JPH08232871A - Oil seal mechanism of vacuum pump for vehicle - Google Patents

Abstract

PURPOSE: To perfectly prevent oil leakage by lapping the transmission shaft side of a spline connected to a rotor with a sleeve. CONSTITUTION: A seal mechanism 30 is formed by disposing a seal material between a shaft hole 1A of a pump casing 1 and a transmission shaft 4 which makes the shaft hole 1A go to the outside and inside of the pump casing 1 and has a rotor 5 provided on the end part in the pump casing 1. A first seal material 31 and a second seal material 32 disposed at a space on the transmission shaft 4 are used as a seal material, and the pump casing 1 is provided with a drain port 36 communicated with the space between the first seal material 31 and the second seal material 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil seal mechanism for a vehicle vacuum pump.

[0002]

2. Description of the Related Art Generally, in a diesel engine vehicle, a vacuum pump is used as a negative pressure source of a brake booster (see Japanese Patent Laid-Open No. 1-164670).

FIG. 4 shows the structure of a conventional vane type vacuum pump sealing mechanism. In this pump, a rotor 5 including a vane 3 is housed in a casing 1.
The rotor 5 is connected to the transmission shaft 4 by a spline 6, and the transmission shaft 4 is led out from the shaft hole 1A of the casing 1 via a bearing 7 and a seal mechanism 8. And the transmission shaft 4
Rotating rotates the rotor 5, and the vane 3 rotates while inscribed in the casing 1 to generate a negative pressure. In the conventional seal mechanism, only one seal member 8 is fitted and fixed to the inner circumference of the shaft hole 1A.

[0004]

In a pump for a vehicle of this type, the oil supplied into the casing 1 for the purpose of lubrication, airtightness maintenance, cooling, etc. is shared with the engine oil. There is a problem that the sliding contact portion between the seal material 8 and the shaft 4 is likely to be worn by the carbon particles contained in the oil. In particular, the wear of the transmission shaft 4 made of metal is unexpectedly large, and the friction causes oil to leak from the seal surface, and the leaked oil may travel along the transmission shaft 4 and be scattered in the engine room, for example. .

On the other hand, in order to increase the reliability of the seal,
It is advisable to provide a plurality of sealing materials 8, but it is necessary to secure a large sliding contact portion (sealing surface) 6b of the sealing material 8, and considering the cutting start portion 6a of the spline 6 with respect to the shaft 4, the axial dimension is remarkably large. There was also the problem of getting bigger.

In consideration of the above circumstances, the present invention can greatly reduce the possibility that oil will be scattered from the shaft hole through the transmission shaft into the engine room, and the pump vacuum can be made compact. An object is to provide an oil seal mechanism for a pump.

[0007]

According to a first aspect of the present invention, between a shaft hole of a pump casing and a transmission shaft that penetrates the shaft hole into and out of the pump casing and has a rotor at an end portion inside the pump casing. In a vehicle vacuum pump oil seal mechanism in which a seal material is disposed on the pump casing, the seal material is a first seal material and a second seal material that are disposed on the transmission shaft at intervals. A drain port communicating with the first sealing material and the second sealing material is provided.

According to a second aspect of the present invention, there is provided an oil seal mechanism for a vehicle vacuum pump according to the first aspect, wherein the first seal material is arranged closer to the rotor than the second seal material is. A sleeve, at least the outer periphery of which is made harder than the transmission shaft, is fitted in a liquid-tight manner to the outer periphery of the transmission shaft at a position corresponding to the sealing material of the first seal member. The feature is that the contact parts are closely attached.

According to a third aspect of the present invention, there is provided an oil seal mechanism for a vacuum pump for a vehicle according to the second aspect, wherein the first sealing material is moved to a position where it blocks a communication port of the drain port. A seal opening portion for releasing the close contact with the inner peripheral sliding contact portion is provided at a position where the inner peripheral sliding contact portion of the first sealing material contacts.

A fourth aspect of the present invention is an oil seal mechanism for a vehicle vacuum pump according to the second or third aspect, wherein the rotor is spline-coupled to the transmission shaft, and a spline on the transmission shaft side is connected to the sleeve. It is characterized by being wrapped.

[0011]

According to the first aspect of the invention, the first rotor located on the rotor side
Even if the sealing surface of the sealing material of No. 2 is worn and oil leaks out to the side of the second sealing material, the oil escapes to the drain port.

