JP2973666B2 - Belt-type continuously variable transmission for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt type continuously variable transmission for a vehicle in which a power transmission belt having a metal belt block connected thereto is wound around a metal variable pulley having a variable effective diameter. It is.

[0002]

2. Description of the Related Art In a vehicle belt-type continuously variable transmission in which a transmission belt in which a metal belt block is connected is wound around a metal variable pulley having a variable effective diameter,
There is a demand for prevention of slippage between the transmission belt and the variable pulley, improvement in transmission efficiency, improvement in durability of friction surfaces, and the like.

On the other hand, after a friction surface between a belt block and a variable pulley constituting a transmission belt is formed on a surface having irregularities of 20 μm or more by shot blasting, the flat area ratio of the tip of a convex portion on the surface is reduced. 20-50
%, There has been proposed a technique for reducing the amount of wear and maintaining a high coefficient of friction by polishing the material to a value of%. For example, this is described in the specification of Japanese Patent Application No. 3-185686 previously filed by the present applicant.

[0004]

However, in such a conventional belt-type continuously variable transmission, residual compressive stress is formed on the surface layer of the treated surface by shot blasting when forming irregularities having a surface roughness of 20 μmRz or more. Although the rolling fatigue strength is increased, the rolling fatigue strength is insufficient if the friction surface between the belt block and the variable pulley is set to a high surface pressure with the recent increase in engine output and torque. As a result, the wear of the friction surface becomes large, and the durability of the belt-type continuously variable transmission may not be sufficiently obtained. Further, the friction coefficient becomes unstable and decreases with the elapse of time due to the above-mentioned wear, so that the transmission belt may slip.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vehicle belt in which the friction between the belt block and the variable pulley has a small amount of wear and a high friction coefficient. An object of the present invention is to provide a continuously variable transmission.

[0006]

According to a first aspect of the present invention, there is provided a transmission belt in which a metal belt block is connected to a metal variable block having a variable effective diameter. In a belt type continuously variable transmission for a vehicle wound around a pulley, a side surface of the belt block that contacts a variable pulley and a friction surface that contacts the belt block of the variable pulley are subjected to shot blast processing.
3 to 10 μm after shot peening
Rz has a surface roughness.

[0007]

[Second means for solving the problem] Achieve such purpose
The gist of the second invention for achieving this is that a metal base is used.
The transmission belt linked with the tilt block has a variable effective diameter.
Vehicle bell wound around a variable metal pulley
In the continuously variable transmission, the belt block's variable
And the variable pulley belt
The friction surface that contacts the lock is shot blasted.
At the same time, 3-10μ using shot peening
mRz surface roughness.

[0008]

[Effects of the first invention and the second invention] As described above,
The side of the belt block that contacts the variable pulley,
The friction surface that contacts the belt block of the variable pulley
After shot blasting or shot blasting
At the same time as shot peening.
Since the surface roughness of the belt block and the variable pulley is reduced to less than 10 μm Rz, the wear of the belt block and the variable pulley on the mutual friction surface is reduced. The friction coefficient on the mutual friction surface is increased, so that the allowable transmission torque is increased, the slip of the transmission belt is prevented at the time of a sudden increase in the torque, or the belt type continuously variable transmission for vehicles is configured to be smaller than before. obtain.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to FIGS.

FIG. 1 is a perspective view showing an essential part of a belt type continuously variable transmission 8 for a vehicle. In the figure, for example, a transmission belt 30 is wound around a variable pulley 10 connected to an engine (not shown) via a clutch or the like and a variable pulley 20 connected to driving wheels via a transmission and a differential gear device (not shown). The output of the engine is transmitted to the drive wheels via a belt-type continuously variable transmission 8. The variable pulleys 10 and 20
Fixed rotating bodies 12 and 22 made of steel fixed to an input shaft and an output shaft (not shown), and movable movable body 1 made of steel movable axially with respect to the input shaft and the output shaft.
4 and 24, and the movable rotators 14 and 24 are axially driven by a hydraulic cylinder (not shown) to change the effective diameter of the variable pulleys 10 and 20, that is, the hanging diameter of the transmission belt 30. Thus, the gear ratio can be changed.

As shown in detail in FIGS. 2 and 3, the transmission belt 30 is provided with a projection 34 and is a steel belt block 35 which is longitudinally connected to each other in a state of being overlapped with each other.
And two endless annular hoops 36 positioned in the notches 35a of the belt block 35 to support the transmission blocks 35.

