JP2006097610A - Method for reducing leak of mechanical seal of open type compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce leak of refrigerant from a mechanical seal when an electromagnetic clutch driving an open type compressor is excited. <P>SOLUTION: A gap between a housing and a main shaft 11 projecting from a cylindrical part 10a of the housing 10 of the open type compressor is liquid-tightly sealed by the mechanical seal 15 and this compressor is driven by the electromagnetic clutch M provided on the main shaft concentrically with the cylindrical part. Diameter of the main shaft and spring characteristics of an elastic support member are established to make the maximum value of sum of force pressing the main shaft 11 forward by inner pressure in the housing, force pressing a rotary side seal ring 17 of the mechanical seal forward toward a stationary side seal ring 16 by inner pressure, and force pressing the rotary side seal ring forward toward the stationary side seal ring larger than the maximum value of force of a friction plate 37 moving in an axial direction pressing the main shaft backward via the elastic support member 32 when the electromagnetic clutch is excited. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for reducing leakage of a mechanical seal in an open type compressor driven via an electromagnetic clutch.

  For example, as shown in Patent Document 1, an open type compressor is provided with a compression mechanism portion that is provided in a housing and compresses a working fluid such as a refrigerant, and a mechanical seal that seals the inside of the housing with respect to the outside. However, it does not include a drive source, and the compression mechanism is driven by a drive source such as a motor provided outside via an electromagnetic clutch or the like.

  FIG. 5 shows an example of such a conventional open compressor. The main shaft 11 of this open type compressor has a large-diameter portion 11a connected to a compression mechanism portion such as a scroll type provided therein supported by a housing 10 by a main rolling bearing 12, and a cylindrical portion 10a formed in the housing 10. A front end portion that protrudes coaxially from the shaft is supported by a front end side rolling bearing (rolling bearing) 13, and a space between the housing 10 and the main shaft 11 is sealed by a mechanical seal 15 including a stationary side seal ring 16 and a rotary side seal ring 17. Has been. The stationary side seal ring 16 is fitted with an O-ring 16a in a liquid-tight manner on the inner periphery of the cylindrical portion 10a, and the axial movement is restricted by an inward flange and a retaining ring at the end of the cylindrical portion 10a. The rotation-side seal ring 17 is liquid-tight and slidable in the axial direction through an O-ring (elastic seal member) 17b at the rear portion of the intermediate portion 11b of the main shaft 11, and is attached to the main shaft 11. A ring-shaped protrusion 17 a at the tip is pressed against the stationary seal ring 16 by a spring 18 interposed between the ring 19 and the stationary ring 19.

  On the outer periphery of the cylindrical portion 10 a of the housing 10, an annular, U-shaped rotor 20 that is driven to rotate by a motor or the like via a transmission belt or the like and is open on the rear side is coaxial with the main shaft 11 via a rolling bearing 21. It is supported by. In the U-shaped cross section of the rotor 20, an electromagnet 25 composed of a yoke 26 made of a magnetic material such as iron and an electromagnetic coil 27 provided in the inside is formed in an annular shape with a U-shaped cross section opened on the front side. And is attached to the cylindrical portion 10a by the support plate 28.

  A hub 30 is splined to the front end portion 11c of the main shaft 11 protruding from the front end side roller bearing 13, and is screwed and fixed by a nut 14. Are contacted via first spacers 33 arranged at three locations in the circumferential direction and fixed by first rivets 34. One end of a leaf spring (elastic support member) 32 is provided between the balancer plate 31 and the second spacer 35 in contact with the front surface of the flange portion 30a at three locations in the circumferential direction, which is approximately in the middle of each first spacer 33. The four members 30 a, 35, 32, and 31 are integrally fixed by a second rivet 36. The other end of each leaf spring 32 is coaxially arranged with the main shaft 11 and fixed by a rivet 38 to a friction plate 37 made of a thick plate of a magnetic material such as an annular iron having the same inner diameter and outer diameter as the rotor 20. Has been. A damper 39 made of a flexible elastic material such as rubber is attached to the balancer plate 31 at three locations in the circumferential direction of the outermost periphery, and a relief hole 31a for avoiding the nut 14 is formed in the center. An intermediate portion of the leaf spring 32 excluding both ends is inclined with respect to a plane orthogonal to the main shaft 11, and the front surface of the friction plate 37 is brought into contact with each damper 39 by the elasticity of each leaf spring 32 in the free state shown in FIG. Thus, axial positioning is performed, whereby a predetermined clutch gap e is formed between the end surface 20a of the rotor 20 and the rear surface of the friction plate 37, and an initial load is applied to each leaf spring 32. . In the structure described above, the electromagnetic clutch M is configured by the rotor 20, the electromagnet 25, and the friction plate 37.

