JPH08325609A - Production of sintered parts impregnated with resin and sintered pulley impregnated with resin - Google Patents

Abstract

PURPOSE: To obtain sintered parts impregnated with a resin having high hermeticity by immersing sintered compacts into a thermosetting resin liquid in an atmosphere specified in a relation between their density and vacuum degrees to impregnate the compacts with the resin, then heating the compacts to cure the resin. CONSTITUTION: The sintered parts, such as pulleys W, are immersed in the vacuum atmosphere into the acrylic thermosetting resin impregnating liquid 2 in a treating device 1 and are impregnated with the resin impregnating liquid 2 in the pores in these pulleys W. The pulleys are then immersed into water 4 to remove the excess resin impregnating liquid 2 and thereafter, the pulleys are heated in a heating vessel 6 to cure the resin impregnating liquid 2 in the pulleys W, by which the sintered parts impregnated with the resin are obtd. The relation 13.45a-4.52logeb-0.35c+046 d-149.0>=2.3 is satisfied in this method when the density of the sintered compacts is defined as a(g/cm<3> ), the vacuum degree of the vacuum atmosphere as b(Torr), the time for opening the atm as c(sec) and the curing temp. as d( deg.C). The cylindrical parts of these pulleys impregnated with the resin are composed of the matrix, the resin parts and the non-impregnated layers.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a resin-impregnated sintered part and a resin-impregnated sintered pulley. The resin-impregnated sintered pulley according to the present invention is a VVT (Variable Va).
It is suitable for use in an Lve Timing) device.

[0002]

2. Description of the Related Art For example, since pores remain in an iron-based sintered body, it is necessary to seal the sintered body in order to prevent a decrease in airtightness (pressure resistance) due to the pores. obtain.
Conventionally, as one means for this sealing treatment, Japanese Patent Laid-Open No. 59-21 has been proposed.
A method of manufacturing a resin-impregnated sintered component disclosed in Japanese Patent No. 5403 is known.

In this manufacturing method, first, as an impregnation step,
The sintered body is impregnated with a resin impregnating solution containing an uncured thermosetting resin to obtain an uncured resin-impregnated sintered body. Then, in the removing step, the excess resin impregnating liquid is removed from the uncured resin-impregnated sintered body by washing to obtain an excess resin-removed sintered body. Then, as a curing step, the surplus resin-removed sintered body is heated to a temperature not lower than the curing temperature of the thermosetting resin to obtain a resin-impregnated sintered part. If there is a part where high accuracy is required depending on the part, the obtained resin-impregnated sintered part is subjected to sizing treatment to be a product.

[0004]

However, when the present inventors manufactured the resin-impregnated sintered part by the above method, the airtightness of the resin-impregnated sintered part was partially varied. In this way, the resin-impregnated sintered part in which the airtightness partially varies causes inconvenience as a product.

Particularly, the resin-impregnated sintered part to be obtained is V
In the case of the pulley W used in the VT device as shown in FIG. 7, pressure oil acts on the web 90 of the pulley W, and a rubber belt is wound around the cylindrical portion 91 continuous with the web 90. In such a pulley 90, many ones containing an acrylic thermosetting resin as a resin impregnating liquid can be adopted. Here, when the belt side of the cylindrical portion 91 has a high airtightness by containing a large amount of the resin impregnating liquid, the resin contacting the belt deteriorates the rubber due to long-term use, and the belt is replaced early. Will cause a situation that requires. On the contrary, when the web 90 has a low airtightness by containing almost no resin impregnating liquid, the pressure oil acting may leak and the performance of the VVT device may be impaired. For this reason, in order to avoid these situations, if the pulley is made of a resin-impregnated sintered product and is made of a cut product after forging, the cost of the product will increase.

[0006] A first object of the present invention is to provide a manufacturing method capable of manufacturing a resin-impregnated sintered part having a stable high airtightness. A second object of the present invention is to provide a resin-impregnated sintered pulley which has high airtightness stably at a desired portion under a low product cost.

