A powder metallurgy friction ring sintering tool and sintering method

Abstract

The application discloses a powder metallurgy friction ring sintering tool and a sintering method. The sintering tool comprises a bottom disc, two cavity discs and a pressing disc which are stacked from bottom to top. A plurality of bottom disc limiting grooves for placing limiting rings are arranged on the bottom disc. A plurality of cavity disc cavity holes are arranged on the cavity disc. Cavity disc limiting grooves for placing limiting rings are arranged at both ends of the cavity disc cavity holes. The positions and numbers of the bottom disc limiting grooves and the cavity disc limiting grooves correspond to each other. Limiting rings are arranged between the bottom disc and the bottom cavity disc, between the bottom cavity disc and the top cavity disc, and between the top cavity disc and the pressing disc. Powder metallurgy friction rings are placed in the cavity disc cavity holes. The end faces of the powder metallurgy friction rings are in contact with the end faces of the two limiting rings respectively. A core rod is inserted into the limiting ring inner hole and the powder metallurgy friction ring inner hole. The sintered powder metallurgy friction ring can meet the shape size and performance requirements of the process technology, and can reduce the sintering cost and improve the sintering efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of powder metallurgy friction ring sintering tool and sintering method. BACKGROUND

[0002] Powder metallurgy friction material is widely used in sliding electrical contact material, self-lubricating material and engineering machinery brake clutch due to its good comprehensive performance. Sintering is a key process in the manufacturing process of powder metallurgy friction material. The main reason is that in the sintering process, the bonding state between the powder particles of the friction body compact is changed from mechanical engagement to atomic crystal bonding. The porosity defects of the compact are gradually reduced, the densification degree is continuously increased, the physical and mechanical properties of the friction body are obviously improved, and finally the powder metallurgy friction material that meets the requirements of shape size and process performance is obtained.

[0003] The traditional sintering method is to sinter the powder metallurgy friction ring compact in a natural state (directly place the pre-pressed friction ring in the sintering furnace) without pressure, or only pressurize the two end faces of the friction ring compact, so as to ensure the height of the sintered product. However, during the sintering process, most of the powder metallurgy friction material will expand in the radial and axial directions, causing the cylindricality and coaxiality of the inner and outer circles of the sintered product to be difficult to meet the standard requirements, the product size fluctuates greatly, and the product performance is inconsistent, thereby affecting the assembly, installation and operation of the powder metallurgy friction ring. In addition, the existing sintering method also has the problems of low working efficiency, high sintering cost and energy waste. SUMMARY

[0004] In order to overcome the above-mentioned shortcomings of the prior art, the present application provides a powder metallurgy friction ring sintering tool and sintering method, which can meet the shape size and performance requirements of the process technology after sintering, and reduce the sintering cost and improve the sintering efficiency.

[0005] The technical scheme adopted by the present application to solve its technical problems is: a powder metallurgy friction ring sintering tool, comprising a bottom disc, two layers of cavity discs and a pressing disc stacked in order from bottom to top, wherein: a plurality of bottom disc limiting grooves for placing limiting rings are provided on the bottom disc, a plurality of cavity disc cavity holes are provided on the cavity disc, limiting grooves for placing limiting rings are provided at both ends of the cavity disc cavity hole, the positions and numbers of the bottom disc limiting grooves and the cavity disc limiting grooves correspond to each other, limiting rings are arranged between the bottom disc and the bottom layer of cavity discs, between the bottom layer of cavity discs and the top layer of cavity discs, and between the top layer of cavity discs and the pressing disc, powder metallurgy friction rings are placed in the cavity disc cavity holes, and the two end faces of the powder metallurgy friction ring are in contact with the end faces of the two limiting rings respectively; a core rod is inserted into the limiting ring inner hole and the powder metallurgy friction ring inner hole.

