Tapered roller bearings and power transmission device

Abstract

Tapered roller bearing (1), with: an inner ring (2) having an inner ring raceway surface (2a); an outer ring (3) which is arranged on an outer circumferential side of the inner ring (2) and concentric to the inner ring (2), and which has an outer ring raceway surface (3a) which is opposite the inner ring raceway surface (2a); a plurality of tapered rollers (4) which are positioned to roll between the inner ring raceway surface (2a) and the outer ring raceway surface (3a); and a cage (10) arranged in an annular space between the inner ring (2) and the outer ring (3), which holds the conical rollers (4), wherein: the cage (10) includes a ring section of small diameter (11), a ring section of large diameter (12) which is opposite the ring section of small diameter (11) at a certain distance, and a plurality of columnar sections (13) which lie between the ring section of small diameter (11) and the ring section of large diameter (12), wherein spaces surrounded by adjacent columnar sections (13), the ring section of small diameter (11) and the ring section of large diameter (12) are formed as pockets (14) which accommodate the conical rollers (4); the small-diameter ring section (11) is arranged between a small shoulder section (5) provided on an axial end face of the inner ring (2) and an axial end section (6) of the outer ring (3), and an inner circumferential surface (11a) and an outer circumferential surface (11b) of the small-diameter ring section (11) can be in sliding contact with the small shoulder section (5) and the one axial end section (6) of the outer ring (3), so that an annular opening section, which is made up of the small shoulder section (5) and the one axial end section (6) of the outer ring (3), is closed; a sliding contact surface (15, 16) is provided in a radially outer side surface (13a) of each columnar section (13), and is in sliding contact with the outer ring raceway surface (3a), so that the cage (10) is radially positioned by the outer ring raceway surface (3a), and a recessed section (17) is provided in the radially outer side surface (13a) of each columnar section (13), and is radially recessed, so that adjacent pockets (14) are in contact with each other; and a bottom surface (17a) of the depression section (17) is a slope which is inclined with respect to the outer ring raceway surface (3a) such that a gap T between the bottom surface (17a) and the outer ring raceway surface (3a) gradually extends axially from the small diameter ring section (11) towards the large diameter ring section (12).

Description

Technical field

[0001] The present invention relates to a tapered roller bearing and a power transmission device which uses the tapered roller bearing. State of the art

[0002] A tapered roller bearing is characterized by having a greater load-bearing capacity and a higher stiffness than other rolling bearings of the same size.

[0003] Fig. Figure 13 shows an axial sectional view illustrating a related tapered roller bearing. As in Fig. As shown in Figure 13, a tapered roller bearing 100 has an inner ring 101, an outer ring 102, a plurality of tapered rollers 103 which are positioned to roll between the inner and outer rings 101 and 102, and an annular holder / cage 104 which holds the tapered rollers 103 at equal intervals around the circumference (see e.g. JP 4 151 347 B2).

[0004] The cage 104 has a small-diameter ring section 105, a large-diameter ring section 106, and a plurality of columnar sections 107 located between the two ring sections 105 and 106. Additionally, pockets 108 for receiving the tapered rollers 103 are formed in the cage 104 through the two ring sections 105 and 106 and adjacent columnar sections 107.

[0005] DD 231 100 A1 discloses a tapered roller bearing with an inner ring, an outer ring, tapered rollers, and a cage that is guided on an outer ring raceway via tapered guide surfaces. The cage has an annular groove that connects individual roller pockets, thus forming a small-diameter annular section and a large-diameter annular section, which are connected by columnar sections.

[0006] JP 2004 - 84 799 A discloses a tapered roller bearing with an inner ring, an outer ring, tapered rollers and a cage which is thick in the radial direction in order to form a narrow lubricating oil flow channel between the outer ring and cage and between the inner ring and cage, thereby reducing the stirring resistance of a lubricating oil and facilitating the reaching of a sliding contact part by the lubricating oil.

[0007] US 2009 / 0003745A1 discloses a tapered roller bearing with a cage that contacts an outer ring when at rest and does not contact the outer ring when in operation, which is used in transmissions or differentials of motor vehicles. Summary of the invention: Problem that the invention is intended to solve

[0008] In general, a tapered roller bearing contains a large number of sliding sections. Consequently, the rotational torque tends to increase compared to that in a ball bearing or similar.

