JPH1047020A - Valve lifter for internal combustion engine, manufacture of the valve lifter, and automatic grinder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of abnormal friction due to thermal deformation of a valve lifter for an internal combustion engine integrally formed of one and the same metallic material and to suppress oscillation movement during working. SOLUTION: A valve lifter 1 for an internal combustion engine comprises a top wall 1a making contact with a cam 6; and an approximately cylindrical skirt part 2 extending approximately orthogonally from a top wall 1a and surrounding the end part of a valve 11. The top wall 1a and the skirt part 2 are formed of one and the same metallic material and the top wall 1a is pressed against the cam 6 through the force of a valve spring 10. Normal temperature, the outside diameter of the top wall 1a side of the skirt part 2 is decreased to a value lower than the outside diameter of the lower end side of the skirt part 2 to form the skit part 2 in a truncated conical shape. When, during working, thermal expansion due to a temperature gradient along the direction of the length of the skirt part 2, the outside diameter of the top wall 1a of the skirt part 2 is substantially equalized with that of the lower end side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve device for opening and closing an intake valve or an exhaust valve of an internal combustion engine. The present invention relates to a valve lifter for an internal combustion engine capable of suppressing the swinging motion of an internal combustion engine, a method of manufacturing the valve lifter, and an automatic grinding machine.

[0002]

2. Description of the Related Art In an internal combustion engine having a direct-acting valve operating mechanism for directly transmitting the lift of a cam of a rotating camshaft to a valve, a valve lifter is provided between the cam and the valve. The valve lifter is slidably disposed in an opening formed in a lifter boss on the cylinder head side, and is pressed against the cam by a valve spring. A certain gap (clearance) is maintained between the opening and the valve lifter, and the valve lifter reciprocates within the opening.
The lubricating oil supplied to the gap between the opening and the valve lifter can prevent the sliding portion from being worn and ensure a smooth sliding motion. However, in recent internal combustion engines in which high rotation and high output are advanced, a high load is applied to a skirt portion of a valve lifter operated at high rotation, and sliding conditions are becoming more and more severe. In addition, since a gap (clearance) of a suitable size is not formed between the skirt portion of the valve lifter and the lifter boss during operation, lubricating oil is not smoothly supplied to the gap, and wear at the sliding portion of the skirt portion of the valve lifter is accelerated. There are drawbacks. As shown in FIG. 9, the conventional valve lifter 1 is slidably disposed in an opening 5 a formed in a lifter boss 5, and a cam face surface 6 a of a cam 6 is provided by a retainer 8 which receives an elastic force of a valve spring 10.
Is always pressed. Cotta 9 on the top of valve 11
Is mounted, and the cotter 9 is connected to the retainer 8. The valve lifter 1 and the valve 11 reciprocate in the opening 5a with the rotation of the cam 6, but the pressing force of the valve spring 10 during the valve lift causes the cam face surface 6a to move to the central portion 7 of the top wall 1a of the valve lifter 1. The central portion 7 generates heat at a high temperature due to local metal-to-metal contact and fluid friction of lubricating oil.

[0003]

