JP2022044966A - Tensioner unit for auxiliary machine belt - Google Patents

Abstract

To provide a tensioner unit for an auxiliary machine belt which can prevent air in a sub reservoir chamber formed at a swing arm from mixing into a hydraulic chamber of a hydraulic damper attached to the swing arm even if an inclined angle of the swing arm supporting a tension pulley is large.SOLUTION: A sub reservoir chamber 25 of a swing arm 20 extends from a portion located blow a fulcrum shaft 40 to a portion located above the fulcrum shaft 40 through a periphery of the fulcrum shaft 40. A communication passage 26 which allows communication between a reservoir chamber 73 of a hydraulic damper 70 and the sub reservoir chamber 25 is open to the sub reservoir chamber 25 at a position below the fulcrum shaft 40. A tensioner unit for an auxiliary machine belt is configured so that air stored in the sub reservoir chamber 25 and an oil surface of a working fluid stay in an area of an upper part, which is higher than an open position of the communication passage 26, even when an inclined angle θ of the swing arm 20 is large.SELECTED DRAWING: Figure 1

Description

The present invention mainly relates to a tensioner unit for an auxiliary belt used for maintaining tension of a belt for driving an engine auxiliary such as an alternator or a water pump.

Auxiliary equipment of an automobile, such as an alternator, a car air conditioner, or a water pump, has its rotating shaft connected to the crankshaft of an engine by an auxiliary belt and is driven via the auxiliary belt. In order to keep the tension of the auxiliary belt within an appropriate range, a tensioner unit for the auxiliary belt is generally used.

As a tensioner unit for auxiliary belts, a swing arm that is swingably supported around the fulcrum axis and a swing arm that swings around the fulcrum axis so that it moves integrally with the swing arm when the swing arm swings. The tension pulley supported by the moving arm, the first and second pins arranged so that the swing arm does not move even if it swings, and the reaction force attached to the swing arm and swinging by the reaction force received from the first pin. A spring that pushes the first pin so as to urge the dynamic arm in one swing direction, and a spring that is attached to the swing arm so as to contact the second pin, which is opposite to the swing direction of the one swing arm. It is known that the attachment space of the tensioner unit for the auxiliary belt that applies tension to the auxiliary belt is reduced by providing a hydraulic damper that cushions the swing in the direction (Patent Document). 1).

In the tensioner unit for auxiliary belt of Patent Document 1, as a hydraulic damper, a cylinder provided in the swing arm so as to move integrally with the swing arm around the fulcrum axis when the swing arm swings, A piston that is slidably inserted into the cylinder and divides the inside of the cylinder into a hydraulic chamber and a reservoir chamber, and a damper rod that is connected to the piston at one end and abuts at the second pin at the other end are adopted. ing. The hydraulic damper and the spring are arranged on the same plane orthogonal to the fulcrum axis. Inside the swing arm, a sub-reservoir chamber located adjacent to the reservoir chamber in a direction orthogonal to the longitudinal direction of the cylinder and a communication passage communicating between the sub-reservoir chamber and the reservoir chamber are formed. ing. The hydraulic damper is located above the fulcrum axis. Further, the sub-reservoir chamber is adjacent to the hydraulic damper on the upper side and protrudes toward the upper side. The communication passage penetrates vertically between the lower end of the sub-reservoir chamber and the reservoir chamber of the hydraulic damper. The hydraulic chamber and reservoir chamber are filled with hydraulic oil so that there is no air. Air and hydraulic oil are housed in two upper and lower layers in the sub-reservoir chamber. The pressure change in the cylinder due to the movement of the piston is absorbed by the air layer in the sub-reservoir chamber.

Japanese Unexamined Patent Publication No. 2019-44941

In the tensioner unit for auxiliary belt as in Patent Document 1, even if the swing arm has an tilt angle with respect to the horizontal depending on the mounting angle of the swing arm and the tilt at the time of swing, the air in the sub-reservoir chamber is connected to the hydraulic pressure. It must be arranged so that it does not go to the hydraulic chamber via the reservoir chamber of the damper.