[0009] Here, reasons / causes for torque loss in the tapered roller bearing are mainly and roughly divided into three categories: rolling viscosity resistance between each bearing ring and each tapered roller, turbulence resistance or resistance due to turbulence of lubricating oil flowing into an interior of the bearing, and sliding friction resistance.

[0010] Of these reasons / causes, the rolling viscosity resistance between each bearing ring and each tapered roller and the turbulence resistance of the lubricating oil flowing into the interior of the bearing account for most of the torque loss and primarily cause an increase in rotational torque.

[0011] The rolling viscosity and turbulence resistance of the lubricating oil depend on the amount of lubricating oil flowing into the annular bearing chamber formed between the inner and outer rings. Suppressing the inflow rate of lubricating oil into this chamber can reduce torque loss.

[0012] In the tapered roller bearing 100 from the in Fig. In the prior art shown in Figure 13, when the inner and outer rings 101 and 102 rotate relative to each other, a pumping motion is generated so that the lubricating oil in the bearing interior can be forced to flow on a raceway surface of each inner and outer ring 101 and 102 from its part of small diameter towards its part of large diameter.

[0013] Thus, the lubricating oil, for example when the tapered roller bearing 100 is partially or completely immersed in lubricating oil, flows through a small-diameter opening section 110 into the bearing interior of the tapered roller bearing 100. The small-diameter opening section 110 is formed by a flange / shoulder section 101a, which is provided on an axial end face of the inner ring 101, and an axial end section of the outer ring 102. Conversely, the lubricating oil flows out of a large-diameter opening section 111 on the other axial end face into the bearing interior of the tapered roller bearing 100.

[0014] To suppress the amount of lubricating oil flowing into the bearing interior, it can therefore be taken into account that the small diameter opening section 110 is closed / sealed by the small diameter ring section 105 of the cage 104 in order to restrict the lubricating oil precisely in that direction from flowing into the bearing interior of the tapered roller bearing 100.

[0015] However, the cage 104 is designed such that gaps are maintained between adjacent tapered rollers 103, while it is positioned axially and radially by the tapered rollers 103, each of which is received in the pockets 108. Furthermore, due to a comparatively large gap that is ensured between each pocket 108 and each tapered roller 103, it cannot be said that the cage 104 rotates consistently with high accuracy between the inner and outer rings 101 and 102 when the inner and outer rings rotate relative to each other.

[0016] Therefore, the small diameter ring section 105, which is part of the cage 104, also rotates intermittently.

[0017] If the small-diameter ring section 105 rotates intermittently, even if it is designed to create a small gap between the small-diameter ring section 105 and the small-diameter opening section 110 so that the small opening section 110 can be closed / sealed by the small-diameter ring section 105, the small gap cannot be maintained consistently, or the small-diameter ring section may touch the circumferential surface of the small-diameter opening section 110, preventing the small-diameter opening section 110 from being permanently closed. This can lead to a problem where the flow rate of the lubricating oil cannot be precisely controlled.

[0018] The present invention was developed taking such circumstances into account. A first object of the invention is to provide a tapered roller bearing that enables precise control of the amount of lubricating oil flowing into the interior of the bearing, thereby reducing torque loss, and to provide a power transmission device that uses the tapered roller bearing.

[0019] Additionally, to reduce torque loss, which is mainly caused by sliding friction resistance occurring in a sliding part between a roller end face and a flange / shoulder section, it is necessary to supply the lubricating oil there.

[0020] Therefore, if the flow rate of lubricating oil is suppressed to reduce torque loss caused by the rolling viscosity and turbulence resistance of the lubricating oil, it is indeed possible to reduce these two factors. However, there is a risk that the torque loss may not be effectively reduced due to an unintended increase in sliding friction. Additionally, there is another risk of seizing due to insufficient lubricating oil.

[0021] Therefore, there is a need for a measure that makes it possible to reduce sliding friction resistance in order to suppress the occurrence of seizing, while limiting the amount of lubricating oil flowing into a bearing interior.

[0022] The invention was developed taking such circumstances into account. A second object of the invention is to provide a tapered roller bearing which enables a reduction of sliding friction resistance in order to suppress the occurrence of seizing, while limiting the amount of lubricating oil flowing into the interior of the bearing in order to reduce rotational torque, and a power transmission device which uses / employs the tapered roller bearing.

