JP2009275798A - Automatic tensioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic tensioner can change a damping torque according to an engine operation state. <P>SOLUTION: The automatic tensioner 20 for keeping belt tension constant by a pulley 21 contacting with a belt 11 of a power transmission device 10 is provided with an arm 22 for supporting the pulley 21, a supporting part 23 for rotatably supporting the arm 22, a spring 25, provided between the arm 22 and the supporting part 23, for energizing the arm 22 to rotate in a predetermined rotation direction for the supporting part 23, a friction part 31 for generating a frictional force by sliding and contacting with a section 22B which relatively moves when the arm 22 rotates for the supporting part 23 and a frictional force variable means 32 for arranging the frictional force to be variable by changing a degree of contact of the frictional part 31 and the section 22B which relatively moves in accordance with the engine operation state. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an auto tensioner that keeps belt tension constant.

  2. Description of the Related Art Conventionally, an auto tensioner is widely known as a device that keeps a belt tension constant for driving an auxiliary machine such as an air conditioner or an alternator. The auto tensioner includes a housing fixed to the engine, an arm rotatable with respect to the housing, and a pulley provided at one end of the arm, and the pulley presses the belt by a reaction force of a coil spring provided in the housing. To keep the belt tension constant. In this auto tensioner, the pulley swings, but the swinging of the pulley is attenuated by generating a damping torque that suppresses the rotation of the arm.

Patent Document 1 discloses an auto tensioner configured to be able to adjust the frictional force between the housing and the arm in accordance with the amount of compression of the coil spring in the axial direction. In this auto tensioner, the damping torque can be changed by adjusting the frictional force.
JP 2008-32037 A

  However, since the auto tensioner described in Patent Document 1 is configured to adjust the amount of compression of the coil spring in the axial direction by the screw member, there is a problem that the damping torque cannot be changed according to the engine operating state.

  Therefore, the present invention has been made paying attention to such problems, and an object thereof is to provide an auto tensioner capable of changing a damping torque in accordance with an engine operating state.

  The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected, it is not limited to this.

The present invention relates to an arm (22) that supports a pulley (21) in an auto tensioner (20) that maintains a constant belt tension by a pulley (21) that abuts on a belt (11) of a power transmission device (10), and an arm The support portion (23) that rotatably supports (22), and the arm (22) is disposed between the support portion (23) and the arm (22) in a predetermined rotation direction with respect to the support portion (23). A spring (25) that urges to rotate, and a friction part (slidably contacting the part (22B) that moves relative to the arm (22) relative to the support part (23)) to generate a frictional force ( 31) and frictional force varying means (32) for varying the frictional force by changing the degree of contact between the frictional part (31) and the relatively moving part (22B) according to the engine operating state;
It is characterized by providing.

  According to the present invention, the swing of the pulley 21 of the auto tensioner 20 can be quickly and efficiently attenuated regardless of the engine operating state.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic configuration diagram of a power transmission device 10 of the engine 100.

  As shown in FIG. 1, the engine 100 includes a power transmission device 10 that drives various auxiliary machines of a vehicle using rotation of a crankshaft. The power transmission device 10 includes a belt 11, a crank pulley 12, an oil pump pulley 13, an alternator pulley 14, an air conditioner pulley 15, and an auto tensioner 20.

  The belt 11 is a so-called V-ribbed belt and is wound around the pulleys 12 to 15 of the power transmission device 10. In the power transmission device 10, the rotation of the crank pulley 12 is transmitted to the oil pump pulley 13, the alternator pulley 14, and the air conditioner pulley 15 by the belt 11.

  Crank pulley 12 is provided at the end of the crankshaft of engine 100. The crank pulley 12 is a drive pulley, and drives driven pulleys such as an oil pump pulley 13, an alternator pulley 14, and an air conditioner pulley 15.

  The oil pump pulley 13 is a pulley for driving the power steering oil pump.

  The alternator pulley 14 is a pulley for driving the alternator.

  The air conditioner pulley 15 is a pulley for driving the air conditioner compressor.