However, since the sub-reservoir chamber of Patent Document 1 is adjacent to the hydraulic damper located on the upper side with respect to the fulcrum axis and protrudes upward, the sub-reservoir chamber is made deeper in consideration of compact mounting space. Therefore, it is difficult to increase the height difference between the oil level of the hydraulic oil and the communication passage. Therefore, the tensioner unit for the auxiliary belt of Patent Document 1 has room for improvement in that the degree of freedom of the tilt angle allowed for the swing arm is small in order to prevent air from entering the hydraulic chamber from the sub-reservoir chamber. ..

Therefore, the problem to be solved by the present invention is that even if the tilt angle of the swing arm supporting the tension pulley is large, the air in the auxiliary reservoir chamber formed in the swing arm is attached to the swing arm of the hydraulic damper. It is an object of the present invention to provide a tensioner unit for an auxiliary belt that can be prevented from being mixed in a hydraulic chamber.

In order to achieve the above-mentioned problems, the present invention has a swing arm that is swingably supported around the fulcrum axis and the swing so as to swing integrally with the swing arm around the fulcrum axis. The tension pulley supported by the arm, the first pin and the second pin arranged so as not to move with respect to the swing arm swinging about the fulcrum axis, and the first pin attached to the swing arm and described above. A spring that pushes the first pin so as to urge the swing arm in one swing direction by a reaction force received from one pin, and a spring attached to the swing arm so as to come into contact with the second pin. A hydraulic damper for cushioning the swing of the swing arm in a direction opposite to the swing direction of the one is provided so that the hydraulic damper moves integrally with the swing arm about the fulcrum axis. It has a cylinder provided on the swing arm, a piston that divides the inside of the cylinder into a hydraulic chamber and a reservoir chamber, and a rod connected to the piston so as to abut on the second pin. A sub-reservoir chamber and a communication passage communicating between the sub-reservoir chamber and the reservoir chamber are formed inside the swing arm, and the hydraulic chamber and the reservoir chamber are filled with hydraulic oil. In the auxiliary belt tensioner unit in which air and hydraulic oil are housed in two upper and lower layers in the sub-reservoir chamber, the sub-reservoir chamber is located around the fulcrum shaft from a portion located below the fulcrum shaft. A configuration is adopted in which the communication passage extends upward through the passage and is open to the sub-reservoir chamber at a position below the fulcrum axis.

According to the above configuration, since the sub-reservoir chamber extends upward from the portion located below the fulcrum axis of the swing arm through the circumference of the fulcrum shaft, the sub-reservoir chamber extends around the fulcrum shaft. The auxiliary reservoir chamber can be expanded upward to accommodate a large amount of hydraulic oil and raise the oil level. Since the communication passage that communicates between the sub-reservoir chamber and the reservoir chamber of the hydraulic damper is open to the sub-reservoir chamber at a position below the fulcrum axis, the height difference between the oil level and the communication passage can be reduced. By increasing the size, even if the tilt angle of the swing arm is large, it is possible to retain air in the upper region of the sub-reservoir chamber, which is higher than the open position of the communication passage, and make it difficult to enter the communication passage. As described above, according to the above configuration, even if the tilt angle of the swing arm is large, it is possible to prevent air from entering the hydraulic chamber from the sub-reservoir chamber.

Specifically, the sub-reservoir chamber is axially adjacent to the hydraulic damper, and the communication passage penetrates between the sub-reservoir chamber and the reservoir chamber in the axial direction. good. By doing so, it is possible to avoid arranging the hydraulic damper and the sub-reservoir chamber on the same plane orthogonal to the fulcrum axis, and to arrange a large sub-reservoir chamber around the fulcrum axis.

It is more preferable that the spring and the hydraulic damper are arranged on the same plane orthogonal to the fulcrum axis. By doing so, it is possible to avoid arranging the hydraulic damper, the spring, and the sub-reservoir chamber on the same plane orthogonal to the fulcrum axis, and easily arrange a large sub-reservoir chamber around the fulcrum axis.

Further, it is more preferable that the sub-reservoir chamber is formed in an elongated hole shape having a hole width in the radial direction orthogonal to the axis of the fulcrum axis and extending in the circumferential direction longer than the hole width. In this way, the sub-reservoir chamber can be expanded upward without significantly expanding the swing arm around the fulcrum axis in the radial direction.

