Shaft seal structure for pump or motor

Abstract

A shaft seal structure for a pump or a motor includes an axially outer seal ring and an axially inner seal ring disposed around a rotating shaft between a housing of the pump or the motor and the rotating shaft, with a seal lip of the axially outer seal ring facing axially outer and a dust lip facing axially inner, and a seal lip of the axially inner seal ring facing axially outer and a dust lip of the axially inner seal ring facing axially inner. A sealing lip of the axial inner side sealing ring faces the axial inner side, and a dustproof lip faces the axial outer side; the check ring is fixed on the rotating shaft on the axial outer side of the axial outer side sealing ring, the check ring at least faces one part of the axial outer side sealing ring in the axial direction, and an axial gap is formed between the check ring and the part of the axial outer side sealing ring. The dustproof performance of the shaft seal structure is improved.

Description

Technical Field

[0001] The present application relates to a shaft seal structure for a pump or a motor, having improved dust-proof performance. Background Art

[0002] A shaft seal needs to be provided between the housing of a pump or a motor and the rotating shaft to seal the inside and outside of the housing, especially to isolate the working medium in the pump or the motor from the external air and engine oil. Since the external air and engine oil often carry particulate matter, in order to improve the sealing effect, a double seal ring structure is sometimes adopted, in which two seal rings are arranged around the rotating shaft back to back. For the double seal ring structure, the sealing lip of the axially outer seal ring needs to be arranged facing axially outward, and the sealing lip of the axially inner seal ring needs to be arranged facing axially inward. In this arrangement, the dust-proof lip of the axially outer seal ring faces axially inward, and the dust-proof effect is weak. Particulate matter easily enters the seal of the axially outer seal ring and may scratch the rotating shaft. Summary of the Utility Model

[0003] The object of the present application is to provide a shaft seal structure for a pump or a motor, which has improved dust-proof performance.

[0004] To this end, in one aspect of the present application, there is provided a shaft seal structure for a pump or a motor, the pump or the motor including a rotating shaft and a housing, the rotating shaft extending from the outside of the housing to the inside of the housing, the shaft seal structure including: an axially outer seal ring and an axially inner seal ring arranged around the rotating shaft between the housing and the rotating shaft, wherein the sealing lip of the axially outer seal ring faces axially outward and the dust-proof lip faces axially inward, while the sealing lip of the axially inner seal ring faces axially inward and the dust-proof lip faces axially outward; and a retaining ring fixed on the rotating shaft axially outside the axially outer seal ring, the retaining ring facing at least a part of the axially outer seal ring axially and being separated from this part by an axial gap.

[0005] In one embodiment, the retaining ring axially covers the sealing lip of the axially outer seal ring and is separated from the sealing lip of the axially outer seal ring by an axial gap.

[0006] In one embodiment, the retaining ring axially covers the sealing lip of the axially outer seal ring and at least a part of the groove between the sealing lip and the outer ring part of the axially outer seal ring, and is separated from the sealing lip of the axially outer seal ring by an axial gap.

[0007] In one embodiment, the retaining ring axially covers the sealing lip of the axially outer seal ring and at least a part of the outer ring part of the axially outer seal ring, and is separated from the outer ring part by an axial gap.

[0008] In one embodiment, the axially outer sealing ring and the axially inner sealing ring are arranged against a positioning ring fixed in the housing.

[0009] In one embodiment, an annular clamping groove and a retaining ring groove directly connected to the axially inner side of the clamping groove are formed on the outer periphery of the rotating shaft. The retaining ring is arranged in the retaining ring groove, and a snap ring is installed in the clamping groove to fix the retaining ring on the rotating shaft through the snap ring.

[0010] In one embodiment, the axial width of the retaining ring groove is smaller than the axial width of the clamping groove, and the bottom diameter of the retaining ring groove is larger than the bottom diameter of the clamping groove; and the axial width of the retaining ring groove is smaller than the thickness of the retaining ring.

[0011] In one embodiment, the bottom diameter of the retaining ring groove is set to be larger than the outer diameter of any part of the rotating shaft located axially outside the retaining ring groove.

