and the four abutment portions (13) cooperate to form four oil drain ports that are connected to the oil storage area (131).

5. The oil distribution plate according to claim 1, characterized in that: A groove (15) is provided on the first end (101) of the oil distribution plate body (10), the oil discharge end of the oil discharge port (12) is connected to the groove (15), and a sealing rubber ring (151) is provided in the groove (15).

6. A plunger pump, characterized in that: The invention comprises a housing (20), an oil distribution plate according to any one of claims 1 to 5, a pump body (30), a plunger (40) and a swash plate (50), wherein the housing (20) has a mounting cavity (21), and two ends of the housing (20) are respectively provided with a first opening (22) and a second opening (23) connected to the mounting cavity (21); the oil distribution plate body (10), the pump body (30), the plunger (40) and the swash plate (50) are sequentially arranged in the mounting cavity (21) from the first opening (22) toward the second opening (23).

7. A plunger pump according to claim 6, characterized in that: A guide groove (24) is provided at the first opening (22) of the shell (20), and the guide groove (24) is arranged along the axial direction of the shell (20). One end of the guide groove (24) is located at the first opening (22) of the shell (20), and the other end of the guide groove (24) extends toward the inside of the shell (20) along the axial direction of the shell (20), and the side wall of the oil distribution plate body (10) is provided with a guide block (16) that is slidably matched with the guide groove (24).

8. A plunger pump according to claim 6, characterized in that: The pump body (30) is provided with a plunger cavity (31) corresponding to the plunger (40); one end of the plunger (40) is elastically connected to the plunger cavity (31); the other end of the plunger (40) extends out of the plunger cavity (31) and is rotatably connected to the swash plate (50); and the pump body (30) is also provided with a connecting groove (32) so that the oil in the oil storage area (131) can flow into the plunger cavity (31) through the connecting groove (32).

9. A plunger pump according to claim 8, characterized in that: The swash plate (50) is provided with a sliding shoe (51) that is rotatably matched with the plunger (40), and an oil groove is provided on a surface of one side of the sliding shoe (51) that is matched with the plunger (40).

10. A plunger pump according to claim 8, characterized in that: An external drive shaft is connected to the second opening (23) of the housing (20); one end of the external drive shaft extends into the housing (20) through the second opening (23) and is fixedly connected to the pump body (30); an oil seal (60) is provided on the housing (20) for sealing a gap between the drive shaft and the second opening (23).

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