Fixed rotating bodies 12, 22 and movable rotating body 1
4, 24 conical surfaces, ie variable pulleys 10 and 20
The friction surface 28 forming the inner wall surface of the V groove and the side surface 38 of the belt block 35 are brought into contact with each other, and power is transmitted by the frictional force between the friction surface 28 and the side surface 38. Therefore, it is required that the friction surface 28 and the side surface 38 maintain a high friction coefficient so that the belt-type continuously variable transmission 8 can obtain a higher allowable torque capacity. In addition, the side surface 38 of the belt block 35 and the variable pulley 1 are arranged so that the durability of the belt type continuously variable transmission 8 is further enhanced.
It is required that the wear amount at the 0 and 20 friction surfaces 28 be further reduced.

For this reason, the variable pulleys 10 and 20
And the side surface 38 of the belt block 35
By using the shot peening treatment, as shown in FIG. 4, irregularities having a surface roughness of 3 to 10 μm Rz are provided. In the present embodiment, as shown in the data described below, one of the technical features is to use a shot peening process when forming irregularities on the surfaces of the friction surface 28 and the side surface 38.

The variable pulleys 10 and 20 are usually
Carburizing, quenching and tempering about M415 material and Hv8
The hardness of the belt block 3
5 is usually made of a material of about SUJ2 and tempered in quenching oil to a hardness of about Hv720, and has a high hardness. Therefore, irregularities of about 3 to 10 μmRz are formed by ordinary shot peening or strong shot peening. Can not do it. For this reason, for example, shot blast processing shown in the following processing conditions is performed to
By forming irregularities of about μmRz and then performing, for example, a shot peening process under the following processing conditions, the friction surface 28 and the side surface 38 have a thickness of 3 to 10 μmRz.
Of the surface roughness is given.

Shot blasting conditions Injection method: Direct pressure air type Injection pressure: 5-6 kg / cm ² Injection distance: 15 cm Injection time: 90 seconds Injection material: Polygonal steel grid Injection material hardness: Hv790-950 Injection material dimensions : (1) 0.177 to 0.710mm (JIS S-G50) ・ ・ ・ 5 to 12μm (blast surface roughness) (2) 1.00 to 1.68mm (JIS S-G140) ・ ・ ・ 12 to 20μm (blast surface Roughness)

Shot peening treatment conditions Injection method: direct pressure air type Injection pressure: 5 kg / cm ² Injection time: 90 seconds Injection material: Steel shot BPC-050 (particle size 0.3)
(50 ~ 0.177mm) Injection material hardness: Hv700 ~ 900

Further, as another processing method described above, an injection material used for shot blasting and an injection material used for shot peening are mixed and used, for example, shot blast peening mixed processing shown in the following mixed injection processing conditions. Is performed, the friction surface 28 and the side surface 38
The surface roughness of 3 to 10 μm Rz can be imparted to the surface .

Shot blast peening mixing condition Injection method: Direct pressure air type Injection pressure: 5-6 kg / cm ² Injection time: 90 seconds Injection distance: 15 cm Injection material: A: Polygonal steel grid JIS S-G100 Hv790-950 1.19 to 0.420mm B: Spherical steel shot BPC-050 Hv700 to 900 0.3
50-0.177mm φ injection material mixing ratio: A: B = 2-3: 8-7

The friction surfaces 28 of the variable pulleys 10 and 20 and the side surfaces 38 of the belt block 35 provided with the surface roughness of 3 to 10 μm Rz by the above shot blasting and shot peening are subjected to only the shot blasting. Compared to the case shown in FIG. 5, the sharpened convex portion in the shot blasting process has a smooth rounded convex shape due to plastic deformation. For this reason, the stress (surface pressure) of the convex portion on the friction surface 28 and the side surface 38 is reduced, and the initial wear during the running-in operation at the beginning of sliding is suppressed. Further, since the friction surface 28 and the side surface 38 are given residual compressive stress by the shot peening process, the rolling fatigue strength (pitting resistance) is improved and the rolling fatigue wear is reduced.