[0007]

[Means for Solving the Problems]

(1) The method for producing a resin-impregnated sintered part according to claim 1, wherein the pores of the sintered body are impregnated with a resin impregnating liquid containing an uncured acrylic thermosetting resin. After immersing in the resin impregnating liquid below, it is exposed to the atmosphere to obtain an uncured resin-impregnated sintered body, and the uncured resin-impregnated sintered body is heated to a temperature not lower than the curing temperature of the acrylic thermosetting resin. A method of manufacturing a resin-impregnated sintered part, comprising: a step of heating to a resin-impregnated sintered part to obtain a resin-impregnated sintered part having a density of a (g / cm ³ ) and a vacuum degree of the vacuum atmosphere. To b (T
orr), the atmospheric opening time is c (seconds), and the curing temperature is d
(° C) 13.45a-4.52log _e b
It is characterized by satisfying −0.35c + 0.46d-149.0 ≧ 2.3.

The degree of vacuum b is preferably 6 Torr or less, more preferably 2 Torr or less. This is because the impregnated state of the resin impregnating liquid is remarkably improved in the high vacuum range, and particularly the impregnated state is rapidly improved from around 6 Torr. Also, during actual operation,
This is because 2 Torr can be stably ensured by depressurizing with the rotary pump.

(2) The resin-impregnated sintered pulley of claim 2 is
In a resin-impregnated sintered pulley having a web on which pressure oil acts and a cylindrical portion which is continuous with the web and around which a rubber belt is wound, the web is formed of a metal sintered body having pores. And a resin portion impregnated into the pores and cured with an acrylic thermosetting resin, the cylindrical portion is formed on the matrix, the resin portion and the outer peripheral side. It is characterized in that it is composed of a non-impregnated layer having no resin portion.

[0010]

In order to solve the above problems, the inventors of the present invention have conducted extensive studies and found that the above conventional manufacturing method does not consider the conditions such as the impregnation step, which may cause the above problems. Then, the invention described in each claim is completed. That is, in the method for producing a resin-impregnated sintered component according to claim 1, as the impregnating step, the sintered body is immersed in a resin impregnating liquid containing an uncured acrylic thermosetting resin in a vacuum atmosphere, and then the atmosphere. To obtain an uncured resin-impregnated sintered body. Then, as a curing step, the uncured resin-impregnated sintered body is heated to the curing temperature of the acrylic thermosetting resin or higher,
Obtain a resin-impregnated sintered part.

Here, as the impregnation rate (%) in the impregnation step, the volume actually impregnated with the resin impregnating liquid is compared with the theoretical pore volume (cm ³ ) calculated from the density (g / cm ³ ) of the sintered body. (Cm ³ ) was determined. And the degree of vacuum (Tor
The relationship between r) and the impregnation rate was obtained. Theoretically, the amount of resin impregnating liquid impregnated in the pores of the sintered body should be simply proportional to the amount of gas remaining in the pores, so the impregnation rate is linear in proportion to the degree of vacuum itself. Although it is considered to change, the obtained result showed a logarithmic function behavior as shown in FIG. 1 (A). That is, it can be seen that the impregnation state is significantly improved in the high vacuum region. The cause of this phenomenon is not clear in detail, but it is presumed that the impregnation is accelerated by the inertial force of the resin impregnating liquid, which is a fluid, at a high speed when the degree of vacuum is high. To be done.

Thus, the inventors obtained the relationship between the natural logarithm of the degree of vacuum and the impregnation rate as shown in FIG. 1 (B), and then determined the density of the sintered body as a (g / cm ³ ) and the vacuum. Degree b (Tor
r), the atmospheric opening time is c (sec), and the curing temperature is d (° C), 13.45a-4.52log _e b-0.3
If 5c + 0.46d-149.0 ≧ 2.3 is satisfied,
It has been discovered that a resin-impregnated sintered part having a desired airtightness can be stably obtained.

Further, in the resin-impregnated sintered pulley of claim 2 obtained by the method of manufacturing a resin-impregnated sintered part of claim 1, the cylindrical portion is composed of a matrix, a resin portion and a non-impregnated layer. Since the non-impregnated layer having no resin portion is formed on the belt side of the cylindrical portion, and the resin and rubber do not come into direct contact with each other, the rubber does not deteriorate even after long-term use. On the other hand, since the cylindrical portion does not require so much airtightness, there is no problem of airtightness due to the non-impregnated layer having no resin portion. On the contrary, in this resin-impregnated sintered pulley, the web constituted by the matrix and the resin portion has high airtightness, and it is difficult for the pressure oil acting thereon to leak.

[0014]

【Example】

(Test) First, the effect of claim 1 is proved by a specific test relating to a method for manufacturing a resin-impregnated sintered pulley. "Impregnation Step" First, a pulley W shown in FIG. 7 is prepared as a sintered body. This pulley W is made of 10 Fe-Cu-C powders.
It was sintered at 30 ° C.