Assuming that the outer diameter of the upper portion of the skirt portion 2 of the valve lifter 1 in contact with the cam 6 is D ₁ and the outer diameter of the lower portion is D ₂ , D ₁ is obtained when the valve lifter 1 is completed.
= D _2, and the skirt portion 2 of the valve lifter 1, FIG. 9
As shown by the solid line, it is general to work with the same outer diameter in the length direction so as to be substantially cylindrical at normal temperature.
In the valve lifter 1 during operation, the top wall 1a of the valve lifter 1 that comes into contact with the cam 6 is heated due to heat generated by frictional loss, and the temperature decreases as the distance from the center 7 increases.
Therefore, while the temperature is high at the top wall 1a of the skirt portion 2 of the valve lifter 1, the temperature distribution is such that the amount of heat radiation increases toward the lower end 4 and the temperature decreases.
And a temperature difference occurs. Equal outer diameter D ₂ of an outer diameter D ₁ and the lower at the top of the skirt portion of the valve lifter 1 (D ₁ =
D ₂ ) Since the outer diameter of the skirt portion 2 of the valve lifter 1 is uniform in the length direction and is straight, the amount of thermal expansion of the top wall 1 a of the valve lifter 1 having a high temperature during engine operation is limited to the lower end 4 having a low temperature. 9, a difference in the amount of thermal expansion occurs due to the temperature distribution, and the outer diameter of the upper end 3 of the skirt portion 2 is larger than the outer diameter of the lower end 4, and in FIG. 9, D ₁ ′> D ₂ ′. Therefore, the valve lifter 1 has an inverted conical shape (inverted tapered shape) indicated by a two-dot chain line and slides in contact with the lifter boss 5. In this case, the upper end 3 of the skirt portion 2 of the valve lifter 1
In this case, the clearance between the lifter boss 5 and the opening 5a is small, the supply amount of the lubricating oil is small, and in the worst case, the lifter diameter may be larger than the lifter boss diameter, and a large contact stress is generated. As a result, the lubricating oil is broken at the contact portion of the upper end 3, so that good lubrication cannot be maintained and abnormal wear occurs. At the lower end 4 of the skirt 2, the heating temperature is lower than at the upper end 3 of the skirt 2, and the thermal expansion is small. For this reason, since the clearance between the lower end 4 and the opening 5 a is larger than that of the upper end 3, the swing motion of the valve lifter 1 is promoted at the upper limit position and the lower limit position (load direction change point) of the stroke. In addition, with the swing operation of the valve lifter 1, the impact force of the lower end 4 of the skirt portion 2 against the lifter boss 5 increases, which causes a problem of noise. Since the lifter boss 5 having the opening for guiding the valve lifter 1 is formed integrally with the cylinder head which is cooled almost uniformly by oil cooling or water cooling, there is almost no temperature difference in the length direction of the opening, and the engine It is maintained in a straight shape even during operation. Therefore, the conventional sliding contact between the skirt portion 2 of the valve lifter 1 and the lifter boss 5 causes the corner of the upper end 3 of the valve lifter 1 to come into strong contact with the lifter boss 5, thereby causing an increase in friction loss and abnormal wear. JP-A-7-23
Japanese Patent No. 3712 discloses a valve lifter in which a cylindrical portion made of fiber reinforced resin and a disk-shaped ceiling made of metal are integrally formed. In this valve lifter, since the linear expansion coefficient of the cylindrical portion made of fiber-reinforced resin is larger than the linear expansion coefficient of the metal ceiling portion, the lower end 4 of the cylindrical portion expands from the upper end during operation. The cylindrical portion is formed in a tapered shape whose outer diameter gradually decreases toward the portion. However, the valve lifter disclosed in this publication shows an example in which the valve lifter is deformed by heat generated during operation in order to form the cylindrical portion made of fiber-reinforced resin and the metal ceiling portion with materials having different linear expansion coefficients. No solution for solving the problems of deformation and oscillating operation due to a temperature gradient when a valve lifter is manufactured from the material described above. Accordingly, the present invention provides a valve lifter for an internal combustion engine, a method of manufacturing a valve lifter, and an automatic grinding machine capable of preventing abnormal wear due to thermal deformation of a valve lifter integrally formed of the same metal material and suppressing swing motion during operation. The purpose is to do.

[0004]

