CA2073887C - Ceramic adjusting shim - Google Patents
Ceramic adjusting shimInfo
- Publication number
- CA2073887C CA2073887C CA 2073887 CA2073887A CA2073887C CA 2073887 C CA2073887 C CA 2073887C CA 2073887 CA2073887 CA 2073887 CA 2073887 A CA2073887 A CA 2073887A CA 2073887 C CA2073887 C CA 2073887C
- Authority
- CA
- Canada
- Prior art keywords
- adjusting shim
- ceramic
- roughness
- shim
- valve
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
- F01L1/20—Adjusting or compensating clearance
- F01L1/205—Adjusting or compensating clearance by means of shims or the like
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
- F01L1/12—Transmitting gear between valve drive and valve
- F01L1/14—Tappets; Push rods
- F01L1/143—Tappets; Push rods for use with overhead camshafts
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
- F01L1/12—Transmitting gear between valve drive and valve
- F01L1/14—Tappets; Push rods
- F01L1/16—Silencing impact; Reducing wear
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Valve-Gear Or Valve Arrangements (AREA)
- Ceramic Products (AREA)
Abstract
The present invention provides a ceramic adjusting shim capable of minimizing the wear of parts contacting the adjusting shim, for example, a cam and a tappet. The ceramic adjusting shim is produced from a ceramic material and has a surface roughness of not more than 2.0 µm in ten-point average roughness Rz.
Description
TTTT~ OF T~ lNv~r-~lON
Ceramic adjusting shim FT~Tn OF T~ ~Nv~:r-.lON
This invention relates to an adjusting shim used in a valve train for an internal combustion engine.
D~CRIPTION OF TU~ PRIOR ART
The adjusting shim is used to regulate a valve clearance. Although a conventional adjusting shim consists usually of a metal, there is known an adjusting shim formed out of a ceramic material for the purpose of reducing the weight thereof and improving the wear resistance thereof.
However, even when the weight of a ceramic adjusting shim is reduced, a decrease in a power loss caused thereby is not substantially recognized in practice since the percentage of the inertial weight of the adjusting shim with respect to the whole inertial weight of the valve train is extremely small.
Moreover, the offensiveness of the shim with respect to the parts with which the shim contacts, so that these two parts wear greatly.
SUMM~RY OF TH~ lNv~ ON
Therefore, an object of the present invention is to provide a ceramic adjusting shim having a smooth surface in which the above-mentioned problems are eliminated.
Ceramic adjusting shim FT~Tn OF T~ ~Nv~:r-.lON
This invention relates to an adjusting shim used in a valve train for an internal combustion engine.
D~CRIPTION OF TU~ PRIOR ART
The adjusting shim is used to regulate a valve clearance. Although a conventional adjusting shim consists usually of a metal, there is known an adjusting shim formed out of a ceramic material for the purpose of reducing the weight thereof and improving the wear resistance thereof.
However, even when the weight of a ceramic adjusting shim is reduced, a decrease in a power loss caused thereby is not substantially recognized in practice since the percentage of the inertial weight of the adjusting shim with respect to the whole inertial weight of the valve train is extremely small.
Moreover, the offensiveness of the shim with respect to the parts with which the shim contacts, so that these two parts wear greatly.
SUMM~RY OF TH~ lNv~ ON
Therefore, an object of the present invention is to provide a ceramic adjusting shim having a smooth surface in which the above-mentioned problems are eliminated.
- 2 ~ 207 3 8 87 According to the present invention, there is provided a ceramic adjusting shim comprising a ceramic material the surface roughness of which is not more than 2.0 ~m in ten-point average roughness (Rz).
As the ceramic material for the ceramic adjusting shim, silicon nitride is mainly used. The surface roughness of the adjusting shim is preferably not more than 0.8 ~m and more preferably not more than 0.2 ~m, in ten-point average roughness (Rz).
BRI~F DESCRIPTION OF TH~ DRAWINGS
FIG. 1 is a longitudinal section of an adjusting shim.
FIG. 2 is a longitudinal section of an adjusting shim and a valve lifter.
FIG. 3 is a longitudinal section of a valve train for an engine.
FIG. 4 is a longitudinal section of an apparatus for testing a product according to the present invention.
D~T~IT.~n D~-~CRIPTION OF TH~ pR~F~RR~n ~MRODTM~NTS
The present invention will be now described in detail hereinbelow.