[0012] In one embodiment, the rotating shaft passes through the end wall of the housing. An axially outer hole section and a sealing section with a reduced diameter relative to the axially outer hole section are formed in the end wall. The axially outer sealing ring and the axially inner sealing ring are arranged in the sealing section. A step surface facing axially outward is formed between the axially outer hole section and the sealing section. The axially outer groove wall of the retaining ring groove is located at a position axially inward and offset relative to the step surface.

[0013] In one embodiment, the retaining ring is fixed on the rotating shaft by an elastic element that applies an elastic acting force to the retaining ring in the axially inward direction; alternatively, the retaining ring is fixed on the rotating shaft by a threaded fit.

[0014] According to the present application, in the shaft seal structure of a pump or a motor, a protective retaining ring is added on the axially outer side of the axially outer sealing ring to prevent external particulate matter from entering the sealing ring. At the same time, during the operation of the pump or the motor, the retaining ring rotates with the rotating shaft, and it is easy to push away or shake off external particulate matter. Therefore, the dust-proof performance of the shaft seal structure of the pump or the motor of the present application is improved, and the sealing ring and the rotating shaft can be prevented from being scratched. Description of the Drawings

[0015] The foregoing and other aspects of the present application will be more fully understood and appreciated through the following detailed description with reference to the accompanying drawings, in which:

[0016] Figure 1 is a cross-sectional view of the shaft seal structure of a pump or a motor according to a feasible embodiment of the present application;

[0017] Figure 2 is Figure 1 an enlarged cross-sectional view of the shaft seal structure shown;

[0018] Figure 3 is Figure 1 An enlarged cross-sectional view at the axial outer sealing ring of the shaft sealing structure shown;

[0019] Figure 4 is Figure 1 A cross-sectional view of the corresponding parts of the housing and the rotating shaft at the shaft sealing structure shown;

[0020] Figure 5 is Figure 4 A partial enlarged view of the circled part in Detailed implementation manners

[0021] This application generally relates to a shaft sealing structure for a pump or a motor. The pump or the motor mentioned here can be a piston pump or a piston motor, or other forms of pumps or motors.

[0022] Taking a piston pump as an example, a typical piston pump includes a rotating shaft carried by a housing, and inside the inner space of the housing, various functional elements of the piston pump are arranged. For example, a cylinder block is fixedly supported on the front part of the rotating shaft, so that the cylinder block can be driven by the rotating shaft to rotate. A plurality of piston chambers are formed in the cylinder block and are arranged around the rotation axis. The front end of each piston chamber leads to the front end face of the cylinder block, and the rear end is open to the rear end face of the cylinder block. A corresponding piston is inserted into the rear end of each piston chamber, and each piston can slide in the piston chamber, and the pistons rotate together with the cylinder block. The rear end of each piston protruding from the piston chamber forms or is connected with a ball head, and the ball head is inserted into a corresponding slipper, so that each slipper can rotate relative to the corresponding ball head. The rear end faces of the slippers are slidably pushed against an inclined plate, and a return disk keeps the slippers simultaneously pushed against the inclined plate. A distribution disk is fixed to the front end face of the cylinder block. The distribution disk has a suction oil groove and a discharge oil groove. When the cylinder block rotates, the front end of each piston chamber slides past the suction oil groove and the discharge oil groove in sequence. Suction oil channels and discharge oil channels are formed in the port plate and are respectively communicated with the suction oil groove and the discharge oil groove. When the piston pump is operating, the working medium is sucked in through the suction oil channel and pumped out through the discharge oil channel. The structures of piston pumps and other types of pumps are well known in the art. In addition, as is well known in the art, a motor can have a basic structure similar to that of a pump. A pump is used to pump the working medium, and a motor is used to be driven by the working medium. Therefore, the shaft sealing structure of this application can be used for both pumps and motors.

[0023] An exemplary structure at the shaft sealing structure of the pump or motor of this application is shown in Figure 1 、 Figure 2 It should be noted that, in order to clearly illustrate the principle of this application, the structures involved in the pump or motor are only schematically shown, not drawn to scale, and some details are omitted in the figures.