  In the above-described open type compressor, even if the rotor 20 is rotated by a drive source such as a motor via a transmission belt (not shown) or the like, if the electromagnetic coil 27 is not energized, an electromagnetic clutch as shown in FIG. Since the clutch gap e is provided between the end face 20a of the rotor 20 and the friction plate 37 while M remains detached, the main shaft 11 is not rotated. However, when the electromagnetic coil 27 is energized, the friction plate 37 is attracted by the electromagnet 25, is brought into contact with the end surface 20a of the rotor 20, the electromagnetic clutch M is engaged, the main shaft 11 is rotated, and the open compressor is operated. The

When such an open type compressor is used for compressing the refrigerant of the air conditioner, the compressor is intermittently operated according to the load of the air conditioner. In such a state, the internal pressure of the refrigerant in the housing 10 becomes the temperature of the refrigerant. Vapor pressure corresponding. The main shaft 11 is pressed forward by this internal pressure, and the flange portion 11f at the rear end of the large-diameter portion 11a of the main shaft 11 comes into contact with the inner ring of the main rolling bearing 12 and stops at that position. Normally, in this state, the position in the axial direction of the step portion 11d between the intermediate portion 11b and the front end portion 11c of the main shaft 11 is protruded somewhat toward the front end side from the end face of the inner ring of the front end side rolling bearing 13, and the step portion 11d A clutch gap adjusting shim 40 is interposed between the end face of the hub 30 attached to the front end portion 11c (see a partially enlarged view of FIG. 5). This type of open-type compressor needs to keep the clutch clearance e within a predetermined range in order to operate stably. However, a plurality of types of clutch clearance adjustment shims 40 of different thicknesses are prepared. By selecting this, the clutch gap e is kept within a predetermined range regardless of the dimensional error of each part.
JP-A-06-050347 (FIG. 1).

  In the mechanical seal 15 of the above-described open type compressor, the electromagnetic clutch M is excited and the friction plate 37 is attracted by the electromagnet 25 and contacted with the end face 20a of the rotor 20 in the axial direction backwardly applied via the leaf spring 32. Due to this thrust, the main shaft 11 may be displaced backward against the forward pressing force caused by the internal pressure of the refrigerant in the housing 10. However, since the rotation-side seal ring 17 is slidably provided in the intermediate portion 11b of the main shaft 11 and is slidably pressed against the stationary-side seal ring 16 by the spring 18, the main shaft 11 faces rearward as described above. It was considered that the rotating side seal ring 17 pressed by the spring 18 does not leave the stationary side seal ring 16 even when displaced. However, when the main shaft 11 is displaced rearward due to the excitation of the electromagnetic clutch M, the inventor temporarily moves the rotary side seal ring 17 away from the stationary side seal ring 16 but temporarily maintains a predetermined internal pressure corresponding to the temperature in the housing 10. It was discovered that refrigerant could leak to the outside.

  This is because, when the electromagnetic clutch M is excited and the main shaft 11 is suddenly displaced backward, the contact portion between the intermediate portion 11b and the elastic seal member 17b does not slip immediately, and the elastic seal member 17b is elastically deformed. The reaction force produces a force that moves the rotation-side seal ring 17 backward. When this force exceeds the pressing force of the spring 18, the rotation-side seal ring 17 is displaced by the main shaft 11, and the annular protrusion 17a at the tip thereof is displaced. Is considered to be away from the stationary seal ring 16. An object of the present invention is to reduce the leakage of a mechanical seal in an open compressor caused by such a cause.

  To this end, according to the first aspect of the present invention, there is provided a method for reducing leakage of a mechanical seal in an open compressor, wherein a front end portion of an intermediate portion of a main shaft that is coaxially projected from a cylindrical portion formed in a housing of an open compressor is provided. A stationary seal ring that is supported by a cylindrical portion via a rolling bearing and is restrained from moving in the axial direction on the inner periphery of the cylindrical portion, and a liquid-tight and axial direction via an elastic seal member at the rear of the intermediate portion The space between the housing and the main shaft is sealed by a mechanical seal composed of a rotating side seal ring that is slidably pressed forward and abutted against the stationary side seal ring, and the outer periphery of the cylindrical portion is coaxial with the main shaft. A rotor that is rotationally driven from the outside is supported, and this rotor and a front end portion of a main shaft that protrudes outside from the cylindrical portion are supported by the front end portion so as to be movable in the axial direction via an elastic support member, and are rotated by an electromagnet. In an open type compressor in which an electromagnetic clutch is formed by a friction plate that is engaged with and disengaged from the end face of the rotor, the rotary side seal ring moves away from the stationary side seal ring when the electromagnetic clutch is energized. In the method for reducing leakage of a mechanical seal in an open type compressor that reduces leakage of the working fluid inside to the outside, the internal pressure of the working fluid generated in a normal operating state presses the main shaft forward, and the internal pressure is the rotation side seal. The maximum sum of the force that pushes the ring forward toward the stationary seal ring and the force that pushes the rotary seal ring forward toward the stationary seal ring is the axial direction when the electromagnetic clutch is excited. Passes through the mechanical seal of the main shaft so that the friction plate moving in the direction of the friction plate is larger than the maximum value of the force pushing the main shaft backward through the elastic support member. And the diameter of The inter, is characterized in that setting the spring characteristics of the elastic support members.

  The method for reducing leakage of a mechanical seal in an open type compressor according to claim 1 is a method in which the internal pressure of the working fluid presses the main shaft forward and rotates by increasing the diameter of the intermediate portion that passes through the mechanical seal of the main shaft. The maximum value of the force that presses the side seal ring forward may be set to be larger than the maximum value of the force that the friction plate presses the main shaft backward when the electromagnetic clutch is excited.