According to the second aspect of the present invention, since the inner peripheral sliding contact portion of the first sealing material is brought into close contact with the hardened outer peripheral surface of the sleeve, wear on the transmission shaft side due to deteriorated oil is reduced. Further, since the sealing surface is secured on the sleeve, it is possible to start cutting the spline from a position near the sealing material with respect to the transmission shaft below the sealing surface.

According to the third aspect of the invention, even if the first seal material is pushed toward the second seal material side by the pressure of the oil and moves, the first seal material does not close the communication port of the drain port. The positive pressure of the oil is released, and the first sealing material does not move any further. At that time, since the communication port of the drain port is not blocked by the first sealing material, the oil that has passed through the first sealing material escapes to the drain port before the second sealing material.

According to the invention of claim 4, since the sleeve and the spline are wrapped, the position of the first sealing material can be brought as close to the rotor side as possible.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A vane vacuum pump to which an embodiment of the present invention is applied will be described below with reference to the drawings.

FIG. 1 is a sectional view showing the overall construction of the vacuum pump, FIG. 2 is an enlarged view of the main parts thereof, and FIG. 3 is a detailed view showing the dimensional relationship of the main parts.

As shown in FIG. 1, in this pump, a rotor 5 having vanes 3 is housed in a casing 1. The rotor 5 is coupled to the transmission shaft 4 by a spline 6, and one end of the transmission shaft 4 is led out from the shaft hole 1A of the casing 1 via the bearing 7 and the seal mechanism 30 to the outside.
A pulley 10 that is driven to rotate by a belt 11 is attached to one end of the transmission shaft 4 that is led out to the outside. The side opening of the casing 1 is closed by a cover 9, and the other end of the transmission shaft 4 is supported by a shaft hole in the cover 9 via a bearing 17.

The cover 9 is provided with an oil supply hole 19 for supplying oil to the rotor 5 in the casing 1,
From the lubrication port 16 provided at the end of the lubrication hole 19, the lubrication hole 19
The engine oil can be supplied to the. Further, the casing 1 is provided with an air suction port 14 and an air and oil discharge port 13.

As shown in FIG. 2, the transmission shaft 4 has middle diameter portions 4b and 4c and a large diameter portion 4d at a portion corresponding to the seal mechanism 30. The middle diameter portions 4b and 4c are the casing 1
And the large diameter portion 4d is formed on the outer side. The portion 4a fitted with the rotor 5 has substantially the same diameter as the medium diameter portions 4b and 4c. O-ring groove 4e in the middle diameter portions 4b and 4c
Is formed, and the O-ring 48 is fitted in the O-ring groove 4e. The middle diameter portions 4b and 4c have the O-ring groove 4e.
A very slight dimensional difference is provided on both sides of the boundary 4c, and the diameter of the portion 4c on the large diameter portion 4d side is slightly larger than that of the portion 4b on the spline 6 side.

A sleeve 4 is provided on the outer periphery of the medium diameter portions 4b and 4c.
0 is fitted. The sleeve 40 includes the medium diameter portions 4b, 4
Of c, it is press-fitted into a portion 4c on the large diameter portion 4d side and integrated with the transmission shaft 4. The size of the press-fitted part is H shown in Fig. 2.
It is 1. The fitting gap between the sleeve 40 and the intermediate diameter portions 4b and 4c is liquid-tightly sealed by an O-ring 48. The sleeve 40 has a wall thickness corresponding to a step between the large diameter portion 4d and the middle diameter portions 4b and 4c, and the end surface 44 of the large diameter portion 4d is abutted against the end surface 44 of the sleeve 40. Is attached to. Only the outer peripheral surface 42 of the sleeve 40 is surface-hardened (for example, hard chrome plating). Sleeve 40
A chamfered portion 43 is provided on the inner and outer peripheries of the end face of, and, in particular, an annular groove 45 as shown in FIG. Has been secured. The annular recessed groove portion 45 will be a seal opening portion described later.

As the sealing material which is the main element of the sealing mechanism 30, a first sealing material 31 and a second sealing material 32 are provided as shown in FIGS. The first sealing material 31 and the second sealing material 32 are arranged in this order from the inner side to the outer side of the casing 1, and a predetermined space 34 is held between them. First sealing material 31
Is the sealing material 31B on the front side (inside the casing 1)
And a seal material 31A on the rear stage side (the outer side thereof).

