Shaft sealing structure

Abstract

A shaft sealing structure, comprising: a shaft seal cover defining a shaft seal chamber containing a pressurized fluid; a rotating shaft rotatably penetrating through the shaft seal cover, the rotating shaft being at least partially located in the shaft seal chamber; a dynamic seal ring arranged in the shaft seal chamber around the rotating shaft and hermetically installed on the rotating shaft; a static seal ring arranged in the shaft seal chamber and hermetically installed on the shaft seal cover, the static seal ring being static with respect to the shaft seal cover; and at least one intermediate seal ring arranged in the shaft seal chamber around the rotating shaft, disposed between the dynamic seal ring and the static seal ring, and able to be in contact with the dynamic seal ring and the static seal ring. The intermediate seal ring comprises an annular flow channel and a flow guide structure, the annular flow channel being arranged around the rotating shaft, and the flow guide structure being arranged in the annular flow channel. The intermediate seal ring is configured in such a way that when the pressurized fluid flows through the annular flow channel in the axial direction of the rotating shaft, the flow guide structure can guide the pressurized fluid to driving the intermediate seal ring to rotate at a speed lower than the rotating speed of the rotating shaft.

Description

Shaft seal structure Field of the Invention

[0001] The present application relates to the field of mechanical sealing structures, and more specifically to a shaft sealing structure. Background Art

[0002] A shaft seal is a commonly used mechanical structure used to prevent the leakage or intrusion of liquids or gases between a rotating shaft and a housing. Traditional shaft seals typically include a dynamic seal ring, which rotates with the rotating shaft, and a static seal ring, which remains stationary relative to the shaft, secured to a shaft seal cover within the housing. The dynamic and static seal rings form a contact seal, for example, achieved by an oil film between their contact surfaces.

[0003] However, for a rotating shaft with a very high rotational speed, the relative linear velocity of the dynamic seal ring fixed to the rotating shaft and the static seal ring fixed to the housing is also very high, resulting in easy wear between the dynamic and static seal rings, thereby shortening the service life of the dynamic and static seal rings and requiring frequent replacement of the dynamic and static seal rings. In addition, the high relative linear velocity between the dynamic and static seal rings can cause vibration or shaking of the shaft seal structure, thus affecting its normal operation. Summary of the Invention

[0004] In order to solve the above technical problems, the present application provides a shaft sealing structure, which is characterized by comprising: a shaft sealing cover, which defines a shaft sealing chamber, and the shaft sealing chamber is used to accommodate a pressure fluid; a rotating shaft, which is rotatable through the shaft sealing cover so that at least a portion of the rotating shaft is located in the shaft sealing chamber; a dynamic sealing ring, which is arranged in the shaft sealing chamber around the rotating shaft and is sealingly installed to the rotating shaft so that the dynamic sealing ring rotates synchronously with the rotating shaft; a static sealing ring, which is arranged in the shaft sealing chamber around the rotating shaft and is sealingly installed to the shaft sealing cover so that the static sealing ring is stationary relative to the shaft sealing cover; and at least one intermediate sealing ring, which is arranged around the rotating shaft The rotating shaft is arranged in the shaft seal chamber, wherein in the axial direction of the rotating shaft, the at least one intermediate sealing ring is arranged between the dynamic sealing ring and the static sealing ring, at least one of the intermediate sealing rings can contact the dynamic sealing ring, and at least one of the intermediate sealing rings can contact the static sealing ring; wherein the at least one intermediate sealing ring includes an annular flow channel and a guide structure, the annular flow channel is arranged around the rotating shaft, the guide structure is arranged in the annular flow channel, and wherein the at least one intermediate sealing ring is arranged so that when the pressure fluid flows through the annular flow channel along the axial direction of the rotating shaft, the guide structure can guide the pressure fluid to drive the at least one intermediate sealing ring to rotate at a speed lower than the speed of the rotating shaft.

[0005] According to one aspect of the shaft sealing structure of the present application, the flow guide structure includes a plurality of hollow portions, the hollow portions passing through the intermediate sealing ring, and the hollow portions having a pair of side walls arranged opposite to each other in the circumferential direction, the side walls being inclined to the axial direction so that when the pressure fluid flows through the hollow portions of the intermediate sealing ring along the axial direction, the pressure fluid is blocked by the side walls, thereby driving the intermediate sealing ring to rotate.

[0006] According to one aspect of the shaft sealing structure of the present application, the flow guide structure includes a plurality of blades, wherein the plurality of blades are arranged at intervals along the circumferential direction in the annular flow channel so that the hollow portion is formed between adjacent blades, and the blades form the sidewalls.

[0007] According to one aspect of the shaft sealing structure of the present application, the flow guide structure includes a plurality of through holes, wherein the plurality of through holes are arranged circumferentially at intervals in the annular flow channel so that each through hole forms the hollow portion, and the hole wall of the through hole forms the side wall.

[0008] According to one aspect of the shaft sealing structure of the present application, it further includes: an oil pump, wherein the oil pump is used to drive the pressure fluid to flow, so that the pressure fluid can drive the intermediate sealing ring to rotate.

[0009] According to one aspect of the shaft sealing structure of the present application, it also includes: a drive ring, which is arranged upstream of the at least one intermediate sealing ring, and the drive ring is arranged to rotate synchronously with the rotating shaft to drive the pressure fluid to flow, so that the pressure fluid can drive the intermediate sealing ring to rotate; wherein the drive ring includes a plurality of through-holes, the through-holes pass through the drive ring, and the through-holes have a pair of side walls arranged opposite to each other in the circumferential direction, and the side walls are inclined to the axial arrangement, so that as the drive ring rotates, the side walls drive the pressure fluid flowing through the through-holes to flow.

