JPH0535248Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an oil seal that can be applied to internal combustion engines, etc. Specifically, the invention includes two slingers and two lips that slide on each slinger. The present invention relates to an axial type oil seal having the following characteristics.

[Prior art]

Conventionally, an oil seal R commonly called a radial type as shown in FIG. 4 has been employed. This oil seal R is set so that negative pressure acts on a space 4 formed between a lip 2 and a dust seal 3 that are in sliding contact with the shaft 1,
A thread 5 is provided inside the lip 2, and the inner periphery of the lip 2 is pressed against the outer periphery of the shaft 1 by a spring 6 surrounding the outer periphery of the lip 2.

This oil seal R is determined by the amount of eccentricity of the shaft 1,
Oil leakage may occur due to the collapse of the oil seal R when press-fitting into the inner diameter of the housing 7, scratches on the lip 2 during insertion, scratches on the outer circumferential surface of the wear ring 9, compatibility of the fixation between the material of the lip 2 and the material of the wear ring 9, etc. The problem is that there are many factors that cause this.

In addition, since the spring 6 presses the lip 2 and the wear ring 9, the contact pressure between the lip 2 and the wear ring 9 is high, and in order to prevent wear due to this, expensive hard chrome plating is required on the outer circumferential surface of the wear ring 9. The oil film on the bottom surface of the lip 2 is as thin as 2.5 microns, making it vulnerable to foreign matter.Therefore, in order to improve reliability, it was necessary to manufacture it from an expensive fluororesin material.

In order to solve the various problems in the radial type oil seal R, an oil seal A commonly called an axial type as shown in FIG. 5 has been put into practical use.

In this oil seal A, the main lip 10 is pressed against the slinger 11 provided in the radial direction of the shaft 1 by its own elastic force, and the main lip 10
0 and a threaded hole 12 provided on the surface of the slinger 11. Furthermore, the main lip 10 forming a space 13 prevents oil leaking from the sliding surface between the main lip 10 and the slinger 11.
Thrower 14 on the side and Thrower 1 on the slinger 11 side
5 prevents the oil from going out, but when operation starts, the oil is returned to the interior 16 by centrifugal force from the sliding surface of the main lip 10 and slinger 11 through the threaded eye 12.

[Problem that the invention attempts to solve]

By the way, in the axial type oil seal A shown in FIG.
The width of oil seal A, that is, the L dimension, is large, so if you want to use it in place of oil seal R installed in an existing internal combustion engine, you usually use a slinger. Due to the structure in which gears, etc. are fixed to the part of the main lip 10, there is a problem that it cannot be used due to restrictions on the installation space.Also, since the centrifugal force of the slinger 11 causes oil to scatter, it is difficult for the main lip 10 to slide between the main lip 10 and the slinger 11. There was a problem in that the main lip 10 wore out prematurely due to lack of lubricating oil on the surface.

In addition, an axial type with a smaller width has been proposed as in Japanese Utility Model Application No. 61-182460, but in this publication, the first seal lip is in elastic contact, so The space between the first seal lip and the second seal lip becomes negative pressure, and the surface pressure of the second seal lip increases, making it more likely to wear out, and furthermore, the first seal lip also tends to become unlubricated. The drawback was that it was easily worn out.

Therefore, the present invention was devised to solve the above-mentioned conventional problems and drawbacks, and the purpose is to provide an oil seal with a smaller width that can be replaced with the existing radial type, and with good lubrication. This will be implemented as follows.

[Means to solve the problem]

The oil seal according to the present invention that achieves the above object includes a double slinger that is fixed to a shaft and that extends in the radial direction and has a main slinger and a second slinger spaced apart from each other; A double lip having a main lip in sliding contact, a second lip in sliding contact with the second slinger, and a dust seal in sliding contact with the shaft are brought into contact within a mounting width, and a main space portion is formed surrounded by the double slinger, the main lip, and the second lip; and forming a subspace surrounded by the second lip, the dust seal, the shaft, and the second slinger;
Further, a thread whose diameter increases as the shaft rotates is formed on the sliding surface of the main slinger, and a thread whose diameter decreases as the shaft rotates on the sliding surface of the second slinger, and the The main linger is provided with a hole that communicates with the oil chamber.

[Effect]

Therefore, the double slinger portion 20 on the shaft 17 side and the housing 1 separately provided opposite thereto.
Since the double lip portion 25 on the side 9a can be disposed in opposition within the mounting member S, this oil seal A can be replaced with the existing radial type oil seal R.

In addition, the main space J formed between both parts 20 and 25
The air is discharged by the rotation of the double slinger 20, but air is sucked in from the hole 33 provided in the main slinger 22 and communicating with the oil chamber 19, the amount of air in the main space J is adjusted, and the double lip 25 is in a negative pressure state. Therefore, the sliding surface pressure of the double lip 25 can be kept low, and the main lip 30 is actively lubricated by the oil sucked in from the hole 33 provided in the main ringer 22, resulting in a good lubrication state. Wear of the main lip 30 can be reduced.