SUMMARY OF THE INVENTION A valve lifter for an internal combustion engine according to the present invention has a top wall in contact with the cam and a substantially cylindrical skirt extending substantially perpendicularly from the top wall and surrounding the end of the valve. . The top wall is pressed against the cam by the valve spring. At room temperature, the outer diameter of the top wall side of the skirt is smaller than the outer diameter of the lower end of the skirt to form a frustoconical shape, and thermal expansion due to temperature gradient along the length of the skirt during operation Occurs,
The outer diameter of the top wall of the skirt portion and the lower end side are substantially equal. In an embodiment of the invention, the cam contacts a shim secured to the top wall. A method of manufacturing a valve lifter for an internal combustion engine according to the present invention includes an outer diameter of a skirt portion of a cup-shaped work having a top wall and a substantially cylindrical skirt portion extending substantially perpendicularly from the top wall and surrounding an end of the valve. And the step of transmitting the measured outer diameter data to the control unit, and the step of calculating the pressing force of the grinding wheel against the skirt portion of the work and the rotation speed of the grinding wheel or the adjusting wheel in the control unit, The process of supplying the work between the grinding wheel of the grinding device and the adjustment wheel, and applying a signal from the control unit to the stepping motor to press the grinding wheel against the skirt portion of the work with the calculated pressing force and control A signal is given from the unit to the motor that rotates the grinding wheel or adjustment wheel, and the grinding wheel or adjustment wheel is rotated at the calculated rotation speed. Te, and forming a skirt frusto conical shape smaller than the outer diameter of the lower end of the outer diameter of the top wall of the skirt portion during normal temperature, and a step of taking out the workpiece from the grinding apparatus. In the embodiment of the present invention, a step of measuring the outer diameter of the skirt portion of the work before processing and selecting the work for each range of the outer diameter or grinding the work between the grinding wheel and the adjusting wheel. The method may include a step of automatically moving the work to an outlet of the grinding device. Further, after the work is completed, the step of measuring the outer diameter of the skirt portion of the work, the step of sending measurement data of the outer diameter of the skirt portion to the control unit, the movement amount of the grinding wheel and the grinding wheel or A step of correcting the rotation speed of the adjusting wheel in the control unit, and driving the stepping motor from the control unit with the corrected movement amount signal to move the grinding wheel, and controlling the motor from the control unit with the corrected rotation speed signal. Driving to rotate the grinding wheel or the adjustment wheel.

[0005] An automatic grinding machine for a valve lifter for an internal combustion engine according to the present invention includes a grinding device provided with a grinding wheel and an adjusting wheel arranged opposite to the grinding wheel. A cup-shaped work having a top wall and a substantially cylindrical skirt extending substantially at right angles from the top wall and surrounding the end of the valve is supplied between the grinding wheel and the adjusting wheel so that the skirt of the work is formed. Be ground. This automatic grinding machine is an external diameter automatic measuring device that measures the external diameter of the skirt portion of the work, a sending device that supplies the work from the external diameter automatic measuring device to the grinding device, and receives the output of the external diameter automatic measuring device. A control unit for calculating the pressing force of the grinding wheel against the skirt portion of the work and the rotational speed of the grinding wheel or the adjusting wheel, and a stepping motor for pressing the grinding wheel against the skirt portion of the work by the pressing force set by the control unit. And a motor that rotates the grinding wheel or the adjusting wheel according to the rotation speed set by the control unit, and adjusts the pressing force of the grinding wheel by the stepping motor and the rotation speed of the motor to process the work into a frusto-conical shape. . In addition, this automatic grinding machine measures the outer diameter of the skirt portion of the work before processing and sorts the work for each range of the outer diameter, guiding the work between the grinding wheel and the adjustment wheel. It may include an outer diameter automatic measuring machine for measuring the outer diameter of the skirt portion of the work after the completion of the processing of the work rail or the work rail. The automatic diameter measuring device sends the measured data of the measured outer diameter of the skirt to the control unit, and the control unit corrects the moving amount of the grinding wheel and the rotation speed of the grinding wheel or the adjusting wheel from the measured data. The stepping motor is driven from the control unit by the corrected movement amount signal to move the grinding wheel, and the motor is driven from the control unit by the corrected rotation speed signal to rotate the grinding wheel or the adjustment wheel. The sorting device includes a plurality of sorting pallets for classifying the work according to the size of the outer diameter of the skirt portion of the work, and a servomotor for moving the sorting pallet with respect to the sending device.