[0010] According to one aspect of the shaft sealing structure of the present application, the drive ring is disposed around the dynamic sealing ring and is connected to the dynamic sealing ring, so that the drive ring and the dynamic sealing ring rotate synchronously.

[0011] According to one aspect of the shaft sealing structure of the present application, it further includes: a flow valve, which is used to limit the flow of the pressure fluid entering the shaft sealing chamber to control the rotation speed of the intermediate sealing ring based on the flow and pressure of the pressure fluid.

[0012] According to one aspect of the shaft sealing structure of the present application, the plurality of blades are configured to control a rotation speed of the intermediate seal ring based on the number, shape, and inclination angle of the blades relative to an axial direction.

[0013] According to one aspect of the shaft sealing structure of the present application, each of the intermediate sealing rings includes an outer ring portion and an inner ring portion, and the outer ring portion surrounds the inner ring portion and is connected to the outside of the inner ring portion so that the outer ring portion and the inner ring portion rotate synchronously; wherein the annular flow channel and the guide structure are arranged on the outer ring portion, and the dynamic sealing ring or the static sealing ring is in contact with the inner ring portion of the adjacent intermediate sealing ring.

[0014] According to one aspect of the shaft sealing 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 that of the outer ring portion.

[0015] According to one aspect of the shaft sealing structure of the present application, the shaft sealing cover has a fluid inlet and a fluid outlet, and the fluid inlet and the fluid outlet are configured to allow pressure fluid to flow into and out of the shaft sealing chamber of the shaft sealing cover; an inlet guide channel is included between the fluid inlet and the shaft sealing chamber of the shaft sealing cover, and an outlet guide channel is included between the fluid outlet and the shaft sealing chamber of the shaft sealing cover, and the inlet guide channel and the outlet guide channel are configured to guide the pressure fluid entering the shaft sealing chamber from the fluid inlet to flow through the dynamic 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 sealing chamber from the fluid outlet after being guided by the outlet guide channel.

[0016] According to one aspect of the shaft sealing structure of the present application, it further includes: a pressure fluid temperature control device, which is arranged upstream of the fluid inlet to control the temperature of the pressure fluid entering the shaft sealing chamber from the fluid inlet.

[0017] According to one aspect of the shaft sealing structure of the present application, the at least one intermediate sealing ring includes one intermediate sealing ring, and the intermediate sealing ring is configured to have a rotation speed that is half of a rotation speed of the rotating shaft.

[0018] According to one aspect of the shaft sealing structure of the present application, the at least one intermediate sealing ring includes a plurality of intermediate sealing rings, and the plurality of intermediate sealing rings are configured such that a rotational speed of the plurality of intermediate sealing rings gradually decreases in a direction from the dynamic sealing ring to the static sealing ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG1A shows a perspective view of a shaft sealing structure according to a first embodiment of the present application;

[0020] FIG1B shows an exploded view of the various components of the shaft sealing structure shown in FIG1A ;

[0021] FIG1C shows a schematic axial cross-sectional view of the shaft sealing structure taken along the cutting line AA in FIG1A ;

[0022] FIG2A shows a perspective view of the intermediate sealing ring in FIG1B ;

[0023] FIG2B shows a cross-sectional view of the intermediate sealing ring in FIG1B ;

[0024] FIG3A shows a perspective view of a shaft sealing structure according to a second embodiment of the present application;

[0025] FIG3B shows an exploded view of the various components of the shaft sealing structure shown in FIG3A ;

[0026] FIG3C shows a schematic axial cross-sectional view of the shaft sealing structure obtained along the cutting line BB in FIG3A ;

[0027] FIG4A shows a perspective view of a shaft sealing structure according to a third embodiment of the present application;

[0028] FIG4B shows an exploded view of the various components of the shaft sealing structure shown in FIG4A ;

[0029] FIG4C shows a schematic axial cross-sectional view of the shaft sealing structure obtained along the cutting line CC in FIG4A ;

[0030] 5A shows a cross-sectional view of an intermediate sealing ring in a shaft sealing structure according to a fourth embodiment of the present application;

[0031] 5B shows a cross-sectional view of an intermediate sealing ring in a shaft sealing structure according to a fifth embodiment of the present application;

[0032] 6A-6C illustrate cross-sectional shapes of blades according to different embodiments of the present application. DETAILED DESCRIPTION

[0033] Various specific embodiments of the present application will be described below with reference to the accompanying drawings, which form a part of this specification. It should be understood that although various directional terms such as "front," "back," "upper," "lower," "left," "right," "top," and "bottom" are used in this application to describe various exemplary structural parts and components of the present application, these terms are used for convenience of description only and are determined based on the exemplary orientations shown in the accompanying drawings. Since the embodiments of the present application can be arranged in different orientations, these directional terms are used for illustration only and are not limiting.

[0034] Figures 1A-1C illustrate a shaft sealing structure 100 according to a first embodiment of the present application. Figure 1A is a perspective view of the shaft sealing structure 100, illustrating the external structure of the shaft sealing structure 100. Figure 1B is an exploded view of the shaft sealing structure 100, illustrating the various components of the shaft sealing structure 100. Figure 1C is an axial cross-sectional view of the shaft sealing structure 100 taken along line AA in Figure 1A at the fluid inlet and fluid outlet, illustrating the internal structure of the shaft sealing structure 100. The dashed box shows a partial enlarged view of the mating between the sealing rings.