Further, a resin impregnating liquid 2 (Sunseal C-100, manufactured by Sanwa Yuka Kogyo Co., Ltd.) is placed in the processing apparatus 1 shown in FIG. 2 (A). -25 to 80 of this resin impregnation liquid 2
The coefficient of thermal expansion at ° C is 2.91 x 10 ^-4 / ° C.
After that, the elevating table 1a is provided in the processing apparatus 1, and a plurality of pulleys W are placed on the elevating table 1a. Then, the shutter 1b provided in the processing apparatus 1 is closed, and the inside of the processing apparatus 1 is evacuated by a pump (not shown). After reaching a predetermined degree of vacuum, the elevating table 1a is lowered to immerse each pulley W in the resin impregnating liquid 2. When a predetermined time has elapsed, the shutter 1b is opened to open the inside of the processing device 1 to the atmosphere. In this way, the resin impregnating liquid 2 is introduced into the pores of the pulley W due to the pressure difference between the predetermined degree of vacuum and the atmosphere.
To obtain an uncured resin-impregnated pulley W.

"Removal Step" As shown in FIG. 2B, the water 4 is put in the cleaning container 3 and the uncured resin-impregnated pulley W taken out from the processing apparatus 1 is moved to the water 4 together with the lifting table 1a.
Soak inside. In this way, the excess resin impregnating liquid 2 is removed from the uncured resin impregnated pulley W as an emulsion in the water 4.

Thereafter, as shown in FIG. 2C, the uncured resin-impregnated pulley W is taken out from the cleaning container 3 together with the lifting table 1a, and the lifting table 1a is blown with air by a nozzle 5 connected to a pump (not shown). . Thus
The water 4 remaining on the surface of the uncured resin-impregnated pulley W is removed to obtain the excess resin-removed pulley W. "Curing Step" As shown in FIG. 2D, the excess resin-removed pulley W is put in the heating container 6 together with the lifting table 1a and heated by the heating device 6a. In this state, the resin impregnated liquid 2 of the pulley W from which the excess resin has been removed is cured to obtain the resin-impregnated sintered pulley W. The resin-impregnated sintered pulley W is subjected to a sizing treatment to obtain a product.

[Evaluation] The density a (g / cm ³ ) of the pulley W before being impregnated with the resin impregnating liquid 2, the vacuum degree b (Torr) of the vacuum atmosphere, the atmospheric opening time c (second), and the curing temperature. A leak test was conducted to evaluate the airtightness by providing a difference between d (° C.) and the curing time e (minutes). In the leak test, the obtained resin-impregnated sintered pulley W was assembled with a jig and an O-ring to form a pressure chamber in the web 90 (see FIG. 7), and a pressure oil of 10 kg / cm ² was loaded into the pressure chamber. By standing for 48 hours in this state, the presence or absence of oil leakage and bleeding was visually observed. The results are shown in Table 1. Table 1
Then, in this leak test, even if one of the three resin-impregnated sintered pulleys W under different conditions had an oil leak or the like, x indicates that no oil leak or the like occurred for all three. Indicate.

[0019]

[Table 1]

Further, each resin-impregnated sintered pulley W is set to Z = 1.
3.45a-4.52log _e b-0.35c + 0.4
It applied to the discriminant of 6d-149.0, and calculated | required the result of the said leak test for every value of the discriminant Z. The results are shown in Fig. 3. From Table 1 and FIG. 3, it can be seen that the discriminant formula Z suitably represents the airtightness. It is also found that when Z ≧ 0, some NG products are produced, whereas when Z ≧ 2.3, all products are OK products. On the other hand, assuming that the degree of vacuum linearly contributes to airtightness and linearly evaluating the relationship between the degree of vacuum and the impregnation rate, NG products and OK products are mixed. It was

Therefore, it is understood that the resin-impregnated sintered pulley W having a stable and high airtightness can be manufactured by performing the impregnation step or the like so as to satisfy the above discriminant Z ≧ 2.3. (Example 1 and Comparative Example 1) As the pulley W before being impregnated with the resin impregnating liquid 2, a pulley having a density of 6.6 (g / cm ³ ) was used, and the resin-impregnated sintered pulley was used under the conditions shown in Table 2. W. Other conditions are the same as the above test.