According to the temperature distribution of the skirt from the top wall to the lower end of the heat-generating part during operation, the skirt of the valve lifter for an internal combustion engine according to the present invention has a small diameter on the top wall side of the skirt at normal temperature. It is formed in a frusto-conical shape with the lower end of the part having a large diameter. During operation, the top wall of the skirt portion becomes a heat generating portion that comes into contact with the cam, and the amount of thermal expansion due to high temperature is large. On the other hand, the lower end of the skirt portion located farthest from the heat generating portion on the top wall has a lower temperature and a smaller thermal expansion than the top wall. Therefore, during operation, the skirt portion thermally expands in accordance with the thermal gradient of the skirt portion, so that the skirt portion of the valve lifter that comes into contact with the lifter boss has a straight shape having substantially the same outer diameter along the entire length, and The entire surface in the axial direction of the skirt portion slides in contact with the lifter boss. This avoids a local hit caused by a difference in thermal expansion due to a temperature distribution along the length of the skirt during operation,
It is possible to suppress the partial occurrence of excessive stress and to prevent abnormal wear between the sliding surfaces. In addition, since the clearance between the lower end of the valve lifter and the lifter boss can be reduced to an appropriate amount, the impact sound of the lower end of the skirt portion against the lifter boss generated by the swing motion of the valve lifter can be reduced. The pressing force of the valve lifter against the skirt portion of the work, which is an unfinished workpiece, was adjusted by the amount of movement of the grinding wheel, and the rotation speed of the adjusting wheel was adjusted to elastically deform the lower end of the skirt portion of the work into a tapered shape. In this state, the skirt is processed into a tapered shape. By utilizing the action of the elastic restoring force of the skirt after the grinding, the skirt can be processed into a frusto-conical shape whose outer diameter gradually increases toward the lower end of the skirt. The deformation mode due to the difference in the shape and material of the valve lifter with respect to the moving amount of the grinding wheel and the transfer speed of the work transferred by the adjusting wheel is grasped in advance, and the non-uniform outer diameter after the intermediate grinding and subsequent nitriding is automatically measured. Control the amount of grinding wheel movement and the rotation of the adjustment wheel that are optimal for each condition. This allows
Grinding with elastic deformation is performed, and an optimum tapered shape is obtained by the restoring force of the skirt portion of the valve lifter at the end of the processing. It is also possible to set the taper shape in advance on the grinding wheel and perform the taper processing, but the outer diameter of the valve lifter after the processing is completed is automatically measured, and the measured value is caused by wear of the grinding wheel etc. The control unit calculates the amount of change in processing accuracy with time, and feedback-controls the amount of movement of the grinding wheel and the rotation of the adjusting wheel, so that a high-precision taper shape can be obtained at low cost overall and always.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a valve lifter according to the present invention will be described below with reference to FIGS. As shown in FIGS. 1 and 2, a retainer 8 and a cotter 9 receiving the elastic force of the valve spring 10 are attached to the valve 11, and the valve lifter 1 is pressed against the cam face surface 6 a of the cam 6 by the elastic force of the valve spring 10. You.
The rotation of the cam 6 causes the valve lifter 1 to reciprocate in the opening 5a.
Is in sliding contact with the top wall 1a of the valve lifter 1. The central portion 7 of the top wall 1a of the valve lifter 1 locally generates heat. Friction heat generated in the central portion 7 of the valve lifter 1 is diffused throughout the valve lifter 1 by heat conduction, and the heating temperature gradually decreases as the distance from the central portion 7 increases. That is, the highest temperature is reached at almost the center of the top wall 1a of the valve lifter 1,
The lowest temperature is at the lower end 4 of the substantially cylindrical skirt portion 2 farthest from the center of the top wall 1a. When the valve lifter 1 is manufactured from an iron-based material, the temperature difference Δt of the upper end 3 of the skirt portion 2 is higher than that of the lower portion 4 by about 20 ° C., so that the temperature difference Δt causes a difference in the amount of thermal expansion. The temperature difference Δt is determined according to the operation state of each internal combustion engine. According to the present invention, the temperature distribution of the skirt portion 2 of the valve lifter 1 during the operation of the engine is predicted, and a normal temperature shape that can compensate for the shape after thermal expansion corresponding to the temperature distribution is set. That is, a smaller outer diameter D ₁ at the upper end 3 of the skirt portion 2 of the valve lifter 1 at room temperature, the outer diameter D ₂ greater in the lower part 4 of the skirt portion 2 of the valve lifter 1 (D ₁ <D _2), almost frustoconical When formed in a (tapered shape), D ₁ ′ = D ₂ ′ due to thermal expansion due to a temperature difference during engine operation. FIG. 3 is a graph showing the relationship between the friction loss torque and the friction loss power in the engine valve mechanism. In the graph of FIG. 3, assuming that the calorific value of the cam face surface 6a and the top wall 1a of the valve lifter 1 is equal to the frictional loss power, the calorific value does not substantially depend on the operating condition due to the rotation speed fluctuation. Therefore, a substantially constant straight shape is maintained during operation by the taper amount set at normal temperature.