[0035] As shown in Figures 1A-1C, the shaft sealing structure 100 includes a shaft sealing cover 101 and a rotating shaft 104. The shaft sealing cover 101 defines a shaft sealing cavity 111. The right end of the rotating shaft 104 extends through the right end surface of the shaft sealing cover 101, while the left end of the rotating shaft 104 is located in the shaft sealing cavity 111 within the shaft sealing cover 101. The shaft sealing structure 100 is used to prevent liquid or gas from leaking or entering the connection between the rotating shaft 104 and the shaft sealing cover 101. Those skilled in the art may, based on actual needs, arrange for the left end of the rotating shaft 104 to extend through the left end surface of the shaft sealing cover 101, as long as the middle portion of the rotating shaft 104 is disposed in the shaft sealing cavity 111 and the shaft sealing structure is configured accordingly. In this embodiment, the rotating shaft 104 rotates about an axis x. Hereinafter, the direction extending along the axis x is defined as the axial direction, the direction around the axis x is defined as the circumferential direction, and the direction perpendicular to the axial direction is defined as the radial direction.

[0036] The shaft seal chamber 111 is used to accommodate a pressurized fluid. The pressurized fluid in this application refers to a fluid with a certain pressure, such as oil with a certain pressure. A fluid inlet 102 and a fluid outlet 103 are provided on the shaft seal cover 101, which are in fluid communication with the shaft seal chamber 111. The oil flows into the shaft seal chamber 111 from the fluid inlet 102 and flows out from the fluid outlet 103. In this embodiment, the shaft seal cover 101 is configured to be in a cylindrical shape extending around the rotating shaft 104 and the axis x. The fluid inlet 102 and the fluid outlet 103 are arranged on the cylindrical circumferential surface of the shaft seal cover 101 and are arranged at a certain distance in the axial direction. Of course, the present application is not limited to this. The shaft seal cover 101 can also be of other shapes, as long as it is arranged around at least one end of the rotating shaft 104. In addition, the fluid inlet 102 and the fluid outlet 103 can also be arranged in other ways, as long as they are in fluid communication with the shaft seal chamber 111.

[0037] As further shown in Figures 1B and 1C, the shaft sealing structure 100 also includes a dynamic sealing ring 105, an intermediate sealing ring 107, and a static sealing ring 106, which are arranged in sequence around the rotating shaft 104 in the axial direction. The dynamic sealing ring 105 is arranged in a shaft sealing chamber 111 around the rotating shaft 104 and is fixedly connected to the rotating shaft 104. A sealing ring 131 is provided between the dynamic sealing ring 105 and the rotating shaft 104 to ensure that the dynamic sealing ring 105 is sealed relative to the rotating shaft 104. The static sealing ring 106 is arranged in the shaft sealing chamber 111 around the rotating shaft 104 and is fixedly connected to the shaft sealing cover 101. A sealing ring 132 is provided between the static sealing ring 106 and the shaft sealing cover 101 to ensure that the static sealing ring 106 is sealed relative to the shaft sealing cover 101. The intermediate seal ring 107 is disposed within the shaft seal chamber 111, surrounding the rotating shaft 104. However, it is not connected to the rotating shaft 104. Instead, it is spaced a certain distance apart from the rotating shaft 104, meaning that the intermediate seal ring 107 is suspended relative to the rotating shaft 104. Of course, in other embodiments, the intermediate seal ring 107 may also be rotationally / slidably connected to the rotating shaft 104 without being suspended. In the orientation shown in FIG1C , the left end face of the intermediate seal ring 107 contacts the dynamic seal ring 105 to form a contact portion 135, and the right end face of the intermediate seal ring 107 contacts the static seal ring 106 to form a contact portion 136. This allows the intermediate seal ring 107 to be secured in place by its abutment against the static and dynamic seal rings 106 and 105. When oil under pressure flows axially through the dynamic seal ring 105, the intermediate seal ring 107, and the static seal ring 106, a sealed connection is formed at their contact points.

[0038] In the present application, an oil film is formed between the intermediate sealing ring 107 and the dynamic sealing ring 105 at the contact portion 135 , and between the intermediate sealing ring 107 and the static sealing ring 106 at the contact portion 136 . The oil film plays a role of lubrication and sealing, so that the oil can only be discharged from the shaft seal cavity 111 from the fluid outlet 103 after flowing through the intermediate sealing ring 107 , and will not leak to the outside of the shaft seal cover 101 .

[0039] The intermediate sealing ring 107 includes an annular flow channel 117 and a flow guide structure 118 arranged in the annular flow channel 117 (see Figures 2A and 2B). The annular flow channel 117 is arranged in the intermediate sealing ring 107 around the rotating shaft 104 to allow fluids such as oil to pass through. When oil with a certain pressure enters the shaft seal chamber 111 from the fluid inlet 102 and flows axially through the annular flow channel 117 of the intermediate sealing ring 107, the flow guide structure 118 is used to guide the oil to drive the intermediate sealing ring 107 to rotate at a rotation speed lower than that of the rotating shaft 104. In some embodiments, the rotation speed of the intermediate sealing ring 107 is related to the pressure and flow rate of the oil. In some embodiments, the rotation speed of the intermediate sealing ring 107 is related to the specific structure of the flow guide structure 118. The more specific structures of the annular flow channel 117 and the flow guide structure 118 will be described in detail in conjunction with Figures 2A and 2B.