〔Example〕

Hereinafter, the drawings showing the present invention as an embodiment will be explained.

The example shown in FIG. 1 shows an axial type oil seal A provided between the crankshaft 17 and the housing 19a of the crank chamber 19 (oil chamber), and its installation width S is shown in FIG. By making the width approximately the same as that of the radial type oil seal R shown in Fig. 1, it can be installed in an existing internal combustion engine.

This oil seal A is attached to a double slinger portion 2 that is press-fitted into the outer diameter of the crankshaft 17.
0 and a double lip part 25 that is press-fitted into the inner diameter of the housing 19a are constructed separately, and the double lip part 25 can be press-fitted from the outside toward the inside of the double slinger part 20 that is press-fitted into the shaft 17, so that both Easy to assemble and disassemble.

The double slinger 20 described above has a shaft 17
A cylindrical portion 21 that is press-fitted into the cylindrical portion 21 and a large-diameter main ringer 22 that extends radially from both ends of the cylindrical portion 21.
and a small diameter second slinger 23,
It is arranged within the width S of the oil seal A in the direction with the small diameter second slinger 23 facing outside. A main lip 3 which will be described later on the outside of this main linger 22
A threaded hole 22a whose diameter increases as the shaft 17 rotates is formed on the sliding surface on which 0 slides, and a shaft is formed on the sliding surface on which a second lip 27 (described later) on the outside of the second slinger 23 slides. 17
A threaded hole 23a whose diameter decreases as the slinger part 20 rotates is formed.
Or manufactured by cutting iron material.

The above-mentioned double lip portion 25 is connected to the housing 1
a cylindrical seal outer ring 26 that is press-fitted into the inner diameter of 9;
A main lip 30 made of a rubber material or the like, which is fixed to a mounting ring 26a bent in the radial direction from the seal outer ring 26, a second lip 27, and a radial dust seal 3 (made of felt, etc.) provided on the outermost side. It consists of

In other words, there is a sub-space K inside the outermost dust seal 3, and the shaft 17 is
A second lip 27 is provided which extends in a direction approaching the second slinger 23, and the inside of this second lip 27 slides onto the thread 23a of the second slinger 23 mentioned above. Further, an extension portion 29 extending inward in the axial direction at a predetermined distance from the outer diameter of the second slinger 23 is integrally formed with a main lip 30 extending radially along the sliding surface of the main slinger 22. It is connected.

And double lip 2 to double slinger 20
5, the main lip 30 comes into sliding contact with the sliding surface of the main slinger 22 located on the inside, and the second lip 27 comes into sliding contact with the second slinger 23 located on the outside, so that the double slinger 20 and the main lip 30 Second trip 2
The main space J surrounded by 7 and the second lip 27
A sub-space K surrounded by the dust seal 3, the shaft 17, and the second slinger 23 is formed.

This double slinger 20 can be arranged in the mounting member S via the second lip 27, the sub-space K, and the dust seal 3 arranged in parallel in the axial direction, and there is a main space between the two slingers 22 and 23. Since the portion J can be formed, the conventional radial type oil seal R shown in FIG.

Further, a thin film 31 made of a resin material equivalent to Teflon is fixed to the entire sliding surface of the second lip 27 in order to prevent wear when the sliding surface is not lubricated. It slides directly onto the slinger 23. Instead of this thin film 31, the entire second lip 27 may be made of a resin material equivalent to Teflon, as shown in FIG. There is no need to manufacture the entire device from an expensive Teflon-equivalent resin material, which has the advantage of reducing manufacturing costs.

In addition, the main lip 30 and the main ringer 22
The outer periphery of the crankshaft is formed into an oil receiving part 32 that is bent to open in a V-shape around the sliding surface in order to easily supply oil to the sliding surface, and to easily receive the oil in the crank chamber 19. It's summery.

Furthermore, a plurality of holes 3 are provided on a circular locus in a portion of the main ringer 22 that is close to the cylindrical portion 21.
3 is provided to adjust the amount of air in the main space J formed between the inner diameter of the extension part 29 and the outer diameter of the cylindrical part 21, and to suck oil from the crank chamber 19.

In other words, the sliding surfaces of the main slinger 22 and the second slinger 23 are provided with threads 22a and 23a in the direction in which the air in the main space J is sucked in and discharged by sliding with the lips 27 and 30. The above-mentioned hole 33 serves as an air suction port for adjusting the amount of air discharged from the main space J, and at the same time, oil can be sucked in to lubricate the sliding part of the main lip 30.

In this way, the air inside the main space J is regulated and does not become a negative pressure state like the oil seal in FIG. Multiple holes 3 that communicate
When the oil sucked into the main space J from the main lip 30 is discharged into the crank chamber 19 through the screw thread 22a due to the centrifugal force caused by the rotation of the main linger 22, the sliding surface of the main lip 30 is actively lubricated. Therefore, wear on the main lip 30 can be reduced.

Since the air in the main space J is discharged from the subspace K by the rotation of the second slinger 23 and does not become a negative pressure, there is no suction of dust from the outside, which has the advantage of preventing wear that turns into dust.