FIG. 6 shows the measurement results of the residual stress value on the friction surface 28 when the shot peening process is performed after the shot blasting process, as indicated by the circles. Also, FIG.
The measurement results of the hardness of the friction surface 28 and the side surface 38 when the shot peening process is performed after the shot blast process are indicated by circles. As is clear from FIG. 6, a residual stress of 8 to 9 times is applied near the surface as compared with the inside of the base material. Also, as is clear from FIG.
In the vicinity of the surface, the hardness is substantially higher than the inside of the base material by about Hv130. 6 and 7 indicate that a flat portion has a thickness of 20 to 50 on the surface after the shot blasting process as described in the specification of Japanese Patent Application No. 3-185686.
% Is shown. Compared to this conventional example,
In the case of this embodiment, the applied residual stress and hardness are significantly large.

Next, the shot blast processing is performed as described above.
And the variable pulleys 10, 20 and the belt blocks 35 irregularities are imparted with a shot peening treatment, the conditions of the durability test was conducted by combining using those respective surface roughness is shown below, the test results The results are shown in Tables 1 and 2.

Endurance test conditions for belt type continuously variable transmission 8 Input shaft rotation speed: 3500 rpm Transmission ratio: 2 Output torque: 16 kgf · m Operating time: 150 hours Variable pulley: Shot blasting after carburizing and quenching JIS SCM415 And a surface having irregularities in the range of 1.2 to 12.4 [mu] m Rz formed by a shot peening treatment Belt block: quenched in JIS SUJ2 in a quenching oil, and then subjected to a shot blasting treatment and a shot peening treatment. .2 to 12.4 μmRz with irregularities formed on the side surface 38

[0023]

[Table 1]

[Table 2]

FIGS. 8 to 27 are graphs showing the results of Tables 1 and 2 collectively in terms of the relationship between the surface roughness and the amount of wear in various combinations of belt blocks and variable pulleys. The following is clear from the results shown in FIGS. First, the variable pulleys 10, 20
In the region where the surface roughness of the friction surface 28 and the side surface 38 of the belt block 35 is smaller than 10 μmRz, that is, FIG.
In regions I, II, IV and V shown in FIG. 8, the wear is slight. However, in the regions I, II, and IV, one of the surfaces has a small surface roughness, so that an oil film is easily formed, and the friction coefficient decreases rapidly when the convex portion is worn. A region where the surface roughness of at least one of the friction surface 28 of the variable pulleys 10 and 20 and the side surface 38 of the belt block 35 is greater than 10 μmRz;
That is, regions III, VI, VII, VIII, IX shown in FIG.
In, the amount of wear increases, and accordingly, the decrease in the coefficient of friction also increases. Further, in a region IX in which the surface roughness of both the friction surfaces 28 of the variable pulleys 10 and 20 and the side surface 38 of the belt block 35 is greater than 10 μmRz, the wear rapidly increases and the rate of decrease in the friction coefficient increases.
Thereby, the wear amount can be evaluated for each region as shown in FIG. 29, and the friction coefficient after the durability test can be evaluated for each region as shown in FIG.

On the other hand, in a region V where the surface roughness of the friction surfaces 28 of the variable pulleys 10 and 20 and the side surface 38 of the belt block 35 is larger than 3 μmRz and smaller than 10 μmRz, the wear amount is small and the friction coefficient is high. In addition, the decrease in friction coefficient with time is small and good. Therefore, the belt-type continuously variable transmission 8 of the present embodiment satisfying the condition of the region V has a small amount of wear on the mutual friction surface between the belt block 35 and the variable pulleys 10 and 20, thereby improving durability. Belt block 35
And the coefficient of friction on the mutual friction surfaces of the variable pulleys 10 and 20 is increased, so that the allowable transmission torque is increased, and the transmission belt 30 is prevented from slipping when the torque increases rapidly. It can be configured smaller than before.

The reason why the belt-type continuously variable transmission 8 of the present embodiment having the condition of the region V can obtain the above-described advantageous effects is considered to be as follows. That is, the friction surface 28 of the variable pulleys 10 and 20 and the belt block 35
As shown in FIG. 6, a large residual compressive stress is applied to the side surface 38 by the shot peening treatment, so that the rolling fatigue life is improved, and accordingly, the amount of wear after the durability test is reduced. The surface shape of the initial high coefficient of friction is maintained even at the end of the test. Further, the frictional surface 28 of the variable pulleys 10 and 20 and the side surface 38 of the belt block 35 promote secondary wear due to the frictional abrasion powder. Is less generated and secondary wear is suitably reduced.