Further, it is preferable that the sub-reservoir chamber extends upward on both sides in the circumferential direction with respect to the communication passage. In this way, the oil of the hydraulic oil is accommodated in the upper regions on both sides in the circumferential direction of the auxiliary reservoir chamber, and the air accommodating amount required to absorb the pressure change in the cylinder due to the movement of the piston is secured. The surface can be raised, thereby gaining a height difference between the oil level and the communication passage.

More preferably, it is preferable that the communication passage is opened at a position at a distance from the inner wall surface on the upper side of the sub-reservoir chamber. In this way, when the swing arm swings, even if the air floating in the hydraulic oil moves along the inner wall surface on the upper side of the auxiliary reservoir chamber, it becomes difficult to enter the communication passage.

As described above, in the present invention, by adopting the above configuration, even if the tilt angle of the swing arm supporting the tension pulley is large, the air in the auxiliary reservoir chamber formed in the swing arm is attached to the swing arm. It is possible to provide a tensioner unit for an auxiliary belt that can be prevented from being mixed into the hydraulic chamber of a hydraulic damper.

Front view showing a tensioner unit for an auxiliary belt according to an embodiment of the present invention. A front view showing a belt transmission device having a tensioner unit for an auxiliary belt of FIG. 1. Bottom view of the tensioner unit for the auxiliary belt shown in FIG. Sectional drawing taken along the line IV-IV of FIG. A perspective view showing the periphery of the fulcrum axis of the auxiliary belt tensioner unit of FIG. 1 in an exploded state. Sectional drawing along the VI-VI line of FIG. Sectional drawing taken along the line VII-VII of FIG.

An embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 2 shows an example of a belt transmission device using the auxiliary belt tensioner unit 1 according to the embodiment of the present invention. This belt transmission device includes a crank pulley 3 attached to a crankshaft 2, a belt 4 wound around the crank pulley 3, an alternator 5 and a water pump 6 connected to the crank pulley 3 via the belt 4. It has an auxiliary belt tensioner unit 1 that pushes the belt 4 to apply tension to the belt 4. Here, the alternator 5 and the water pump 6 are auxiliary equipment of the automobile, and the belt 4 is an auxiliary equipment belt that transmits the rotation of the crankshaft 2 to the auxiliary equipment (alternator 5 and water pump 6).

As shown in FIGS. 1, 3, and 4, the auxiliary belt tensioner unit 1 includes a bracket 10 attached to the engine block 7, a swing arm 20 swingably supported with respect to the bracket 10, and a swing arm 20. A tension pulley 30 attached to the swing arm 20 is provided.

As shown in FIG. 5, a plurality of through holes 11 are formed in the bracket 10. The through hole 11 is for fixing the bracket 10 to the engine block 7 with the bolt 8 as shown in FIG.

As shown in FIGS. 1 and 4, the swing arm 20 is swingably supported around the fulcrum shaft 40. The tension pulley 30 is supported by the swing arm 20 so as to move integrally with the swing arm 20 around the fulcrum shaft 40 when the swing arm 20 swings. A belt 4 is wound around the outer circumference of the tension pulley 30.

Here, the direction along the axis of the fulcrum axis 40 is referred to as an axial direction. The circumferential direction around the axis of the fulcrum axis 40 is called the circumferential direction, and the direction orthogonal to the axis is called the radial direction. Further, the side far from the engine block 7 is the front side in the axial direction, and the side closer to the engine block 7 is the rear side in the axial direction.

As shown in FIGS. 4 and 5, the bracket 10 has a flat plate portion 12 orthogonal to the axial direction. The flat plate portion 12 is formed with a shaft hole 13 that penetrates the flat plate portion 12 in the axial direction. The swing arm 20 is formed with a shaft hole 21 facing the shaft hole 13 in the axial direction. Cylindrical slide bearings 51 and 52 are fitted between the plate surface of the shaft hole 13 of the flat plate portion 12, the fulcrum shaft 40, and the swing arm 20. The fulcrum shaft 40 is fixed to the bracket 10 by passing the slide bearings 51 and 52 through the shaft portion and pressing the shaft portion through the shaft hole 21 into the shaft hole 13. The slide bearings 51 and 52 rotatably support the swing arm 20 with respect to the outer circumference of the fulcrum shaft 40 and the bracket 10 in the circumferential direction, and the head of the fulcrum shaft 40, the bracket 10, and the swing arm 20. Supports the axial load acting in between.