FIG. 4 shows a process diagram relating to the taper processing of the skirt portion 2 of the valve lifter 1 according to the present embodiment, and FIG. 5 shows a finish grinder for tapering the skirt portion 2.
As shown in FIG. 4, the workpiece 50 that has been subjected to lace (lathe) processing, heat treatment, intermediate grinding and nitriding is automatically conveyed to the first automatic outer diameter measuring device 25 by the feeder 20 shown in FIG. Laser displacement meter 2 of first outer diameter automatic measuring device 25
By 5a, to measure the outer diameter D ₂ of the skirt portion 2 of the lower end 4 of the workpiece 50. The measured outer diameter data is stored in a control unit (CPU) composed of a computer.
To the control unit 40 in the measurement order.
Is taken as data in a memory (RAM). The control unit 40 discriminates the data received from the laser displacement meter 25 a for each preset size range, and outputs a selection signal to the selection device 26. Therefore, the valve lifters 1 in the same dimension range are transported to the corresponding sorting pallet 27,
Sorting is performed for each dimension range. The position of the sorting pallet 27 is changed at any time with respect to the sorting number.
The control unit 40 takes in the position detection data output from the servomotor 28 for driving the control unit 7, and gives a selection signal to the selection device 26, and the selection device 26 transports the data from the first outside diameter automatic measurement device 25. The selected valve lifter 1 is sorted into a predetermined sorting pallet 27 and distributed. When the discharge of all the works 50 contained in the specific sorting pallet 27 out of the plurality of sorting pallets 27 is completed, the sorting pallet 2 is
7, the next sorting pallet 27 is moved to a position corresponding to the sending device 22. In the present specification, a detailed description of the movement control of the sorting pallet will be omitted.

The delivery device 22 introduces the work 50 from the sorting pallet 27 to the entrance 23a of the transport rail 23, and finishes the grinding using the grinding wheel 12 and the adjusting wheel 13.
The transfer rail 23 is disposed between the grinding wheel 12 and the adjusting wheel 13, and as shown in FIG.
3 along. The grinding wheel 12 includes a pair of bearings 14.
Is rotatably arranged around a shaft 12a supported by the servo motor 31 controlled by the output of the control unit 40. Bearing 14 and servo motor 3
1 is supported by a vertically movable frame 18, and the frame 18 is vertically moved by a stepping motor 29. The vertical position of the frame 18 and the grinding wheel 12 can be finely adjusted by a stepping motor 29. The adjusting wheel 13 is rotatably arranged by a servomotor 30 around a shaft 13 a supported by a pair of bearings 15. The servo motor 30 includes an inverter (not shown) that converts a DC signal sent from the control unit 40 into an AC signal and controls the rotation speed of the adjusting vehicle 13. Therefore, the adjusting wheel 13 guides the movement of the workpiece 50 along the transport rail 23 and controls the transport speed of the workpiece 50.

The shaft 12a of the grinding wheel 12 and the adjusting wheel 1
3 is set in parallel with the shaft 13a, and the grinding wheels 1 attached to the shafts 12a and 13a, respectively.
2b and the adjustment wheel 13 are installed in parallel with the guide surface 13b.
Therefore, when the grinding wheel 12 is pressed against the work 50 with a small pressing force and ground, the processing surface of the skirt portion 2 of the work 50 becomes substantially straight, but the pressing force of the grinding wheel 12 against the skirt portion 2 of the work 50 increases. Then, a slight elastic deformation occurs in the skirt portion 2 of the valve lifter 1.
Since the rigidity decreases toward the lower end 4 of the skirt portion 2 during the elastic deformation, the amount of elastic deformation of the skirt portion 2 gradually increases toward the lower end 4, and as shown in FIG. Is smaller than the outer diameter of the upper end 3, and the skirt portion 2 is deformed into an inversely tapered shape. Therefore, the closer to the lower end 4, the greater the amount of elastic deformation, the lower the pressing force of the grinding wheel 12, the less the grinding allowance, and the side surface of the skirt 2 of the work 50 is tapered. Thus, the work 50
Is deformed into an inversely tapered shape, the skirt portion 2 of the work 50 is subjected to a pressing force F _{1 in the} radial direction by the grinding wheel 12 and a transfer force F ₂ toward the completed pallet 24 provided at the end of the transfer rail 23. Is applied. The work 50 moving on the transport rail 23 is processed by the large-diameter grinding wheel 12 with the pressing force F ₁ while being guided by the adjusting wheel 13, and given the propulsive force with the transport force F ₂ to complete the pallet 2.
Move toward 4.