[0022]

[Table 2]

The pressure pass rate (%) of the obtained resin-impregnated sintered pulley W of Example 1 and Comparative Example 1 was determined. Results are also in Table 2
Shown in In addition, the resin-impregnated sintered pulley W of Example 1 has about 8
When 00 units were manufactured and assembled into a VVT device and engine evaluation and actual vehicle evaluation were performed, no inconvenience such as oil leakage occurred.

From Table 2 and the evaluation of the actual machine, it can be seen that the resin-impregnated sintered pulley W of Example 1 is excellent for use in the VVT device. (Example 2 / Comparative Example 2) As the pulley W before being impregnated with the resin impregnating liquid 2, one having a density of 6.6 (g / cm ³ ) was used, the degree of vacuum was 2 (Torr), and the open time to the atmosphere was 0. .9
An uncured resin-impregnated pulley W is obtained under the condition of (sec). The uncured resin-impregnated pulley W is subjected to a removing step to obtain the excess resin-removed pulley W.

In the second embodiment, the excess resin-removed pulley W is placed in the heating container 6 having a set temperature of 150 (° C.) for 12.5.
Insert for (minutes) (discriminant Z = 5.3). On the other hand, Comparative Example 2
Then, the pulley W from which the excess resin has been removed is set to the set temperature 90.
Put in warm water (℃) for 12.5 (minutes). Thus
The resin-impregnated sintered pulley W of Example 2 and Comparative Example 2 is obtained.
Other conditions are the same as the above test.

FIG. 4 shows the metallographic structure on the outer peripheral side of the cylindrical portion 91 of the resin-impregnated sintered pulley W of Example 2 before the sizing treatment. In addition, the cylindrical portion 9 of the resin-impregnated sintered pulley W
The metallographic structure inside 1 is shown in FIG. Further, FIG. 6 shows the metal structure of the surface side of the web 90 of the resin-impregnated sintered pulley W. 4 to 6 are backscattered electron images of the scanning electron microscope, in which the resin portion formed by curing the resin impregnating liquid is black and the metal portion is white.

4 to 6, in the resin-impregnated sintered pulley W of Example 2, the web 90 is composed of the matrix and the resin part, and the cylindrical part 91 is composed of the matrix, the resin part and the non-impregnated layer. You can see that This non-impregnated layer was formed on the outer peripheral side of the cylindrical portion 91 with a thickness of 0.3 (mm) from the surface. On the other hand, in the resin-impregnated sintered pulley W of Comparative Example 2, the web 90 and the cylindrical portion 91 were composed of the matrix and the resin portion.

Further, the resin-impregnated sintered pulleys W of Example 2 and Comparative Example 2 were subjected to sizing treatment to obtain products, and a belt durability bench test was conducted using these products. In the belt endurance bench test, when the life of the belt of the comparative example 2 at which the belt was broken was 1, the life of the product of the example 2 was 8.4 times. This is because in the product of Comparative Example 2, the resin directly contacts the rubber and the resin attacks the belt during long-term use, whereas in the product of Example 2, the resin is not impregnated without the resin portion. This is because the layer is formed on the belt side of the cylindrical portion 91 so that the resin and the rubber do not come into direct contact with each other, so that the resin does not attack the belt even after long-term use. Further, in the product of Comparative Example 2, since the resin was not completely cured, it is considered that the resin is separated from the cylindrical portion 91 by the centrifugal force and the attacking force on the belt is increased.

Further, when the product of the second embodiment is assembled in the VVT device, the web 90 composed of the matrix and the resin portion has high airtightness, and it is difficult for the working pressure oil to leak. On the other hand, since the cylindrical portion 91 does not require so much airtightness, there is no problem of airtightness due to the non-impregnated layer having no resin portion. Therefore, Example 2
The product of (1) has high airtightness on the web 90 stably at a low product cost. Therefore, if this product is adopted in a VVT device, the VVT device does not require belt replacement even after long-term use and can exhibit excellent performance.

When the resin-impregnated sintered pulley W having the non-impregnated layer having no resin portion on the cylindrical portion 91 is to be manufactured as described above, according to the test results of the present inventors, 135-1.
It was effective to cure the resin impregnating liquid 2 in the atmosphere within the temperature range of 80 (° C). The cause of this is unknown in detail, but by curing the resin impregnating liquid 2 in a specific temperature region in the atmosphere, a part of the uncured acrylic thermosetting resin is vaporized from the outer peripheral side of the cylindrical portion 91. It is presumed that this is due to hardening after that. If the temperature is lower than 135 (° C.), the vaporization of the resin impregnating liquid 2 is not sufficient, and the thickness of the non-impregnated layer becomes less than 0.1 (mm), so that the belt is attacked. On the contrary, when the temperature exceeds 180 (° C.), the resin impregnating liquid 2 is carbonized, and it is difficult to obtain sufficient airtightness of other parts.