[0006] The present application also provides a powder metallurgy friction ring sintering method, comprising the following steps:

[0007] Step one, place the base plate on the bell jar furnace base;

[0008] Step two, place the limiting ring in the base plate limiting groove;

[0009] Step three, place the bottom layer cavity disc, and the limiting ring in step two is placed in the cavity disc limiting groove on the bottom surface of the bottom layer cavity disc;

[0010] Step four, place the powder metallurgy friction ring in the cavity hole of the bottom layer cavity disc;

[0011] Step five, place the limiting ring in the cavity disc limiting groove on the top surface of the bottom layer cavity disc;

[0012] Step six, place the top layer cavity disc, and the limiting ring in step five is placed in the cavity disc limiting groove on the bottom surface of the top layer cavity disc;

[0013] Step seven, place the powder metallurgy friction ring in the cavity hole of the top layer cavity disc;

[0014] Step eight, place the limiting ring in the cavity disc limiting groove on the top surface of the top layer cavity disc;

[0015] Step nine, insert the core rod from the inner hole of the limiting ring in step eight downward until the bottom circular end surface of the core rod is in contact with the bottom of the base plate limiting groove, and the top circular end surface of the core rod is flush with the top surface of the top layer cavity disc;

[0016] Step ten, place the pressing plate on the top circular end surface of the limiting ring in step eight;

[0017] Step eleven, repeat steps one to ten to form a sintering tower body of a certain height, and apply pressure to the top layer pressing plate of the tower body during sintering.

[0018] Compared with the prior art, the positive effects of the present application are:

[0019] (1) The sintering tool provided by the present application has good limiting effect, which ensures the uniformity and stability of the product size, and ensures that the performance of the product after sintering meets the technical requirements;

[0020] (2) The sintering tool of the present application breaks the traditional thinking mode of precise control of pressure to ensure product height, and through ingenious structural design, the sintered product size is consistent, and the sintering efficiency is effectively improved, energy consumption and production cost are saved;

[0021] (3) The sintering tool of the present application can ensure the infiltration and circulation of sintering atmosphere during sintering by designing central holes in the base plate, cavity disc and pressing plate and reserving gaps between each disc, and can ensure the sintering quality.

[0022] (4) The sintering tool of the present application can effectively control the product's size after sintering, and ensure that the product's height, cylindricity and coaxiality of inner and outer circles can all meet the standard requirements.

[0023] (5) The sintering tool of the present application can effectively avoid the fluctuation of sintering size and sintering performance caused by the fluctuation of sintering equipment pressure.

[0024] (6) The sintering tool of the present application can be assembled in cycles and overlaps, has high sintering efficiency, can save energy and reduce product production cost. BRIEF DESCRIPTION OF DRAWINGS

[0025] The present application will be described by way of example and with reference to the accompanying drawings, in which:

[0026] Figure 1 is a structural schematic view of the assembled pressureless sintering tool;

[0027] Figure 2 is a structural schematic view of the base plate 100;

[0028] Figure 3 is a structural schematic view of the limiting ring 200;

[0029] Figure 4 is a structural schematic view of the cavity plate 300;

[0030] Figure 5 is a structural schematic view of the mandrel 500;

[0031] Figure 6 is a structural schematic view of the pressure plate 600;

[0032] Figure 7 is a structural schematic view of the powder metallurgy friction ring 400;

[0033] The reference signs in the drawings include: 100 - base plate, 110 - base plate center circular through hole, 120 - base plate limiting groove, 200 - limiting ring, 210 - limiting ring inner hole, 300 - cavity plate, 310 - cavity plate center circular through hole, 320 - cavity plate cavity hole, 330 - cavity plate limiting groove, 400 - powder metallurgy friction ring, 410 - powder metallurgy friction ring inner hole, 500 - mandrel, 600 - pressure plate, 610 - pressure plate center circular through hole. DETAILED DESCRIPTION

[0034] As shown in Figure 1 , the friction ring sintering tool provided by the present application comprises: a base plate 100, a cavity plate 300, a mandrel 500, a limiting ring 200 and a pressure plate 600, wherein:

[0035] As shown in Figure 2As shown, the chassis 100 is provided with a central circular through hole 110, and a plurality of chassis limiting grooves 120 are provided around the central circular through hole.

[0036] like Figure 3 As shown, the limiting ring 200 is provided with a limiting ring inner hole 210.

[0037] like Figure 4 As shown, the cavity disk 300 has a central circular through hole 310 at its center, and a plurality of cavity holes 320 are provided around the central circular through hole. Both ends of the cavity holes are provided with cavity limiting grooves 330.

[0038] The structure of the core rod 500 is as follows: Figure 5 As shown, the bottom round end face of the mandrel 500 contacts the bottom of the bottom plate limiting groove 120, and the top round end face of the mandrel 500 is flush with the top surface of the top cavity plate 300. Figure 1 As shown.