After the grinding, the pressing force of the grinding wheel 12 is released from the work 50, and the deformation of the skirt portion 2 is restored to its original shape by its own elastic force, so that the skirt portion 2 having a substantially tapered shape is obtained. . Measurement data of the outer diameter of the skirt portion 2 before processing and deformation mode data of the skirt portion 2 based on the material, thickness, and shape of the workpiece 50 are input to the control unit 40, and the control unit 40 performs arithmetic processing, and performs a grinding process. 12 and the rotation speed of the adjusting wheel 13 are determined. The pressing force F ₁ of the grinding wheel 12 is driven by a stepping motor 29 and is controlled by a control signal from a control unit 40 that determines the pressing force of the grinding wheel 12. The variable rotation control of the adjusting wheel 13 and / or the grinding wheel 12 is performed by the control signal of the control unit 40 and the servo motors 30 and 31, and the optimum taper amount is set. As described above, by adjusting the pressing force F ₁ of the grinding wheel 12 and the rotation speed of the adjusting wheel 13, the conveyance speed of the work 50 can be controlled, and the optimum taper amount of the skirt portion 2 can be set.

Further, since the taper setting conditions are delicately changed by the amount of wear of the grinding wheel 12, the outer diameter of the finished product is measured by the laser displacement meter 32a in the second automatic outer diameter measuring device 32 of the valve lifter 1. The measured grinding value is taken into the control unit 40. The control unit 40
From the measured data, the movement amount of the grinding wheel 12 and the grinding wheel 12
Alternatively, the rotational speed of the adjusting wheel 13 is corrected. The control unit 40 calculates the shape change count, drives the stepping motor 29 from the control unit 40 with the corrected movement amount signal to move the grinding wheel 12, and also uses the corrected rotation speed signal to control the servo motor from the control unit 40. The grinding wheels 12 and / or the adjusting wheels 31 are rotated by driving the wheels 30 and 31. As described above, the control unit 40 performs the feedback control of the pressing force of the grinding wheel 12 and the rotation speed of the adjustment wheel 13 or the grinding wheel 12, thereby always processing the workpiece 50 to have an outer diameter shape within a certain range. It becomes possible. After the final measurement, it is stored in the completed pallet 24 and the grinding and finishing process is completed. As described above, in this embodiment, the existing equipment is used without significant modification, and the movement amount of the grinding wheel 12 and the adjustment wheel 13 or the grinding wheel 12 are measured based on the measurement data of the outer diameter of the skirt portion 2 before the grinding finish processing. By adjusting the rotation speed of the workpiece 50, the transfer speed of the work 50 can be controlled, the skirt 2 of the valve lifter 1 can be elastically deformed, and the skirt 2 of the work 50 can be processed into a tapered shape.