[0040] When the rotating shaft 104 rotates, the dynamic seal ring 105 rotates synchronously with the rotating shaft 104, while the static seal ring 106 remains fixed to the shaft seal cover 101. At this time, the intermediate seal ring 107 rotates at a slower speed than the rotating shaft 104. Therefore, compared to a shaft seal structure in which the dynamic seal ring 105 is in direct contact with the static seal ring 106, the relative rotational speeds between the dynamic seal ring 105 and the intermediate seal ring 107, and between the intermediate seal ring 107 and the static seal ring 106, are lower, thereby reducing wear between them and extending their service life. In one specific embodiment, if the rotating shaft 104 and the dynamic seal ring 105 rotate at 8000 rpm, when the dynamic seal ring 105 and the static seal ring 106 are in direct contact, the relative rotational speed of the dynamic seal ring 105 relative to the static seal ring 106 is 8000 rpm. However, in this embodiment, if the rotation speed of the intermediate sealing ring 107 is 4000 rpm, the relative rotation speed between the dynamic sealing ring 105 and the intermediate sealing ring 107, and between the intermediate sealing ring 107 and the static sealing ring 106 is reduced to 4000 rpm, thereby reducing the wear of each sealing ring.

[0041] More specifically, the rotating shaft 104 has a stepped shape with a decreasing diameter from left to right, comprising a first step 141, a second step 142, and a third step 143, with the diameters of these first, second, and third steps decreasing in sequence. The dynamic seal ring 105 is mounted on the second step 142 of the rotating shaft 104, with its left side abutting the first step 141 and a portion of its right side extending beyond the third step 143. The intermediate seal ring 107 and the static seal ring 106 are positioned around the third step 143 of the rotating shaft 104, with a gap between them.

[0042] The intermediate sealing ring 107 includes an inner ring portion 108 and an outer ring portion 109. The outer ring portion 109 is fixedly connected to the outer side of the inner ring portion 108 around the inner ring portion 108 so 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 made into an integral part so that the integral part composed of the inner ring portion 108 and the outer ring portion 109 has good overall strength. In this embodiment, the outer ring portion 109 is used to set the driving structure that drives the intermediate sealing ring 107 to rotate, and the inner ring portion 108 is used to set the sealing contact structure between the intermediate sealing ring 107 and the dynamic sealing ring 105 and the static sealing ring 106. In other words, the annular flow channel 117 and the flow guide structure 118 are set on the outer ring portion 109. The left side of the inner ring portion 108 of the intermediate seal ring 107 contacts the dynamic seal ring 105 to form a contact portion 135, and the right side of the inner ring portion 108 contacts the static seal ring 106 to form a contact portion 136. The outer ring portion 109 and the inner ring portion 108 can be made of the same material or different materials. When made of different materials, the material of the inner ring portion 108 has a higher hardness than the material of the outer ring portion 109. For example, the outer ring portion 109 is made of plastic and the inner ring portion 108 is made of metal. This can save materials and costs while ensuring the wear resistance of the intermediate seal ring 107.

[0043] Although the above description provides an example of the specific structure, position and connection relationship of the rotating shaft 104 , the dynamic sealing ring 105 , the static sealing ring 106 and the intermediate sealing ring 107 , the present application is not limited thereto.

[0044] An inlet guide channel 115 is constructed between the fluid inlet 102 and the shaft seal chamber 111, and an outlet guide channel 116 is constructed between the shaft seal chamber 111 and the fluid outlet 103. The inlet guide channel 115 and the outlet guide channel 116 are configured to allow the pressurized fluid (oil in this embodiment) entering the shaft seal chamber 111 from the fluid inlet 102 to be guided through the inlet guide channel 115, flow along the axial direction of the rotating shaft 104 through the dynamic seal ring 105, the intermediate seal ring 107, and the static seal ring 106, and then be guided through the outlet guide channel 116 before exiting the shaft seal chamber 111 through the fluid outlet 103. Specifically, the shaft seal cover 101 includes an annular outer wall 151 and an annular inner wall 152 surrounding the rotating 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 each other via a connecting portion 153. The annular inner wall 152 is spaced apart from both end caps 154. The shaft seal chamber 111 is defined by an annular inner wall 152. The inlet guide channel 115 and the outlet guide channel 116 are defined by the annular outer wall 151, the annular inner wall 152, and the end cap 154, and are separated by a connecting portion 153. The fluid inlet 102 and the fluid outlet 103 radially penetrate the annular outer wall 151. As a result, the inlet guide channel 115 and the outlet guide channel 116 have an annular and zigzag shape. The pressurized fluid flowing into the inlet guide channel 115 from the fluid inlet 102 flows toward the left end cap 154 ​​while also flowing circumferentially, then enters the shaft seal chamber 111 through the gap between the annular inner wall 152 and the left end cap 154. Furthermore, the pressurized fluid in the shaft seal chamber 111 also flows circumferentially, entering the outlet guide channel 116 through the gap between the annular inner wall 152 and the right end cap 154, and then is discharged through the fluid outlet 103. The annular inlet guide channel 115 and the outlet guide channel 116 enable the pressure fluid to enter and exit the shaft sealing chamber 111 more evenly.

[0045] In this embodiment, the shaft sealing structure 100 also 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 through pipelines to form a circulation loop of the pressure fluid. Specifically, the oil pump is arranged upstream of the fluid inlet 102, the pressure fluid temperature control device is arranged upstream of the oil pump, and the fluid outlet 103 is arranged upstream of the pressure fluid temperature control device. After the pressure fluid (such as oil) leaves the shaft sealing chamber 111 from the fluid outlet 103, it passes through the external pressure fluid temperature control device for cooling, then flows through the oil pump to increase the pressure of the pressure fluid, and finally the pressure fluid with increased pressure returns to the shaft sealing chamber 111 through the fluid inlet 102 to form a pressure fluid circulation. In some embodiments, the pressure fluid temperature control device can be an oil cooler, which is used to cool down the fluid that has become hot due to the high temperature in the shaft sealing chamber 111 for reuse. The oil pump can be a fixed frequency oil pump or a variable frequency oil pump, which is used to increase the pressure fluid flowing out of the oil cooler to a suitable pressure to drive the pressure fluid to flow along the pressure fluid circulation path and drive the middle sealing ring 107 to rotate at a suitable speed.