[0039] like Figure 6 As shown, the pressure plate 600 is provided with a central circular through hole 610.

[0040] like Figure 7 As shown, the powder metallurgy friction ring 400 is provided with a powder metallurgy friction ring inner hole 410.

[0041] like Figure 1 As shown, the limiting ring 200 mates with the chassis limiting groove 120 or the cavity plate limiting groove 330. The powder metallurgy friction ring 400 mates with the cavity plate cavity hole 320, and its two end faces respectively contact the end faces of the two limiting rings 200; the mandrel 500 mates with the inner hole 210 of the limiting ring and the inner hole 410 of the powder metallurgy friction ring respectively; the pressure plate 600 contacts the end face of the limiting ring 200. The positions and numbers of the chassis limiting groove 120 and the cavity plate limiting groove 330 correspond. After the sintering fixture is assembled, under the support of the limiting ring 200, a certain gap is left between the chassis 100 and the bottom cavity plate 300, a certain gap is left between the bottom cavity plate 300 and the top cavity plate 300, and a certain gap is left between the pressure plate 600 and the top cavity plate 300. The length of the mandrel 500 is equal to the distance between the top surface of the top cavity plate and the bottom surface of the chassis limiting groove.

[0042] The base plate 100, limiting ring 200, cavity plate 300, mandrel 500 and pressure plate 600 of the sintering fixture are all made of high-strength graphite.

[0043] Implementation method:

[0044] 1) Place the sintering base 100 on the bell furnace base;

[0045] 2) Place several of the aforementioned limiting rings 200 into the chassis limiting grooves 120 respectively;

[0046] 3) Put the several cavity disc 300 bottom surface cavity disc limiting slot 330 on the limiting ring 200 of step 2), because the depth of the bottom disc limiting slot 120 and the depth of the cavity disc limiting slot 330 are less than the height of the limiting ring 200, so there is a certain distance gap between the bottom disc 100 and the cavity disc 300;

[0047] 4) Put several powder metallurgy friction rings 400 in the cavity disc cavity hole 320 of the cavity disc 300 of step 3) respectively;

[0048] 5) Put another several limiting rings 200 in the cavity disc limiting slot 330 on the top surface of the cavity disc 300 of step 3) respectively;

[0049] 6) Put another several cavity disc limiting slots 330 on the bottom surface of the cavity disc 300 on the limiting ring 200 of step 5), because the depth of the two cavity disc limiting slots 330 is less than the height of the limiting ring 200, so there is a certain distance gap between the two cavity discs.

[0050] 7) Put another several powder metallurgy friction rings 400 in the cavity disc cavity hole 320 of the cavity disc 300 of step 6) respectively.

[0051] 8) Put another several limiting rings 200 in the cavity disc limiting slot 330 on the top surface of the cavity disc 300 of step 6) respectively.

[0052] 9) Put several core rods 500 into the inner hole 210 of the limiting ring of step 8), the inner hole of the powder metallurgy friction ring of step 7), the inner hole of the limiting ring of step 5), the inner hole of the powder metallurgy friction ring of step 4), and the inner hole of the limiting ring of step 2) in turn, the bottom circular end surface of the core rod 500 is in contact with the bottom of the bottom disc limiting slot 120, and the top circular end surface of the core rod 500 is flush with the top surface of the top layer cavity disc 300.

[0053] 10) Put the pressing plate 600 on the top circular end surface of the several limiting rings 200 of step 8).

[0054] 11) Repeat steps 1) to 10) to form a sintering tower body of a certain height, and apply pressure to the top layer pressing plate of the tower body during sintering.

[0055] The working principle of the present application is:

[0056] The friction ring sintering tool can effectively guarantee the coaxiality of the inner and outer circles of the sintered powder metallurgy friction ring through the limiting effect of the limiting rings at the upper and lower ends of the cavity disc and the core rod; and can effectively guarantee the cylindricity of the sintered powder metallurgy friction ring under the action of the cavity hole of the cavity disc and the core rod. During the sintering process, a certain pressure is applied to the top pressing disc, when the end face of the limiting ring is not in contact or starts to be in contact with the bottom face of the limiting groove, the limiting ring directly applies pressure to the powder metallurgy friction ring; when the end face of the limiting ring is completely in contact with the bottom face of the limiting groove, the limiting ring will not continue to apply pressure to the powder metallurgy friction ring, so as to guarantee that the height of the sintered powder metallurgy friction ring is the designed height, and also guarantee the stability and uniformity of the performance.