The tension pulley 30 is arranged so as to face the swing arm 20 in the axial direction. The swing arm 20 is provided with a pulley shaft 22 that projects from the surface facing the tension pulley 30 toward the tension pulley 30. The pulley shaft 22 is located at a position that faces the fulcrum shaft 40 in the radial direction. A predetermined radial distance is provided between the fulcrum shaft 40 and the pulley shaft 22. The fulcrum shaft 40 passes through one end side in the longitudinal direction of the swing arm 20, and the pulley shaft 22 is arranged on the other end side in the longitudinal direction of the swing arm 20. In order to realize this facing arrangement, the protruding direction of the pulley shaft 22 is set to be opposite to the protruding direction (front side in the axial direction) of the fulcrum shaft 40 with respect to the bracket 10 (rear side in the axial direction).

The tension pulley 30 has a pulley 31 and a rolling bearing 32. The inner ring of the rolling bearing 32 is fitted to the outer circumference of the pulley shaft 22. The outer ring of the rolling bearing 32 is integrated with the inner circumference of the pulley 31. The inner ring of the rolling bearing 32 is fixed to the pulley shaft 22 by a bolt 33. The bolt 33 is screwed into a screw hole formed in the pulley shaft 22. As a result, the rolling bearing 32 is in a state of rotatably supporting the tension pulley 30 with respect to the pulley shaft 22, and the tension pulley 30 is attached to the swing arm 20.

As shown in FIG. 6, a spring 60 and a hydraulic damper 70 are attached to the inside of the swing arm 20.

As the spring 60, a compression coil spring is adopted. A plurality of springs 60 are provided around the fulcrum shaft 40. A first recess 23 for accommodating the spring 60 is formed around the fulcrum shaft 40 of the swing arm 20. A plurality of first recesses 23 are formed at intervals in the circumferential direction. One end of the spring 60 housed in the first recess 23 is supported by the inner surface of the first recess 23, and the other end of the spring 60 pushes the first pin 80 via the cylindrical cap 61.

The first pin 80 is arranged so as not to move even if the swing arm 20 swings. The tubular cap 61 is slidably supported by a guide sleeve 62 provided in the first recess 23. The first pin 80 is fixed to the bracket 10 by press-fitting into the pin hole 14 formed in the bracket 10 as shown in FIG. As shown in FIG. 6, the first pin 80 is provided in a state of protruding forward in the axial direction with respect to the axial front surface of the flat plate portion 12 of the bracket 10, and the protruding portion is inserted into the first recess 23. It has become.

A plurality of first pins 80 are provided corresponding to the plurality of springs 60. That is, the plurality of first pins 80 are provided in the same number as the number of springs 60, and the first pins 80 are arranged around the fulcrum shaft 40 at intervals in the circumferential direction. Here, the spring 60 urges the swing arm 20 in one swing direction by the reaction force received from the first pin 80. The circumferential direction (counterclockwise rotation direction in the figure) on the side of the spring 60 as viewed from the first pin 80 is the urging direction of the swing arm 20 by the spring 60, and the urging force of the spring 60 causes the tension pulley 30 in FIG. Is pressed down on the belt 4.

As shown in FIG. 6, the hydraulic damper 70 and the spring 60 are incorporated in the swing arm 20 so as to be located on the same plane orthogonal to the fulcrum axis 40. The hydraulic damper 70 is attached to a cylindrical cylinder 71 provided in the swing arm 20 and a cylinder 71 so as to move integrally with the swing arm 20 around a fulcrum shaft 40 when the swing arm 20 swings. It has a piston 74 that is slidably inserted and divides the inside of the cylinder 71 into a hydraulic chamber 72 and a reservoir chamber 73, and a rod 75 that is connected to the piston 74 at one end and abuts on the second pin 90 at the other end. .. The second pin 90 is arranged so as not to move even if the swing arm 20 swings.