Referring first to FIG. 3, a reference numeral 1 denotes a cylinder head of an engine, 2 a cam, 3 a valve lifter, 4 an adjusting shim, 5 an intake or exhaust valve, 6 a valve seat and 7 a valve spring.
In the valve train shown in FIG. 3, the valve lifter 3 is driven by the cam 2, and the displacement of the cam 2 is transmitted to the intake or exhaust valve 5. As may be understood from FIG. 3, an adjusting shim 4 is disposed between the valve lifter 3 and cam 2. A
longitudinal section of the adjusting shim 4 is shown in FIG. 1.
When a ceramic adjusting shim having a smooth surface is used, a frictional loss occurring between the cam and the ceramic adjusting shim can be reduced, so that a power loss of the internal combustion engine can be minimized. Moreover, the offensiveness of the ceramic adjusting shim with respect to the cam 2 and valve lifter 3 shown in FIG. 3 decreases, and the wear of these two parts can therefore be reduced.
In this case, the roughness of the surface (designated by a reference numeral 8 in FIG. 1), which the cam contacts of the ceramic adjusting shim is not more than 0.2 ~m in ten-point average roughness (Rz), and a torque loss caused thereby becomes smaller than that in a case where a conventional metal adjusting shim is used. When the ten-point average roughness (Rz) is up to 0.2 ~m, a torque loss decreases in accordance with a decrease in the surface roughness.
In a region in which the ten-point average roughness is (Rz) of the contact surface is less than 0.2 ~m, a torque loss caused thereby is substantially equal to that in a case where the ten-point average roughness is 0.2 ~m.
In a region in which the roughness of the surfaces (designated by reference numerals 9 and 10 in FIG. 1), which the valve lifter contacts, of the ceramic adjusting shim is not more than 0.8 ~m in ten-point average roughness, a wear loss of the ~aL
'~
valve lifter decreases sharply in accordance with a decrease in the surface roughness of the ceramic adjusting shim, and, in a region in which the surface roughness of the same shim is less than 0.2 ~m, a wear loss of the valve lifter becomes substantially constant.
The present invention will now be described concretely on the basis of its embodiments.
Example 1 The same adjusting shims as shown in FIG. 1 were produced out of a silicon nitride ceramic sintered body having a relative density of not less than 98%.
The surface, which a cam contacts, i.e. the surface designated by a reference numeral 8 shown in FIG. 1, of each of the adjusting shims was finished under various conditions by a diamond wheel to set the roughness of the surfaces of these adjustin~ shims to levels shown in Table 1. Each of the adjusting shims thus produced was subjected to the evaluation of power loss with respect to the power consumption of a motor rotated at a predetermined number of revolutions per minute (2000 RPM and 4000 RPM in terms of number of revolutions per minute of engine), by using a motoring system shown in FIG. 4 and simulating an over head camshaft type valve train. Table 1 shows the results of the above with the results of similar evaluation of power loss caused by conventional steel adjusting shims which constitute comparative examples.
Table 1 No. Material for Surface roughness Power consumption adjusting Rz of contact of motor (kW ) shim surface (~m) 2000 RPM 4000 RPM
1 Silicon 1.5 1.13 1.24 nitride 2 Silicon 1.2 1.11 1.22 nitride 3 Silicon 1.0 1.08 1.18 nitride 4 Silicon 0.7 1.00 1.10 nitride Silicon 0.5 0.94 1.03 nitride 6 Silicon 0.2 0.90 0.99 nitride 7 Silicon 0.05 0.89 0.98 nitride *8 Silicon 2.5 1.20 1.32 nitride *9 Silicon 5.0 1.32 1.45 nitride (not processed) *10 Cr-Mo steel 5.0 1.17 1.28 * comparative example Example 2:
The adjusting shims produced out of various kinds of ceramic materials were subjected to the evaluation of power loss caused thereby by a method identical with that used in Example 1, and the results are shown in Table 2.