  The auto tensioner 20 is a device that keeps the belt tension of the belt 11 constant. The auto tensioner 20 includes a pulley 21 that presses the belt 11 by a reaction force of a coil spring. When the belt tension decreases, the pulley 21 moves in the P direction to increase the belt tension. On the other hand, when the belt tension of the belt 11 increases, the pulley 21 moves in the Q direction to reduce the belt tension.

  The configuration of the auto tensioner 20 will be described with reference to FIG. FIG. 2A is a schematic configuration diagram of the auto tensioner 20. FIG. 2B is a view showing a BB cross section of the auto tensioner 20 in FIG.

  The auto tensioner 20 includes a pulley 21, an arm 22, and a housing 23.

  A pulley 21 that presses the belt 11 is rotatably installed at a distal end portion 22 </ b> A of the arm 22.

  The arm 22 has a cylindrical portion 22 </ b> B, and the cylindrical portion 22 </ b> B is inserted into the housing 23. The arm 22 is fixed to the distal end portion 24 </ b> A of the shaft 24 so as to be rotatable with respect to the housing 23. The center of the cylindrical portion 22B of the arm 22 and the center of the shaft 24 are configured to coincide with each other.

  The housing 23 is fixed to the cylinder block of the engine 100. An insertion portion 23 </ b> B for inserting the shaft 24 is formed on the bottom surface 23 </ b> A of the housing 23. The shaft 24 is rotatably inserted into the insertion portion 23B, and the arm 22 is fixed to the distal end portion 24A.

  A coil spring 25 is interposed between the cylindrical portion 22B of the arm 22 and the housing 23 in a twisted state. One end portion 25 </ b> A of the coil spring 25 is fixed to the bottom surface of the housing 23, and the other end portion 25 </ b> B is fixed to the cylindrical portion 22 </ b> B of the arm 22. The auto tensioner 20 configured as described above uses the reaction force of the twisted coil spring 25 as the rotational force of the arm 22 and presses the pulley 21 against the belt 11 via the arm 22 to apply a predetermined belt tension.

  On the other hand, the auto tensioner 20 is provided with a damping torque generating mechanism 30 to attenuate the swing of the pulley 21.

  The damping torque generation mechanism 30 includes a friction part 31 and a solenoid 32.

  The friction part 31 is a resin member, and is formed in an annular shape having a notch part 31A in the circumferential direction as shown in FIG. The friction portion 31 is disposed such that the outer peripheral side surface 31B is in sliding contact with the inner peripheral surface 22C of the cylindrical portion 22B of the arm 22. Therefore, when the arm 22 rotates, a frictional force is generated between the friction portion 31 and the cylindrical portion 22B of the arm 22. This frictional force becomes a damping torque that suppresses the rotation of the arm 22 and attenuates the swing of the pulley 21.

  As shown in FIG. 2A, a pair of solenoids 32 is provided on the inner peripheral side of the friction part 31 and at the tip of the insertion part 23B. The solenoid 32 drives the plunger 32B inserted through the coil 32A by electromagnetic force. The pair of solenoids 32 are configured such that when a voltage is applied to the coil 32 </ b> A, the plunger 32 </ b> B presses the friction part 31 from the inside to increase the outer diameter of the friction part 31.

  In the auto tensioner 20 configured as described above, the voltage value applied to the solenoid 32 is controlled in accordance with the engine rotation speed, the driving amount of the plunger 32B is adjusted, and the damping torque is changed.

  FIG. 3 is a diagram showing the relationship between the engine speed and the damping torque.

  As shown in FIG. 3, the damping torque is set so as to increase as the engine speed decreases. This is because as the engine rotational speed decreases, the rotational speed fluctuation amount increases, the belt tension change amount also increases, and the pulley 21 of the auto tensioner 20 is likely to swing.

  Therefore, as the engine speed decreases, the voltage applied to the solenoid 32 is increased and the driving amount of the plunger 32B is increased. If it does so, the friction part 31 will be diameter-expanded, the contact degree of the friction part 31 and the cylindrical part 22B will become strong, and the frictional force which generate | occur | produces between the friction part 31 and the cylindrical part 22B will increase. This increases the damping torque, so that the swing of the pulley 21 can be quickly attenuated even at a low engine speed.

  As described above, in the auto tensioner 20 of the present embodiment, the following effects can be obtained.

  The auto tensioner 20 includes a friction portion 31 that is in sliding contact with the inner peripheral surface 22C of the cylindrical portion 22B of the arm 22 and a solenoid 32 that presses the friction portion 31 from the inside. In the auto tensioner 20, the voltage applied to the solenoid 32 is adjusted according to the engine rotation speed, and the degree of contact between the friction portion 31 and the cylindrical portion 22 </ b> B of the arm 22 is changed. Thereby, the frictional force generated between the friction part 31 and the cylindrical part 22B of the arm 22 can be changed, and the damping torque can be controlled. Therefore, the swing of the pulley 21 of the auto tensioner 20 can be quickly and efficiently attenuated regardless of the engine operating state.

(Second Embodiment)
FIG. 4 is a schematic configuration diagram of the auto tensioner 20 of the second embodiment.

  The basic configuration of the auto tensioner 20 of the second embodiment is substantially the same as that of the first embodiment, but differs in the arrangement position of the solenoid 32. That is, the solenoid 32 is arranged in the notch 31A of the friction part 31, and the difference will be mainly described below.

  FIG. 4A is a cross-sectional view of the auto tensioner 20 of the second embodiment at the same position as the BB position of FIG.

  As shown in FIG. 4A, a pair of solenoids 32 of the damping torque generation mechanism 30 are provided in the cutout portion 31 </ b> A of the friction portion 31. The pair of solenoids 32 is configured such that when a voltage is applied to the coil 32 </ b> A, the plunger 32 </ b> B presses the end surface 31 </ b> C of the friction part 31 to increase the outer diameter of the friction part 31.

  In the auto tensioner 20 of the second embodiment configured as described above, the voltage applied to the solenoid 32 is increased and the driving amount of the plunger 32B is increased as the engine speed decreases. Then, the notch 31A of the friction part 31 is pushed and widened, and the outer diameter of the friction part 31 is increased, so that the frictional force between the friction part 31 and the cylindrical part 22B of the arm 22 increases. As a result, the damping torque increases, so that the swing of the pulley 21 can be quickly attenuated even at a low engine speed, and the same effect as in the first embodiment can be obtained.

  In the friction portion 31, as shown in FIG. 4B, a second cutout portion 31D is provided on the opposite side of the cutout portion (first cutout portion) 31A, and a spring 33 is disposed in the second cutout portion 31D. You may do it. When the first cutout portion 31A of the friction portion 31 is pushed and expanded by the solenoid 32 in accordance with the decrease in the engine rotation speed, the spring 33 on the second cutout portion 31D side is compressed. Since the outer diameter of the friction portion 31 is increased by the drive of the plunger 32 </ b> B of the solenoid 32 and the reaction force of the spring 33, the friction force between the friction portion 31 and the cylindrical portion 22 </ b> B of the arm 22 increases. Even if the auto tensioner 20 is configured as shown in FIG. 4B, the damping torque can be changed according to the engine operating state.

(Third embodiment)
FIG. 5 is a schematic configuration diagram of the auto tensioner 20 of the third embodiment.

  The basic configuration of the auto tensioner 20 of the third embodiment is substantially the same as that of the first embodiment, but differs in how to generate a damping torque. That is, the friction part 31 is fixed to the shaft 24, and the damping torque is generated by reducing the diameter of the band 34 arranged around the friction part 31, and the difference will be mainly described below. .

  FIG. 5A is a cross-sectional view of the auto tensioner 20 of the third embodiment at the same position as the BB position of FIG.

  As shown in FIG. 5A, the friction part 31 is formed in a cylindrical shape, and is fixed to the shaft 24 so that the center of the friction part 31 and the center of the shaft 24 coincide. The friction part 31 is provided in a part of the shaft 24 in the axial direction. The friction portion 31 rotates integrally with the shaft 24.

  A band 34 is provided on the outer peripheral side of the friction portion 31. The band 34 is a metal member, and is wound around the friction part 31 so as to cover the outer peripheral surface of the friction part 31. The band 34 has a notch 34A in a part in the circumferential direction. The end portions 34B and 34C of the band 34 are formed so as to protrude radially outward from the notch portion 34A. One end portion 34 </ b> B of the band 34 is fixed by a fixing portion 35 formed to protrude from the bottom surface 23 </ b> A of the housing 23. A solenoid 32 is provided on the other end 34C side.

  The solenoid 32 is provided on the opposite side of the other end 34C from the side where the ends face each other. The solenoid 32 is configured such that when a voltage is applied to the coil 32A, the plunger 32B presses the end portion 34C of the band 34 to reduce the notch amount of the notch portion 34A.

  In the auto tensioner 20 of the third embodiment configured as described above, the voltage applied to the solenoid 32 is increased and the drive amount of the plunger 32B is increased as the engine speed decreases. Then, the cutout portion 34A of the band 34 is compressed and the inner diameter of the band 34 is reduced, so that the degree of contact between the band 34 and the friction portion 31 is increased, and is generated between the band 34 and the friction portion 31. The frictional force increases. When the frictional force increases in this way, the damping torque that suppresses the rotation of the shaft 24 and attenuates the swing of the pulley 21 also increases. Therefore, the swing of the pulley 21 can be quickly attenuated even at a low engine speed, and the same effect as in the first embodiment can be obtained.

  In the auto tensioner 20, as shown in FIG. 5B, the band 34 may be wound around the friction portion 31 so as to intersect at one point. In this case, the solenoid 32 is provided on the side of the end portion 34 </ b> C that is not fixed by the fixing portion 35. The solenoid 32 is configured such that when a voltage is applied to the coil 32 </ b> A, the plunger 32 </ b> B presses the end 34 </ b> C of the band 34 to reduce the inner diameter of the band 34. In the auto tensioner 20 configured as shown in FIG. 5B, when the voltage applied to the solenoid 32 is increased in accordance with the decrease in the engine rotation speed, the end portion 34C of the band 34 is pressed by the plunger 32B. Since the inner diameter of 34 is reduced, the frictional force between the band 34 and the friction portion 31 increases. When the frictional force increases in this way, the damping torque that suppresses the rotation of the shaft 24 and attenuates the swing of the pulley 21 also increases. Therefore, even if the auto tensioner 20 is configured as shown in FIG. 5B, the damping torque can be changed according to the engine operating state.

(Fourth embodiment)
FIG. 6 is a schematic configuration diagram of the auto tensioner 20 of the fourth embodiment.

  The basic configuration of the auto tensioner 20 of the fourth embodiment is substantially the same as that of the first embodiment, but differs in the way of generating the damping torque. That is, the friction part 31 is pressed against the inner end face 22D of the cylindrical part 22B of the arm 22 from the bottom face 23A side of the housing 23 to generate a damping torque, and the difference will be mainly described below.

  As shown in FIG. 6A, the friction part 31 is formed in a disk shape. The friction part 31 is inserted through the shaft 24. One end surface of the friction portion 31 is disposed so as to be in sliding contact with the inner end surface 22D of the cylindrical portion 22B of the arm 22. Therefore, when the arm 22 rotates, a frictional force is generated between the end surface of the friction portion 31 and the inner end surface 22D of the cylindrical portion 22B. This frictional force becomes a damping torque that suppresses the rotation of the arm 22 and attenuates the swing of the pulley 21.

  A pair of solenoids 32 are fixed to the bottom surface 23 </ b> A of the housing 23. The pair of solenoids 32 are configured such that when a voltage is applied to the coil 32A, the plunger 32B presses the friction portion 31 from the bottom surface 23A side of the housing 23 to the inner end surface 22D of the cylindrical portion 22B of the arm 22.

  In the auto tensioner 20 of the fourth embodiment configured as described above, the voltage applied to the solenoid 32 is increased as the engine speed decreases. Then, since the friction part 31 is pressed against the inner end face 22D of the cylindrical part 22B of the arm 22 by the plunger 32B, the degree of contact between the friction part 31 and the inner end face 22D of the cylindrical part 22B is increased, and the inner end face of the friction part 31 and the arm 22 is increased. The frictional force generated with 22D increases. As a result, the damping torque increases, so that the swing of the pulley 21 can be quickly attenuated even at a low engine speed, and the same effect as in the first embodiment can be obtained.

  In the auto tensioner 20, as shown in FIG. 4B, the disc-shaped friction part 31 is inserted into the insertion part 23B, and a pair of solenoids 32 are provided on the inner end face 22D of the cylindrical part 22B of the arm 22. May be. The friction part 31 is fixed to the tip of the plunger 32 </ b> B of the solenoid 32. In the auto tensioner 20 configured as shown in FIG. 4B, when the voltage applied to the solenoid 32 is increased in accordance with the decrease in the engine speed, the friction portion 31 is strongly pressed against the bottom surface 23A of the housing 23 by the plunger 32B. It is done. As a result, the frictional force between the friction part 31 and the bottom surface 23A of the housing 23 increases, so that the damping torque can be changed according to the engine operating state.

(Fifth embodiment)
FIG. 7 is a schematic configuration diagram of the auto tensioner 20 of the fifth embodiment.

  The basic configuration of the auto tensioner 20 of the fifth embodiment is substantially the same as that of the first embodiment, but differs in how to generate a damping torque. That is, the side surface of the cylindrical portion 22B of the arm 22 is sandwiched by the friction portion 31 so as to generate a damping torque, and the difference will be mainly described below.

  As shown in FIG. 7, a pair of friction portions 31 are provided so as to sandwich the side surface of the cylindrical portion 22 </ b> B of the arm 22.

  Of the pair of friction portions 31, the friction portion 31 disposed on the inner peripheral side of the cylindrical portion 22B is fixed to the inside of the first arm portion 36A of the bifurcated arm 36 formed so as to straddle the side surface of the cylindrical portion 22B. The The bifurcated arm 36 is supported by a support portion 37. The bifurcated arm 36 is arranged so as to be slidable in the vertical direction in the figure relative to the support portion 37. The tip of the plunger 32B of one solenoid 32 of the pair of solenoids 32 is fixed inside the second arm portion 36B of the bifurcated arm 36. Further, the friction part 31 arranged on the outer peripheral side of the cylindrical part 22B is fixed to the tip of the plunger 32B of the other solenoid 32.

  In the auto tensioner 20 of the fifth embodiment configured as described above, the applied voltage to the solenoid 32 is increased and the plunger 32B of the solenoid 32 is driven as the engine speed decreases. When one plunger 32B fixed to the second arm portion 36B is driven, the bifurcated arm 36 slides downward in the figure, so that the friction portion 31 provided on the first arm portion 36A is connected to the cylindrical portion 22B of the arm 22. The frictional force between the friction portion 31 and the inner peripheral surface 22C of the cylindrical portion 22B is increased by being pressed against the inner peripheral surface 22C. At this time, the other plunger 32B presses the friction portion 31 against the outer peripheral surface 22E of the cylindrical portion 22B of the arm 22, so that the frictional force between the friction portion 31 and the outer peripheral surface 22E of the cylindrical portion 22B increases. As a result, the damping torque increases, so that the swing of the pulley 21 can be quickly attenuated even at a low engine speed, and the same effect as in the first embodiment can be obtained.

  It should be noted that the present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

  For example, in the fifth embodiment, an example in which one damping torque generation mechanism 30 is provided is illustrated, but a plurality of damping torque generation mechanisms 30 may be provided along the circumferential direction of the cylindrical portion 22B of the arm 22.

  Moreover, in 1st Embodiment-5th Embodiment, although the friction part 31 and the band 34 were driven with the plunger 32B of the solenoid 32, it is not restricted to this. For example, a pair of electromagnets in which a coil is wound around an iron core may be provided, and the friction part 31 and the band 34 may be driven using the repulsive force of the mutual magnetic force.

It is a schematic block diagram of a power transmission device. It is a schematic block diagram of the auto tensioner of 1st Embodiment. It is a figure which shows the relationship between an engine speed and damping torque. It is a schematic block diagram of the auto tensioner of 2nd Embodiment. It is a schematic block diagram of the auto tensioner of 3rd Embodiment. It is a schematic block diagram of the auto tensioner of 4th Embodiment. It is a schematic block diagram of the auto tensioner of 5th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Engine 10 Power transmission device 20 Auto tensioner 30 Damping torque generation mechanism 11 Belt 21 Pulley 22 Arm 22A Tip part 22B Cylindrical part 22C Inner peripheral surface 22D Inner end surface 22E Outer peripheral surface 23 Housing (support part)
24 Shaft (Rotating shaft)
25 Coil spring 31 Friction part 31A Notch part, 1st notch part 31C End surface 31D 2nd notch part 32 Solenoid (friction force variable means)
33 Spring (elastic member)
34 Band 35 Fixing part 36 Forked arm 36A 1st arm part 36B 2nd arm part

Claims (9)

In the auto tensioner that keeps the belt tension constant by the pulley that contacts the belt of the power transmission device,
An arm that supports the pulley;
A support portion for rotatably supporting the arm;
A spring disposed between the arm and the support, and biasing the arm so that the arm rotates in a predetermined rotation direction with respect to the support;
When the arm rotates with respect to the support part, a friction part that slidably contacts a relatively moving part and generates a frictional force;
Friction force varying means for varying the friction force by changing the degree of contact between the friction part and the relatively moving part according to the engine operating state;
An auto tensioner comprising: The arm has a cylindrical part inserted into the support part,
The friction part is an annular shape having a notch in the circumferential direction, and is arranged so as to contact the cylindrical part from the inner peripheral surface side of the cylindrical part,
The frictional force varying means adjusts the outer diameter of the frictional part by pressing the side surface of the frictional part from the inner peripheral side according to the engine rotational speed, and adjusts the degree of contact between the frictional part and the cylindrical part. Configured to change,
The auto tensioner according to claim 1. The arm has a cylindrical part inserted into the support part,
The friction part is an annular shape having a first cutout part in the circumferential direction, and is arranged so as to contact the cylindrical part from the inner peripheral surface side of the cylindrical part,
The frictional force changing means adjusts the outer diameter of the frictional part by pressing the frictional part end surface of the first notch part of the frictional part from both sides according to the engine rotational speed, and the frictional part and the cylinder Configured to change the degree of contact with the part,
The auto tensioner according to claim 1. The friction portion is provided with a second cutout portion on the opposite side in the circumferential direction of the first cutout portion, and an elastic member is interposed in the second cutout portion.
The auto tensioner according to claim 3. A band wound around the outer peripheral surface of the friction part,
The friction portion is fixed to the rotation center of the arm and is provided on an outer periphery of a rotation shaft that rotates integrally with the arm,
The frictional force changing means is configured to adjust an inner diameter of the band by pressing one end of the band according to an engine rotation speed, and to change a contact degree between the band and the friction part.
The auto tensioner according to claim 1. The friction portion is fixed to the rotation center of the arm and is inserted through a rotation shaft that rotates integrally with the arm, and is disposed so as to contact the end surface of the arm,
The frictional force changing means is configured to change the degree of contact between the frictional part and the cylindrical part by pressing the frictional part against an end surface of the arm according to an engine rotational speed.
The auto tensioner according to claim 1. The friction portion is fixed to the rotation center of the arm and is inserted through a rotation shaft that rotates integrally with the arm, and is disposed so as to contact the end surface of the support portion,
The frictional force changing means is configured to change the degree of contact between the frictional part and the support part by pressing the frictional part against an end surface of the support part according to an engine speed.
The auto tensioner according to claim 1. The arm has a cylindrical part inserted into the support part,
The friction portion is disposed on both sides of the outer peripheral side surface and the inner peripheral side surface of the cylindrical portion,
The frictional force changing means is configured to change the degree of contact between the frictional part and the cylindrical part by pressing the frictional part so as to sandwich the side surface of the cylindrical part according to the engine rotation speed. The
The auto tensioner according to claim 1. The frictional force generating means increases the degree of contact between the frictional part and the relatively moving part so that the frictional force increases as the engine rotational speed decreases.
The auto tensioner according to any one of claims 1 to 8, wherein

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