CN117759718A - Shaft sealing structure - Google Patents

Abstract

A shaft seal structure comprising: a shaft seal cover defining a shaft seal cavity for receiving a pressurized fluid; a rotating shaft rotatably passing through the shaft cover, the rotating shaft being at least partially located in the shaft seal cavity; a movable seal ring disposed in the shaft seal cavity around the rotary shaft and sealingly mounted to the rotary shaft; a static seal ring disposed in the shaft seal cavity and sealingly mounted to the shaft seal cover, the static seal ring being stationary relative to the shaft seal cover; and at least one intermediate seal ring disposed in the shaft seal cavity around the rotation shaft, the intermediate seal ring disposed between the movable seal ring and the stationary seal ring, the intermediate seal ring being capable of contacting the movable seal ring and the stationary seal ring; wherein the intermediate sealing ring comprises an annular flow passage and a flow guiding structure, the annular flow passage is arranged around the rotating shaft, the flow guiding structure is arranged in the annular flow passage, and the intermediate sealing ring is arranged so that when pressure fluid flows through the annular flow passage along the axial direction of the rotating shaft, the flow guiding structure can guide the pressure fluid to drive the intermediate sealing ring to rotate at a speed lower than the rotating speed of the rotating shaft.

Description

Shaft sealing structure

Technical Field

The application relates to the field of mechanical sealing structures, and more particularly relates to a shaft sealing structure.

Background

Shaft seals are a common mechanical structure for preventing leakage or ingress of liquid or gas from between the rotating shaft and the housing. In conventional shaft sealing structures, a dynamic seal ring is fixed to a rotary shaft to rotate together with the rotary shaft, and a static seal ring is fixed to a shaft seal cover of a housing to remain stationary with respect to the rotary shaft. The movable sealing ring is contacted with the static sealing ring, and the sealing is realized by virtue of an oil film between contact surfaces of the movable sealing ring and the static sealing ring.

However, for a rotating shaft with a high rotation speed, the relative linear speed of the movable sealing ring fixed on the rotating shaft relative to the static sealing ring fixed on the shell is also high, so that the movable sealing ring and the static sealing ring are easy to wear, the service lives of the movable sealing ring and the static sealing ring are shortened, and the movable sealing ring and the static sealing ring are required to be replaced frequently. In addition, because the relative linear velocity between the movable sealing ring and the static sealing ring is high, the vibration or the shaking of the shaft sealing structure can be caused, so that the normal operation of the shaft sealing structure is influenced.

Disclosure of Invention

In order to solve the technical problem, the application provides a shaft seal structure, its characterized in that includes: a shaft seal cover defining a shaft seal cavity for containing a pressurized fluid; a rotation shaft rotatably passing through the shaft seal cover such that at least a portion of the rotation shaft is located in the shaft seal cavity; a moving seal ring disposed in the shaft seal cavity around the rotating shaft and sealingly mounted to the rotating shaft such that the moving seal ring rotates in synchronization with the rotating shaft; a stationary seal ring disposed in the shaft seal cavity around the rotation shaft and sealingly mounted to the shaft seal cover such that the stationary seal ring is stationary relative to the shaft seal cover; and at least one intermediate seal ring disposed in the shaft seal cavity around the rotary shaft, wherein the at least one intermediate seal ring is disposed between the movable seal ring and the stationary seal ring in an axial direction of the rotary shaft, at least one of the intermediate seal rings is contactable with the movable seal ring, and at least one of the intermediate seal rings is contactable with the stationary seal ring; wherein the at least one intermediate sealing ring comprises an annular flow passage arranged around the rotation shaft and a flow guiding structure arranged in the annular flow passage, and wherein the at least one intermediate sealing ring is arranged such that, when a pressure fluid flows through the annular flow passage in the axial direction of the rotation shaft, the flow guiding structure is capable of guiding the pressure fluid to drive the at least one intermediate sealing ring to rotate at a lower speed than the rotation of the rotation shaft.

According to an aspect of the shaft sealing structure of the present application, the flow guiding structure includes a plurality of hollowed-out portions penetrating through the intermediate sealing ring, and the hollowed-out portions have a pair of side walls disposed opposite to each other in a circumferential direction, the side walls being disposed obliquely to the axial direction, so that when a pressure fluid flows through the hollowed-out portions of the intermediate sealing ring in the axial direction, the pressure fluid is blocked by the side walls, thereby driving the intermediate sealing ring to rotate.

According to one aspect of the shaft sealing structure of the application, the flow guiding structure comprises a plurality of blades, wherein the blades are circumferentially arranged at intervals in the annular flow passage, so that the hollowed-out parts are formed between the adjacent blades, and the blades form the side walls.

According to one aspect of the shaft sealing structure of the application, the flow guiding structure comprises a plurality of through holes, wherein the through holes are circumferentially arranged at intervals in the annular flow passage, so that each through hole forms the hollowed-out part, and the hole walls of the through holes form the side walls.

According to one aspect of the shaft seal structure of the present application, further comprising: and the oil pump is used for driving the pressure fluid to flow so that the pressure fluid can drive the middle sealing ring to rotate.

According to one aspect of the shaft seal structure of the present application, further comprising: a drive ring disposed upstream of the at least one intermediate seal ring and configured to rotate in synchronization with the rotation shaft to drive the pressure fluid flow such that the pressure fluid can drive the intermediate seal ring to rotate; wherein the drive ring includes a plurality of through portions penetrating the drive ring, and the through portions have a pair of side walls disposed opposite in a circumferential direction, the side walls being disposed obliquely to the axial direction such that the side walls drive the flow of the pressure fluid flowing through the through portions as the drive ring rotates.