[0046] Figures 2A and 2B respectively illustrate a perspective view and a cross-sectional view of the intermediate sealing ring 107 in Figure 1B , illustrating the specific structure of the intermediate sealing ring 107. As shown in Figure 2A , an annular flow channel 117 is disposed in the outer ring portion 109 of the intermediate sealing ring 107, surrounding the rotating shaft 104. The annular flow channel 117 axially penetrates the outer ring portion 109 to allow pressurized fluid to flow axially through the annular flow channel 117. A flow guide structure 118 is disposed in the annular flow channel 117 and includes a plurality of blades 110 and a plurality of hollow portions 114. The blades 110 are circumferentially spaced apart in the annular flow channel 117, forming a hollow portion 114 between adjacent blades 110. Each hollow portion 114 has a pair of circumferentially opposed sidewalls 234, which form the sidewalls of the blades 110. Each sidewall 234 of the blade 110 is arranged obliquely relative to the axial direction of the rotating shaft 104, so that when the pressurized fluid flows through the hollow portion 114 of the intermediate sealing ring 107 along the axial direction, the pressurized fluid is blocked by the sidewall 234, thereby driving the intermediate sealing ring 107 to rotate. When the pressurized fluid flows through each hollow portion 114, the pressure fluid having different pressures and flow rates generates different driving forces on the sidewall 234 to drive the intermediate sealing ring 107 to rotate, and thus the rotational speeds of the intermediate sealing ring 107 also vary. As will be understood by those skilled in the art, the blade 110 and the hollow portion 114 can be configured in any shape, as long as the sidewall 234 of the blade 110 can block the pressurized fluid when the pressurized fluid flows through the hollow portion 114, thereby driving the intermediate sealing ring 107 to rotate.

[0047] Specifically, the outer ring portion 109 includes an annular outer wall 235 and an annular inner wall 236, and the inner wall 236 is connected to the inner ring portion 108. The outer wall 235 and the inner wall 236 are coaxially arranged and spaced apart to form an annular flow channel 117. Each blade 110 is arranged to be connected between the outer wall 235 and the inner wall 236 at an angle inclined to the axial direction, so as to divide the annular flow channel 117 into a plurality of hollow portions 114. For blades 110 with different numbers, shapes, and inclination angles relative to the axial direction, when the pressure fluid with the same pressure and flow rate flows through the various blades 110, the driving force generated on the side wall 234 to drive the rotation of the intermediate sealing ring 107 is also different in magnitude, and therefore the speed at which the intermediate sealing ring 107 is driven to rotate is also different.

[0048] Therefore, the rotation speed of the intermediate seal ring 107 can be controlled based on the number, shape, and inclination angle of the blades 110 relative to the axial direction, or based on the flow rate and pressure of the pressure fluid.

[0049] In other embodiments, the flow-guiding structure 118 does not include multiple blades, but instead includes multiple through holes, wherein the multiple through holes are arranged circumferentially at intervals in the annular flow channel 117 so that each through hole forms a hollow portion 114, and the side walls for blocking the pressure fluid are formed by the hole walls of the through holes.

[0050] 3A-3C illustrate the specific structure of the shaft sealing structure 300 according to the second embodiment of the present application. FIG3A shows a stereoscopic view of the shaft sealing structure 300, FIG3B shows an exploded view of the various components of the shaft sealing structure 300, and FIG3C shows an axial cross-sectional view of the shaft sealing structure 300 taken along line BB at the fluid inlet and fluid outlet. As shown in FIG3A-3C, the structure of the shaft sealing structure 300 is substantially the same as that of the shaft sealing structure 100, with the difference that the shaft sealing structure 300 further includes a drive ring 313. The drive ring 313 is axially arranged upstream of the intermediate sealing ring 107 and is roughly aligned with the outer ring portion 109 of the intermediate sealing ring 107, so that the pressure fluid needs to flow through the drive ring 313 before flowing through the outer ring portion 109 of the intermediate sealing ring 107. In this embodiment, the drive ring 313 rotates synchronously with the rotating shaft 104. The rotation of the drive ring 313 increases the pressure of the pressure fluid flowing through it to drive the pressure fluid to continue flowing through the middle sealing ring 107, and the pressure fluid can drive the middle sealing ring 107 to rotate.

[0051] Specifically, the drive ring 313 surrounds the dynamic seal ring 105 and is fixedly connected to the dynamic seal ring 105, so that the drive ring 313 rotates synchronously with the dynamic seal ring 105 and the rotating 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 can also be directly fixed to the rotating shaft 104. The drive ring 313 contacts and seals the left side of the inner ring portion 108 of the intermediate seal ring 107.

[0052] The structure of the drive ring 313 is substantially similar to that of the outer ring portion 109 of the intermediate sealing ring 107. The drive ring 313 also includes a plurality of through-portions 314 extending radially and axially through the drive ring 313. Each through-portion 314 of the drive ring 313 is substantially aligned with each hollow portion 114 of the intermediate sealing ring 107. Each through-portion 314 here also has a pair of circumferentially opposed sidewalls that are inclined relative to the axial direction, such that as the drive ring 313 rotates, the sidewalls can drive the flow of pressurized fluid through the through-portion 314. In the embodiment shown in the figure, when the drive ring 313 is driven by the rotating shaft 104 to rotate at high speed, pressurized fluid upstream of the drive ring 313 is drawn through the through-portions 314 of the drive ring 313, increasing its pressure. The pressurized fluid then flows through the hollow portion 114 in the outer ring portion 109 of the intermediate sealing ring 107, driving the intermediate sealing ring 107 to rotate at a speed lower than that of the rotating shaft 104.