  According to a first aspect of the present invention, there is provided a mechanical seal leakage reduction method for reducing the amount of clutch displacement of an electromagnetic clutch, thereby causing the internal pressure of the working fluid to push the main shaft forward and the rotation-side seal ring forward. The maximum value of the sum of the pressing forces may be set to be larger than the maximum value of the force with which the friction plate presses the main shaft backward when the electromagnetic clutch is excited.

  2. The method for reducing leakage of a mechanical seal in an open type compressor according to claim 1, wherein the elastic support member is a leaf spring that connects a hub fixed to the front end portion of the main shaft and a friction plate, and a leaf spring for a plane perpendicular to the main shaft. By reducing the inclination angle, the maximum value of the sum of the force that the internal pressure of the working fluid presses the main shaft forward and the force that presses the rotary side seal ring forward is You may set so that it may become larger than the maximum value of the force which presses a main shaft back.

  According to a first aspect of the present invention, there is provided a method for reducing leakage of a mechanical seal in an open type compressor by reducing at least one of a spring constant and an initial load of an elastic support member so that the internal pressure of the working fluid presses the main shaft forward. And the maximum value of the force that pushes the rotating side seal ring forward is set to be larger than the maximum value of the force that the friction plate pushes the spindle backward when the electromagnetic clutch is excited. May be.

  According to a sixth aspect of the present invention, there is provided a mechanical seal leakage reducing method for an open type compressor in which a front end portion of an intermediate portion of a main shaft protruding coaxially from a cylindrical portion formed in a housing of the open type compressor is a rolling bearing. It is supported on the cylindrical part through the stationary part, and the stationary seal ring provided on the inner periphery of the cylindrical part is restrained from moving in the axial direction and the rear part of the intermediate part is liquid-tight and axially slid through the elastic seal member Sealed between the housing and the main shaft by a mechanical seal consisting of a rotary seal ring that is freely provided and pressed forward and abuts against the stationary seal ring, and the outer periphery of the cylindrical portion is coaxial with the main shaft from the outside. A rotor that is driven to rotate is supported, a hub is fixed to the front end portion of the main shaft that protrudes outward from the cylindrical portion, and the rotor and the hub are supported by an electromagnet through an elastic support member so as to be movable in the axial direction. In an open-type compressor in which an electromagnetic clutch is formed by a friction plate that is engaged with and disengaged from the end face of the motor, the rotating side seal ring moves away from the stationary side seal ring when the electromagnetic clutch is excited. In a method for reducing leakage of a mechanical seal in an open type compressor that reduces leakage of working fluid in a housing to the outside, an end face of an inner ring of a rolling bearing that supports a front end part of an intermediate part and an end face of a hub or the end face thereof A play adjusting shim is interposed between the members to limit play in the axial direction of the main shaft with respect to the inner ring.

  7. The method of reducing leakage of a mechanical seal in an open type compressor according to claim 6, wherein the rotating side seal ring is brought into contact with the stationary side seal ring by a spring interposed between the main shaft and a play adjusting shim. Is the axial elastic force generated between the rotating side seal ring and the intermediate part due to the elastic deformation of the elastic seal member due to the relative displacement between the main shaft and the rotating side seal ring caused by the play in the axial direction of the main shaft with respect to the inner ring of the rolling bearing. Is preferably limited to be equal to or less than the pressing force of the spring.

  The method for reducing leakage of a mechanical seal in an open type compressor according to claim 6 or 7 includes a play adjusting shim between the end face of the inner ring of the rolling bearing and the end face of the hub or a member abutting on the end face. Instead of mounting, the axial position of the stepped part between the intermediate part and the front end part of the main shaft is almost coincident with the end face of the inner ring of the rolling bearing, and the end face of the hub or the member abutting on the end face of the rolling bearing is You may make it contact | abut to the end surface and step part of an inner ring | wheel, and to limit the play of the axial direction of a main shaft with respect to an inner ring | wheel.

  According to the first aspect of the present invention, when the electromagnetic clutch is energized, the open side compressor that reduces the leakage of the working fluid in the housing due to the rotation side seal ring moving away from the stationary side seal ring. In the mechanical seal leakage reduction method in the above, the force that the internal pressure of the working fluid generated in the normal operating state presses the main shaft forward, and the force that the internal pressure presses the rotary side seal ring forward toward the stationary side seal ring, The maximum sum of the forces that push the rotating side seal ring forward toward the stationary side seal ring is the friction plate that moves in the axial direction when the electromagnetic clutch is excited. The diameter of the intermediate part that passes through the mechanical seal of the main shaft and the spring characteristics such as the spring constant and initial load of the elastic support member so that it is greater than the maximum pressing force Since it is constant, the force friction plate which moves in the axial direction when the electromagnetic clutch is energized to press the main shaft backwards via the elastic supporting member, the main shaft will not be displaced rearwardly. Therefore, even if temporarily, the rotating side seal ring does not move away from the stationary side seal ring and the working fluid in the housing does not leak to the outside.