Table 2 No. Material for Surface roughness Power consumption adjusting Rz of contact of motor (kW) shim surface (~m) 2000 RPM 4000 RPM
11 Zirconia 0.05 0.91 1.00 12 Zirconia 1.0 1.11 1.22 13 Composite 1.0 1.09 1.19 material of SiC-Si3N4 14 Composite 0.2 0.92 1.01 material of SiC-Si3N4 *15 Zirconia 5.0 1.34 1.47 *16 Composite 8.0 material of (not processed)1.36 1.49 SiC-Si3N4 *10 Cr-Mo steel 5.0 1.17 1.28 * comparative examples Example 3:
Each of the adjusting shims produced under the same conditions as in Example 1 was subjected to a 200-hour.continuous operation test with a motor rotated at a predetermined number of revolutions per minute (6000 RPM in terms of number of revolutions per minute of engine), by using the motoring system used in Example 1, and the wear loss, which was determined after the tests had been completed, of the valve lifter was evaluated. The evaluating of the wear loss of the valve lifter was done by measuring the inner diameter, which is shown by a reference numeral 11 in FIG. 2, of the valve lifter before and after each test was conducted, and determining the quantity of variation thereof. The results of the evaluation are shown in Table 3.
Table 3 No. Material for Surface Roughness Rz Wear adjusting shim of contact surface loss**
(~m) (~m) 17 Silicon nitride 1.5 12 lO18 Silicon nitride 1.2 11 19 Silicon nitride 1.0 10 20 Silicon nitride 0.7 5 21 Silicon nitride 0.5 3 22 Silicon nitride 0.2 1523 Silicon nitride 0.05 <1 *24 Silicon nitride 2.5 18 *25 Silicon nitride 5.0 20 (not processed) - * comparative example ** Wear loss: Difference between the inner diameter of valve lifter measured before test was conduct~d and that thereof measured after test was conducted.
The present invention is not limited to these embodiments. The surfaces of the adjusting shims were smoothed by being processed with a diamond wheel.
Even if these surfaces are smoothed by being subjected to chemical and physical surface treatments (etching and coating), or a chemical applying treatment which is conducted before and after the sintering of a ceramic material, obtaining the same effect as those in the embodiments can be expected. The same effect can also be expected even if the roughness of the surfaces designated by the reference numerals 8, 9 and 10 in FIG. 1 is set to different levels according to different purposes.
The adjusting shim according to the present invention enables a power loss and wear resistance of a valve train to be reduced and increased respectively, and the fuel consumption, performance and durability of an internal combustion engine to be improved.
., .
As the ceramic material for the ceramic adjusting shim, silicon nitride is mainly used. The surface roughness of the adjusting shim is preferably not more than 0.8 ~m and more preferably not more than 0.2 ~m, in ten-point average roughness (Rz).
BRI~F DESCRIPTION OF TH~ DRAWINGS
FIG. 1 is a longitudinal section of an adjusting shim.
FIG. 2 is a longitudinal section of an adjusting shim and a valve lifter.
FIG. 3 is a longitudinal section of a valve train for an engine.
FIG. 4 is a longitudinal section of an apparatus for testing a product according to the present invention.
D~T~IT.~n D~-~CRIPTION OF TH~ pR~F~RR~n ~MRODTM~NTS
The present invention will be now described in detail hereinbelow.
Referring first to FIG. 3, a reference numeral 1 denotes a cylinder head of an engine, 2 a cam, 3 a valve lifter, 4 an adjusting shim, 5 an intake or exhaust valve, 6 a valve seat and 7 a valve spring.
In the valve train shown in FIG. 3, the valve lifter 3 is driven by the cam 2, and the displacement of the cam 2 is transmitted to the intake or exhaust valve 5. As may be understood from FIG. 3, an adjusting shim 4 is disposed between the valve lifter 3 and cam 2. A
longitudinal section of the adjusting shim 4 is shown in FIG. 1.
When a ceramic adjusting shim having a smooth surface is used, a frictional loss occurring between the cam and the ceramic adjusting shim can be reduced, so that a power loss of the internal combustion engine can be minimized. Moreover, the offensiveness of the ceramic adjusting shim with respect to the cam 2 and valve lifter 3 shown in FIG. 3 decreases, and the wear of these two parts can therefore be reduced.
In this case, the roughness of the surface (designated by a reference numeral 8 in FIG. 1), which the cam contacts of the ceramic adjusting shim is not more than 0.2 ~m in ten-point average roughness (Rz), and a torque loss caused thereby becomes smaller than that in a case where a conventional metal adjusting shim is used. When the ten-point average roughness (Rz) is up to 0.2 ~m, a torque loss decreases in accordance with a decrease in the surface roughness.