According to an aspect of the shaft seal structure of the present application, the drive ring is disposed around the movable seal ring and is connected to the movable seal ring such that the drive ring rotates in synchronization with the movable seal ring.

According to one aspect of the shaft seal structure of the present application, further comprising: a flow valve for restricting the flow of the pressure fluid into the shaft seal cavity to control the rotational speed of the intermediate seal ring based on the flow and pressure of the pressure fluid.

According to one aspect of the shaft sealing structure of the present application, the plurality of blades (110) are arranged to control the rotational speed of the intermediate sealing ring (107) based on the number, shape and angle of inclination with respect to the axial direction of the blades (110).

According to an aspect of the shaft seal structure of the present application, each of the intermediate seal rings includes an outer ring portion and an inner ring portion, the outer ring portion being connected to an outer side of the inner ring portion around the inner ring portion so that the outer ring portion and the inner ring portion rotate in synchronization; wherein the annular flow passage and the flow guiding structure are provided on the outer ring portion, and the movable seal ring or the stationary seal ring is in contact with the inner ring portion of the adjacent intermediate seal ring.

According to an aspect of the shaft seal structure of the present application, the outer ring portion and the inner ring portion are made of different materials, and the material of the inner ring portion has a higher hardness than the material of the outer ring portion.

According to one aspect of the shaft seal structure of the present application, the shaft seal cover has a fluid inlet and a fluid outlet arranged to flow pressurized fluid into and out of the shaft seal cavity of the shaft seal cover; an inlet guide channel is included between the fluid inlet and the shaft seal cavity of the shaft cover, an outlet guide channel is included between the fluid outlet and the shaft seal cavity of the shaft cover, the inlet guide channel and the outlet guide channel are configured to guide pressure fluid entering the shaft seal cavity from the fluid inlet to flow through the movable sealing ring, the at least one intermediate sealing ring and the static sealing ring along the axial direction of the rotating shaft after being guided by the inlet guide channel, and then flow out of the shaft seal cavity from the fluid outlet after being guided by the outlet guide channel.

According to one aspect of the shaft seal structure of the present application, further comprising: and the pressure fluid temperature control device is arranged at the upstream of the fluid inlet so as to control the temperature of the pressure fluid entering the shaft seal cavity from the fluid inlet.

According to one aspect of the shaft sealing structure of the present application, the at least one intermediate sealing ring comprises one intermediate sealing ring, which is set to a rotation speed half of the rotation speed of the rotating shaft.

According to one aspect of the shaft seal structure of the present application, the at least one intermediate seal ring includes a plurality of intermediate seal rings configured such that a rotational speed of the plurality of intermediate seal rings gradually decreases in a direction from the dynamic seal ring to the static seal ring.

Drawings

FIG. 1A illustrates a perspective view of a shaft seal structure according to a first embodiment of the present application;

FIG. 1B illustrates an exploded view of the various components of the shaft seal structure of the first embodiment of FIG. 1A;

FIG. 1C shows an axial cross-sectional view of the shaft seal structure of the first embodiment taken along section line A-A in FIG. 1A;

FIG. 2A shows a perspective view of the intermediate seal ring of FIG. 1B;

FIG. 2B illustrates a cross-sectional view of the intermediate seal ring of FIG. 1B;

FIG. 3A illustrates a perspective view of a shaft seal structure according to a second embodiment of the present application;

FIG. 3B illustrates an exploded view of the various components of the shaft seal structure of the second embodiment of FIG. 3A;

FIG. 3C shows an axial cross-sectional view of the second embodiment shaft seal structure taken along section line B-B in FIG. 3A;

FIG. 4A illustrates a perspective view of a shaft seal structure according to a third embodiment of the present application;

FIG. 4B illustrates an exploded view of the various components of the shaft seal structure of the third embodiment of FIG. 4A;

FIG. 4C shows an axial cross-sectional view of the shaft seal structure of the third embodiment taken along section line C-C in FIG. 4A;

FIG. 5A shows a cross-sectional view of an intermediate seal ring in a fourth embodiment according to the present application;

FIG. 5B illustrates a cross-sectional view of an intermediate seal ring in a fifth embodiment according to the present application;

fig. 6A-6C illustrate cross-sectional shapes of blades in various embodiments according to the present application.

Detailed Description

Various embodiments of the present application are described below with reference to the accompanying drawings, which form a part hereof. It is to be understood that, although various terms indicating directions, such as "front", "rear", "upper", "lower", "left", "right", "top", "bottom", etc., may be used herein to describe various exemplary structural parts and components of the present application, these terms are used herein for convenience of description and are determined based on the exemplary orientations shown in the drawings. Since embodiments in this application may be arranged in different orientations, these directional terms are used for purposes of illustration only and are in no way limiting.

Fig. 1A-1C illustrate a shaft seal structure 100 according to a first embodiment of the present application. Wherein fig. 1A shows a perspective view of a shaft seal structure 100 for illustrating an external structure of the shaft seal structure 100. Fig. 1B shows an exploded view of the shaft seal structure 100 for illustrating various components of the shaft seal structure 100, and fig. 1C shows an axial cross-sectional view of the shaft seal structure 100 taken along line A-A at a fluid inlet and a fluid outlet for illustrating the internal structure of the shaft seal structure 100. Wherein the dashed box shows a partial enlargement.