The front-stage sealing material 31B reduces the burden on the rear-stage sealing material 31A and reduces the overall axial dimension of the latter-stage sealing material 31A, which reliably seals with the lip that makes surface contact with the sleeve. For,
It has a small lip that comes into line contact with the sleeve, has an axial dimension smaller than that of the latter-stage sealing material 31A, and is configured to trap large particles.

As shown in FIG. 2, the first sealing material 31 is inserted until it abuts on the rear end wall 51 of the shaft hole 1A,
It is fitted to the inner peripheral surface of the shaft hole 1A. The lip portion 31p _B of the first sealing member 31 (front side of the seal member 31B and the rear stage side of the sealing member 31A), @ 31 P _A is in close contact with the outer peripheral surface 42 of the sleeve 40. The second seal member 32 is fitted and fixed at a predetermined position in the shaft hole 1A, and the lip portion 32p thereof is in direct contact with the outer peripheral surface of the large diameter portion 4d of the transmission shaft 4.

Since the second sealing material 32 is exposed to the atmosphere both inside and outside, the lip portion 32p comes into contact with the large diameter portion 4d at two locations axially separated from each other, and the grease is interposed therebetween. Has a concave portion for holding, and this grease prevents friction at the contact portion of the lip portion 32p with the large diameter portion 4d.

As described above, the first sealing material 31 and the second sealing material 31
The seal members 32 are arranged at intervals 34, the end of the sleeve 40 is located between them, and the communication port 36a of the drain port 36 formed in the casing 1 is formed.
Is open. In this case, the position of the communication port 36a is set as follows in relation to the position of the annular recessed groove portion (seal opening portion) 45 secured at the end portion of the sleeve 40.
That is, before the seal material 31A on the rear side of the first seal material 31 moves to the position that closes the communication port 36a,
The lip portion 31p of the sealing material 31A is positioned in the annular groove 45.

In other words, when the sealing material 31A moves by being pressed by the oil pressure inside the casing 1 and the lip portion 31p of the sealing material 31A reaches the annular recessed groove portion 45, the sealing material 31 still completely fills the communication port 36a. The dimension S2 from the end of the sealing material 31 to the end of the communication port 36a so that it is not blocked
And the dimension S1 from the lip portion 31p to the annular groove portion 45
And are set in the following relationship.

S2 = S1 + (1 mm to 2 mm) Although the end of the drain port 36 may be left open as it is, a connecting pipe 36d is provided and a tube 37 is provided.
The oil may be guided to a specific portion below the engine room or an oil pan by connecting the above.

Next, the operation will be described.

In the seal mechanism 30 of this pump, the sleeve 40 is fitted on the outer periphery of the transmission shaft 4, and the first seal member 31 (the seal member 31 is attached to the hardened outer peripheral surface 42 of the sleeve 40).
Since the lip portions 31p (A, 31B) are brought into close contact with each other, wear on the transmission shaft 4 side (actually, the sleeve 40) due to deteriorated oil is reduced, and the possibility of oil leakage is reduced.

In this case, the portion in contact with the second seal material 32 is not hardened, but since the deteriorated oil hardly flows to the second seal material 32 side, there is no problem. Further, since the transmission shaft 4 itself is not hardened, the cost for hardening is not so high.

Further, the first sealing material 3 is provided on the sleeve 40.
1 (seal material 31A and seal material 32) lip portion 31
Since the sliding contact surface (sealing surface) of p is secured, it is possible to start cutting the spline 6 in a state of being wrapped with the sleeve 40 from a position near the sealing material 31 with respect to the transmission shaft 4 on the lower side thereof. In the figure, 6a is the cutting start portion of the spline, and the wrap dimension H2 with the sleeve 4 can be made large. Therefore, it becomes possible to achieve compactness in the axial direction.

Further, even if the seal surface of the first seal material 31 is worn and oil leaks out to the second seal material 32 side, the first seal material 31 and the second seal material 32 are also leaked.
Since the drain port 36 is communicated between these, the oil can escape to the drain port 36 and be guided to a specific location. Therefore, it is possible to reliably prevent oil leakage from the end of the transmission shaft 4 to the pulley 10 side, and solve the problem of oil scattering into the engine room.
Further, depending on the state of oil discharged from the drain port 36, oil leakage can be detected in advance before it becomes important.