  By increasing the diameter of the intermediate part that passes through the mechanical seal of the main shaft, the maximum value of the sum of the force that the internal pressure of the working fluid presses the main shaft forward and the force that presses the rotary side seal ring forward is In the invention of claim 2, the friction plate is set to be larger than the maximum value of the force with which the friction plate presses the main shaft backward when excited, as in the invention of claim 1, when the electromagnetic clutch is excited. The friction plate moving in the axial direction presses the main shaft backward via the elastic support member, so that the main shaft is not displaced rearward, so the rotation side seal ring is temporarily separated from the stationary side seal ring. The working fluid in the housing will not leak to the outside.

  By reducing the clutch displacement of the electromagnetic clutch, the maximum value of the sum of the force that the internal pressure of the working fluid presses the main shaft forward and the force that presses the rotation side seal ring forward is when the electromagnetic clutch is excited. In the invention of claim 3, the friction plate is set so as to be larger than the maximum value of the force pushing the main shaft in the backward direction. Similarly to the invention of claim 1, the friction plate moves in the axial direction when the electromagnetic clutch is excited. Because the friction plate presses the main shaft rearward via the elastic support member, the main shaft is not displaced rearward, so the rotating side seal ring moves temporarily away from the stationary side seal ring. The working fluid inside does not leak to the outside.

  The elastic support member is a leaf spring that connects the hub fixed to the front end of the main shaft and the friction plate. By reducing the angle of inclination of the leaf spring with respect to a plane perpendicular to the main shaft, the internal pressure of the working fluid moves the main shaft forward. The maximum value of the sum of the pressing force and the pressing force of the rotary seal ring forward is set to be larger than the maximum value of the friction plate pressing the main shaft backward when the electromagnetic clutch is excited. In the invention of claim 4, as in the invention of claim 1, when the electromagnetic clutch is excited, the friction plate 37 that moves in the axial direction presses the spindle backward through the elastic support member, so that the spindle is Since it does not displace backward, the rotating side seal ring temporarily moves away from the stationary side seal ring, so that the working fluid in the housing does not leak to the outside.

  By reducing at least one of the spring constant and the initial load of the elastic support member, the maximum value of the sum of the force that the internal pressure of the working fluid presses the main shaft forward and the force that presses the rotary seal ring forward is In the invention of claim 5, which is set to be larger than the maximum value of the force with which the friction plate presses the main shaft rearward when the electromagnetic clutch is excited, the electromagnetic clutch is excited as in the invention of claim 1. The friction plate that moves in the axial direction when it is pressed will not be displaced backward due to the force that pushes the main shaft backward via the elastic support member. The working fluid in the housing does not leak to the outside by moving away from the direction.

  According to the invention of claim 6, when the electromagnetic clutch is energized, the open side compression ring reduces the leakage of the working fluid in the housing due to the rotation side seal ring moving away from the stationary side seal ring. In the mechanical seal leakage reduction method in the machine, a play adjusting shim is interposed between the end surface of the inner ring of the rolling bearing supporting the front end portion of the intermediate portion and the end surface of the hub or a member in contact with the end surface. Since the axial play of the main shaft relative to the inner ring is limited, the main shaft is displaced rearward by the force of the friction plate that moves in the axial direction when the electromagnetic clutch is excited to press the main shaft rearward via the elastic support member. Things will disappear. Therefore, even if temporarily, the rotating side seal ring does not move away from the stationary side seal ring and the working fluid in the housing does not leak to the outside.

  The rotating side seal ring is abutted against the stationary side seal ring by a spring interposed between the main shaft and the play adjusting shim, the main shaft and the rotating side generated by the axial play of the main shaft with respect to the inner ring of the rolling bearing. 8. The invention according to claim 7, wherein the axial elastic force generated between the rotating side seal ring and the intermediate portion due to elastic deformation of the elastic seal member accompanying relative displacement between the seal rings is limited to be equal to or less than the pressing force of the spring. For example, even if the main shaft is slightly displaced backward due to the force that the friction plate moving in the axial direction when the electromagnetic clutch is excited presses the main shaft rearward via the elastic support member, the displacement is elastic. The rotating side seal ring is not separated from the stationary side seal ring by being absorbed by the elastic deformation of the seal member. Therefore, the working fluid in the housing does not leak to the outside.

  Instead of interposing a play adjusting shim between the end surface of the inner ring of the rolling bearing and the end surface of the hub or a member abutting on the end surface, the axial position of the step portion between the intermediate portion and the front end portion of the main shaft is set. A request to limit the play in the axial direction of the main shaft with respect to the inner ring by causing the end face of the hub or a member to be in contact with the end face of the inner ring of the rolling bearing or the stepped portion to abut with the end face of the inner ring of the rolling bearing. According to the invention of claim 8, as in the inventions of claims 6 and 7, the friction plate that moves in the axial direction when the electromagnetic clutch is energized by the force that pushes the main shaft backward via the elastic support member. Even if the main shaft is not displaced backward or slightly backward, the displacement is absorbed by the elastic deformation of the elastic seal member and the rotating side seal ring is not separated from the stationary side seal ring. In, the working fluid in the housing is not leak outside.

  In the following, a method for reducing leakage of a mechanical seal in an open compressor according to the present invention will be described with reference to the embodiments shown in FIGS. In each of these embodiments, the present invention is applied to a scroll-type open-type compressor used for compressing a refrigerant of a heat pump type air conditioner.