Claims

1. A powder metallurgy friction ring sintering tooling characterized by: The application relates to a sintering tower body, which comprises, from bottom to top, a bottom disc, two layers of cavity discs and a pressing disc, wherein a plurality of bottom disc limiting grooves for placing limiting rings are arranged on the bottom disc, a plurality of cavity disc cavity holes are arranged on the cavity discs, limiting rings are arranged at both ends of the cavity disc cavity holes, the positions and numbers of the bottom disc limiting grooves and the cavity disc limiting grooves correspond to each other, limiting rings are arranged between the bottom disc and the bottom layer of cavity discs, between the bottom layer of cavity discs and the top layer of cavity discs and between the top layer of cavity discs and the pressing disc, powder metallurgy friction rings are placed in the cavity disc cavity holes, the two end faces of the powder metallurgy friction rings are in contact with the end faces of the two limiting rings respectively, a core rod is inserted into the inner holes of the limiting rings and the powder metallurgy friction rings, limiting rings are arranged in the bottom disc limiting grooves and the cavity disc limiting grooves on the bottom surface of the bottom layer of cavity discs corresponding to the bottom disc limiting grooves, the height of the limiting rings is greater than the sum of the depth of the bottom disc limiting grooves and the depth of the cavity disc limiting grooves, limiting rings are arranged in the cavity disc limiting grooves on the top surface of the bottom layer of cavity discs and the cavity disc limiting grooves on the bottom surface of the top layer of cavity discs corresponding to the cavity disc limiting grooves on the top surface of the bottom layer of cavity discs, the height of the limiting rings is greater than the sum of the depths of the two cavity disc limiting grooves, and limiting rings are arranged in the cavity disc limiting grooves on the top surface of the top layer of cavity discs, the height of the limiting rings is greater than the depth of the cavity disc limiting grooves.

2. The sintering fixture for powder metallurgy friction rings according to claim 1, characterized in that: The bottom circular end face of the core rod is in contact with the bottom part of the bottom disc limiting groove, and the top circular end face of the core rod is flush with the top surface of the top layer of cavity discs.

3. The sintering fixture for powder metallurgy friction rings according to claim 1, characterized in that: A central circular through hole is arranged on the bottom disc.

4. The sintering fixture for powder metallurgy friction rings according to claim 1, characterized in that: A central circular through hole is arranged on the cavity disc.

5. The powder metallurgy friction ring sintering fixture of claim 1, wherein: A central circular through hole is arranged on the pressing disc.

6. The powder metallurgy friction ring sintering fixture of claim 1, wherein: The bottom disc, the limiting rings, the cavity discs, the core rod and the pressing disc are all made of high-strength graphite.

7. A sintering method based on the sintering jig for powder metallurgical friction ring according to claim 1, characterized in that: The application further discloses a sintering method of the sintering tower body. Step one: placing the bottom disc on the bell jar furnace base; Step two: placing limiting rings in the bottom disc limiting grooves; Step three: placing the bottom layer of cavity discs, so that the limiting rings in step two are placed in the cavity disc limiting grooves on the bottom surface of the bottom layer of cavity discs; Step four: placing powder metallurgy friction rings in the cavity disc cavity holes of the bottom layer of cavity discs; Step five: placing limiting rings in the cavity disc limiting grooves on the top surface of the bottom layer of cavity discs; Step six: placing the top layer of cavity discs, so that the limiting rings in step five are placed in the cavity disc limiting grooves on the bottom surface of the top layer of cavity discs; Step seven: placing powder metallurgy friction rings in the cavity disc cavity holes of the top layer of cavity discs; Step eight: placing limiting rings in the cavity disc limiting grooves on the top surface of the top layer of cavity discs; Step nine: inserting the core rod into the inner hole of the limiting ring in step eight downwards until the bottom circular end face of the core rod is in contact with the bottom part of the bottom disc limiting groove, and the top circular end face of the core rod is flush with the top surface of the top layer of cavity discs; Step ten: placing the pressing disc on the top circular end face of the limiting ring in step eight; Step eleven: repeating steps one to ten to form a sintering tower body with a set height, and applying pressure to the top layer of pressing discs during the sintering process.

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