As shown in fig. 1A to 1C, the shaft sealing structure 100 includes a shaft seal cover 101 and a rotary shaft 104, and a shaft seal cavity 111 is defined in the shaft seal cover 101. The right end of the rotary shaft 104 protrudes from the right end face of the shaft cover 101, and the left end of the rotary shaft 104 is located in the shaft seal cavity 111 in the shaft cover 101. The shaft sealing structure 100 is used to prevent liquid or gas from leaking or entering between the junction of the rotary shaft 104 and the shaft seal cover 101. The left end of the rotary shaft 104 may also be penetrated from the left end surface of the shaft cover 101 according to actual needs by a person skilled in the art, as long as the middle part of the rotary shaft 104 is arranged in the shaft seal cavity 111, and a sealing structure is correspondingly arranged. In the present embodiment, the rotation shaft 104 rotates about the axis x. The extending direction of the axis x is defined as axial, the direction around the axis x as circumferential, and the direction perpendicular to the axial as radial.

The shaft seal cavity 111 is for receiving a pressurized fluid therein. The pressure fluid in the present application refers to a fluid having a certain pressure, for example, oil having a certain pressure. The shaft seal cover 101 is provided with a fluid inlet 102 and a fluid outlet 103 which are in fluid communication with the shaft seal cavity 111, and oil flows into the shaft seal cavity 111 from the fluid inlet 102 and flows out from the fluid outlet 103. In the present embodiment, the shaft cover 101 is provided in a cylindrical shape extending around the rotation shaft 104 and the axis x, and the fluid inlet 102 and the fluid outlet 103 are provided on a cylindrical circumferential surface of the shaft seal cover 101 and are provided at a distance in the axial direction. Of course, the present application is not limited thereto, and the shaft seal cover 101 may be of a shape other than a cylindrical shape as long as it is provided around one end of the rotation shaft 104. And the fluid inlet 102 and the fluid outlet 103 may be otherwise provided in fluid communication with the shaft seal cavity 111.

As further shown in connection with fig. 1B and 1C, the shaft seal structure 100 further includes a movable seal ring 105, an intermediate seal ring 107, and a stationary seal ring 106, which are disposed sequentially around the rotary shaft 104 in the axial direction. The movable seal ring 105 is disposed in the shaft seal cavity 111 around the rotary shaft 104 and is fixedly connected with the rotary shaft 104. A seal ring 131 is provided between the movable seal ring 105 and the rotary shaft 104 to ensure that the movable seal ring 105 is sealed against the rotary shaft 104. The stationary seal ring 106 is disposed in the shaft seal chamber 111 around the rotary shaft 104 and is fixedly connected with the shaft seal cover 101. A sealing ring 132 is provided between the stationary sealing ring 106 and the shaft seal cover 101 to ensure that the stationary sealing ring 106 seals against the shaft seal cover 101. The intermediate sealing ring 107 is arranged in the shaft seal chamber 111 around the rotation shaft 104, but is not connected to the rotation shaft 104, but is spaced from the rotation shaft 104, i.e. the intermediate sealing ring 107 is suspended in relation to the rotation shaft 104. Of course, in other embodiments, the intermediate seal ring 107 may also be rotatably/slidably coupled to the rotating shaft 104 without the need for a floating arrangement. The left end face of the intermediate seal ring 107 is in contact with the movable seal ring 105, and the right end face of the intermediate seal ring 107 is in contact with the stationary seal ring 106, so that the intermediate seal ring 107 is fixed in position by abutment with the stationary seal ring 106 and the movable seal ring 105. When oil having a certain pressure flows in axial direction through the sealing ring 105, the intermediate sealing ring 107 and the stationary sealing ring 106 in this order, a sealing connection is formed at the contact points thereof.

Also, the intermediate seal ring 107 includes an annular flow passage 117 and a flow guiding structure 118 disposed in the annular flow passage 117. An annular flow passage 117 is provided around the rotary shaft 104 outside the intermediate seal ring 107. When oil under pressure enters the shaft seal cavity 111 from the fluid inlet 102 and flows axially through the annular flow passage 117 of the intermediate seal ring 107, the flow guiding structure 118 serves to guide the oil to drive the intermediate seal ring 107 to rotate at a lower rotational speed than the rotational shaft 104. In some embodiments, the rotational speed of the intermediate seal ring 107 is related to the pressure and flow rate of the oil. In some embodiments, the rotational speed of the intermediate seal ring 107 is related to the specific configuration of the flow directing structure 118. More specific configurations of the annular flow passage 117 and the flow directing structure 118 will be described in detail in connection with fig. 2A and 2B.

And the intermediate seal ring 107 and the movable seal ring 105 form an oil film at the contact portion 135 and the intermediate seal ring 107 and the stationary seal ring 106 at the contact portion 136, the oil film functioning to lubricate and seal so that the oil can be discharged from the fluid outlet to the shaft seal cavity 111 only after flowing through the intermediate seal ring 107, without leaking to the outside of the shaft seal cover 101.

When the rotary shaft 104 rotates, the movable seal ring 105 rotates synchronously with the rotation of the rotary shaft 104, and the stationary seal ring 106 remains fixed to the shaft cover 101. At this time, the intermediate seal ring 107 rotates at a lower rotational speed than the rotary shaft 104. As a result, relative rotational speeds between the movable seal ring 105 and the intermediate seal ring 107, and between the intermediate seal ring 107 and the stationary seal ring 106 are reduced relative to a shaft seal structure in which the movable seal ring 105 is in direct contact with the stationary seal ring 106, and therefore wear therebetween can be reduced to extend the working life. In a specific embodiment, if the rotational speed of the rotating shaft 104 and the movable seal ring 105 is 8000rpm, the relative rotational speed of the movable seal ring 105 with respect to the stationary seal ring 106 is 8000rpm in the case that the movable seal ring 105 is in direct contact with the stationary seal ring 106. However, in the present embodiment, if the rotational speed of the intermediate seal ring 107 is 4000rpm, the relative rotational speed between the movable seal ring 105 and the intermediate seal ring 107, and between the intermediate seal ring 107 and the stationary seal ring 106 is reduced to 4000rpm, whereby wear of the respective seal rings can be reduced.