[0024] As shown in Figure 1As shown, the pump or motor includes a rotating shaft 1 that extends from outside the housing of the pump or motor through the housing 2 (specifically, the end wall of the housing 2) into the interior of the housing. A pair of sealing rings is arranged around the rotating shaft 1 in the housing 2, namely an axially outer sealing ring 3 and an axially inner sealing ring 4, which are arranged in a back-to-back orientation. Specifically refer to Figure 2 , where the sealing lip 3a of the axially outer sealing ring 3 faces axially outward and the dust-proof lip 3b faces axially inward, while the sealing lip 4a of the axially inner sealing ring 4 faces axially inward and the dust-proof lip 4b faces axially outward. The sealing lips 3a, 4a usually have clamping springs, so that a pair of sealing rings can tightly seal the rotating shaft 1.

[0025] Furthermore, as shown in Figure 1 、 Figure 2 , a positioning ring 5 is arranged between the pair of sealing rings 3, 4, which is fixed in the housing 2. In addition, on the axially outer side of the axially outer sealing ring 3, a protective retaining ring 6 is arranged, and a snap ring 7 is installed on its axially outer side for fixing the retaining ring 6 on the rotating shaft 1.

[0026] It can be clearly seen from Figure 2 that the dust-proof lip 3b of the axially outer sealing ring 3 is located axially inward of the sealing lip 3a, so the dust-proof lip 3b cannot prevent particulate matter from passing over the sealing lip 3a and entering the axially outer sealing ring 3. By arranging the retaining ring 6 on the axially outer side of the axially outer sealing ring 3 in this application, it is possible to prevent external particulate matter from entering the pair of sealing rings, especially from entering the axially outer sealing ring 3.

[0027] Refer to the enlarged view in Figure 3 . Looking axially, the retaining ring 6 faces most of the axially outer sealing ring 3, at least axially blocking the sealing lip 3a; preferably, in addition to blocking the sealing lip 3a, the retaining ring 6 also blocks at least a part, preferably at least most of, the axially outer groove 3d of the axially outer sealing ring 3 that is located between the sealing lip 3a and the outer ring part 3c and faces axially outward.

[0028] Refer to Figure 4 . Between the axially outer hole section 2a and the axially inner hole section 2b of the through hole in the housing 2, a sealing section 2c with a reduced diameter relative to these two hole parts is formed. A ring groove 2d is formed at approximately the axial center of the sealing section 2c for arranging the positioning ring 5 therein. A step surface 2e facing axially outward is formed between the axially outer hole section 2a and the sealing section 2c.

[0029] The positioning ring 5 can be in the form of an elastic snap ring so that it can be compressed and then inserted into the ring groove 2d and then released to be fixed in the ring groove 2d. A pair of sealing rings is arranged on the axial two sides of the positioning ring 5.

[0030] Refer to Figure 4 、 Figure 5, an annular card slot 1a and a retaining ring groove 1b directly connected to the inner side of the card slot 1a axially are formed on the outer periphery of the rotating shaft 1. The axial width of the retaining ring groove 1b is smaller than that of the card slot 1a, and the bottom diameter of the groove is larger than that of the card slot 1a.

[0031] A retaining ring 6 is installed in the retaining ring groove 1b, and the axial width of the retaining ring groove 1b is slightly smaller than the thickness of the retaining ring 6. The retaining ring 6 can be in the form of a thin metal plate in a circular ring shape and does not have the ability to expand or contract radially. The retaining ring 6 can use a circular washer as a standard part, or can be specifically made according to the specific structure and size of the pump or motor, for example, made by stamping metal sheets. The snap ring 7 can use a circlip as a standard part, or can be specifically made according to the size of the retaining ring 6, for example, made by stamping steel sheets.

[0032] The thickness of the retaining ring 6 is usually much smaller than that of the snap ring 7. For example, it is less than 1 / 5 of the thickness of the snap ring 7. The bottom diameter of the retaining ring groove 1b is set to be slightly larger than the outer diameter of any part of the rotating shaft 1 located axially outside the retaining ring groove 1b, so that the retaining ring 6 can be easily placed into the retaining ring groove 1b.

[0033] The axial width of the card slot 1a is slightly larger than the thickness of the snap ring 7. The snap ring 7 is in the form of an open elastic snap ring. After being expanded, it can be placed into the card slot 1a across the axially outer part of the rotating shaft 1, and then released and contracted to be clamped tightly in the card slot 1a, thereby fixing the retaining ring 6 against the axially outer groove wall 1c of the retaining ring groove 1b on the rotating shaft 1.