FIG. 31 shows variable pulleys 10, 20 using shot blasting and shot peening.
When the surface roughness of the friction surface 28 and the side surface 38 of the belt block 35 is set to be larger than 3 μmRz and smaller than 10 μmRz, that is, the value of the allowable transmission torque of the belt-type continuously variable transmission 8 of this embodiment is determined by, for example, Hei 3-18
FIG. 6 is a graph shown in comparison with the conventional one described in the specification of US Pat. No. 5,686. This allowable transmission torque means that the transmission belt 30 and the variable pulley 10
This is the limit torque at which slippage occurs between the motor and the motor.
As is clear from FIG. 31, the allowable transmission torque value of the belt-type continuously variable transmission 8 of this embodiment is 2 kgf ·
m higher. Since the wear resistance of the friction surfaces 28 of the variable pulleys 10 and 20 and the surface of the side surface 38 of the belt block 35 is improved, the surface pressure can be increased, and as a result, the allowable transmission torque can be increased.

As described above, the belt-type continuously variable transmission 8 of the present embodiment can obtain a high allowable transmission torque, so that the following effects can be obtained. That is, the variable pulley 10,
Since the required driving torque can be transmitted even if the clamping pressure on the transmission belt 30 at 20 is reduced, the transmission efficiency is improved and the durability of the transmission belt 30 is increased. Also,
As described above, the pinching pressure on the power transmission belt 30 can be reduced, so that it is possible to increase the thickness of the belt block 35, so that the weight of the belt block 35 and the power transmission belt 30 can be reduced. Thus, the durability of the hoop 36 is improved. Further, the transmission belt 30
, The noise generated from the transmission belt 30 is further reduced.

Further, the surfaces of the friction surfaces 28 of the variable pulleys 10 and 20 and the side surfaces 38 of the belt block 35 of this embodiment are subjected to a shot blasting process or a shot blasting process.
It is only necessary to perform a process of making the surface roughness larger than 3 μmRz and smaller than 10 μmRz by using the shot peening process simultaneously with the blasting process, and there is an advantage that a polishing process for forming a flat surface after the blasting process is not required.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a main part of a belt-type continuously variable transmission according to one embodiment of the present invention.

FIG. 2 is a perspective view showing the transmission belt of FIG. 1 in detail.

FIG. 3 is a perspective view showing the belt block of FIG. 3 in detail.

4 is an enlarged sectional view showing an example of a surface state formed by using at least shot peening on the friction surface of the variable pulley and the side surface of the belt block in the embodiment of FIG. 1;

FIG. 5 is a diagram corresponding to FIG. 4, showing a surface state formed using only the shot blasting process.

6 is a graph showing the relationship between the hardness on the friction surface and the depth from the surface of the variable pulley of the embodiment of FIG. 1 in comparison with the conventional case.

7 is a graph showing the relationship between the hardness on the friction surface of the variable pulley of the embodiment of FIG. 1 and the side surface of the belt block and the depth from the surface in comparison with the conventional case.

FIG. 8 shows a surface roughness of the side surface of the belt block of 2.5 μm.
9 is a graph showing the relationship between the amount of wear of the belt block and the surface roughness of the friction surface of the variable pulley when Rz.

FIG. 9 shows a surface roughness of 3.2 μm on the side surface of the belt block.
9 is a graph showing the relationship between the amount of wear of the belt block and the surface roughness of the friction surface of the variable pulley when Rz.

FIG. 10 shows a surface roughness of the side surface of the belt block of 6.5 μm.
5 is a graph showing the relationship between the amount of wear of the belt block and the surface roughness of the friction surface of the variable pulley when mRz.

FIG. 11 shows a surface roughness of the side surface of the belt block of 9.6 μm.
5 is a graph showing the relationship between the amount of wear of the belt block and the surface roughness of the friction surface of the variable pulley when mRz.

FIG. 12 shows that the surface roughness of the side surface of the belt block is 10.6.
5 is a graph showing the relationship between the amount of wear of the belt block and the surface roughness of the friction surface of the variable pulley when μmRz.

FIG. 13 shows that the surface roughness of the friction surface of the variable pulley is 2.8 μm.
6 is a graph showing the relationship between the amount of wear of the variable pulley and the surface roughness of the side surface of the belt block when Rz.

FIG. 14 shows that the surface roughness of the friction surface of the variable pulley is 3.2 μm.
6 is a graph showing the relationship between the amount of wear of the variable pulley and the surface roughness of the side surface of the belt block when Rz.

FIG. 15 shows that the surface roughness of the friction surface of the variable pulley is 6.5 μm.
6 is a graph showing the relationship between the amount of wear of the variable pulley and the surface roughness of the side surface of the belt block when Rz.