  First, the first embodiment shown in FIG. 1 will be described. The open type compressor according to the first embodiment is the same as the conventional open type compressor shown in FIG. 5, in which the internal pressure of the refrigerant in the housing 10 presses the main shaft 11 forward in the normal operating state, and the internal pressure The maximum value of the sum of the force that pushes the rotating side seal ring 17 forward toward the stationary side seal ring 16 and the force that pushes the rotating side seal ring 17 forward toward the stationary side seal ring 16 is the electromagnetic clutch M. The friction plate 37 that moves in the axial direction when is excited passes through the mechanical seal 15 so as to be larger than the maximum value of the force that pushes the main shaft 11 backward via the leaf spring (elastic support member) 32. The diameter D of the intermediate part 11b of the main shaft 11 which is a part is set to a large diameter.

  In the first embodiment, the rotor 20 is rotationally driven by a drive source such as a motor via a transmission belt (not shown) wound around a belt groove 20b formed on the outer periphery thereof. Driven intermittently through an electromagnetic clutch M comprising an electromagnet 25 and an electromagnetic coil 27 and controlled according to the air conditioning load, the internal pressure of the refrigerant in the housing 10 in this state becomes a vapor pressure corresponding to the temperature of the refrigerant. The main shaft 11 is pressed forward by this internal pressure, and the flange portion 11f at the rear end of the large-diameter portion 11a of the main shaft 11 comes into contact with the inner ring of the main rolling bearing 12 and stops at that position. As described above, normally, the axial position of the step portion 11d between the intermediate portion 11b and the front end portion 11c of the main shaft 11 is protruded somewhat toward the front end side from the end surface of the inner ring of the front end side roller bearing 13, and this step portion 11d. Between the clutch clearance adjusting shim 40 and the end face of the inner ring of the front end side rolling bearing 13 is interposed between the clutch clearance adjusting shim 40 and the end face of the hub 30 attached to the front end portion 11c. Provided (see a partially enlarged view of FIG. 5).

  In the first embodiment, the main shaft is driven by the axially backward thrust applied through the leaf spring 32 when the electromagnetic clutch M is excited and the friction plate 37 is attracted by the electromagnet 25 and abuts against the end surface 20a of the rotor 20. 11 is pressed rearward, as described above, the internal pressure of the refrigerant in the housing 10 in the normal operating state presses the main shaft 11 forward, and this internal pressure causes the rotary side seal ring 17 to be stationary. When the electromagnetic clutch M is energized, the maximum value of the force that pushes forward toward 16 and the force that pushes the rotary seal ring 17 forward toward the stationary seal ring 16 moves in the axial direction. The mechanical seal is set so that the friction plate 37 is larger than the maximum value of the force that pushes the main shaft 11 backward via the leaf spring 32 (= the thrust in the axial direction backward). Since the diameter D of the middle portion 11b of the main shaft 11 is a portion through 5 are set to large, no such be the main shaft 11 despite the presence of the gap d as described above is displaced rearwardly. Therefore, the rotation-side seal ring 17 is not displaced rearward along with the main shaft 11, so that the rotation-side seal ring 17 moves away from the stationary-side seal ring 16 even if temporarily, and the refrigerant in the housing 10 flows. There is no leakage outside.

  In the first embodiment, a clutch gap adjusting shim 40 is interposed between the step portion 11d between the intermediate portion 11b and the front end portion 11c of the main shaft 11 and the end surface of the hub 30. If the thickness of the adjustment shim 40 is reduced, the clutch clearance (clutch displacement amount) e is reduced, so that the force that pushes the main shaft 11 backward via the leaf spring 32 when the electromagnetic clutch M is excited is reduced. The In this way, the increase in the diameter D of the intermediate portion 11b of the main shaft 11 can be reduced, or the increase in the diameter D can be eliminated, and the same effect as in the first embodiment can be obtained.

  Next, the second embodiment shown in FIG. 2 will be described. In the open type compressor of the second embodiment, in the conventional open type compressor shown in FIG. 5, the inclination angles of the plurality of leaf springs 32 connecting the hub 30 and the friction plate 37 with respect to the plane orthogonal to the main shaft 11 are set. By reducing the maximum value of the sum of the force that the internal pressure of the refrigerant presses the main shaft 11 forward and the force that presses the rotary side seal ring 17 forward, the friction plate 37 is moved to the main shaft when the electromagnetic clutch M is excited. 11 is set so as to be larger than the maximum value of the force for pressing backward.

  When the three leaf springs 32 that connect the hub 30 and the annular friction plate 37 disposed coaxially to the hub 30 are inclined with respect to a plane orthogonal to the main shaft 11, each leaf spring 32 includes When bending, not only a bending stress but also a tensile stress is generated, so that the spring constant increases. As the inclination angle of the leaf spring 32 with respect to the plane orthogonal to the main shaft 11 increases, the increase of the spring constant increases. As the spring constant increases, the backward pressing force applied to the main shaft 11 when the electromagnetic clutch M is energized also increases, so that the internal pressure of the refrigerant pushes the main shaft 11 forward and the rotation-side seal ring 17. The maximum value of the forward pressing force is set to be larger than the maximum value of the friction plate 37 pressing the main shaft 11 backward when the electromagnetic clutch M is excited, so that the rotary side seal ring 17 is stationary. It becomes difficult to prevent separation from the ring 16. However, this difficulty can be overcome by reducing the inclination angles of the plurality of leaf springs 32 connecting the hub 30 and the friction plate 37 with respect to a plane orthogonal to the main shaft 11 as in the second embodiment. it can.