Furthermore, even if the first seal material 31 (particularly the seal material 31A) is pushed toward the second seal material 32 side by the pressure of the oil and moves, the first seal material 31 is drain port 36. Before closing the communication port 36a, the lip portion 31p reaches the annular recessed groove portion 45, so that the positive pressure of the oil is released here. Therefore, the first sealing material 31 does not move any further. At that time, the communication port 36 of the drain port 36
Since a is not blocked by the first sealing material 31,
The oil that has passed through the seal material 31 of the second seal material 32
Escape to drain port 36 before. Therefore, the first
Even if the sealing member 31 of FIG. 3 moves, the leaked oil can be surely released to the drain port 36, and the oil can be prevented completely.

In the above embodiment, the first sealing material 3
Although 1 is composed of two stages of sealing materials 31A and 31B on the rear stage side and the front stage side, it may be only one stage.

Although only the outer peripheral surface of the sleeve 40 is made harder than the transmission shaft 4 by the surface hardening treatment, the whole surface may be hardened or the hard material may be selected instead of the hardening treatment. Good.

[0036]

As described above, according to the first aspect of the present invention, the sealing material has two stages of the first sealing material and the second sealing material, and if oil leaks from the first sealing material. Also,
Since it is made to escape to the drain port, it is possible to guide the oil from the drain port to a specific place and to detect the oil leak at an early stage, and to prevent the oil leak from the second sealing material. it can. Therefore, it is possible to avoid a situation in which the oil is scattered along the transmission shaft into the engine room.

According to the second aspect of the present invention, since wear on the transmission shaft side due to deteriorated oil is reduced, it is possible to reduce the possibility of oil leakage. Further, since the transmission shaft itself is not hardened, the cost for hardening does not increase so much. Further, since the spline cutting start position with respect to the transmission shaft can be brought close to the sealing material, it is possible to make the axial direction compact.

According to the third aspect of the present invention, even if the first seal member moves, the leaked oil can be surely released to the drain port, and the oil leakage to the end side of the transmission shaft is prevented completely. Can be planned.

According to the invention of claim 4, since the sleeve and the spline are overlapped with each other, the position of the rotor and the position of the first seal member can be brought close to each other, and the pump can be made compact.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a vane type vacuum pump including a sealing mechanism according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of the seal mechanism according to the embodiment of the present invention.

FIG. 3 is a detailed view of essential parts of an embodiment of the present invention.

FIG. 4 is a sectional view of a conventional example.

[Explanation of reference numerals] 1 casing 1A shaft hole 4 transmission shaft 5 rotor 6 spline 30 sealing mechanism 31 first sealing material 31p lip portion (inner peripheral sliding contact portion) 32 second sealing material 36 drain port 36a communication port 40 sleeve 42 outer peripheral surface subjected to surface hardening treatment 45 annular groove (seal open part)

Claims (4)

[Claims] 1. A vacuum pump for a vehicle, wherein a seal material is arranged between a shaft hole of a pump casing and a transmission shaft which penetrates the shaft hole into and out of the pump casing and has a rotor at an end of the pump casing. In the oil seal mechanism, the sealing material is a first sealing material and a second sealing material that are arranged on the transmission shaft with a space, and the pump casing includes the first sealing material and the second sealing material. An oil seal mechanism for a vacuum pump for a vehicle, comprising a drain port communicating with a seal material. 2. The oil seal mechanism for a vehicle vacuum pump according to claim 1, wherein the first seal member is arranged closer to the rotor than the second seal member is, and A sleeve, at least the outer periphery of which is made harder than the transmission shaft, is fluid-tightly fitted to the outer periphery of the transmission shaft at a corresponding position in a liquid-tight manner, and the inner periphery sliding contact portion of the first sealing material is attached to the outer periphery of the sleeve. An oil seal mechanism for a vacuum pump for vehicles, characterized in that 3. An oil seal mechanism for a vacuum pump for a vehicle according to claim 2, wherein the first seal member moves before the first seal member moves to a position that closes the communication port of the drain port. An oil seal mechanism for a vacuum pump for a vehicle, comprising a seal opening portion that releases contact with the inner peripheral sliding contact portion at a position where the inner peripheral sliding contact portion contacts. 4. The oil seal mechanism for a vehicle vacuum pump according to claim 2, wherein the rotor is spline-coupled to the transmission shaft, and a spline on the transmission shaft side wraps with the sleeve. An oil seal mechanism for a vehicle vacuum pump.