In this embodiment, the following operation and effect can be obtained. 1 At the time of normal temperature, the skirt portion 2 of the valve lifter 1 is formed in a truncated conical shape in which the upper end 3 side of the skirt portion 2 of the valve lifter 1 has a small diameter and the lower end 4 side of the skirt portion 2 has a large diameter. Compensate for thermal expansion due to distribution,
The shape of the opening 5a of the lifter boss 5 can be adapted. (2) Abnormal local contact with the lifter boss 5 and abnormal wear between the sliding surfaces due to a difference in thermal expansion displacement due to a temperature difference between the upper end 3 and the lower end 4 during operation, and a significant improvement in durability can be achieved. (3) By reducing the clearance at the lower end 4 of the skirt portion 2 of the valve lifter 1, it is possible to reduce the impact sound of the lower end 4 against the lifter boss 5 due to the swing operation of the valve lifter 1. 4 Based on the measurement and selection of the outer diameter of the skirt portion 2 of the valve lifter 1 and the measurement data of the skirt portion 2, the grinding wheel 12
The computer movement and rotation of the adjusting wheel 13 are controlled by computer.
The skirt portion 2 of the valve lifter 1 can be tapered with elastic deformation. 5. The amount of movement of the grinding wheel 12 can be determined without significantly modifying existing equipment, and continuous feeding of the work 50 and tapering can be achieved. 6. A highly accurate tapered shape of the skirt portion 2 of the valve lifter 1 can be formed by continuous processing without reducing productivity. The embodiment of the present invention is not limited to the above example, and can be changed. For example, the shim 16 may be fixed to the upper part of the valve lifter 1 and contact the shim 16 with the top wall 1a formed by the surface of the shim 16. Shim 16 is the valve lifter 1
Can be crimped or fixed by welding.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An iron-based metal valve lifter 1 in contact with a cam 6 has an outer diameter of 26 mm and a coefficient of linear expansion of 12.3 × 10
^-6 , the outer diameter at the upper part of the skirt portion 2 is D ₁ , and the outer diameter at the lower part is D _2, and D ₂ −D ₁ when the valve lifter 1 is completed.
= [Delta] d is, the temperature of the upper portion of the skirt portion 2 t _1, when the temperature of the lower and t _2, the temperature difference _{t 1 -t 2 Δt = 10 ℃} , 2
Δd = 3 μm, 6 μm, 9 μm at 0 ° C. and 30 ° C., respectively
It is.

[0015]

As described above, according to the present invention, abnormal wear due to thermal deformation of a valve lifter integrally formed of the same metal material can be prevented and swinging movement during operation can be suppressed. Can be greatly improved. Further, continuous production of valve lifters can be performed without reducing production capacity using conventional equipment.

[Brief description of the drawings]

FIG. 1 is a sectional view of a valve operating mechanism using a valve lifter according to an embodiment of the present invention.

FIG. 2 is a front view of the valve lifter shown in FIG. 1;

FIG. 3 is a graph showing a relationship among an engine speed, friction torque, and friction loss power.

FIG. 4 is a process diagram according to an embodiment of the present invention.

FIG. 5 is a plan view of a finish grinding machine.

FIG. 6 is a sectional view of a grinding device of a finish grinding machine.

FIG. 7 is a partially enlarged view of a grinding device to which a workpiece is supplied.

FIG. 8 is a sectional view showing another embodiment of the present invention in which a shim is fixed to an upper portion of a valve lifter.

FIG. 9 is a sectional view of a conventional valve lifter.

[Explanation of symbols]

1. Valve lifter, 1a top wall, 2. Skirt part, 3. Upper end, 4 Lower end, 5. Lifter boss, 6. Cam, 6a Cam face face, 8.
・ Retainer, 9 ・ ・ Cotter, 10 ・ ・ Valve spring, 11 ・ ・ Valve, 12 ・ ・ Cutting wheel, 13
..Adjustment vehicle, 25, 32..Automatic outer diameter measuring device, 2
0 ·· feeder, 23 ·· conveyor rail, 26 ·· sorting device, 27 ·· sorting pallet, 29 ··· stepping motor, 30, 31 ·· servo motor, 40 ·
・ Control unit, 50 ・ ・ Work,

Claims (11)