[0053] In this embodiment, the shaft sealing structure 300 also includes a flow valve and a pressure fluid temperature control device. The fluid inlet 102 and the fluid outlet 103 are connected to the flow valve and the pressure fluid temperature control device through pipelines to form a circulation of the pressure fluid. The flow valve is arranged upstream of the fluid inlet 102, the pressure fluid temperature control device is arranged upstream of the flow valve, and the fluid outlet 103 is arranged upstream of the pressure fluid temperature control device. In this embodiment, the pressure increase of the pressure fluid is achieved by the drive ring 313, rather than by an oil pump as in the shaft sealing structure 100. Therefore, there is no need to set an oil pump upstream of the fluid inlet 102, but a flow valve, such as a throttle valve, is set, which is used to limit the flow of the pressure fluid entering the shaft sealing chamber 111. Thus, by setting the flow valve and the drive ring 313, the rotation speed of the intermediate sealing ring 107 can be controlled based on the flow of the pressure fluid.

[0054] 4A-4C illustrate the specific structure of the shaft sealing structure 400 according to the third embodiment of the present application. FIG4A shows a three-dimensional view of the shaft sealing structure 400. FIG4B shows an exploded view of the various components of the shaft sealing structure 400. FIG4C shows an axial cross-sectional view of the shaft sealing structure 400 taken along the CC line at the fluid inlet and the fluid outlet. The dotted box shows a partial enlarged view. As shown in FIG4A-4C, the structure of the shaft sealing structure 400 is substantially the same as that of the shaft sealing structure 300, with the difference being that two intermediate sealing rings 107 are provided between the dynamic sealing ring 105 and the static sealing ring 106. In this embodiment, the two intermediate sealing rings 107 are respectively an intermediate sealing ring 107a and an intermediate sealing ring 107b, which have the same shape and structure. The intermediate sealing ring 107a is located upstream of the intermediate sealing ring 107b. The left end surface of intermediate seal ring 107a contacts dynamic seal ring 105 to form contact portion 435, the right end surface of intermediate seal ring 107b contacts static seal ring 106 to form contact portion 436, and the right end surface of intermediate seal ring 107a contacts the left end surface of intermediate seal ring 107b to form contact portion 437. Thus, the two intermediate seal rings 107 are secured in place by abutting against static seal ring 106 and dynamic seal ring 105, and are sealed together via contact portions 435, 436, and 437. Although an embodiment in which two intermediate seal rings 107 are disposed between dynamic seal ring 105 and static seal ring 106 is shown here, those skilled in the art will appreciate that three or more intermediate seal rings 107 may also be disposed between dynamic seal ring 105 and static seal ring 106, depending on specific needs. It suffices that the intermediate seal rings 107 on the most upstream side and the most downstream side of the intermediate seal rings 107 are in contact with the dynamic seal ring 105 and the static seal ring 106 , respectively, and that adjacent intermediate seal rings 107 are in contact with each other.

[0055] By providing two or more intermediate sealing rings 107, the rotational speed of each intermediate sealing ring 107 gradually decreases in the direction of pressure fluid flow, that is, in the direction of pressure fluid flow from the dynamic sealing ring 105 to the static sealing ring 106. This reduces the relative speed between adjacent sealing rings, particularly the relative speed between the dynamic sealing ring 105 and the intermediate sealing ring 107, and between the intermediate sealing ring 107 and the static sealing ring, thereby reducing wear on each sealing ring. In a specific embodiment, if the rotational speed of the rotating shaft 104 and the dynamic sealing ring 105 is 8000 rpm, then when the dynamic sealing ring 105 is in direct contact with the static sealing ring 106, the relative rotational speed of the dynamic sealing ring 105 relative to the static sealing ring 106 is 8000 rpm. However, in this embodiment, if the rotational speed of intermediate seal ring 107a is 6000 rpm and the rotational speed of intermediate seal ring 107b is 3000 rpm, the relative rotational speed between dynamic seal ring 105 and intermediate seal ring 107a is reduced to 2000 rpm, and the relative rotational speed between intermediate seal ring 107b and static seal ring 106 is reduced to 3000 rpm. It will be understood by those skilled in the art that the greater the number of intermediate seal rings 107, the better the wear reduction effect.

[0056] FIG5A shows a cross-sectional view of an intermediate sealing ring 507a in a shaft sealing structure according to a fourth embodiment of the present application. FIG5B shows a cross-sectional view of an intermediate sealing ring 507b in a shaft sealing structure according to a fifth embodiment of the present application. As shown in FIG5A and FIG5B , the structures of the intermediate sealing rings 507a and 507b are substantially the same as the structure of the intermediate sealing ring 107, with the difference being the number of hollow portions. In the intermediate sealing ring 107 shown in FIG2B , the number of hollow portions 114 is 30. In the intermediate sealing ring 507a shown in FIG5A , the number of hollow portions 514a is 20. In the intermediate sealing ring 507b shown in FIG5B , the number of hollow portions 514b is 10. It is understood that the number of hollow portions 114 may also be other numbers. Assuming the other structural elements of the shaft seal and the pressure and flow rate of the pressurized fluid remain unchanged, the fewer the number of hollows, that is, the fewer the number of blades, the greater the flow rate of the pressurized fluid passing through the hollows and the lower the pressure, thus driving the intermediate seal ring at a lower rotational speed. Conversely, the greater the number of hollows, that is, the more blades, the smaller the flow rate of the pressurized fluid passing through the hollows and the higher the pressure, thus driving the intermediate seal ring at a higher rotational speed.

[0057] 6A-6C are schematic diagrams showing the cross-sectional shapes of blades according to different embodiments of the present application. The left side of each blade is close to the direction of the dynamic sealing ring, that is, it is located upstream in the flow direction of the pressure fluid, and the right side is close to the direction of the static sealing ring, that is, it is located downstream in the flow direction of the pressure fluid. The arrows indicate the flow direction of the pressure fluid, and the flow direction is the direction of the axis x. Among them, the blade shapes of blade 110a and blade 110c are roughly the same, but the inclination angles of the center lines relative to the axis x are different. The inclination angles of the center lines of blade 110a and blade 110b relative to the axis x are roughly the same, but the blade shapes are different.

[0058] For blade 110a and blade 110c, the inclination angle of blade 110a relative to axis x is greater than that of blade 110c, and the resistance force of the pressure fluid flowing through blade 110a is also greater than the resistance force of the pressure fluid flowing through blade 110c. Therefore, when other structures of the shaft sealing structure and the pressure and flow rate of the pressure fluid remain unchanged, the rotation speed of the intermediate sealing ring including blade 110a is greater than the rotation speed of the intermediate sealing ring including blade 110c.

[0059] In addition, as shown in the figure, the thickness of blade 110b is uniform, and the angles between the two side walls and the axis x are the same. In contrast, the thickness of blades 110a and 110c are uneven, so the angles between the two side walls of blades 110a and 110c relative to the axis x are different. The greater the difference in the angles between the two sides of blades 110a and 110c relative to the axis x, the greater the velocity difference of the fluid on both sides of blades 110a and 110c, and thus the greater the pressure difference on both sides of blades 110a and 110c. Therefore, under the same blade setting and the same pressure and flow of the pressure fluid, the rotation speed of blades 110a and 110c is higher than that of blade 110b.

[0060] Therefore, by providing blades 110 with different shapes and different inclination angles, the intermediate sealing ring 107 can be controlled to reach a suitable rotation speed.

[0061] The shaft sealing structure of the present application reduces the relative linear speed among the dynamic sealing ring, the intermediate sealing ring and the static sealing ring by setting an intermediate sealing ring whose rotation speed is between the dynamic sealing ring and the static sealing ring, thereby reducing the wear of each sealing ring and extending the service life.

[0062] The shaft sealing structure of the present application does not require an additional reduction mechanism to reduce the rotation speed of the intermediate sealing ring. Instead, the intermediate sealing ring is driven to rotate by the flow of pressurized fluid. It is not only simple in structure but also occupies little space and does not generate additional vibration and noise due to the reduction mechanism.

[0063] Furthermore, in the shaft sealing structure of the present application, the pressure fluid flows substantially in the shaft sealing cavity in the axial direction, and flows sequentially through each contact portion in the axial direction, so as to better form an oil film layer at each contact portion to achieve a more reliable sealing effect.

[0064] In addition, the shaft sealing structure of the present application may also include one of the additional components such as a flow valve, an oil pump, a pressure fluid temperature control device, etc., which, on the one hand, allows the pressure fluid to circulate, thereby increasing the stability of the shaft sealing structure, and on the other hand, can more accurately control the rotation speed of the intermediate sealing ring.

[0065] Although the present application has been disclosed in conjunction with the embodiments described above, various alternatives, modifications, variations, improvements and / or substantially equivalent schemes, whether known or foreseeable now or in the future, are all obvious to those skilled in the art. In addition, the technical effects and / or technical problems described in this specification are exemplary rather than restrictive, so the disclosure of this specification can be used to solve other technical problems and have other technical effects. Therefore, the embodiments of the present application stated above are intended to be illustrative rather than restrictive. Various changes can be made without departing from the spirit or scope of the present application. Therefore, the present application is intended to include all known or previously developed alternatives, modifications, variations, improvements and / or substantially equivalent schemes.

Claims

1. A shaft sealing structure (100), characterized in that include: A shaft sealing cover (101), wherein the shaft sealing cover (101) defines a shaft sealing chamber (111), and the shaft sealing chamber (111) is used to contain a pressure fluid; a rotating shaft (104), the rotating shaft (104) rotatably passing through the shaft sealing cover (101), and at least a portion of the rotating shaft (104) is located in the shaft sealing chamber (111); a dynamic sealing ring (105), the dynamic sealing ring (105) being disposed in the shaft sealing chamber (111) around the rotating shaft (104) and being sealingly mounted to the rotating shaft (104) so ​​that the dynamic sealing ring (105) and the rotating shaft (104) rotate synchronously; a static sealing ring (106), the static sealing ring (106) being disposed in the shaft sealing chamber (111) around the rotating shaft (104) and being sealingly mounted to the shaft sealing cover (101) so that the static sealing ring (106) is stationary relative to the shaft sealing cover (101); and At least one intermediate sealing ring (107), the at least one intermediate sealing ring (107) being arranged around the rotating shaft (104) in the shaft sealing chamber (111), wherein in the axial direction of the rotating shaft (104), the at least one intermediate sealing ring (107) is arranged between the dynamic sealing ring (105) and the static sealing ring (106), and the at least one intermediate sealing ring (107) is capable of contacting the dynamic sealing ring (105), and the at least one intermediate sealing ring (107) is capable of contacting the static sealing ring (106); The at least one intermediate sealing ring (107) comprises an annular flow channel (117) and a flow guide structure (118), wherein the annular flow channel (117) is arranged around the rotating shaft (104), and the flow guide structure (118) is arranged in the annular flow channel (117), and wherein the at least one intermediate sealing ring (107) is arranged such that when a pressure fluid flows through the annular flow channel (117) along the axial direction of the rotating shaft (104), the flow guide structure (118) can guide the pressure fluid to drive the at least one intermediate sealing ring (107) to rotate at a speed lower than the rotation speed of the rotating shaft (104).

2. The shaft sealing structure (100) according to claim 1, characterized in that: The flow guide structure (118) includes a plurality of hollow portions (114), the hollow portions (114) passing through the intermediate sealing ring (107), and each of the plurality of hollow portions (114) has a pair of side walls arranged opposite to each other in the circumferential direction, the side walls being inclined with respect to the axial direction, so that when the pressure fluid flows through the hollow portion (114) of the intermediate sealing ring (107) along the axial direction, the pressure fluid is blocked by the side walls, thereby driving the intermediate sealing ring (107) to rotate.

3. The shaft sealing structure (100) according to claim 2, characterized in that: The flow guide structure (118) comprises a plurality of blades (110), wherein the plurality of blades (110) are arranged at intervals along the circumferential direction in the annular flow channel (117), so that the hollow portions (114) are formed between adjacent blades (110), and the blades (110) form the side walls.

4. The shaft sealing structure (100) according to claim 2, characterized in that: The flow guiding structure (118) comprises a plurality of through holes, wherein the plurality of through holes are arranged at intervals along the circumferential direction in the annular flow channel (117), so that each through hole forms the hollow portion (114), and the hole wall of the through hole forms the side wall.

5. The shaft sealing structure (100) according to claim 1, characterized in that Also includes: An oil pump is used to drive the pressure fluid to flow so that the pressure fluid can drive the middle sealing ring (107) to rotate.

6. The shaft sealing structure (100) according to claim 1, characterized in that Also includes: a drive ring (313), the drive ring (313) being arranged upstream of the at least one intermediate sealing ring (107), and the drive ring (313) being arranged to rotate synchronously with the rotating shaft (104) to drive the pressure fluid to flow, so that the pressure fluid can drive the intermediate sealing ring (107) to rotate; The drive ring (313) includes a plurality of through portions (314), wherein the through portions (314) penetrate the drive ring (313), and the through portions (314) have a pair of side walls arranged opposite to each other in the circumferential direction, and the side walls are inclined to the axial direction so that as the drive ring (313) rotates, the side walls drive the pressure fluid flowing through the through portions (314) to flow.

7. The shaft sealing structure (100) according to claim 6, characterized in that: The driving ring (313) is arranged around the dynamic sealing ring (105) and is connected to the dynamic sealing ring (105) so that the driving ring (313) and the dynamic sealing ring (105) rotate synchronously.

8. The shaft sealing structure (100) according to claim 1, characterized in that Also includes: A flow valve is used to limit the flow of the pressure fluid entering the shaft seal chamber (111) so as to control the rotation speed of the intermediate sealing ring (107) based on the flow and pressure of the pressure fluid.

9. The shaft sealing structure (100) according to claim 3, characterized in that: The plurality of blades (110) are configured to control a rotation speed of the intermediate sealing ring (107) based on the number, shape, and angle of inclination relative to an axial direction of the blades (110).

10. The shaft sealing structure (100) according to claim 1, characterized in that: Each of the intermediate sealing rings (107) comprises an outer ring portion (109) and an inner ring portion (108), wherein the outer ring portion (109) surrounds the inner ring portion (108) and is connected to the outer side of the inner ring portion (108), so that the outer ring portion (109) and the inner ring portion (108) rotate synchronously; The annular flow channel (117) and the flow guide structure (118) are arranged on the outer ring portion (109), and the dynamic sealing ring (105) or the static sealing ring (106) is in contact with the inner ring portion (108) of the adjacent intermediate sealing ring (107).

11. The shaft sealing structure (100) according to claim 10, characterized in that: The outer ring portion (109) and the inner ring portion (108) are made of different materials, and the material of the inner ring portion (108) has a higher hardness than the material of the outer ring portion (109).

12. The shaft sealing structure (100) according to claim 1, characterized in that: The shaft seal cover (101) has a fluid inlet (102) and a fluid outlet (103), and the fluid inlet (102) and the fluid outlet (103) are configured to allow pressure fluid to flow into and out of a shaft seal chamber (111) of the shaft seal cover (101); An inlet guide channel (115) is included between the fluid inlet (102) and the shaft seal chamber (111) of the shaft seal cover (101), and an outlet guide channel (116) is included between the fluid outlet (103) and the shaft seal chamber (111) of the shaft seal cover (101). The inlet guide channel (115) and the outlet guide channel (116) are configured to guide the pressure fluid entering the shaft seal chamber (111) from the fluid inlet (102) through the inlet guide channel (115), and then flow through the dynamic seal ring (105), the at least one intermediate seal ring (107) and the static seal ring (106) along the axial direction of the rotating shaft (104), and then flow out of the shaft seal chamber (111) from the fluid outlet (103) after being guided by the outlet guide channel (116).

13. The shaft sealing structure (100) according to claim 12, characterized in that Also includes: A pressure fluid temperature control device is provided upstream of the fluid inlet (102) to control the temperature of the pressure fluid entering the shaft seal chamber (111) from the fluid inlet (102).

14. The shaft sealing structure (100) according to claim 1, characterized in that: The at least one intermediate sealing ring (107) includes one intermediate sealing ring (107), and the intermediate sealing ring (107) is configured to rotate at a speed that is half the rotation speed of the rotating shaft (104).

15. The shaft sealing structure (100) according to claim 1, characterized in that: The at least one intermediate sealing ring (107) includes two or more intermediate sealing rings (107), and the two or more intermediate sealing rings (107) are configured such that a rotation 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).

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