More specifically, the rotation shaft 104 has a stepped shape with a diameter decreasing from left to right, and includes a first stepped portion 141, a second stepped portion 142, and a third stepped portion 143, and the diameters of the first stepped portion 141, the second stepped portion 142, and the third stepped portion 143 decrease in order. The movable seal ring 105 is mounted on the second stepped portion 142 of the rotary shaft 104, and its left side abuts the first stepped portion 141, and a portion of its right side protrudes outside the third stepped portion 143. The intermediate seal ring 107 and the stationary seal ring 106 are disposed around the third stepped portion 143 of the rotary shaft 104 with a gap therebetween.

The intermediate seal ring 107 includes an inner ring portion 108 and an outer ring portion 109, the outer ring portion 109 being fixedly connected to the outside of the inner ring portion 108 around the inner ring portion 108 such that the outer ring portion 109 and the inner ring portion 108 rotate synchronously. In some embodiments, the inner ring portion 108 and the outer ring portion 109 are integrally formed such that the integral part formed by the inner ring portion 108 and the outer ring portion 109 has good overall strength. In the present embodiment, the outer ring portion 109 is used to provide a driving structure for driving the intermediate seal ring 107 to rotate, and the inner ring portion 108 is used to provide a sealing connection structure of the intermediate seal ring 107 with the movable seal ring 105 and the stationary seal ring 106. That is, the annular flow passage 117 and the flow guiding structure 118 are provided on the outer ring portion 109. And the left side of the inner ring portion 108 of the intermediate seal ring 107 is in contact with the movable seal ring 105 to form a contact portion 135, and the right side of the inner ring portion 108 is in contact with the stationary seal ring 106 to form a contact portion 136. The outer ring portion 109 and the inner ring portion 108 may be made of the same material or may be made of different materials. When made of a different material, the material of the inner ring portion 108 has a higher hardness than the material of the outer ring portion 109, such as the outer ring portion 109 being made of plastic and the inner ring portion 108 being made of metal, so that it is possible to save materials and costs while ensuring the wear resistance of the intermediate seal ring 107.

Although the foregoing description gives one example of the specific structure, position and connection relationship of the rotary shaft 104, the movable seal ring 105, the stationary seal ring 106 and the intermediate seal ring 107, the present application is not limited thereto.

An inlet guide channel 115 is configured between the fluid inlet 102 and the shaft seal cavity 111, and an outlet guide channel 116 is configured between the shaft seal cavity 111 and the fluid outlet 103. The inlet guide channel 115 and the outlet guide channel 116 are configured to guide the pressurized fluid entering the shaft seal cavity 111 from the fluid inlet 102, after being guided by the inlet guide channel 115, to flow through the seal ring 105, the intermediate seal ring 107 and the stationary seal ring 106 in the axial direction of the rotating shaft 104, and after being guided by the outlet guide channel 116, to flow out of the shaft seal cavity 111 from the fluid outlet 103. Specifically, the shaft seal cover 101 includes an annular outer wall 151 and an annular inner wall 152 surrounding the rotary shaft 104, and end caps 154 connected to both ends of the annular outer wall 151. The annular outer wall 151 surrounds the annular inner wall 152 and is spaced apart therefrom and is connected to one another by a connecting portion 153. The annular inner wall 152 is spaced from the end cap 154. The shaft seal cavity 111 is defined by an annular inner wall 152. The inlet guide channel 115 and the outlet guide channel 116 are defined by an annular outer wall 151, an annular inner wall 152, and an end cap 154, and are separated by a connection 153. The fluid inlet 102 and the fluid outlet 103 extend radially through the annular outer wall 151. Thus, the inlet guide passage 115 and the outlet guide passage 116 are annular and zigzag-shaped. The pressure fluid flowing in from the fluid inlet 102 and the pressure fluid discharged from the fluid outlet 103 flow in the circumferential direction while also flowing in the direction of the end cap 154, and then enter the shaft seal cavity 111 from the gap between the annular inner wall 152 and the end cap 154. The annular shape of the inlet guide channel 115 and the outlet guide channel 116 enables a more uniform entry of the pressurized fluid into the shaft seal cavity 111 and exit from the shaft seal cavity 111.

In this embodiment, the shaft seal structure 100 further includes an oil pump and a pressure fluid temperature control device. The fluid inlet 102 and the fluid outlet 103 are connected to the oil pump and the pressure fluid temperature control device by pipes to form a circulation loop of the pressure fluid. Specifically, the oil pump is disposed upstream of the fluid inlet 102, the pressure fluid temperature control device is disposed upstream of the oil pump, and the fluid outlet 103 is disposed upstream of the pressure fluid temperature control device. After the pressure fluid, such as oil, leaves the shaft seal cavity 111 from the fluid outlet 103, it passes through an external pressure fluid temperature control device to cool, then flows through an oil pump to increase the pressure of the pressure fluid, and finally the pressure fluid after the pressure increase returns to the shaft seal cavity 111 through the fluid inlet 102 to constitute a pressure fluid cycle. In some embodiments, the pressure fluid temperature control device may be an oil cooler for cooling down fluid that is heated up due to the high temperature within the shaft seal cavity 111 for reuse. The oil pump may be a fixed-frequency oil pump or a variable-frequency oil pump for increasing the pressure fluid flowing out of the oil cooler to a suitable pressure to drive the pressure fluid to flow in accordance with the pressure fluid circulation path and to drive the intermediate seal ring 107 to rotate at a suitable rotational speed.