Further, in the product of Example 2, since the outer peripheral side of the cylindrical portion 91 of the resin-impregnated sintered pulley W after curing is subjected to the sizing treatment, the pores of the non-impregnated layer are crushed, which causes the belt to be damaged. The aggression is further reduced. Therefore, technical matters other than the technical matters described in claims 1 and 2 included in the second embodiment will be additionally described below.

In the curing step, the uncured resin-impregnated sintered body was
The method for producing a resin-impregnated sintered component according to claim 1, wherein heating is performed in the atmosphere within a temperature range of 5 to 180 ° C. The resin-impregnated sintered pulley according to claim 2, wherein the surface of the non-impregnated layer is subjected to a sizing treatment.

[0033]

As described above in detail, in the method for producing a resin-impregnated sintered component according to the first aspect, by adopting the configuration of the first aspect, a resin-impregnated sintered component stably having high airtightness is produced. can do. Further, in the resin-impregnated sintered pulley according to the second aspect, by adopting the configuration of the second aspect, it is possible to stably have high airtightness at a desired portion under a low product cost.

Therefore, if the obtained resin-impregnated sintered pulley is adopted in a VVT device, the VVT device does not require belt replacement even after long-term use and can exhibit excellent performance. .

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the degree of vacuum and the impregnation rate.

FIG. 2 is a schematic process drawing showing each process of the test and the manufacturing method of Examples 1 and 2.

FIG. 3 is a diagram showing a relationship between a discriminant of a resin-impregnated sintered pulley and a leak test according to a test.

FIG. 4 is a 100 × electron scanning micrograph showing a metal structure on the outer peripheral side of a cylindrical portion of a resin-impregnated sintered pulley of Example 2.

5 is a 100 × electron scanning micrograph showing a metal structure inside a cylindrical portion of a resin-impregnated sintered pulley of Example 2. FIG.

FIG. 6 is a 100 × electron scanning micrograph showing the metal structure on the surface side of the web of the resin-impregnated sintered pulley of Example 2.

FIG. 7 is a sectional view showing a pulley as a sintered body.

[Explanation of symbols]

 W ... Pulley (sintered body) 2 ... Resin impregnating liquid 90 ... Web 91 ... Cylindrical part

[Procedure amendment]

[Submission date] June 15, 1995

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 4

[Correction method] Change

[Correction content]

[Figure 4]

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 5

[Correction method] Change

[Correction content]

[Figure 5]

[Procedure 3]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 6

[Correction method] Change

[Correction content]

[Figure 6]

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Masahiko Inuzuka 1 Toyota-cho, Toyota-shi, Aichi Toyota Automobile Co., Ltd.

Claims (2)

[Claims] 1. A sintered body is immersed in a resin impregnating liquid under a vacuum atmosphere so as to impregnate pores of the sintered body with a resin impregnating liquid containing an uncured acrylic thermosetting resin. An impregnation step of opening to the atmosphere to obtain an uncured resin-impregnated sintered body, and a curing step of heating the uncured resin-impregnated sintered body to a temperature not lower than the curing temperature of the acrylic thermosetting resin to obtain a resin-impregnated sintered part A method of manufacturing a resin-impregnated sintered part, comprising: a (g / cm ³ ) the density of the sintered body, b (Torr) the degree of vacuum of the vacuum atmosphere, and c ( Seconds),
When the curing temperature is d (° C), 13.45a-4.52log _e b-0.35c + 0.
46d-149.0 ≧ 2.3 is satisfied, and a method for producing a resin-impregnated sintered component. 2. A resin-impregnated sintered pulley having a web on which pressure oil acts and a cylindrical portion which is continuous with the web and around which a rubber belt is wound, wherein the web is a metal in which pores remain. A matrix made of a sintered body and a resin part impregnated in the pores and cured with an acrylic thermosetting resin, and the cylindrical part includes the matrix, the resin part, and the outer peripheral side. And a non-impregnated layer having no resin portion formed on the resin impregnated sintered pulley.