As shown in FIGS. 6 and 7, the swing arm 20 is formed with a second recess 24 for accommodating the hydraulic damper 70. Most of the second recess 24 is located on the same circumference as the first recess 23. The second recess 24 is formed in the shape of a hole that is closed at one end side in the direction (string direction) along one chord that does not pass through the center of the same circumference and is open at the other end side. The closed end of the second recess 24 projects in the chord direction from the same circumference. The hydraulic damper 70 is arranged below the fulcrum shaft 40. Here, the downward direction corresponds to the gravitational direction and corresponds to the downward direction in FIGS. 1 and 2.

The cylinder 71 is formed in a bottomed cylinder shape in which one end is open and the other end is closed. The cylinder 71 is fitted in the second recess 24 and is fixed in the second recess 24 by a wear ring 76 press-fitted into the inner circumference of the second recess 24. The inner circumference of the wear ring 76 slidably supports the outer circumference of the rod 75. Further, an oil seal 77 for slidably penetrating the rod 75 is incorporated in the second recess 24.

The piston 74 is housed in the cylinder 71 so as to be slidable in the longitudinal direction of the cylinder 71. The piston 74 is provided with a check valve 78 that opens and closes an oil passage that communicates between the hydraulic chamber 72 and the reservoir chamber 73. The check valve 78 only allows the flow of hydraulic oil from the reservoir chamber 73 side to the hydraulic chamber 72 side. A minute leak gap is formed between the sliding surface of the piston 74 and the cylinder 71. The hydraulic chamber 72 incorporates a damper spring 79 that pushes the piston 74 in a direction in which the volume of the hydraulic chamber 72 increases.

The second pin 90 is fixed to the bracket 10. The bracket 10 is formed with a pin hole 15 for press-fitting and fixing the second pin 90. The second recess 24 of the swing arm 20 is formed with a through hole for inserting the second pin 90 into the second recess 24. The second pin 90 is provided in a state of protruding forward in the axial direction with respect to the axial front surface of the flat plate portion 12 of the bracket 10, and the tip of the rod 75 is in contact with the protruding portion.

As shown in FIG. 6, the circumferential direction on the side with the hydraulic damper 70 as seen from the second pin 90 (leftward rotation direction in the figure) is the circumferential direction on the side with the spring 60 as seen from the second pin 90 (in the figure). The hydraulic damper 70 and the second pin 90 are arranged so as to be in the same direction as the counterclockwise rotation direction). As a result, the hydraulic damper 70 swings the swing arm 20 in the swing direction opposite to the direction in which the spring 60 urges the swing arm 20 (in the right direction in which the tension pulley 30 separates from the belt 4 in FIG. 2). It is designed to buffer the movement.

As shown in FIG. 1, the inclination angle θ of the swing arm 20 is an angle formed by a plane connecting the axis O1 of the fulcrum shaft 40 and the rotation center _O2 of the tension pulley 30 and _a horizontal plane. The plane corresponds to the cut surface of the IV-IV line in FIG. 1, the horizontal plane corresponds to the oil surface of the hydraulic oil (Oil) in FIG. ₁ , and the inclination angle θ is from the axis O1 to the center of rotation O. Corresponds to the depression or elevation angle when looking at ₂ . The tilt angle θ is determined by a combination of the mounting angle of the swing arm 20 and the angle at which the swing arm 20 rotates about the fulcrum axis 40 during operation of the belt transmission device. The mounting angle of the swing arm 20 corresponds to the tilt angle θ when the swing arm 20 naturally settles down when tension does not act from the belt 4. The tilt angle θ of the swing arm 20 drawn in FIG. 1 corresponds to the mounting angle of the swing arm 20 in the belt transmission device shown in FIG.

When the tension of the belt 4 becomes small during the operation of the belt transmission device, the swing arm 20 swings in the counterclockwise direction due to the urging force of the spring 60 (see FIG. 6) to absorb the slack of the belt 4. At this time, the piston 74 shown in FIGS. 6 and 7 moves in the direction in which the volume of the hydraulic chamber 72 increases due to the urging force of the damper spring 79. Further, the check valve 78 opens, and hydraulic oil flows from the reservoir chamber 73 to the hydraulic chamber 72.