Fig. 2A and 2B show perspective and cross-sectional views, respectively, of the intermediate seal ring in fig. 1B for explaining a specific structure of the intermediate seal ring 107. As shown in fig. 2A, an annular flow passage 117 is provided around the rotary shaft 104 outside the outer ring portion 109 of the intermediate seal ring 107, the annular flow passage 117 penetrating the outer ring portion 109 in the axial direction so that the pressure fluid can flow through the annular flow passage 117 in the axial direction. The flow guiding structure 118 is disposed in the annular flow passage 117, and includes a plurality of blades 110 and a plurality of hollow portions 114, where the plurality of blades 110 are circumferentially spaced in the annular flow passage 117, so that the hollow portions 114 are formed between adjacent blades 110. Each of the hollowed-out portions 114 has a pair of side walls 234 disposed opposite to each other in the circumferential direction, and the side walls 234 constitute a plurality of blades 110. Each side wall 234 of the vane 110 is disposed obliquely to the axial direction of the rotary shaft 104 so that when the pressure fluid flows through the hollowed-out portion 114 of the intermediate seal ring 107 in the axial direction, the pressure fluid can be blocked by the side wall 234, thereby driving the intermediate seal ring 107 to rotate. When the pressure fluid flows through each hollow portion 114, the driving force generated by the pressure fluid with different pressure and flow rate on the side wall 234 to drive the middle sealing ring 107 to rotate is different, so that the rotation speed to drive the middle sealing ring 107 to rotate is also different. As will be appreciated by those skilled in the art, the vane 110 and the hollowed out portion 114 may be configured in any shape, as long as the sidewall 234 of the vane 110 is capable of blocking the pressurized fluid as it flows through the hollowed out portion 114 to drive the intermediate seal ring 107 to rotate.

Specifically, the outer ring portion 109 includes an annular outer wall 235 and an annular inner wall 236, the inner wall 236 being connected to the inner ring portion 108. The outer wall 235 and the inner wall 236 are coaxially disposed and spaced apart to form the annular flow passage 117. Each vane 110 is disposed to connect between the outer wall 235 and the inner wall 236 at an angle oblique to the axial direction to divide the annular flow passage 117 into a plurality of hollowed-out portions 114. The amount of driving force generated on the side wall 234 to drive the intermediate seal ring 107 to rotate is also different for different numbers, shapes, and angles of inclination with respect to the axial direction of the blades 110 when the same pressure and flow rate of the pressure fluid flows through the various blades 110, and thus the rotational speed to drive the intermediate seal ring 107 to rotate is also different.

Therefore, the rotational speed of the intermediate seal ring 107 can be controlled based on the number, shape, and inclination angle of the blades 110 with respect to the axial direction, or based on the flow rate and pressure of the pressure fluid.

In other embodiments, the flow directing structure 118 does not include a plurality of vanes, but rather includes a plurality of through holes, wherein the plurality of through holes are circumferentially spaced in the annular flow passage 117 such that each through hole forms the hollowed out portion 114 and the sidewall for blocking the pressurized fluid is formed by the walls of the through holes.

Fig. 3A to 3C show a specific structure of a shaft seal structure 300 according to a second embodiment of the present application. Wherein fig. 3A shows a perspective view of the shaft seal structure 300, fig. 3B shows an exploded view of the various components of the shaft seal structure 300, and fig. 3C shows an axial cross-sectional view of the shaft seal structure 300 taken along line B-B at the fluid inlet and fluid outlet. As shown in fig. 3A-3C, the shaft seal structure 300 is generally identical in structure to the shaft seal structure 100, except that the shaft seal structure 300 further includes a drive ring 313. The drive ring 313 is axially disposed upstream of the intermediate seal ring 107 and generally aligned with the outer ring portion 109 of the intermediate seal ring 107 such that pressurized fluid needs to flow past the drive ring 313 before flowing past the outer ring portion 109 of the intermediate seal ring 107. In the present embodiment, the driving ring 313 rotates in synchronization with the rotation shaft 104, the pressure of the pressure fluid flowing therethrough is increased by the rotation of the driving ring 313 to drive the pressure fluid to continue to flow through the intermediate seal ring 107, and the pressure fluid can drive the intermediate seal ring 107 to rotate.

Specifically, the drive ring 313 is disposed around the movable seal ring 105 and is fixedly connected with the movable seal ring 105 such that the drive ring 313 rotates in synchronization with the movable seal ring 105 and the rotary shaft 104. In some embodiments, the drive ring 313 is integrally formed with the dynamic seal ring 105. In other embodiments, the drive ring 313 may also be directly fixed to the rotating shaft 104.

The drive ring 313 is generally similar in structure to the outer ring portion 109 of the intermediate seal ring 107, and the drive ring 313 also includes a plurality of through-portions 314 disposed therethrough, the through-portions 314 of the drive ring 313 being generally aligned with the hollowed-out portions 114 of the intermediate seal ring 107. Here too, the through portion 314 has a pair of side walls disposed opposite to each other in the circumferential direction, the side walls being disposed obliquely to the axial direction so that the side walls can drive the flow of the pressure fluid flowing through the through portion 314 as the drive ring 313 rotates. In the embodiment shown in the figures, when the driving ring 313 is rotated at a high speed by the rotation shaft 104, the pressure fluid upstream of the driving ring 313 is sucked through the through portion 314 of the driving ring 313 to increase the pressure of the pressure fluid, and the pressure fluid after the pressure increase then flows through the hollowed-out portion 114 in the outer ring portion 109 of the intermediate seal ring 107 to drive the intermediate seal ring 107 to rotate at a lower speed than the rotation shaft 104.

In this embodiment, the shaft seal structure 300 further includes a flow valve and a pressure fluid temperature control device. The fluid inlet 102 and the fluid outlet 103 are connected by piping to a flow valve and a pressure fluid temperature control device to form a circulation of the pressure fluid. A flow valve is provided upstream of the fluid inlet 102, a pressure fluid temperature control device is provided upstream of the flow valve, and a fluid outlet 103 is provided upstream of the pressure fluid temperature control device. In the present embodiment, the pressure increase of the pressure fluid is achieved by the drive ring 313, not by the oil pump as in the shaft seal structure 100. Accordingly, there is no need to provide an oil pump upstream of the fluid inlet 102, but a flow valve, such as a throttle valve, is provided for restricting the flow of pressure fluid into the shaft seal cavity 111. Thus, by providing the flow valve and the drive ring 313, the rotational speed of the intermediate seal ring 107 can be controlled based on the flow rate of the pressure fluid.

Fig. 4A to 4C show a specific structure of a shaft seal structure 400 according to a third embodiment of the present application. Wherein fig. 4A shows a perspective view of a shaft seal structure 400. Fig. 4B shows an exploded view of the various components of the shaft seal structure 400. Fig. 4C shows an axial cross-sectional view of the shaft seal structure 400 at the fluid inlet and fluid outlet, taken along line C-C. Wherein the dashed box shows a partial enlargement. As shown in fig. 4A-4C, the shaft seal structure 400 is substantially identical in structure to the shaft seal structure 300, except that two intermediate seal rings 107 are provided between the movable seal ring 105 and the stationary seal ring 106. In the present embodiment, the two intermediate seal rings 107 are an intermediate seal ring 107a and an intermediate seal ring 107b, respectively, which are identical in shape and structure. The intermediate seal ring 107a is located upstream of the intermediate seal ring 107 b. The left end face of the intermediate seal ring 107a contacts the movable seal ring 105 to form a contact portion 435, the right end face of the intermediate seal ring 107b contacts the stationary seal ring 106 to form a contact portion 436, and the right end face of the intermediate seal ring 107a contacts the left end face of the intermediate seal ring 107b to form a contact portion 437. Thereby, the two intermediate seal rings 107 can also be fixed in position by abutment with the stationary seal ring 106 and the movable seal ring 105, and are sealingly connected by the contact portions 435, 436, and 437. Although an embodiment is shown herein in which two intermediate seal rings 107 are provided between the movable seal ring 105 and the stationary seal ring 106, it will be appreciated by those skilled in the art that three or more intermediate seal rings 107 may be provided between the movable seal ring 105 and the stationary seal ring 106 as desired. Of these intermediate seal rings 107, the intermediate seal ring 107 on the most upstream side and the most downstream side is brought into contact with the movable seal ring 105 and the stationary seal ring 106, respectively, and the adjacent intermediate seal rings 107 are brought into contact with each other.

By providing two or more intermediate sealing rings 107, the rotational speed of each intermediate sealing ring 107 is gradually reduced in the direction of the flow of the pressure fluid, i.e. in the direction of the flow of the pressure fluid from the driven sealing ring 105 to the stationary sealing ring 106, thus reducing the relative speed between each adjacent sealing ring, in particular between the moving sealing ring 105 and the intermediate sealing ring 107 and between the intermediate sealing ring 107 and the stationary sealing ring, and thus reducing the wear of each sealing ring. In a specific embodiment, if the rotational speed of the rotating shaft 104 and the moving seal ring 105 is 8000rpm, the relative rotational speed of the moving seal ring 105 with respect to the stationary seal ring 106 is 8000rpm with the moving seal ring 105 in direct contact with the stationary seal ring 106. However, in the present embodiment, if the rotational speed of the intermediate seal ring 107a is 6000rpm and the rotational speed of the intermediate seal ring 107b is 3000rpm, the relative rotational speed between the movable seal ring 105 and the intermediate seal ring 107a is reduced to 2000rpm and the relative rotational speed between the intermediate seal ring 107b and the stationary seal ring 106 is reduced to 3000rpm. Those skilled in the art will appreciate that the greater the number of intermediate seal rings 107, the better the wear reduction effect.

Fig. 5A shows a cross-sectional view of an intermediate seal ring 507a in a shaft seal structure according to a fourth embodiment of the present application. Fig. 5B shows a cross-sectional view of an intermediate seal ring 507B in a shaft seal structure according to a fifth embodiment of the present application. As shown in fig. 5A and 5B, the structures of the intermediate seal ring 507a and the intermediate seal ring 507B are substantially the same as those of the intermediate seal ring 107, except that the number of hollowed-out portions is different. In the intermediate seal ring 107 shown in fig. 2B, the number of hollowed-out portions 114 is 30. In the intermediate seal ring 507a shown in fig. 5A, the number of hollowed-out portions 514a is 20. In the intermediate seal ring 507B shown in fig. 5B, the number of hollowed-out portions 514B is 10. It is understood that the hollowed-out portions 114 may be other numbers. In the case of other structures of the shaft sealing structure and the pressure and flow rate of the pressure fluid, the smaller the number of hollowed-out parts, that is, the smaller the number of blades, the larger the flow rate of the pressure fluid passing through the hollowed-out parts, and the smaller the pressure, and thus the lower the rotation speed of the driving intermediate seal ring. Conversely, the greater the number of hollowed-out portions, i.e., the greater the number of blades, the smaller the flow rate of the pressure fluid passing through the hollowed-out portions, and the greater the pressure, and thus the greater the rotational speed of the driving intermediate seal ring.