  In the second embodiment, in order to reduce the inclination angle of each leaf spring 32 in this way, the thickness of the spacers 33 and 35 and the side of the damper 39 in contact with the friction plate 37 is reduced. In addition, the three leaf springs 32 that connect the hub 30 and the annular friction plate 37 disposed coaxially to the hub 30 do not extend in the radial direction, but are generally in a circle passing through the three second rivets 36. It is arranged obliquely in the circumferential direction so as to extend in the tangential direction. Note that the backward pressing force applied to the main shaft 11 when the electromagnetic clutch M is energized is reduced by a plurality of links that connect the hub 30 and the friction plate 37 with respect to a plane orthogonal to the main shaft 11 as in the second embodiment. Not only the inclination angle of the leaf spring 32 is decreased, but also by either or both of a decrease in the spring constant and a decrease in the initial load of the leaf spring 32 by changing the plate thickness and shape of the leaf spring 32. Good.

  In the first and second embodiments described above, when the temperature of the refrigerant decreases due to a decrease in environmental temperature or the like, the vapor pressure of the refrigerant decreases, the internal pressure decreases, and the force that pushes the main shaft 11 forward decreases. To do. Therefore, even if the force that pushes the main shaft 11 backward through the leaf spring 32 when the electromagnetic clutch M is excited is the same, the main shaft 11 is displaced rearward when the temperature decreases, and the rotation-side seal ring is moved accordingly. 17 may be separated from the stationary seal ring 16 to cause refrigerant leakage. However, if the setting of the spring characteristics such as the diameter D of the intermediate portion 11b of the main shaft 11 or the spring constant of the leaf spring 32 and the initial load is appropriate, such a risk is small. The amount is relatively small.

  Next, the third embodiment shown in FIG. 3 will be described. The open type compressor of the third embodiment is the same as the conventional open type compressor shown in FIG. 5 between the step part 11d between the intermediate part 11b and the front end part 11c of the main shaft 11 and the end face of the hub 30. The diameter of the interposed clutch clearance adjustment shim 40 is substantially the same as the diameter of the hub 30, and the end surface of the inner ring of the front end side rolling bearing 13 that supports the front end of the intermediate portion 11b of the main shaft 11 and the clutch clearance adjustment shim. 40, a play adjusting shim 41 is interposed to limit play in the axial direction of the main shaft 11 with respect to the inner ring. In this way, the internal pressure of the refrigerant in the housing 10 presses the main shaft 11 forward, the internal pressure presses the rotary seal ring 17 forward toward the stationary seal ring 16, and the rotary side. The friction plate 37, which moves in the axial direction when the electromagnetic clutch M is excited, has a maximum sum of the forces that push the seal ring 17 forward toward the stationary seal ring 16 via the leaf spring 32. Even if the force is smaller than the maximum value of the force that presses the rear side backward, the force with which the friction plate 37 presses the main shaft 11 rearward via the leaf spring 32 causes the play adjustment shim 41 to be pushed from the hub 30. Thus, it is transmitted to and received by the inner ring of the front end side rolling bearing 13 supported by the cylindrical portion 10a of the housing 10, and the main shaft 11 is not displaced rearward. Therefore, even if temporarily, the rotation side seal ring 17 does not move away from the stationary side seal ring 16 and the refrigerant in the housing 10 does not leak to the outside. The clutch clearance adjusting shim 40 may be omitted, and the play adjusting shim 41 may be interposed between the end surface of the inner ring of the front end side rolling bearing 13 and the end surface of the hub 30.

  In the third embodiment, the rotation-side seal ring 17 of the mechanical seal 15 is pressed forward by a spring 18 interposed between the mechanical seal 15 and the front-end annular protrusion 17 a is brought into contact with the stationary-side seal ring 16. (See FIG. 5) The play adjusting shim 41 is an O-ring (elastic seal) associated with the relative displacement between the main shaft 11 and the rotation-side seal ring 17 caused by play in the axial direction of the main shaft 11 with respect to the inner ring of the front end side roller bearing 13. Member) 17b is restricted so that the axial elastic force generated between the rotation-side seal ring 17 and the intermediate portion 11b by the elastic deformation of the spring 17b is equal to or less than the pressing force of the spring 18. In this way, when the electromagnetic clutch M is energized, the friction plate 37 that moves in the axial direction presses the main shaft 11 backward via the leaf spring 32, so that the main shaft 11 is slightly displaced rearward. Even if it exists, the displacement is absorbed by the elastic deformation of the O-ring 17 b, and the rotation-side seal ring 17 does not leave the stationary-side seal ring 16. Therefore, the refrigerant in the housing 10 does not leak to the outside.

  Next, the fourth embodiment shown in FIG. 4 will be described. In the third embodiment shown in FIG. 3, the open type compressor of the fourth embodiment is configured such that the axial position of the step portion 11 d between the intermediate portion 11 b and the front end portion 11 c of the main shaft 11 is the cylindrical shape of the housing 10. The end face of the hub 30 is made to coincide with the end face of the inner ring of the front end side roller bearing 13 and the step part 11d through the clutch clearance adjusting shim 40 at the same time. The play in the axial direction of the main shaft 11 with respect to the inner ring is restricted so as to be in contact with the inner ring. In this manner, as in the third embodiment, when the electromagnetic clutch M is excited, the maximum value of the force that presses the main shaft 11 forward and the force that presses the rotation-side seal ring 17 forward is obtained. Even if the friction plate 37 is smaller than the maximum value of the force that pushes the main shaft 11 backward via the leaf spring 32, the friction plate 37 pushes the main shaft 11 backward via the leaf spring 32. The force to be transmitted is received and received from the hub 30 to the inner ring of the front end side roller bearing 13 supported by the cylindrical portion 10a of the housing 10, and the main shaft 11 is not displaced rearward. Therefore, even if temporarily, the rotation side seal ring 17 does not move away from the stationary side seal ring 16 and the refrigerant in the housing 10 does not leak to the outside. The clutch gap adjusting shim 40 may be omitted, and the end face of the hub 30 may be brought into direct contact with the end face of the inner ring of the front end side rolling bearing 13 and the step portion 11d.

  Further, in the fourth embodiment, as in the third embodiment, the rotation-side seal ring 17 of the mechanical seal 15 is pressed forward by the spring 18 interposed between the main shaft 11 and the annular protrusion 17a at the tip is pressed on the stationary side. The end face of the hub 30 is brought into contact with the inner ring of the front end side roller bearing 13 and the step portion 11d of the main shaft 11 at the same time, either directly or via the clutch gap adjusting shim 40, and thereby the front end side roller bearing 13. Axial elasticity generated between the rotating side seal ring 17 and the intermediate portion 11b due to elastic deformation of the O-ring 17b accompanying relative displacement between the main shaft 11 and the rotating side seal ring 17 caused by play in the axial direction of the main shaft 11 with respect to the inner ring The force is limited to be equal to or less than the pressing force of the spring 18. In this way, when the electromagnetic clutch M is energized, the friction plate 37 that moves in the axial direction presses the main shaft 11 backward via the leaf spring 32, so that the main shaft 11 is slightly displaced rearward. Even if it exists, the displacement is absorbed by the elastic deformation of the O-ring 17 b, and the rotation-side seal ring 17 does not leave the stationary-side seal ring 16. Therefore, the refrigerant in the housing 10 does not leak to the outside.

  In each of the above-described embodiments, the spring 18 that presses the annular protrusion 17a of the rotation-side seal ring 17 against the stationary-side seal ring 16 is an L-shaped spring bracket 18a that is in contact with the rear side of the O-ring 17b. And a rotation-side holding plate 19 provided on the main shaft 11. However, the spring 18 may be directly interposed between the rotation-side seal ring 17 and the rotation-side holding plate 19. In this case, the O-ring 22 is an annular formed on the inner peripheral surface of the rotation-side seal ring 17. What is necessary is just to provide in a groove | channel.

It is drawing explaining 1st Embodiment of the leak reduction method of the mechanical seal in the open type compressor by this invention. It is drawing explaining 2nd Embodiment of the leak reduction method of the mechanical seal in the open type compressor by this invention. It is drawing explaining 3rd Embodiment of the leak reduction method of the mechanical seal in the open type compressor by this invention. It is drawing explaining 4th Embodiment of the leak reduction method of the mechanical seal in the open type compressor by this invention. 1 is a diagram illustrating an example of an open type compressor according to the prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Housing, 10a ... Cylindrical part, 11 ... Main shaft, 11b ... Intermediate part, 11c ... Front end part, 13 ... Rolling bearing (front end side rolling bearing), 15 ... Mechanical seal, 16 ... Static side seal ring, 17 ... Rotation Side seal ring, 17b ... elastic seal member (O-ring), 18 ... spring, 20 ... rotor, 20a ... end face, 25 ... electromagnet, 30 ... hub, 32 ... elastic support member (plate spring), 37 ... friction plate, 41 ... play adjustment shim, M ... electromagnetic clutch.

Claims (8)

The front end portion of the intermediate portion of the main shaft that is coaxially projected from the cylindrical portion formed in the housing of the open type compressor is supported by the cylindrical portion via a rolling bearing, and axially extends to the inner periphery of the cylindrical portion. A stationary seal ring provided with restricted movement and a rear portion of the intermediate portion are provided in a liquid-tight and axially slidable manner via an elastic seal member, and are pressed forward to come into contact with the stationary seal ring. A seal between the housing and the main shaft is sealed by a mechanical seal comprising a rotating side seal ring, and a rotor that is rotationally driven from the outside coaxially with the main shaft is supported on the outer periphery of the cylindrical portion. Electromagnetically generated by a friction plate that is supported on the front end of the main shaft protruding outward from the cylindrical portion via an elastic support member and is engaged with and disengaged from the end surface of the rotor by an electromagnet. In the open type compressor formed with a latch, when the electromagnetic clutch is excited, the rotating side seal ring moves away from the stationary side seal ring, and the working fluid in the housing leaks to the outside. In the method for reducing leakage of a mechanical seal in an open-type compressor, the internal pressure of the working fluid generated in a normal operation state presses the main shaft forward, and the internal pressure pushes the rotary side seal ring to the stationary side. When the electromagnetic clutch is energized, the maximum value of the force that pushes forward toward the seal ring and the force that pushes the rotation side seal ring forward toward the stationary seal ring is the axial direction. The main shaft is adjusted so that the moving friction plate is larger than the maximum value of the force that pushes the main shaft backward through the elastic support member. And the diameter of the intermediate portion through the serial mechanical seal leakage reduction method of a mechanical seal in an open type compressor, which comprises setting the spring characteristics of the elastic support member. The method for reducing leakage of a mechanical seal in an open type compressor according to claim 1, wherein an internal pressure of the working fluid is directed toward the main shaft by increasing a diameter of the intermediate portion passing through the mechanical seal of the main shaft. The maximum value of the sum of the pressing force and the force pressing the rotation side seal ring forward is larger than the maximum value of the friction plate pressing the main shaft rearward when the electromagnetic clutch is excited. It sets so that it may become. The leakage reduction method of the mechanical seal in the open type compressor characterized by the above-mentioned. 2. The method for reducing leakage of a mechanical seal in an open compressor according to claim 1, wherein the internal pressure of the working fluid presses the main shaft forward and the rotation side by reducing a clutch displacement amount of the electromagnetic clutch. The maximum value of the sum of the forces that press the seal ring forward is set to be greater than the maximum value of the forces that the friction plate presses the main shaft backward when the electromagnetic clutch is excited. A method for reducing leakage of a mechanical seal in an open type compressor. 2. The method for reducing leakage of a mechanical seal in an open type compressor according to claim 1, wherein the elastic support member is a leaf spring that connects the friction plate with a hub fixed to a front end portion of the main shaft, and is orthogonal to the main shaft. By reducing the inclination angle of the leaf spring with respect to the plane, the maximum value of the sum of the force that the internal pressure of the working fluid presses the main shaft forward and the force that presses the rotary seal ring forward is the electromagnetic clutch. A method of reducing leakage of a mechanical seal in an open type compressor, wherein the friction plate is set to be larger than a maximum value of a force that pushes the main shaft backward when the friction plate is excited. The method for reducing leakage of a mechanical seal in an open type compressor according to claim 1, wherein at least one of a spring constant and an initial load of the elastic support member is reduced, so that the internal pressure of the working fluid is directed toward the main shaft. The maximum value of the sum of the force that presses the rotary side seal ring and the force that presses the rotary side seal ring forward is greater than the maximum value of the force that the friction plate presses the spindle backward when the electromagnetic clutch is excited. A method for reducing leakage of a mechanical seal in an open type compressor, characterized in that The front end portion of the intermediate portion of the main shaft that is coaxially projected from the cylindrical portion formed in the housing of the open type compressor is supported by the cylindrical portion via a rolling bearing, and axially extends to the inner periphery of the cylindrical portion. A stationary seal ring provided with restricted movement and a rear portion of the intermediate portion are provided in a liquid-tight and axially slidable manner via an elastic seal member, and are pressed forward to come into contact with the stationary seal ring. A seal between the housing and the main shaft is sealed by a mechanical seal comprising a rotating side seal ring, and a rotor driven to rotate from the outside coaxially with the main shaft is supported on the outer periphery of the cylindrical portion. A hub is fixed to the front end portion of the main shaft that protrudes to the outside, and the rotor and the hub are supported by an elastic support member so as to be movable in the axial direction. The electromagnet disengages from the end surface of the rotor. friction When the electromagnetic clutch is energized in the open compressor formed by the electromagnetic clutch, the rotating side seal ring moves away from the stationary side seal ring, and the working fluid in the housing is moved to the outside. In a method for reducing leakage of a mechanical seal in an open type compressor that reduces leakage, between an end surface of an inner ring of the rolling bearing that supports a front end portion of the intermediate portion and an end surface of the hub or a member that is in contact with the end surface. A method for reducing leakage of a mechanical seal in an open type compressor, wherein a play adjusting shim is interposed to limit play in the axial direction of the main shaft with respect to the inner ring. 7. The method for reducing leakage of a mechanical seal in an open type compressor according to claim 6, wherein the rotary side seal ring is brought into contact with the stationary side seal ring by a spring interposed between the main shaft and the idle side seal ring. The shim is formed between the rotating side seal ring and the intermediate portion by elastic deformation of the elastic seal member due to relative displacement between the main shaft and the rotating side seal ring caused by play in the axial direction of the main shaft with respect to the inner ring of the rolling bearing. A method for reducing leakage of a mechanical seal in an open-type compressor, wherein the axial elastic force generated in the cylinder is limited to be equal to or less than a pressing force of the spring. 8. The method for reducing leakage of a mechanical seal in an open type compressor according to claim 6 or 7, wherein a play adjusting shim is provided between an end face of the inner ring of the rolling bearing and an end face of the hub or a member abutting on the end face. The axial position of the step portion between the intermediate portion and the front end portion of the main shaft is made to substantially coincide with the end surface of the inner ring of the rolling bearing, and is brought into contact with the end surface of the hub or this. A method for reducing leakage of a mechanical seal in an open type compressor, wherein a member is brought into contact with an end face of an inner ring of the rolling bearing and the stepped portion to limit play in the axial direction of the main shaft with respect to the inner ring.

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