[0034] In the installed position, the axially outer end face of the outer ring part 3c of the axially outer sealing ring 3 is usually axially flush with the step face 2e, and the groove wall 1c of the retaining ring groove 1b is slightly axially inwardly offset relative to the step face 2e, so that the axially inner surface of the retaining ring 6 is located slightly axially inward relative to the step face 2e (that is, relative to the axially outer end face of the outer ring part 3c), which is beneficial to improving the sealing performance of the retaining ring 6. In addition, axially, there is a small gap between the retaining ring 6 and the facing part of the axially outer sealing ring 3. Refer to Figure 3 , there is a small axial gap between the radially inner part of the retaining ring 6 and the facing sealing lip 3a. In addition, the radially outer part of the retaining ring 6 faces most of the groove 3d, and the outer diameter of the retaining ring 6 is slightly smaller than the inner diameter of the axially outer end of the outer ring part 3c, so that the retaining ring 6 does not contact any part of the axially outer sealing ring 3.

[0035] As an alternative, the retaining ring 6 can also be designed to axially cover at least a part of the outer ring part 3c of the axially outer sealing ring 3. In this case, the radially inner part of the retaining ring 6 should be located at a position slightly axially outwardly offset relative to the axially outer end face of the outer ring part 3c, so that the retaining ring 6 does not contact the outer ring part 3c.

[0036] When the rotating shaft 1 rotates, the retaining ring 6 rotates with the rotating shaft 1, while a pair of sealing rings are both fixed in the housing 2. There is a small gap between the facing parts of the retaining ring 6 and the axially outer sealing ring 3, which can prevent the rotating retaining ring 6 from contacting the stationary axially outer sealing ring 3.

[0037] According to the present application, the retaining ring 6 separates the outside from the sealing rings. In addition, when the pump or motor is operating, the rotating shaft 1 rotates, driving the retaining ring 6 to rotate. The rotation of the retaining ring 6 generates an air vortex flow axially outside. This vortex flow will block and throw away the external particulate matters, preventing the particulate matters from entering the sealing rings, especially the axially outer sealing ring 3. Therefore, by adopting the shaft seal structure of the present application, the dust-proof performance of the pump or motor is improved, the rotating shaft 1 is more effectively prevented from being scratched, and the particulate matters are prevented from entering the interior of the housing 2. In addition, the cooperation mode between the retaining ring 6 and the snap ring 7 makes it easy to remove the retaining ring 6 and the snap ring 7 for overhauling the sealing rings.

[0038] The shaft seal structure of the present application is not limited to that shown and described above, but various adaptive modifications can be made under the principle of the present application.

[0039] For example, in the example described above, the retaining ring 6 is fixed to the rotating shaft 1 by the snap ring 7. However, the retaining ring 6 can also be fixed to the rotating shaft 1 by using an elastic element that applies an elastic acting force to the retaining ring 6 in the axially inward direction. For example, replace the snap ring 7 with an open disc spring; the open end with a smaller diameter of the disc spring is fixed in the card slot on the rotating shaft 1, and the open end with a larger diameter of the disc spring pushes against the retaining ring 6 in the axially inward direction. By adopting such an elastic element, the loosening of the retaining ring 6 can be avoided, and the noise generated when the retaining ring 6 rotates with the rotating shaft 1 can be reduced.

[0040] Alternatively, the snap ring 7 can be cancelled, and the retaining ring 6 can be designed to have a bushing part, and the bushing part is fixed to the rotating shaft by means of thread engagement. For a pump or motor with unidirectional operation, this solution can make the thread locking rotation direction of the bushing part opposite to the rotation direction of the rotating shaft 1, so as to realize self-locking of the retaining ring 6 when the pump or motor is operating.

[0041] Other solutions for fixing the retaining ring 6 to the rotating shaft 1 can also be designed by those skilled in the art.

[0042] Regardless of the specific structure of the retaining ring 6 adopted, the shaft seal structure of the present application can effectively improve the dust-proof ability of the pump or motor.