Fig. 6A-6C show schematic cross-sectional shapes of blades according to various embodiments of the present application. The left side of each vane is adjacent to the direction of the moving seal ring, i.e. upstream in the direction of the pressure fluid flow, and the right side is adjacent to the direction of the stationary seal ring, i.e. downstream in the direction of the pressure fluid flow. Arrows show the direction of flow of the pressurized fluid. The blade 110a and the blade 110c have substantially the same blade shape, but have different inclination angles with respect to the axis x. The angle of inclination of the blades 110a and 110b with respect to the axis x is substantially the same, but the blade shapes are different.

For the vane 110a and the vane 110c, the inclination angle of the vane 110a with respect to the axis x is larger than that of the vane 110c with other structures of the shaft seal structure and the pressure and flow rate of the pressure fluid unchanged, and the blocking force of the pressure fluid flowing through the vane 110a is also larger than that of the vane 110c, so that the rotation speed of the intermediate seal ring including the vane 110a is larger than that of the intermediate seal ring including the vane 110 c.

In addition, as shown, the angle between the sides of the vane 110b is the same, in contrast to the different angles between the sides of the vanes 110a and 110c relative to the axis x, the greater the difference between the angles between the sides of the vanes 110a and 110c relative to the axis x, the greater the difference in velocity of the fluid across the vanes 110a and 110c, and thus the greater the pressure differential across the vanes 110a and 110c, and thus the higher the rotational speed of the vanes 110a and 110c relative to the vane 110b at the same vane setting and pressure and flow of the same pressure fluid.

Thus, by providing blades 110 of different shapes and different angles of inclination, the intermediate seal ring 107 can be controlled to achieve a suitable rotational speed.

The utility model provides a shaft seal structure is through setting up the intermediate seal ring of rotational speed between moving sealing ring and quiet sealing ring, reduces the relative linear velocity between moving sealing ring, intermediate seal ring and the quiet sealing ring to reduce the wearing and tearing of each sealing ring, increase of service life.

The shaft sealing structure does not need an additional speed reducing mechanism to reduce the rotation speed of the middle sealing ring, but drives the middle sealing ring to rotate through the flow of pressure fluid, so that the shaft sealing structure is simple in structure, occupies small space, and cannot generate additional vibration and noise due to the speed reducing mechanism.

In addition, in the shaft sealing structure, the pressure fluid basically flows along the axial direction in the shaft sealing cavity, and sequentially flows through each contact part in the axial direction, so that an oil film layer is better formed at each contact part to realize a more reliable sealing effect.

In addition, the shaft sealing structure can further comprise one of additional components such as a flow valve, an oil pump and a pressure fluid temperature control device, so that the pressure fluid can circulate on one hand, the stability of the shaft sealing structure is improved, and on the other hand, the rotating speed of the intermediate sealing ring can be controlled more accurately.

While the present application has been disclosed in conjunction with the embodiments described above, various alternatives, modifications, variations, improvements, and/or substantial equivalents, whether known or that may be presently or later to be considered, will be apparent to those of ordinary skill in the art. In addition, technical effects and/or technical problems described in the present specification are exemplary and not limiting, so the disclosure of the present specification may be used to solve other technical problems and have other technical effects. Accordingly, the foregoing set forth embodiments of the present application are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit or scope of the application. Accordingly, this application is intended to embrace all known or earlier developed alternatives, modifications, variations, improvements and/or substantial equivalents.

Claims (15)

1. A shaft seal structure (100), characterized by comprising:

a shaft seal cover (101), the shaft seal cover (101) defining a shaft seal cavity (111), the shaft seal cavity (111) for containing a pressurized fluid;

-a rotation shaft (104), the rotation shaft (104) rotatably passing through the shaft seal cover (101), and at least a portion of the rotation shaft (104) being located in the shaft seal cavity (111);

-a dynamic seal ring (105), the dynamic seal ring (105) being arranged in the shaft seal cavity (111) around the rotation shaft (104) and being sealingly mounted to the rotation shaft (104) such that the dynamic seal ring (105) rotates in synchronization with the rotation shaft (104);

-a static sealing ring (106), said static sealing ring (106) being arranged in said shaft seal cavity (111) around said rotation shaft (104) and sealingly mounted to said shaft seal cover (101) such that said static sealing ring (106) is stationary with respect to said shaft seal cover (101); and

-at least one intermediate sealing ring (107), which at least one intermediate sealing ring (107) is arranged in the shaft seal cavity (111) around the rotation shaft (104), wherein in the axial direction of the rotation shaft (104), the at least one intermediate sealing ring (107) is arranged between the movable sealing ring (105) and the stationary sealing ring (106), at least one intermediate sealing ring (107) being contactable with the movable sealing ring (105), and at least one intermediate sealing ring (107) being contactable with the stationary sealing ring (106);

wherein the at least one intermediate sealing ring (107) comprises an annular flow channel (117) and a flow guiding structure (118), the annular flow channel (117) being arranged around the rotation shaft (104), the flow guiding structure (118) being arranged in the annular flow channel (117), and wherein the at least one intermediate sealing ring (107) is arranged such that the flow guiding structure (118) is capable of guiding the pressure fluid to drive the at least one intermediate sealing ring (107) to rotate at a lower speed than the rotation shaft (104) rotates when the pressure fluid flows through the annular flow channel (117) in the axial direction of the rotation shaft (104).