In a region in which the ten-point average roughness is (Rz) of the contact surface is less than 0.2 ~m, a torque loss caused thereby is substantially equal to that in a case where the ten-point average roughness is 0.2 ~m.
In a region in which the roughness of the surfaces (designated by reference numerals 9 and 10 in FIG. 1), which the valve lifter contacts, of the ceramic adjusting shim is not more than 0.8 ~m in ten-point average roughness, a wear loss of the ~aL
'~
valve lifter decreases sharply in accordance with a decrease in the surface roughness of the ceramic adjusting shim, and, in a region in which the surface roughness of the same shim is less than 0.2 ~m, a wear loss of the valve lifter becomes substantially constant.
The present invention will now be described concretely on the basis of its embodiments.
Example 1 The same adjusting shims as shown in FIG. 1 were produced out of a silicon nitride ceramic sintered body having a relative density of not less than 98%.
The surface, which a cam contacts, i.e. the surface designated by a reference numeral 8 shown in FIG. 1, of each of the adjusting shims was finished under various conditions by a diamond wheel to set the roughness of the surfaces of these adjustin~ shims to levels shown in Table 1. Each of the adjusting shims thus produced was subjected to the evaluation of power loss with respect to the power consumption of a motor rotated at a predetermined number of revolutions per minute (2000 RPM and 4000 RPM in terms of number of revolutions per minute of engine), by using a motoring system shown in FIG. 4 and simulating an over head camshaft type valve train. Table 1 shows the results of the above with the results of similar evaluation of power loss caused by conventional steel adjusting shims which constitute comparative examples.
Table 1 No. Material for Surface roughness Power consumption adjusting Rz of contact of motor (kW ) shim surface (~m) 2000 RPM 4000 RPM
1 Silicon 1.5 1.13 1.24 nitride 2 Silicon 1.2 1.11 1.22 nitride 3 Silicon 1.0 1.08 1.18 nitride 4 Silicon 0.7 1.00 1.10 nitride Silicon 0.5 0.94 1.03 nitride 6 Silicon 0.2 0.90 0.99 nitride 7 Silicon 0.05 0.89 0.98 nitride *8 Silicon 2.5 1.20 1.32 nitride *9 Silicon 5.0 1.32 1.45 nitride (not processed) *10 Cr-Mo steel 5.0 1.17 1.28 * comparative example Example 2:
The adjusting shims produced out of various kinds of ceramic materials were subjected to the evaluation of power loss caused thereby by a method identical with that used in Example 1, and the results are shown in Table 2.
Table 2 No. Material for Surface roughness Power consumption adjusting Rz of contact of motor (kW) shim surface (~m) 2000 RPM 4000 RPM
11 Zirconia 0.05 0.91 1.00 12 Zirconia 1.0 1.11 1.22 13 Composite 1.0 1.09 1.19 material of SiC-Si3N4 14 Composite 0.2 0.92 1.01 material of SiC-Si3N4 *15 Zirconia 5.0 1.34 1.47 *16 Composite 8.0 material of (not processed)1.36 1.49 SiC-Si3N4 *10 Cr-Mo steel 5.0 1.17 1.28 * comparative examples Example 3:
Each of the adjusting shims produced under the same conditions as in Example 1 was subjected to a 200-hour.continuous operation test with a motor rotated at a predetermined number of revolutions per minute (6000 RPM in terms of number of revolutions per minute of engine), by using the motoring system used in Example 1, and the wear loss, which was determined after the tests had been completed, of the valve lifter was evaluated. The evaluating of the wear loss of the valve lifter was done by measuring the inner diameter, which is shown by a reference numeral 11 in FIG. 2, of the valve lifter before and after each test was conducted, and determining the quantity of variation thereof. The results of the evaluation are shown in Table 3.
Table 3 No. Material for Surface Roughness Rz Wear adjusting shim of contact surface loss**
(~m) (~m) 17 Silicon nitride 1.5 12 lO18 Silicon nitride 1.2 11 19 Silicon nitride 1.0 10 20 Silicon nitride 0.7 5 21 Silicon nitride 0.5 3 22 Silicon nitride 0.2 1523 Silicon nitride 0.05 <1 *24 Silicon nitride 2.5 18 *25 Silicon nitride 5.0 20 (not processed) - * comparative example ** Wear loss: Difference between the inner diameter of valve lifter measured before test was conduct~d and that thereof measured after test was conducted.
