JPS6353399B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention mainly relates to a shaft seal mechanism of a water pump for circulating and supplying cooling water to an internal combustion engine. (Conventional technology) Conventionally, this type of water pump has:
A rotor is fixed to a pump shaft rotatably supported inside a pump body having an inlet port and an outlet port so as to rotate together with the shaft, and the rotation of the rotor causes the pump to move out from the inlet port. It is configured to continuously send water (cooling water) to the let port (see, for example, Japanese Patent Laid-Open No. 82096/1982). In the shaft seal structure of a conventional water pump, as shown in FIG. , is mounted in a state slightly lifted from the outer peripheral surface of the pump shaft 6. On the other hand, the outer cylinder 13 fixed to the inner wall 1a of the pump body 1 has a seal ring 32 made of carbon or the like at the end facing the floating seat 31.
Packing 33 equipped with is assembled,
This seal ring 32 is constantly pressed against the floating seat 31 by the force of a spring 34. As a result, the floating seat 31 and the seal ring 32 are always in sliding contact, thereby preventing water from leaking from the pump chamber 5 in the pump body 1 to the bearing 7 side that supports the pump shaft 6. A sealing mechanism is configured to prevent this. Furthermore, shaft seal mechanisms that use magnetic fluid as shaft seal mechanisms for dealing with gases have been known (see, for example, Japanese Utility Model Publication No. 57-41504). The general structure of this magnetic fluid seal is
As shown in FIG. 6, a shaft cover 44 is assembled via an O-ring 43 to the outer periphery of a shaft 41 which is rotatably supported by a bearing 42 inside a casing 40. Further, an annular magnet 47 is assembled between a pair of annular blocks 46 fixed to the inner peripheral surface of the casing 40 via an O-ring 45. A plurality of annular minute protrusions 4 are provided on the outer periphery of the shaft cover 44 facing each of these annular blocks 46.
A magnetic fluid 49 is provided between the annular microprotrusion 48 and the inner peripheral surface of each annular block 46. By this,
A magnetic fluid 49 becomes part of the magnetic circuit formed by the magnet 47 and is connected to the shaft 4 as is well known.
A gas seal is established between the outer periphery of the shaft cover 44 on the first side and the inner periphery of the circular block 46 on the casing 40 side. (Problems to be solved by the invention) In the shaft seal mechanism shown in FIG.
Water vapor is generated by frictional heat between the floating sheet 31 and the seal ring 32 on their frictional sliding surfaces, and this water vapor is discharged to the outside through the drain hole 4 of the pump body 1. The fact that water vapor is released to the outside from the drain hole 4 on the side of the bearing 7 that supports the pump shaft 6 means that water leaks between the floating seat 31 and the seal ring 32. The result is almost the same as that which occurred, and the generation of water vapor itself is an undesirable phenomenon for a shaft seal mechanism. Further, if dust enters the inside of the pump body 1 through the drain hole 4 and gets caught in the frictional sliding surfaces of the floating seat 31 and the seal ring 32, there is a risk of causing a seal failure between them. It was hot. Although the magnetic fluid seal shown in Figure 6 above has a relatively good sealing function as a shaft seal mechanism for dealing with gas and other gases, it cannot be used as is as a shaft seal mechanism for water pumps. There are difficulties.
That is, when the water from the water pump comes into contact with the magnetic fluid 49 shown in FIG. 6, the fluid melts into one another and forms a kind of emulsion, causing the problem that the magnetic fluid cannot maintain its function as a seal. (Means for Solving the Problems) In order to solve the above problems, the present invention is configured as follows. That is, in FIG. 1, a floating seat 1 is attached to a rotor 8 that rotates together with a pump shaft 6 inside a pump body 1.
1 is mounted so as to be suspended from the outer peripheral surface of the shaft 6 and to rotate together with the rotor 8. A seal ring 16 is attached to the inner wall 1a of the body 1 facing the floating seat 11 while floating from the outer peripheral surface of the pump shaft 6, and this seal ring 16 receives the force of the spring 15. It is constantly pressed against the floating sheet 11 with a predetermined pressing force. A magnet is used for at least one of the floating seat 11 and the seal ring 16, and a magnet is used between the inner peripheral surfaces of the floating seat 11 and the seal ring 16 and the outer peripheral surface of the pump shaft 6. A magnetic fluid seal 19 is configured using the formed magnetic circuit. (Function) In the above configuration, the floating sheet 1
The water vapor generated by the frictional heat of the frictional sliding surface between the floating sheet 11 and the seal ring 16 is absorbed by the magnetic flux formed between the inner peripheral surfaces of the floating sheet 11 and the seal ring 16, and the outer peripheral surface of the pump shaft 6. It will be sealed by a fluid seal 19.
Although it is difficult for this magnetic fluid seal 19 to seal against water as described above, it can sufficiently seal against water vapor, and the water vapor can be effectively sealed against the floating sheet 11 and the seal. Intrusion to the left in FIG. 1 between the inner peripheral surface of the ring 16 and the outer peripheral surface of the shaft 6 is prevented. Further, the frictional heat generated on the frictional sliding surface between the floating sheet 11 and the seal ring 16 is efficiently radiated to the pump shaft 6 side through the magnetic fluid seal 19, and The generation of water vapor on the friction sliding surface is reduced. (Example) Examples of the present invention will be specifically described below with reference to FIGS. 1 to 4. First, in FIG. 2, which shows a part of the water pump in cross section, the approximately middle portion of the pump shaft 6 that is provided penetrating inside the pump body 1 is as follows.
It is rotatably supported by a bearing 7 that is press-fitted and fixed inside the pump body 1. The end of the pump shaft 6 is located in the pump chamber 5 within the pump body 1, and a rotor 8 made of a magnetic material such as iron is fitted therein by means such as press fitting so that it can rotate together with the shaft 6. Fixed. That is, when the rotor 8 is rotationally driven through the pump shaft 6, the cooling water sucked into the pump chamber 5 from the inlet port 2 of the pump body 1 is sent out from the outlet port 3 to, for example, a cooling water circulation path of an internal combustion engine. It is. As is clear from FIG. 1, which is an enlarged view of the main part of FIG. is formed. Inside this recess 9 is a floating sheet 11 made of a magnet.
It is press-fitted into the rotor 8 with a sealing O-ring 10 interposed therebetween. On the other hand, an outer cylinder 13 is fixed to the inner wall 1a of the pump body 1, and a packing 14 made of a material such as rubber that can be expanded and contracted in the left and right directions in FIGS. 1 and 2 is assembled to the outer cylinder 13. It is being A seal ring 16 made of a magnetic material such as iron is fixed to the tip of this packing 14, and the floating sheet 11 in this seal ring 16
A sliding plate 17 made of carbon, phenolic resin, or the like is coated on the surface opposite to the sliding plate 17 by baking or other means. Further, a spring 15 is attached to the outer cylinder 13 and acts on the seal ring 16 so as to constantly press the end surface of the seal ring 16 on the sliding plate 17 side against the floating seat 11. As a result, even when the floating seat 11 is rotating together with the rotor 8, the seal ring 16 is always in sliding contact with the floating seat 11, and the pump chamber 5 is closed on this frictional sliding surface. This creates a seal against cooling water. The floating seat 11 and the seal ring 16 (including the outer cylinder 13) are both placed in a floating state with a gap t as shown in FIG. ing. Further, the inside of the pump body 1 on the side in which the bearing 7 is installed communicates with the outside air through a plurality of drain holes 4 formed in the body 1. A plurality of micro protrusions 20 are formed along the axial direction on the outer circumference of the pump shaft 6, which faces the inner circumferential surfaces of the floating seat 11 and the seal ring 16, respectively. Specifically, these microprotrusions 20 are attached to the pump shaft 6.
It is constructed by forming a plurality of annular grooves on the outer periphery of the groove. The minute protrusions 20 formed on the outer circumference of the pump shaft 6 in this way, the floating seat 11 and the seal ring 1
The magnetic fluid 21 is in the gap t between the inner peripheral surface of the
is injected. Thereby, as described above, the magnetic circuit of the floating sheet 11 made of magnets is formed by the floating sheet 11 itself, the seal ring 16, the magnetic fluid 21, the pump shaft 6, and the rotor 8. At this time,
The magnetic fluid 21 is concentrated at the tip of the minute protrusion 20 on the outer periphery of the pump shaft 6 in the above-mentioned gap t, and a magnetic fluid seal 19 is formed in this gap t. The reason why a plurality of the microprotrusions 20 are formed is to increase the sealing pressure of the magnetic fluid seal 19 in the gap t. In addition, the above rotor 8
and the floating sheet 11,
The reason why the O-ring 10 is used in place of the conventional buffer rubber 30 shown in FIG. 5 is to reduce the magnetic resistance between the rotor 8 and the floating sheet 11 in the magnetic circuit constituting the magnetic fluid seal 19. This is to reduce it as much as possible. The magnetic fluid 21 described above is made by stably dispersing ferromagnetic fine powder in a liquid phase medium, and solid-liquid separation due to sedimentation or aggregation does not occur under gravity or a normal magnetic field, and the liquid has no magnetic properties. It has the well-known property of behaving as if it were. Here, the above-mentioned ferromagnetic fine powder is powder such as Fe ₂ O ₃ , Fe, Co, etc.
Liquid phase medium refers to water, oil, mercury, etc. Further, as shown in the following table, this magnetic fluid 21 has a higher thermal conductivity than air.

[Table] In the water pump shaft seal mechanism configured as described above, the rotation of the pump shaft 6 causes the rotor 8 to continuously rotate within the pump chamber 5 of the pump body 1, thereby injecting cooling water. It is continuously sent out from the outlet port 2 to the outlet port 3. The side having the pump chamber 5 and the above-mentioned drain hole 4 is the rotor 8.
Floating seat 11 fixed to the floating seat 11 and seal ring 1 always pressed against the floating seat 11
6 and are sealed by mutual friction sliding surfaces. Note that the friction sliding surface of the seal ring 16 has
As described above, since the sliding plate 17 made of a non-magnetic material such as carbon or phenol resin is coated, the floating sheet 11 made of a magnet and the seal ring 1 made of a magnetic material are coated.
This avoids a situation in which the members 6 and 6 are strongly attracted to each other by magnetic force and their mutual frictional resistance increases. As the rotor 8 rotates continuously,
Frictional heat is generated on the frictional sliding surface between the floating sheet 11 and the seal ring 16, and the cooling water is accordingly heated.
Steam is generated in the gap t between the inner circumferential surfaces of the seal ring 1 and the seal ring 16 and the outer circumferential surface of the pump shaft 6. However, this water vapor is prevented from flowing toward the side having the drain hole 4 due to the sealing function of the magnetic fluid seal 19 described above. Furthermore, as is clear from the table above, the magnetic fluid 21 constituting the magnetic fluid seal 19 has a much higher thermal conductivity than air, so the frictional sliding between the floating sheet 11 and the seal ring 16 is The frictional heat generated on the surface is radiated to the pump shaft 6 through the magnetic fluid 21, and the generation of water vapor due to this frictional heat is significantly reduced. Furthermore, even if dust or the like enters the inside of the pump body 1 from the outside through the drain hole 4, this dust is blocked by the magnetic fluid 21, and the frictional sliding between the floating sheet 11 and the seal ring 16 is prevented. This prevents the risk of dust getting stuck on the surface and causing problems such as water leakage. In the embodiment shown in FIG. 3, magnets are used for both the floating sheet 11 and the seal ring 16.
The frictional sliding surfaces of the seal ring 16 and the seal ring 16 are set to have the same polarity (both are N pole or S pole). According to this embodiment, the magnetic force of the magnetic circuit for forming the magnetic fluid seal 19 is further increased, and the sealing function of the magnetic fluid seal 19 is also significantly increased. In addition, floating sheet 1
1 and the seal ring 16 have the same polarity as described above, so that a repulsive force is generated. Therefore, these floating sheets 1
In order to maintain the sealing performance between the seal ring 1 and the seal ring 16, it is necessary to set the elasticity of the spring 15 to be large enough to correspond to the repulsive force caused by the magnet. In the embodiment shown in FIG.
Components that are considered to have the same or equivalent configuration as those of the embodiment shown in FIG. 2 and FIG. Incidentally, redundant explanation will be similarly omitted regarding the embodiment shown in FIG. 4, which will be described next. The embodiment shown in FIG. 4 is an embodiment in which a non-magnetic material is used for the pump shaft 6, and the outer circumference of the pump shaft 6 corresponding to the inner circumference of the floating seat 11 and the seal ring 16 ,
A cylindrical shaft cover 22 made of a magnetic material such as iron is assembled to the shaft 6 with an O-ring 24 interposed therebetween. Microscopic protrusions 23 for forming the magnetic fluid seal 19 are formed on the outer periphery of the shaft cover 22, and between these microprotrusions 23 and the inner circumferential surfaces of the floating sheet 11 and the seal ring 16. A magnetic fluid 21 is injected into. In the magnetic fluid seal 19 of this embodiment, for example, when a magnet is used in the floating sheet 11, the magnetic circuit of this magnet is formed by the floating sheet 11, the seal ring 16, the magnetic fluid 21, the shaft cover 22, and the rotor 8. configured. (Effects of the Invention) As described above, the present invention provides a water sealing structure based on sliding contact between a floating seat and a seal ring, as well as a water sealing structure based on sliding contact between a floating seat and a seal ring. By configuring a magnetic fluid seal between the floating sheet and the seal ring, water vapor generated on the friction sliding surface between the floating sheet and the seal ring can be sealed by the magnetic fluid seal. It is possible to effectively radiate the frictional heat generated on the frictional sliding surface to the pump shaft side. This makes it possible to suppress the generation of water vapor itself as much as possible, and the synergistic effect of these makes it possible to provide a highly reliable water pump shaft seal mechanism. Furthermore, in the present invention, even if dust enters from the outside of the water pump through the drain hole, this dust is blocked by the above-mentioned magnetic fluid seal, and the dust is transferred to the friction sliding surface between the floating seat and the seal ring. This will prevent problems such as getting stuck in the water and causing water leaks.

[Brief explanation of drawings]

1 to 4 show embodiments of the present invention;
The figure is an enlarged sectional view showing the shaft seal mechanism of the water pump, Figure 2 is a sectional view showing a part of the water pump, and Figure 3 shows the second embodiment in correspondence with Figure 1. FIG. 4 is a cross-sectional view of the third embodiment in correspondence with FIG. 1, FIG. 5 is a cross-sectional view of a conventional water pump shaft seal mechanism, and FIG. 1 is a sectional view of a conventional magnetic fluid seal for gas. 1... Pump body, 2... Inlet port, 3... Outlet port, 6... Pump shaft, 8... Rotor, 11... Floating seat, 15... Spring, 16... Seal ring, 19... ...Magnetic fluid seal.

Claims (1)

[Claims] 1. A pump shaft rotatably supported inside a pump body having an inlet port and an outlet port, a rotor fixed to rotate together with the shaft, and a rotor that is suspended from the outer circumferential surface of the pump shaft with respect to the rotor. A floating seat is attached to the inner wall of the body opposite to the floating seat, and a seal is also attached to the inner wall of the body while floating from the outer circumferential surface of the pump shaft, and is pressed against the floating seat by a predetermined spring force. A shaft seal mechanism for a water pump comprising a ring, wherein a magnet is used in at least one of the floating seat and the seal ring, and the inner circumferential surfaces of the floating seat and the seal ring and the outer circumferential surface of the pump shaft. A shaft seal mechanism for a water pump, comprising a magnetic fluid seal using a magnetic circuit formed by the magnet.