[Claims] A top wall contacting the cam and a substantially cylindrical skirt extending substantially perpendicularly from the top wall and surrounding the end of the valve, the top wall being pressed against the cam by a valve spring. In a valve lifter for an internal combustion engine, the outer diameter of the top wall of the skirt is smaller than the outer diameter of the lower end of the skirt at room temperature, and the skirt is formed into a truncated conical shape. Wherein the outer diameter of the top wall of the skirt portion and the lower end thereof become substantially equal when thermal expansion occurs due to a temperature gradient along the internal combustion engine. 2. The valve lifter for an internal combustion engine according to claim 1, wherein the cam contacts a shim fixed to the top wall. 3. Measuring the outer diameter of the skirt of the cup-shaped workpiece having a top wall and a substantially cylindrical skirt extending substantially perpendicularly from the top wall and surrounding the end of the valve; Sending the outer diameter data to the control unit, calculating the pressing force of the grinding wheel against the skirt of the work and the rotation speed of the grinding wheel or the adjusting wheel in the control unit, adjusting the grinding wheel of the grinding device A step of supplying a work to a car, and a step of applying a signal to the stepping motor from the control unit to press the grinding wheel against the skirt portion of the work with a calculated pressing force, and to control the grinding wheel or the adjusting wheel from the control unit. Applying a signal to the motor that rotates to rotate the grinding wheel or adjustment wheel at the calculated rotation speed,
An internal combustion process comprising: a step of forming the skirt portion into a frustoconical shape by making the outer diameter of the top wall side of the skirt portion smaller than the outer diameter of the lower end side at room temperature; and removing the work from the grinding device. A method of manufacturing an engine valve lifter. 4. The method for manufacturing a valve lifter for an internal combustion engine according to claim 3, further comprising a step of measuring an outer diameter of a skirt portion of the work before processing and selecting the work for each range of the outer diameter. 5. The method for manufacturing a valve lifter for an internal combustion engine according to claim 3, further comprising the step of automatically moving the work to the outlet of the grinding device while grinding the work between the grinding wheel and the adjusting wheel. 6. A process for measuring the outer diameter of the skirt portion of the work after the completion of the processing of the work, a process of sending measurement data of the outer diameter of the skirt portion to the control unit, A step of correcting the rotational speed of the grinding wheel or the adjusting wheel in the control unit, and moving the grinding wheel by driving the stepping motor from the control unit with the corrected movement amount signal,
4. The method for manufacturing a bubble lifter for an internal combustion engine according to claim 3, further comprising: driving a motor from a control unit with the corrected rotation speed signal to rotate a grinding wheel or an adjustment wheel. 7. A substantially cylindrical body including a grinding device having a grinding wheel and an adjustment wheel disposed opposite the grinding wheel, extending substantially perpendicularly from the top wall and surrounding the end of the valve. In a valve lifter automatic grinding machine for an internal combustion engine that grinds the skirt portion of a work by supplying a cup-shaped work having a skirt portion between a grinding wheel and an adjustment wheel, the outer diameter of the skirt portion of the work is measured. An external diameter automatic measuring device, a sending device for supplying a work from the external diameter automatic measuring device to the grinding device, a pressing force of the grinding wheel against the skirt portion of the work by receiving an output of the external diameter automatic measuring device and a grinding wheel or A control unit that calculates the rotational speed of the adjusting wheel; a stepping motor that presses the grinding wheel against the skirt of the work with the pressing force set by the control unit; And a motor that rotates the grinding wheel or adjustment wheel according to the rotation speed set by the tool unit, and adjusts the pressing force of the grinding wheel by the stepping motor and the rotation speed of the motor to process the workpiece into a frusto-conical shape. Automatic grinding machine for valve lifters for internal combustion engines. 8. The automatic grinding machine for a valve lifter for an internal combustion engine according to claim 7, further comprising a sorting device that measures an outer diameter of a skirt portion of the work before processing and sorts the work for each range of the outer diameter. . 9. The automatic valve lifter grinding machine for an internal combustion engine according to claim 7, further comprising a transfer rail for guiding a work between the grinding wheel and the adjusting wheel. 10. An apparatus for automatically measuring an outer diameter of a skirt portion of a work after completion of processing of the work, wherein the automatic outer diameter measuring device sends measurement data of the measured outer diameter of the skirt portion to a control unit. Then, the control unit corrects the moving amount of the grinding wheel and the rotation speed of the grinding wheel or the adjustment wheel from the measurement data, and drives the stepping motor from the control unit with the corrected moving amount signal to move the grinding wheel,
8. The grinding wheel or the adjustment wheel is driven by driving a motor from the control unit with the corrected rotation speed signal.
An automatic bubble lifter grinding machine for an internal combustion engine according to claim 1. 11. The sorting device according to claim 8, wherein the sorting device includes a plurality of sorting pallets for classifying the work according to the size of the outer diameter of the skirt portion of the work, and a servomotor for moving the sorting pallet with respect to the sending device. An automatic grinding machine for a valve lifter for an internal combustion engine according to the above.