On the other hand, when the tension of the belt 4 shown in FIG. 2 becomes large, the swing arm 20 swings in the clockwise rotation direction due to the tension of the belt 4, and absorbs the tension of the belt 4. At this time, since the piston 74 shown in FIGS. 6 and 7 moves in the direction of reducing the volume of the hydraulic chamber 72, the check valve 78 closes, and the hydraulic oil is transferred from the hydraulic chamber 72 to the reservoir chamber 73 through the above-mentioned leak gap. Flows, and the viscous resistance of the hydraulic oil causes a damper action.

As shown in FIGS. 1, 4, and 7, inside the swing arm 20, there is an auxiliary reservoir chamber 25 located adjacent to the reservoir chamber 73 in a direction orthogonal to the longitudinal direction of the cylinder 71. A communication passage 26 that communicates between the sub-reservoir chamber 25 and the reservoir chamber 73 is formed.

As shown in FIG. 1, the hydraulic chamber 72 and the reservoir chamber 73 are filled with hydraulic oil so that air does not exist. Air and hydraulic oil are housed in two upper and lower layers in the sub-reservoir 25.

As shown in FIG. 7, the sub-reservoir chamber 25 is formed in a hole shape that is open toward the front side in the axial direction at a portion adjacent to the front side in the axial direction with respect to the hydraulic damper 70. As shown in FIGS. 1, 4, and 7, the sub-reservoir chamber 25 is sealed by the bore cap 100 press-fitted into the inner circumference of the sub-reservoir chamber 25. The bore cap 100 is prevented from coming off from the swing arm 20 by crimping the end faces of the swing arm 20 on the front side in the axial direction at a plurality of locations around the bore cap 100.

As shown in FIG. 1, the communication passage 26 extends axially between the sub-reservoir chamber 25 and the reservoir chamber 73 at a position below the fulcrum shaft 40 and as shown in FIG. 7.

As shown in FIG. 1, the sub-reservoir chamber 25 is formed in an elongated hole shape having a hole width in the radial direction and extending in the circumferential direction longer than the hole width. Of the inner circumference of the sub-reservoir 25, the inner wall surfaces on both the upper and lower sides connecting both ends in the circumferential direction are circularly isolated surfaces. As shown in FIG. 7, the bottom surface of the hole in the sub-reservoir 25 has a constant depth. It should be noted that the illustration of the hydraulic oil is omitted in FIG. 7.

As shown in FIG. 1, the sub-reservoir chamber 25 extends upward from a portion located below the fulcrum shaft 40 through the periphery of the fulcrum shaft 40. The portion on one side of the auxiliary reservoir chamber 25 in the circumferential direction with respect to the communication passage 26 extends in the circumferential direction toward the upper side, while the portion on the other side in the circumferential direction of the sub-reservoir chamber 25 with respect to the communication passage 26 also extends upward. It extends in the circumferential direction toward it. Considering the angle around the axis O of the fulcrum axis 40, the sub _- reservoir chamber 25 covers a range of 180 °. The communication passage 26 is open at a central position that bisects the entire length of the auxiliary reservoir chamber 25 in the circumferential direction.

The amount of hydraulic oil stored in the sub-reservoir 25 is set so that a height difference can be left between the oil level of the hydraulic oil and the communication passage 26 within the possible swing range of the swing arm 20. This height difference is such that even if the swing arm 20 swings when the tension of the belt 4 fluctuates, the air contained in the sub-reservoir 25 stays in the upper region higher than the open position of the communication passage 26. It is for doing. Air is contained in the upper regions on both sides of the sub-reservoir 25 in the circumferential direction.

The communication passage 26 is open at a position at a distance d from the inner wall surface on the upper side of the sub-reservoir chamber 25. When the swing arm 20 rotates counterclockwise or clockwise around the fulcrum shaft 40, the air floating in the hydraulic oil of the sub-reservoir chamber 25 is assumed to flow from the right side to the left side of FIG. 1 along the upper inner wall surface of the sub-reservoir chamber 25. Even if the air moves from the left side to the right side in FIG. 1, the moving air does not reach the communication passage 26 because the above-mentioned distance d is provided.