FIG. 16 shows a surface roughness of the friction surface of the variable pulley of 9.6 μm.
6 is a graph showing the relationship between the amount of wear of the variable pulley and the surface roughness of the side surface of the belt block when Rz.

FIG. 17: The surface roughness of the friction surface of the variable pulley is 10.8 μ
5 is a graph showing the relationship between the amount of wear of the variable pulley and the surface roughness of the side surface of the belt block when mRz.

FIG. 18 shows a surface roughness of the side surface of the belt block of 2.5 μm.
5 is a graph showing a relationship between a friction coefficient after a durability test and a surface roughness of a friction surface of a variable pulley when mRz.

FIG. 19 shows a surface roughness of 3.2 μm on the side surface of the belt block.
5 is a graph showing a relationship between a friction coefficient after a durability test and a surface roughness of a friction surface of a variable pulley when mRz.

FIG. 20 shows that the surface roughness of the side surface of the belt block is 6.5 μ.
5 is a graph showing a relationship between a friction coefficient after a durability test and a surface roughness of a friction surface of a variable pulley when mRz.

FIG. 21 shows that the surface roughness of the side surface of the belt block is 9.6 μm.
5 is a graph showing a relationship between a friction coefficient after a durability test and a surface roughness of a friction surface of a variable pulley when mRz.

FIG. 22 shows that the side surface of the belt block has a surface roughness of 10.6.
4 is a graph showing a relationship between a friction coefficient after a durability test and a surface roughness of a friction surface of a variable pulley in a case of μmRz.

FIG. 23: The surface roughness of the friction surface of the variable pulley is 2.8 μm
4 is a graph showing the relationship between the friction coefficient after the durability test and the surface roughness of the side surface of the belt block when Rz.

FIG. 24: The surface roughness of the friction surface of the variable pulley is 3.2 μm
4 is a graph showing the relationship between the friction coefficient after the durability test and the surface roughness of the side surface of the belt block when Rz.

FIG. 25: The surface roughness of the friction surface of the variable pulley is 6.5 μm
4 is a graph showing the relationship between the friction coefficient after the durability test and the surface roughness of the side surface of the belt block when Rz.

FIG. 26: The surface roughness of the friction surface of the variable pulley is 9.6 μm
4 is a graph showing the relationship between the friction coefficient after the durability test and the surface roughness of the side surface of the belt block when Rz.

FIG. 27: The surface roughness of the friction surface of the variable pulley is 10.8 μ
4 is a graph showing a relationship between a friction coefficient after a durability test and a surface roughness of a side surface of a belt block when mRz.

FIG. 28 is a diagram illustrating a combination of a friction surface of a variable pulley and a surface roughness of a side surface of a belt block used in an endurance test for each region.

FIG. 29 is a diagram showing an evaluation of a wear amount for each region based on a durability test result.

FIG. 30 is a diagram showing the evaluation of the friction coefficient for each region based on the durability test result.

FIG. 31 is a diagram showing an allowable transmission torque of the belt-type continuously variable transmission of the embodiment of FIG. 1 in comparison with a conventional one.

[Explanation of symbols]

 10, 20 Variable pulley 28 Friction surface of variable pulley 30 Transmission belt 35 Belt block 38 Side surface of belt block

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-81537 (JP, A) JP-A-60-109661 (JP, A) JP-A-62-184270 (JP, A) JP-A-1- 92069 (JP, A) JP-A-2-138533 (JP, A) JP-A-2-163359 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F16H 9/00-9 / 26 F16G 5/16-5/18 F16H 55/32-55/56

Claims (2)

(57) [Claims] 1. A vehicle belt-type continuously variable transmission in which a transmission belt connected to a metal belt block is wound around a metal variable pulley having a variable effective diameter. The side that contacts the pulley,
A belt-type continuously variable transmission for a vehicle, wherein a friction surface of the variable pulley contacting the belt block has a surface roughness of 3 to 10 μmRz by performing shot blasting and then using shot peening. 2. A transmission having a metal belt block connected thereto.
The moving belt is wound around a variable metal pulley with a variable effective diameter.
In a belt-type continuously variable transmission for a vehicle, the side surface of which is in contact with the variable pulley of the belt block,
And friction of the variable pulley in contact with the belt block
The surface is shot blasted and shot
Surface roughness of 3 to 10 μmRz by using
A belt type continuously variable transmission for vehicles.