2. The shaft seal structure (100) of claim 1, wherein:

the flow guiding structure (118) comprises a plurality of hollowed-out parts (114), the hollowed-out parts (114) penetrate through the middle sealing ring (107), and each of the hollowed-out parts (114) is provided with a pair of side walls which are arranged opposite to each other in the circumferential direction, and the side walls are inclined to the axial direction, so that when pressure fluid flows through the hollowed-out parts (114) of the middle sealing ring (107) along the axial direction, the pressure fluid is blocked by the side walls, and the middle sealing ring (107) is driven to rotate.

3. The shaft seal structure (100) of claim 2, wherein:

the flow guiding structure (118) comprises a plurality of blades (110), wherein the blades (110) are circumferentially arranged at intervals in the annular flow channel (117) so that hollowed-out parts (114) are formed between adjacent blades (110), and the blades (110) form the side walls.

4. The shaft seal structure (100) of claim 2, wherein:

the flow guiding structure (118) comprises a plurality of through holes, wherein the through holes are circumferentially arranged at intervals in the annular flow passage (117) so that each through hole forms the hollowed-out part (114), and the hole walls of the through holes form the side walls.

5. The shaft seal structure (100) of claim 1, further comprising:

-an oil pump for driving the flow of the pressure fluid such that the pressure fluid can drive the rotation of the intermediate sealing ring (107).

6. The shaft seal structure (100) of claim 1, further comprising:

-a drive ring (313), the drive ring (313) being arranged upstream of the at least one intermediate seal ring (107), and the drive ring (313) being arranged to rotate synchronously with the rotation shaft (104) to drive the pressure fluid flow such that the pressure fluid can drive the intermediate seal ring (107) to rotate;

wherein the drive ring (313) includes a plurality of through portions (314), the through portions (314) penetrate the drive ring (313), and the through portions (314) have a pair of side walls disposed opposite in a circumferential direction, the side walls being disposed obliquely to the axial direction such that as the drive ring (313) rotates, the side walls drive the flow of the pressure fluid flowing through the through portions (314).

7. The shaft seal (100) of claim 6, wherein:

the drive ring (313) is arranged around the movable sealing ring (105) and is connected with the movable sealing ring (105) so that the drive ring (313) and the movable sealing ring (105) synchronously rotate.

8. The shaft seal structure (100) of claim 1, further comprising:

-a flow valve for limiting the flow of the pressure fluid into the shaft seal cavity (111) to control the rotational speed of the intermediate sealing ring (107) based on the flow and pressure of the pressure fluid.

9. A shaft seal arrangement (100) according to claim 3, characterized in that:

the plurality of blades (110) is arranged to control the rotational speed of the intermediate seal ring (107) based on the number, shape and angle of inclination of the blades (110) with respect to the axial direction.

10. The shaft seal structure (100) of claim 1, wherein:

each intermediate seal ring (107) comprises an outer ring portion (109) and an inner ring portion (108), the outer ring portion (109) being connected to the outside of the inner ring portion (108) around the inner ring portion (108) such that the outer ring portion (109) and the inner ring portion (108) rotate synchronously;

wherein the annular flow channel (117) and the flow guiding structure (118) are arranged on the outer ring part (109), and the movable sealing ring (105) or the static sealing ring (106) is in contact with the inner ring part (108) of the adjacent intermediate sealing ring (107).

11. The shaft seal structure (100) of claim 10, wherein:

the outer ring portion (109) is made of a different material than the inner ring portion (108), the material of the inner ring portion (108) having a higher hardness than the material of the outer ring portion (109).

12. The shaft seal structure (100) of claim 1, wherein:

the shaft seal cover (101) has a fluid inlet (102) and a fluid outlet (103), the fluid inlet (102) and the fluid outlet (103) being arranged to flow a pressurized fluid into and out of a shaft seal cavity (111) of the shaft seal cover (101);

an inlet guide channel (115) is included between the fluid inlet (102) and the shaft seal cavity (111) of the shaft seal cover (101), an outlet guide channel (116) is included between the fluid outlet (103) and the shaft seal cavity (111) of the shaft seal cover (101), the inlet guide channel (115) and the outlet guide channel (116) are configured to guide pressure fluid entering the shaft seal cavity (111) from the fluid inlet (102) to flow through the movable seal ring (105), the at least one intermediate seal ring (107) and the stationary seal ring (106) in the axial direction of the rotating shaft (104) after being guided by the inlet guide channel (115), and then to flow out of the shaft seal cavity (111) from the fluid outlet (103) after being guided by the outlet guide channel (116).

13. The shaft seal structure (100) of claim 12, further comprising:

-a pressure fluid temperature control device arranged upstream of the fluid inlet (102) to control the temperature of the pressure fluid entering the shaft seal cavity (111) from the fluid inlet (102).

14. The shaft seal structure (100) of claim 1, wherein:

the at least one intermediate sealing ring (107) comprises one intermediate sealing ring (107), the intermediate sealing ring (107) being arranged to rotate at half the rotational speed of the rotating shaft (104).

15. The shaft seal structure (100) of claim 1, wherein:

the at least one intermediate sealing ring (107) comprises two or more intermediate sealing rings (107), the two or more intermediate sealing rings (107) being configured such that the rotational speed of the two or more intermediate sealing rings (107) gradually decreases in a direction from the dynamic sealing ring (105) to the static sealing ring (106).