Even if the tilt angle θ of the swing arm 20 becomes a large elevation angle or depression angle and the entire amount of air contained in the sub-reservoir chamber 25 moves to one side in the circumferential direction of the sub-reservoir chamber 25, the air is a continuous passage. It stays in the upper area higher than the open position of 26 and does not reach the passage 26.

As described above, in the auxiliary belt tensioner unit 1, the auxiliary reservoir chamber 25 extends upward from the portion located below the fulcrum shaft 40 through the periphery of the fulcrum shaft 40, and is connected to the communication passage 26. Is open to the sub-reservoir chamber 25 at a position below the fulcrum shaft 40, so that the circumference of the fulcrum shaft 40 is utilized for forming the sub-reservoir chamber 25 to expand the sub-reservoir chamber 25 upward. A large amount of hydraulic oil is accommodated to raise the oil level, and the height difference between the oil level and the communication passage 26 is increased. As a result, even if the inclination angle θ of the swing arm 20 is large, the communication passage 26 Air can be retained in the upper region of the sub-reservoir 25 higher than the open position to make it difficult to enter the communication passage 26. That is, in the auxiliary belt tensioner unit 1, even if the tilt angle θ of the swing arm 20 that supports the tension pulley 30 is large, the air in the sub-reservoir chamber 25 formed in the swing arm 20 is attached to the swing arm 20. It is possible to prevent the hydraulic damper 70 from being mixed in the hydraulic chamber 72 (see FIG. 7).

Further, in the auxiliary belt tensioner unit 1, the auxiliary reservoir chamber 25 is axially adjacent to the hydraulic damper 70, and the communication passage 26 penetrates between the auxiliary reservoir chamber 25 and the reservoir chamber 73 in the axial direction. (See FIG. 7), avoiding arranging the hydraulic damper 70 and the sub-reservoir chamber 25 on the same plane orthogonal to the fulcrum axis 40 (see FIGS. 6 and 7), and around the fulcrum axis 40. A large sub-reservoir 25 can be arranged in (see FIGS. 1 and 7).

Further, in the auxiliary belt tensioner unit 1, the spring 60 and the hydraulic damper 70 are arranged on the same plane orthogonal to the fulcrum axis 40 (see FIG. 6), so that the spring 60 and the hydraulic damper 70 are arranged on the same plane. It is possible to avoid arranging the 70 and the sub-reservoir 25 (see FIGS. 4, 6 and 7), and easily arrange a large sub-reservoir 25 around the fulcrum shaft 40 (FIGS. 1 and 7). reference).

Further, the tensioner unit 1 for an auxiliary belt is formed in an elongated hole shape in which the auxiliary reservoir chamber 25 has a hole width in the radial direction orthogonal to the axis of the fulcrum shaft 40 and extends in the circumferential direction longer than the hole width. As a result, the sub-reservoir chamber 25 can be expanded upward (see FIG. 1) without significantly expanding the swing arm 20 in the radial direction around the fulcrum shaft 40 (see FIGS. 3 to 7).

Further, in the auxiliary belt tensioner unit 1, the auxiliary reservoir chamber 25 extends upward on both sides in the circumferential direction with respect to the communication passage 26, so that air is provided in the upper region on both sides in the circumferential direction of the auxiliary reservoir chamber 25. To secure the amount of air required to absorb the pressure change in the cylinder 71 due to the movement of the piston 74 (see FIGS. 1 and 7), raise the oil level of the hydraulic oil, and raise the oil level. And the height difference between the passage 26 and the passage 26 can be earned.

Further, the tensioner unit 1 for the auxiliary belt operates when the swing arm 20 swings because the communication passage 26 is opened at a position where the distance d is taken from the inner wall surface on the upper side of the sub-reservoir 25. Even if the air floating on the oil moves along the inner wall surface on the upper side of the auxiliary reservoir chamber 25, it becomes difficult to enter the communication passage 26.

In this embodiment, an example is shown in which the sub-reservoir chamber 25 extends half a circumference around the fulcrum shaft 40, but the positional relationship between the shape and volume of the sub-reservoir chamber 25 and the communication passage 26 is the belt transmission device shown in FIG. The air in the sub-reservoir chamber 25 shown in FIG. 1 can be retained in the upper region higher than the open position of the communication passage 26 within the swing range permissible for the swing arm 20 around the fulcrum shaft 40. It should be set as follows. For example, it is possible to form a sub-reservoir chamber as an annular hole that is continuous all around the circumference in the circumferential direction, and further accommodate a large amount of hydraulic oil to raise the oil level.

Further, an example is shown in which the tension pulley 30 is arranged at a position radially opposed to the fulcrum shaft 40, the hydraulic damper 70 and the spring 60 (see FIGS. 3 to 5), but the auxiliary reservoir is located around the fulcrum shaft 40. It is also possible to arrange the pulley shaft in the remaining angle region that does not form the chamber 25 so that the tension pulley faces the spring or the like in the axial direction.

Further, although the fulcrum shaft 40 is passed through the swing arm 20 and the fulcrum shaft 40 is fixed to the bracket 10, the fulcrum shaft may be integrally formed with the swing arm or the bracket. It is also possible to use rolling bearings instead of the sliding bearings 51 and 52 that support between the fulcrum shaft 40, the swing arm 20, and the bracket 10.

It is also possible to omit the bracket 10 and provide the fulcrum shaft, the first pin, and the second pin directly on the engine block 7.

The embodiments disclosed this time should be considered to be exemplary and not restrictive in all respects. Therefore, the scope of the present invention is shown by the scope of claims rather than the above description, and it is intended that all modifications within the meaning and scope equivalent to the scope of claims are included.

1 Auxiliary belt tensioner unit 20 Swing arm 25 Sub-reservoir room 26 Continuous passage 30 Tension pulley 40 Abutment shaft 60 Spring 70 Hydraulic damper 71 Cylinder 72 Hydraulic chamber 73 Reservoir chamber 74 Piston 75 Rod 80 First pin 90 Second pin

Claims (6)

A swing arm that is swingably supported around the fulcrum axis,
A tension pulley supported by the swing arm so as to swing integrally with the swing arm around the fulcrum axis.
The first pin and the second pin arranged so as not to move with respect to the swing arm swinging around the fulcrum axis,
A spring attached to the swing arm and pushing the swing arm so as to urge the swing arm in one swing direction by a reaction force received from the first pin.
A hydraulic damper, which is attached to the swing arm so as to come into contact with the second pin and cushions the swing of the swing arm in a direction opposite to the swing direction of the one, is provided.
A cylinder provided in the swing arm so that the hydraulic damper moves integrally with the swing arm about the fulcrum axis, and a piston for partitioning the inside of the cylinder into a hydraulic chamber and a reservoir chamber. With a rod connected to the piston so as to abut the second pin,
A sub-reservoir chamber and a communication passage communicating between the sub-reservoir chamber and the reservoir chamber are formed inside the swing arm, and the hydraulic chamber and the reservoir chamber are filled with hydraulic oil. In the auxiliary belt tensioner unit in which air and hydraulic oil are stored in two upper and lower layers in the sub-reservoir.
The sub-reservoir chamber extends upward from a portion located below the fulcrum axis through the periphery of the fulcrum axis, and the communication passage extends below the fulcrum axis. A tensioner unit for an auxiliary belt, which is open to the sub-reservoir chamber. The first aspect of the present invention, wherein the sub-reservoir chamber is axially adjacent to the hydraulic damper, and the communication passage penetrates between the sub-reservoir chamber and the reservoir chamber in the axial direction. Tensioner unit for auxiliary belt. The tensioner unit for an auxiliary belt according to claim 2, wherein the spring and the hydraulic damper are arranged on the same plane orthogonal to the fulcrum axis. The auxiliary belt according to claim 2 or 3, wherein the auxiliary reservoir chamber is formed in an elongated hole shape having a hole width in the radial direction orthogonal to the axis of the fulcrum axis and extending in the circumferential direction longer than the hole width. Tensioner unit for. The tensioner unit for an auxiliary belt according to any one of claims 1 to 4, wherein the sub-reservoir chamber extends upward on both sides in the circumferential direction with respect to the communication passage. The tensioner unit for an auxiliary belt according to claim 5, wherein the communication passage is open at a position separated from the inner wall surface on the upper side of the sub-reservoir chamber.

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