Further, the main lip 30 deforms the main slinger 22 by 2 to 3 mm to apply a pressing surface pressure, and the other second lip 27 deforms the second slinger 23 by 0.5 to 1 mm to apply a pressing surface pressure. All you need to do is give
In addition to not being subjected to negative pressure as described above, both lips 27 and 30 can maintain extremely low surface pressure, thereby improving wear resistance. It has the advantage of being insensitive to falling, reducing precision in machining and assembly, and improving productivity.

When the internal combustion engine is stopped, the main lip 3
The oil in the crank chamber 19 leaking from the engine 0 remains in the main space J in the state shown in FIG. 3 and does not leak outside. When the internal combustion engine is started, the oil O accumulated in this main space J is moved to the threaded area 2 due to the centrifugal force of the main linger 22.
When it is discharged into the crank chamber 19 through 2a, it lubricates the sliding surface of the main lip 30.
Wear of the main lip 30 immediately after starting is prevented.

Radial type oil seal R shown in Figure 4
In the case of , there is a disadvantage that there is no function to store the oil leaking from the main lip 2 and it flows out to the outside.
In the axial type oil seal A of the present invention, oil leaking from the main lip 30 is removed from the main space J.
Since the oil can be stored in the engine and returned to the crank chamber 19 at the time of starting, oil leakage from the oil seal can be eliminated and reliability can be improved.

The reference numeral 35 shown in FIG. 1 is a gear fixed to the crankshaft 17 in the crank chamber 19, and the reference numeral 36
is a flywheel fixed to the end of the crankshaft 17.

[Effect of idea]

As explained above, the present invention includes a double slinger that is fixed to the shaft and has a main slinger and a second slinger that extend in the radial direction and are spaced apart from each other, and a double slinger that is fixed to the inner diameter of the housing and that slides into contact with the main slinger. A double lip having a main lip, a second lip in sliding contact with the second slinger, and a dust seal in sliding contact with the shaft are in contact with each other within a mounting width, and a main space surrounded by the double slinger, the main lip, and the second lip is formed; A subspace surrounded by the second lip, the dust seal, the shaft, and the second slinger is formed, and a threaded hole whose diameter increases as the shaft rotates is formed on the sliding surface of the main slinger. Since threads whose diameters decrease as the shaft rotates are formed in the main linger, and holes communicating with the oil chamber are provided in the main linger, the following effects can be achieved.

(1) Since the double slinger on the shaft side and the double lip on the housing side can be made to face each other within the mounting width, this oil seal can be replaced with an existing radial type oil seal, and its assembly and Decomposition can be easily performed.

(2) The air in the main space is discharged by the rotation of the double lip, but the air is sucked in through a hole in the main slinger that communicates with the oil chamber, the amount of air is adjusted, and the double lip is in a negative pressure state. Therefore, the sliding surface pressure of each double lip can be kept low, and since the main lip is actively lubricated by the oil sucked in from the aforementioned hole, wear of the main lip can be reduced.

(3) When the internal combustion engine is stopped, oil can be stored in the main space, and when the engine is started, the oil is discharged into the oil chamber by the sliding movement of the main ringer and main lip. This lubricates the sliding surfaces of the main lip and prevents friction on the main lip immediately after starting.

(4) Air in the main space is discharged from the subspace by rotation of the second slinger and no negative pressure is created, so dust is not sucked in from the outside and abrasion of the main lip due to dust can be prevented.

[Brief explanation of the drawing]

Figures 1 to 3 show an embodiment of the present invention; Figure 1 is a longitudinal cross-sectional side view of an oil seal provided between the crankshaft and the housing of the crank chamber; FIG. 3 is a vertical side view of an oil seal showing another example of the second lip. 4 and 5 show a conventional example, with FIG. 4 being a longitudinal side view showing a radial type oil seal, and FIG. 5 being a longitudinal side view showing an axial type oil seal. 17...Shaft, 19...Oil chamber (crank chamber), 19a...Housing, 20...Duffle slinger, 21...Cylindrical portion, 22...Main slinger, 23...Second slinger, 25...Double lip, 26... ... Seal outer ring, 27 ... Second lip, 30 ... Main lip, 33 ... Hole, J
...Main space part, K...Subspace part.

Claims (1)

[Scope of utility model registration request] A double slinger fixed to the shaft and provided with a main slinger extending in the radial direction and a second slinger spaced apart from each other, a main lip fixed to the inner diameter of the housing and slidingly contacting the main slinger, and a second lip slidingly contacting the second slinger. A double lip having a dust seal that makes sliding contact with the shaft faces each other within the installation width, and forms a main space surrounded by the double slinger, the main lip, and the second lip, and the second lip, the dust seal, the shaft, and the second slinger forming an enclosed subspace,
Further, a thread whose diameter increases as the shaft rotates is formed on the sliding surface of the main slinger, and a thread whose diameter decreases as the shaft rotates on the sliding surface of the second slinger, and the An oil seal with a hole in the main ring that communicates with the oil chamber.