The present invention is not limited to these embodiments. The surfaces of the adjusting shims were smoothed by being processed with a diamond wheel.
Even if these surfaces are smoothed by being subjected to chemical and physical surface treatments (etching and coating), or a chemical applying treatment which is conducted before and after the sintering of a ceramic material, obtaining the same effect as those in the embodiments can be expected. The same effect can also be expected even if the roughness of the surfaces designated by the reference numerals 8, 9 and 10 in FIG. 1 is set to different levels according to different purposes.
The adjusting shim according to the present invention enables a power loss and wear resistance of a valve train to be reduced and increased respectively, and the fuel consumption, performance and durability of an internal combustion engine to be improved.
., .
Claims (4)
1. A ceramic valve clearance adjusting shim comprising a ceramic material, the adjusting shim contacting a cam and a valve lifter and being movably disposed on the valve lifter characterized in that the surface roughness of surfaces of the adjusting shim contacting the cam and the valve lifter is not more than 0.2 µm in ten-point average roughness (Rz) according to Japanese Industrial Standard (JIS) B 0601.
2. The ceramic valve clearance adjusting shim according to claim 1, wherein said ceramic material consists mainly of silicon nitride.
3. The ceramic valve clearance adjusting shim according to claim 1 or 2, wherein the roughness of the surface which contacts the cam is identical with the roughness of the surfaces which contact the valve lifter.
4. The ceramic valve clearance adjusting shim according to claims 1 or 2, wherein the roughnesses of the surfaces are different.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3-179511 | 1991-07-19 | ||
| JP3179511A JPH08226311A (en) | 1991-07-19 | 1991-07-19 | Ceramic adjusting shim |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2073887A1 CA2073887A1 (en) | 1993-01-20 |
| CA2073887C true CA2073887C (en) | 1996-11-19 |
Family
ID=16067078
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2073887 Expired - Fee Related CA2073887C (en) | 1991-07-19 | 1992-07-15 | Ceramic adjusting shim |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0523691B1 (en) |
| JP (1) | JPH08226311A (en) |
| CA (1) | CA2073887C (en) |
| DE (1) | DE69205742T2 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE69312679T2 (en) * | 1993-03-26 | 1998-02-19 | Fuji Valve | Compensation element structure for a valve lifter of an internal combustion engine |
| JPH07127402A (en) * | 1993-10-29 | 1995-05-16 | Sumitomo Electric Ind Ltd | Combination of adjusting shim and cam |
| JPH07269309A (en) * | 1994-03-28 | 1995-10-17 | Fuji Oozx Inc | Tappet shim for internal combustion engine |
| US5410995A (en) * | 1994-04-15 | 1995-05-02 | Cummins Engine Company, Inc. | Valve crosshead assembly with wear-reducing contact pad |
| JP4493106B2 (en) | 1997-12-26 | 2010-06-30 | 富士フイルム株式会社 | Digital camera |
| US6237441B1 (en) | 1998-03-19 | 2001-05-29 | Sumitomo Electric Industries, Ltd. | Combination of shim and cam |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4366785A (en) * | 1980-09-19 | 1983-01-04 | Caterpillar Tractor Co. | Tappet with wear resisting insert |
| DE3239325A1 (en) * | 1982-10-23 | 1984-04-26 | Feldmühle AG, 4000 Düsseldorf | Valve tappet for an internal combustion engine |
| DE3522403A1 (en) * | 1985-06-22 | 1987-01-02 | Stettner & Co | VALVE ADJUSTING PLATE |
-
1991
- 1991-07-19 JP JP3179511A patent/JPH08226311A/en active Pending
-
1992
- 1992-07-15 CA CA 2073887 patent/CA2073887C/en not_active Expired - Fee Related
- 1992-07-16 DE DE1992605742 patent/DE69205742T2/en not_active Expired - Lifetime
- 1992-07-16 EP EP19920112147 patent/EP0523691B1/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| EP0523691A2 (en) | 1993-01-20 |
| DE69205742D1 (en) | 1995-12-07 |
| DE69205742T2 (en) | 1996-07-04 |
| CA2073887A1 (en) | 1993-01-20 |
| EP0523691A3 (en) | 1993-03-03 |
| EP0523691B1 (en) | 1995-11-02 |
| JPH08226311A (en) | 1996-09-03 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |