JP2019148302A - Belt tensioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a belt tensioner capable of suppressing generation of sound caused by contact between an arm and a stopper. A belt tensioner 40 has a tensioner pulley 70 that abuts on a belt 30, an arm 80 that has a tensioner pulley 70 connected to one end thereof and rotatably supports the tensioner pulley 70, and an arm 80 that swings. It is provided with a base 50 that can support the arm 80 and a stopper 53 that limits the amount of swing of the arm 80. When the swing amount of the arm 80 is limited by the stopper 53, the belt tensioner 40 is provided with a leaf spring 110 as a cushioning member arranged between the arm 80 and the stopper 53 to alleviate the impact acting on the arm 80. Has been done. [Selection diagram] Fig. 2

Description

  The present invention relates to a belt tensioner.

  The belt tensioner described in Patent Document 1 adjusts the tension of a belt wound around a crank pulley and a plurality of auxiliary machine pulleys of an internal combustion engine. The belt tensioner includes a base, a pair of arms provided so as to be able to swing with respect to the base, and a tensioner pulley connected to the distal end portions of the pair of arms. The tensioner pulley is in contact with the belt wound around the auxiliary pulley so as to push the belt from the outside. Of the pair of arms, one end of the biasing member is connected to one arm, and the other end of the biasing member is connected to the other arm. By this urging member, the tip ends of the pair of arms are urged in a direction approaching each other, and the tensioner pulley is pressed against the belt from the outside. Thus, tension is applied to the belt by the tensioner pulley pushing the belt. The arm is provided with a stopper. The stopper restricts the rotation range of the arm.

JP 2017-125565 A

  In the belt tensioner described in Patent Document 1, when the amount of rotation of the arm increases, the arm contacts the stopper. For this reason, in the belt tensioner described in Patent Document 1, there is a possibility that noise is generated when the swinging of the arm is limited by the stopper. Regarding this point, Patent Document 1 does not disclose anything and there is room for improvement.

  A belt tensioner for solving the above-described problems is a tensioner pulley that abuts on a belt wound around a crank pulley and an auxiliary pulley, and the tensioner pulley is connected to one end, and rotatably supports the tensioner pulley. A belt tensioner comprising: an arm that swings; a base that supports the arm in a swingable manner; and a stopper that limits the swing amount of the arm, wherein the arm swing amount is limited by the stopper. And a buffer member that is disposed between the stopper and reduces the impact acting on the arm.

  In the above configuration, when the swinging amount of the arm is limited by the stopper, the buffer member is disposed between the arm and the stopper to mitigate the impact acting on the arm. Therefore, it is possible to suppress the generation of sound when the swinging of the arm is limited by the stopper.

The side view which shows typically the structure of the belt tensioner assembled | attached to the internal combustion engine. The schematic diagram which expands and shows the structure of a belt tensioner. The schematic diagram which expands and shows the periphery of an accommodation recessed part. The schematic diagram which shows the rocking | fluctuation aspect of the arm in a belt tensioner. (A) is a schematic diagram which shows the state of a leaf | plate spring when an arm contact | abuts to a stopper, (b) is a schematic diagram which shows the state of a leaf | plate spring when an arm rock | fluctuates further to the stopper side. The graph which shows the relationship between an arm rocking | fluctuation amount and a spring reaction force. (A) is a schematic diagram showing a part of the configuration of another example of the belt tensioner in an enlarged manner, and (b) is a schematic diagram showing a part of the configuration of another example of the belt tensioner in an enlarged manner.

One embodiment of a belt tensioner will be described with reference to FIGS.
As shown in FIG. 1, a crank pulley 11 is arranged on one side of the engine body 10 of the internal combustion engine. The crank pulley 11 is formed in a disk shape. One end of the crankshaft 12 is inserted through the center of the crank pulley 11. One end of the crankshaft 12 connected to the crank pulley 11 is disposed outside the engine main body 10, and the other end side (the back side in FIG. 1) extends from the one end to the inside of the engine main body 10. ing. The crankshaft 12 is rotatably supported by the engine body 10. The crank pulley 11 rotates as the crankshaft 12 rotates. A first auxiliary pulley 13 is disposed on the side of the crank pulley 11 (right side in FIG. 1). The first auxiliary machine pulley 13 is formed in a disc shape. A first drive shaft 14 in the compressor of the air conditioner is inserted through the center of the first auxiliary pulley 13. The first drive shaft 14 rotates integrally with the first auxiliary machine pulley 13.

  An idler pulley 15 is disposed between the crank pulley 11 and the first auxiliary pulley 13 and above the crank pulley 11 and the first auxiliary pulley 13. The idler pulley 15 is formed in a disc shape. A rotating shaft 16 is inserted through the center of the idler pulley 15. The rotating shaft 16 is fixed to the side surface of the engine body 10. The idler pulley 15 can rotate around the rotation shaft 16. A second auxiliary pulley 17 is disposed above the idler pulley 15 and closer to the crankshaft 12 than the idler pulley 15 (left side in FIG. 1). The second auxiliary machine pulley 17 is formed in a disc shape. A second drive shaft 18 of a water pump is inserted through the center of the second auxiliary pulley 17. The second drive shaft 18 rotates integrally with the second auxiliary machine pulley 17. Further, a third auxiliary pulley 19 is disposed above the idler pulley 15 and closer to the first auxiliary pulley 13 side (right side in FIG. 1) than the idler pulley 15. The third auxiliary pulley 19 is formed in a disc shape. A third drive shaft 21 of the motor generator 20 is inserted through the center of the third auxiliary pulley 19. The third drive shaft 21 rotates integrally with the third auxiliary pulley 19.

  An annular belt 30 is wound around the crank pulley 11, the first auxiliary pulley 13, the idler pulley 15, the second auxiliary pulley 17, and the third auxiliary pulley 19. As a whole, the belt 30 is wound so as to surround the crank pulley 11, the first auxiliary pulley 13, the second auxiliary pulley 17, and the third auxiliary pulley 19 from the outside. The belt 30 is wound so as to surround the idler pulley 15 from the inside. The belt 30 has a function of transmitting the rotational torque of the crank pulley 11 to other pulleys.

  The motor generator 20 includes a housing 22 that rotatably supports the third drive shaft 21. The housing 22 is formed in a bottomed cylindrical shape. A belt tensioner 40 is fixed to the bottom 22 </ b> A of the housing 22.

  As shown in FIG. 2, the belt tensioner 40 has a plate-like base 50 fixed to the bottom 22 </ b> A of the housing 22 of the motor generator 20. The base 50 includes a fixed portion 51 and a pair of support portions 52 that are bent and extended from both ends of the fixed portion 51. The pair of support portions 52 are separated from each other, and the third auxiliary pulley 19 is disposed between the pair of support portions 52. Each of the pair of support portions 52 is provided with a stopper 53 erected from the support portion 52. The stopper 53 includes a plate-like outer plate portion 53A connected to the outer edge 52A of the support portion 52, and a bulging portion 53B bulging from the outer plate portion 53A to the inner edge 52B side of the support portion 52. Become. In the direction along the outer edge 52A of the support portion 52, the bulging portion 53B is curved so that the center portion is located on the innermost edge 52B side. Bolt holes (not shown) are formed at both ends of the fixing portion 51. The base 50 is fixed to the housing 22 by fastening the bolts 35 inserted through these bolt holes to the bottom 22 </ b> A of the housing 22 of the motor generator 20.

  The belt tensioner 40 has a pair of tensioner arms 60 connected to the base 50. The configuration of the pair of tensioner arms 60 is symmetrical with respect to the central axis L of the belt tensioner 40. Below, the structure of the 1st tensioner arm 60A arrange | positioned under the 3rd accessory pulley 19 among a pair of tensioner arms 60 is demonstrated, and the 2nd arrange | positioned above the 3rd accessory pulley 19 is demonstrated. About the same structure of tensioner arm 60B, a common code | symbol is attached | subjected and description is abbreviate | omitted.

  The first tensioner arm 60 </ b> A has a tensioner pulley 70 that is in contact with the belt 30. The tensioner pulley 70 is formed in a disc shape. The tensioner pulley 70 is connected to the arm 80. The arm 80 has a plate-like main body 81. The main body 81 has a swing end 82 that supports the tensioner pulley 70. The swing end portion 82 extends along the outer edge 52 </ b> A of the support portion 52 of the base 50. A support shaft 85 is connected to one end of the swing end 82. The support shaft 85 is inserted through the center of the tensioner pulley 70 and supports the tensioner pulley 70 in a rotatable manner. That is, the arm 80 has a tensioner pulley 70 connected to one end thereof, and rotatably supports the tensioner pulley 70. An insertion hole 82 </ b> A is formed at the other end of the swing end 82. A swing shaft 86 is inserted through the insertion hole 82A. The swing shaft 86 is erected on the support portion 52 of the base 50. The main body 81 is assembled to the base 50 so as to be rotatable relative to the base 50 about the swing shaft 86.

The main body 81 has an inclined portion 83 that extends obliquely with respect to the swing end portion 82, and an urging end portion 84 that extends from the inclined portion 83 in a direction orthogonal to the central axis L. Yes.
The belt tensioner 40 is provided with a coil spring 100 connected to a pair of tensioner arms 60. The coil spring 100 is assembled to the urging end portions 84 of the pair of tensioner arms 60 in a compressed state. That is, the coil spring 100 has one end connected to the biasing end 84 of the first tensioner arm 60A and the other end connected to the biasing end 84 of the second tensioner arm 60B. The biasing end portions 84 of the pair of tensioner arms 60 are biased by the coil spring 100 in directions away from each other. In other words, each arm 80 of the pair of tensioner arms 60 is swung around the swing shaft 86 by the biasing force of the coil spring 100, and the tensioner pulley 70 is brought closer to each other. By this action, the tensioner pulley 70 is pressed against the belt 30 from the outside. Each tensioner pulley 70 pushes the belt 30 to apply tension to the belt 30.

  As shown in FIG. 3, the swinging end portion 82 of the main body portion 81 is formed with an accommodation recess 88 at the outer edge portion facing the stopper 53. The housing recess 88 includes an opening recess 89 and a fitting wall 90. The opening recess 89 has a bottom surface 89A and a pair of side surfaces 89B standing from an edge of the bottom surface 89A. The fitting wall portion 90 is erected on the side surface 89B on the support shaft 85 side among the pair of side surfaces 89B of the opening recess 89. The opening recess 89 and the fitting wall 90 form an opening of the housing recess 88. The fitting wall 90 has a facing surface 90 </ b> A that faces the bottom surface 89 </ b> A of the opening recess 89. The housing recess 88 includes a housing chamber 91 formed by a bottom surface 89 </ b> A, a side surface 89 </ b> B, and a facing surface 90 </ b> A, and an opening chamber 92 that communicates with the housing chamber 91.

  A leaf spring 110 as a buffer member is housed in the housing recess 88. The leaf spring 110 includes a flexible portion 111 whose cross section is formed in an arc shape, and a first flat plate portion 112 and a second flat plate portion 113 extending in opposite directions from the periphery of the flexible portion 111. The first flat plate portion 112 is disposed in the accommodation chamber 91, and the flexible portion 111 and the second flat plate portion 113 are disposed in the opening chamber 92. The plate thickness of the first flat plate portion 112 is slightly thicker than the gap between the bottom surface 89A of the housing recess 88 and the facing surface 90A. Therefore, in a state where the first flat plate portion 112 is disposed in the storage chamber 91, the leaf spring 110 is supported by being sandwiched between the bottom surface 89A and the facing surface 90A. As shown in FIG. 3, in the state where the leaf spring 110 is assembled to the accommodation recess 88, the second flat plate portion 113 is in contact with the bottom surface 89 </ b> A of the accommodation recess 88, but on the side surface 89 </ b> B of the accommodation recess 88. There is no contact.

  For example, during operation of the internal combustion engine, due to the influence of torque fluctuation of the crankshaft 12, the tension of the belt 30 where the tensioner pulley 70 of the first tensioner arm 60A contacts the tensioner pulley 70 of the second tensioner arm 60B In some cases, the tension may be greater than the tension of the belt 30 in contact. In this case, the tensioner pulley 70 is pressed by the belt 30 and the arm 80 of the first tensioner arm 60 </ b> A swings against the urging force of the coil spring 100. Thereby, the swinging end portion 82 of the first tensioner arm 60A moves to the stopper 53 side. As a result, the tensioner pulley 70 moves to the outside of the belt 30 and reduces the tension of the belt 30.

  As indicated by a two-dot chain line in FIG. 4, when the first tensioner arm 60 </ b> A swings in this way, the flexible portion 111 of the leaf spring 110 assembled in the accommodation recess 88 of the first tensioner arm 60 </ b> A expands the stopper 53. Abuts on the protruding portion 53B. As a result, the leaf spring 110 is disposed between the arm 80 and the stopper 53. In this state, the swing range of the first tensioner arm 60A is limited by the stopper 53. Thereby, it is suppressed that the swing range of the first tensioner arm 60A becomes excessively large.

  Further, in the second tensioner arm 60 </ b> B, the arm 80 swings by the biasing force of the coil spring 100 as the tension of the belt 30 decreases. As a result, the swinging end portion 82 of the second tensioner arm 60B moves the tensioner pulley 70 to the inside of the belt 30 to increase the tension of the belt 30.

  For example, when starting the internal combustion engine, the motor generator 20 is driven to rotate the third auxiliary pulley 19. Thereby, the rotational torque of the motor generator 20 is transmitted to the crankshaft 12 through the belt 30. At this time, the tension of the belt 30 in the portion where the tensioner pulley 70 of the first tensioner arm 60A abuts decreases, and the tension of the belt 30 in the portion of the second tensioner arm 60B where the tensioner pulley 70 abuts increases. There is a case. In this case, in the belt tensioner 40, the first tensioner arm 60A swings away from the stopper 53 and moves the tensioner pulley 70 to the inside of the belt 30. In the belt tensioner 40, the second tensioner arm 60 </ b> B swings toward the side closer to the stopper 53 and moves the tensioner pulley 70 to the outside of the belt 30. As described above, the belt tensioner 40 adjusts the tension of the belt 30 by swinging the pair of tensioner arms 60 according to the tension of the belt 30.

  The operation and effect of this embodiment will be described. In the following, a case where the swing of the first tensioner arm 60 </ b> A of the pair of tensioner arms 60 is limited by the stopper 53 will be described as an example. Since the same applies to the case where the swing of the second tensioner arm 60B is limited by the stopper 53, the description thereof is omitted.

  (1) As shown in FIG. 5A, a leaf spring 110 is provided as a buffer member in the housing recess 88 of the arm 80. When the swinging amount of the arm 80 is limited by the stopper 53, the leaf spring 110 contacts the stopper 53, and the leaf spring 110 is disposed between the arm 80 and the stopper 53. The leaf spring 110 bends when the flexible portion 111 is pressed by the stopper 53, and absorbs the force transmitted from the stopper 53 to the arm 80. Thereby, when the arm 80 is restricted from swinging by the stopper 53, the impact acting on the arm 80 is reduced. Therefore, the generation of sound when the swing of the arm 80 is restricted by the stopper 53 can be suppressed.

  (2) As indicated by the solid arrow in FIG. 5B, when the arm 80 further swings toward the stopper 53, the flexible portion 111 of the leaf spring 110 is further bent. 5B, the second flat plate portion 113 of the leaf spring 110 moves in the direction close to the side surface 89B of the housing recess 88 and contacts the side surface 89B. In this state, since the second flat plate portion 113 is in a state in which further movement is restricted by the side surface 89B, the flexible portion 111 of the leaf spring 110 is not in contact with the side surface 89B. It becomes hard to bend compared with a state. Thus, when the 2nd flat plate part 113 contact | abuts to the side surface 89B, the spring constant in the leaf | plate spring 110 will change before and after that.

  As shown in FIG. 6, when the swinging amount R of the arm 80 toward the stopper 53 is less than the first swinging amount R1 where the leaf spring 110 and the stopper 53 abut (R <R1), the arm 80 moves from the stopper 53. No reaction force acts, and the spring reaction force resulting from the elastic return of the leaf spring 110 is zero. When the swing amount R of the arm 80 becomes equal to or greater than the first swing amount R1 at which the leaf spring 110 and the stopper 53 abut, the flexible portion 111 of the leaf spring 110 is bent and deformed to generate a spring reaction force. When the swing amount R of the arm 80 is less than the second swing amount R2 when the second flat plate portion 113 contacts the side surface 89B of the receiving recess 88 (R1 ≦ R <R2), the swing amount R of the arm 80 increases. The amount of bending of the flexible portion 111 of the leaf spring 110 increases, and the spring reaction force increases. In this state, as the swinging amount R of the arm 80 increases, the second flat plate portion 113 of the leaf spring 110 moves in a direction closer to the side surface 89 </ b> B of the housing recess 88. When the swing amount R of the arm 80 becomes equal to or greater than the second swing amount R2 (R2 ≦ R), the second flat plate portion 113 is in contact with the side surface 89B, and the spring constant of the leaf spring 110 is greater than before. Will increase. In this state, the rate of increase in the spring reaction force with respect to the increase in the swing amount R of the arm 80 is greater than when the swing amount R of the arm 80 is less than the second swing amount R2. That is, in the graph shown in FIG. 6, when the swing amount R of the arm 80 is greater than or equal to the first swing amount R1 and less than the second swing amount R2 (R1 ≦ R <R2), The slope K2 when the swing amount is R2 or more (R2 ≦ R) is larger. As described above, the leaf spring 110 is bent to absorb the impact when it is in contact with the stopper 53, but when the swing amount of the arm 80 is large, it is more difficult to bend the leaf spring 110 than when the swing amount is small. As a result, the swing speed of the arm 80 can be gradually reduced. In this way, by causing the leaf spring 110 to function so as to gradually decrease the swing speed of the arm 80, it is possible to appropriately reduce the impact when the swing amount of the arm 80 is limited by the stopper 53.

This embodiment can be implemented with the following modifications. The present embodiment and the following modifications can be implemented in combination with each other within a technically consistent range.
-The arrangement | positioning aspect of the leaf | plate spring 110 in the said embodiment can be changed suitably. For example, in a state where the leaf spring 110 and the stopper 53 are not in contact with each other, the leaf spring 110 is arranged in the housing recess 88 with the second flat plate portion 113 of the leaf spring 110 in contact with the side surface 89B of the housing recess 88. It may be.

  In the embodiment described above, the housing recess 88 is provided in the arm 80, and the leaf spring 110 is disposed in the housing recess 88. In place of such a configuration, the arm 80 may not be provided with the housing recess 88, but the stopper 53 may be provided with a recess similar to the housing recess 88, and the leaf spring 110 may be housed as a buffer member in the recess. Further, if the leaf spring 110 can be held in the belt tensioner 40, the housing recess 88 can be omitted.

  The belt tensioner 40 includes a pair of tensioner arms 60, but one tensioner arm 60 may be omitted. In this case, an urging force can be applied to the tensioner arm 60 by fixing one end of the coil spring 100.

  -The structure of a buffer member is not restricted to the thing of the said embodiment. For example, the configuration shown in FIGS. 7A and 7B can be adopted as a belt tensioner having a buffer member. In the configuration shown in FIGS. 7A and 7B, unlike the above-described embodiment, the arm 80 is not provided with the accommodating recess 88.

  The belt tensioner 120 shown in FIG. 7A has a compression coil spring 130 as a buffer member. One end of the compression coil spring 130 is connected to the outer edge of the swing end portion 82 of the arm 80. The other end of the compression coil spring 130 is connected to the inner surface of the outer plate portion 53 </ b> A of the stopper 53. That is, the compression coil spring 130 is disposed between the arm 80 and the stopper 53. In this configuration, when the arm 80 swings toward the stopper 53, the compression coil spring 130 disposed between the arm 80 and the stopper 53 is compressed, and the arm 80 is stopped by the elastic force of the compression coil spring 130. The swing speed when swinging to the 53 side decreases. As a result, the impact acting on the arm 80 is mitigated when the arm 80 comes into contact with the stopper 53 and the swing amount thereof is limited. Therefore, in this configuration, it is possible to suppress the generation of sound when the swing of the arm 80 is restricted by the stopper 53, as compared to a configuration in which the arm 80 contacts the stopper 53 without providing the compression coil spring 130.

  Further, the belt tensioner 140 shown in FIG. 7B has an elastic body 150 as a buffer member. The stopper 160 of the belt tensioner 120 is erected on the support portion 52 of the base 50 and is formed in a plate shape. The stopper 160 is connected to the outer edge 52 </ b> A of the support portion 52. The elastic body 150 is connected to the inner side surface 160A of the stopper 160 on the arm 80 side, and is made of an elastic material such as rubber. The elastic body 150 is formed in a shape bulging from the stopper 160 to the arm 80 side. The elastic body 150 bulges so that the center portion is located closest to the arm 80 in the direction along the outer edge 52A of the support portion 52. In this configuration, when the arm 80 swings toward the stopper 160, the arm 80 and the elastic body 150 come into contact with each other, and the elastic body 150 is disposed between the arm 80 and the stopper 160. When the swing of the arm 80 is restricted by the stopper 160, the elastic body 150 is compressed, and the swing speed when the arm 80 swings toward the stopper 160 is reduced by the elastic force of the elastic body 150. As a result, the impact acting on the arm 80 when the swing amount of the arm 80 is limited by the stopper 160 is mitigated. Therefore, in this configuration, it is possible to suppress the generation of sound when the swing of the arm 80 is restricted by the stopper 160 as compared with the configuration in which the arm 80 contacts the stopper 160 without providing the elastic body 150.

The base 50 can be omitted. In this case, the stoppers 53 and 160 may be connected to the bottom 22A of the housing 22 of the motor generator 20.
Although the belt tensioner 40 is assembled to the motor generator 20, it may be assembled to another auxiliary machine such as a compressor or a water pump.

  DESCRIPTION OF SYMBOLS 10 ... Engine main body, 11 ... Crank pulley, 12 ... Crank shaft, 13 ... 1st auxiliary machine pulley, 14 ... 1st drive shaft, 15 ... Idler pulley, 16 ... Rotating shaft, 17 ... 2nd auxiliary machine pulley, 18 ... Second drive shaft, 19 ... third auxiliary pulley, 20 ... motor generator, 21 ... third drive shaft, 22 ... housing, 22A ... bottom, 30 ... belt, 35 ... bolt, 40 ... belt tensioner, 50 ... base, DESCRIPTION OF SYMBOLS 51 ... Fixed part, 52 ... Support part, 52A ... Outer edge, 52B ... Inner edge, 53 ... Stopper, 53A ... Outer plate part, 53B ... Swelling part, 60 ... A pair of tensioner arms, 60A ... First tensioner arm, 60B ... Second tensioner arm, 70 ... Tensioner pulley, 80 ... Arm, 81 ... Body part, 82 ... Oscillating end part, 83 ... Inclined part, 84 ... Biasing end part, 85 ... Support shaft, 86 ... Oscillating axis , DESCRIPTION OF SYMBOLS 7 ... Insertion hole, 88 ... Housing recessed part, 89 ... Opening recessed part, 89A ... Bottom surface, 89B ... Side surface 89B, 90 ... Fitting wall part, 90A ... Opposite surface, 91 ... Housing chamber, 92 ... Opening chamber, 100 ... Coil spring DESCRIPTION OF SYMBOLS 110 ... Leaf spring 111 ... Flexible part 112 ... 1st flat plate part 113 ... 2nd flat plate part 120 ... Belt tensioner 130 ... Compression spring, 140 ... Belt tensioner, 150 ... Elastic body, 160 ... Stopper , 160A ... inside surface.

Claims (1)

A tensioner pulley that contacts the belt wound around the crank pulley and the auxiliary pulley;
The tensioner pulley is connected to one end, and an arm that rotatably supports the tensioner pulley;
A base for swingably supporting the arm;
A belt tensioner comprising a stopper for limiting the swing amount of the arm;
A belt tensioner provided with a buffer member that is disposed between the arm and the stopper to reduce an impact acting on the arm when a swing amount of the arm is limited by the stopper.