[0043] Although the present application is described here with reference to specific embodiments, the scope of the present application is not limited to the details shown. Various modifications can be made to these details without departing from the basic principle of the present application.

Claims

1. A shaft seal structure for a pump or a motor, the pump or the motor comprising a rotating shaft (1) and a housing (2), the rotating shaft (1) extending from the outside of the housing (2) to the inside of the housing (2), characterized in that: The shaft sealing structure comprises: An axially outer sealing ring (3) and an axially inner sealing ring (4) are arranged around the rotating shaft (1) between the housing (2) and the rotating shaft (1), wherein the sealing lip of the axially outer sealing ring (3) faces axially outward and the dustproof lip faces axially inward, while the sealing lip of the axially inner sealing ring (4) faces axially inward and the dustproof lip faces axially outward; and A retaining ring (6) is fixed on the rotating shaft (1) on the axially outer side of the axially outer sealing ring (3); the retaining ring (6) faces at least a part of the axially outer sealing ring (3) in the axial direction and is separated from the part by an axial gap.

2. The shaft seal structure for a pump or a motor according to claim 1, characterized in that: The retaining ring (6) covers the sealing lip of the axially outer sealing ring (3) in the axial direction and is separated from the sealing lip of the axially outer sealing ring (3) by an axial gap.

3. The shaft seal structure for a pump or a motor according to claim 1, characterized in that: The retaining ring (6) axially covers the sealing lip of the axially outer sealing ring (3) and at least a portion of the groove (3d) located between the sealing lip and the outer ring portion (3c) of the axially outer sealing ring (3), and is separated from the sealing lip of the axially outer sealing ring (3) by an axial gap.

4. The shaft seal structure for a pump or a motor according to claim 1, characterized in that: The retaining ring (6) axially covers the sealing lip of the axially outer sealing ring (3) and at least a part of the outer ring portion (3c) of the axially outer sealing ring (3), and is separated from the outer ring portion (3c) by an axial gap.

5. The shaft seal structure for a pump or a motor according to claim 1, characterized in that: The axially outer sealing ring (3) and the axially inner sealing ring (4) are arranged against a positioning ring (5) fixed in the housing (2).

6. The shaft seal structure for a pump or a motor according to any one of claims 1 to 5, characterized in that: The outer periphery of the rotating shaft (1) forms an annular retaining groove (1a) and a retaining ring groove (1b) directly connected to the axial inner side of the retaining groove (1a); the retaining ring (6) is arranged in the retaining ring groove (1b); a retaining ring (7) is installed in the retaining groove (1a); and the retaining ring (6) is fixed to the rotating shaft (1) via the retaining ring (7).

7. The shaft seal structure for a pump or a motor according to claim 6, characterized in that: The axial width of the retaining ring groove (1b) is smaller than the axial width of the clamping groove (1a), and the groove bottom diameter of the retaining ring groove (1b) is larger than the groove bottom diameter of the clamping groove (1a); and The axial width of the retaining ring groove (1b) is smaller than the thickness of the retaining ring (6).

8. The shaft seal structure for a pump or a motor according to claim 6, characterized in that: The groove bottom diameter of the retaining ring groove (1b) is set larger than the outer diameter of any portion of the rotating shaft (1) located axially outside the retaining ring groove (1b).

9. The shaft seal structure for a pump or a motor according to claim 6, characterized in that: The rotating shaft (1) passes through the end wall of the housing (2); an axially outer hole section (2a) and a sealing section (2c) having a reduced diameter relative to the axially outer hole section (2a) are formed in the end wall; the axially outer sealing ring (3) and the axially inner sealing ring (4) are arranged in the sealing section (2c); a step surface (2e) facing the axial outer side is formed between the axially outer hole section (2a) and the sealing section (2c); and a groove wall (1c) of the retaining ring groove (1b) facing the axially outer side is located at a position offset axially inward relative to the step surface (2e).

10. The shaft seal structure for a pump or a motor according to any one of claims 1 to 5, characterized in that: The retaining ring (6) is fixed to the rotating shaft (1) by means of an elastic element which applies an elastic force to the retaining ring (6) in an axially inward direction; or, the retaining ring (6) is fixed to the rotating shaft (1) by means of threaded engagement.

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