[0023] Additionally, if the lubricating oil between each bearing ring and each tapered roller is reduced to a required quantity, the aforementioned rolling viscosity resistance can be further reduced, thus reducing the torque loss accordingly.

[0024] If the torque loss can be reduced in this way, fuel consumption can be improved or the amount of carbon dioxide emissions can be reduced.

[0025] The invention was developed taking such circumstances into account. A third object of the invention is to provide a tapered roller bearing which makes it possible to precisely suppress the amount of lubricating oil flowing into the interior of the bearing, while reducing the amount of lubricating oil between each bearing ring and each tapered roller, in order to reduce torque loss, and to provide a power transmission device which uses the tapered roller bearing. methods for problem solving

[0026] To achieve the aforementioned first objective, the invention provides a tapered roller bearing comprising: an inner ring having an inner ring raceway surface; an outer ring arranged on an outer circumferential side of the inner ring and concentric to the inner ring, and having an outer ring raceway surface opposite the inner ring raceway surface; and a plurality of tapered rollers positioned to roll between the inner ring raceway surface and the outer ring raceway surface.and a cage arranged in an annular space between the inner ring and the outer ring, holding the conical rollers, the cage comprising a small-diameter ring section, a large-diameter ring section opposite the small-diameter ring section at a certain distance, and a plurality of columnar sections situated between the small-diameter ring section and the large-diameter ring section, wherein spaces surrounded by adjacent columnar sections, the small-diameter ring section and the large-diameter ring section are designed as pockets to receive the conical rollers;the small-diameter ring section is arranged between a small shoulder section provided on an axial end face of the inner ring and an axial end section of the outer ring, and an inner circumferential surface and an outer circumferential surface of the small-diameter ring section can be in sliding contact with the small shoulder section and the one axial end section of the outer ring, so that an annular opening section, which is made up of the small shoulder section and the one axial end section of the outer ring, is closed;and a sliding contact surface is provided in a radially outer side surface of each columnar section, and is in sliding contact with the outer ring raceway surface, so that the cage is radially positioned by the outer ring raceway surface, and a recessed section is provided in the radially outer side surface of each columnar section, and is radially recessed, so that adjacent pockets are in contact with each other.

[0027] According to the tapered roller bearing, as configured above, the amount of lubricating oil flowing into the annular space can be reduced by the small-diameter ring section closing the annular opening section formed by the small shoulder section and the axial end section of the outer ring. This reduces the torque loss of the tapered roller bearing.

[0028] Additionally, when the column-shaped sections are in sliding contact with the outer ring raceway surface, the cage of the aforementioned tapered roller bearing is radially positioned and guided towards the outer ring raceway surface in order to rotate on it. Therefore, the cage can rotate continuously and accurately between the inner and outer rings, and the small-diameter ring section that seals the annular opening can also rotate continuously and accurately. Consequently, the annular opening can be sealed so reliably that the flow of lubricating oil can be precisely controlled.

[0029] On the other hand, if, in the aforementioned tapered roller bearing, the columnar sections of the cage are in sliding contact with the outer ring raceway surface, the turbulence effect of the lubricating oil near the outer ring raceway surface can be improved, thus enhancing the pumping action by increasing the flow rate of the lubricating oil. This, in turn, improves the effect of drawing external lubricating oil into the annular space.

[0030] With reference to this point, the aforementioned tapered roller bearing features a recessed section in the radially outer side surface of each columnar section. This recess allows adjacent pockets to communicate with each other. This facilitates the flow of lubricating oil near the outer ring raceway surface between adjacent pockets, thereby reducing turbulence and preventing excessive oil flow. Consequently, the pumping action is mitigated, preventing excessive oil flow into the annular space. Therefore, the amount of lubricating oil entering the annular space, which is an interior space of the bearing, can be precisely controlled.

[0031] In this way, according to the aforementioned tapered roller bearing, the amount of lubricating oil flowing into the interior of the bearing can be suppressed in order to reduce torque loss.

[0032] Since the circumferential speed of each columnar section is higher on the larger diameter side, the turbulence effect of the lubricating oil is enhanced, and the larger diameter section contributes more to the pumping action. Conversely, if the amount of lubricating oil flowing through the recessed section is increased, the pumping effect may be weakened.

[0033] Consequently, in the aforementioned tapered roller bearing, a bottom surface of the recess section is an inclined plane that is inclined with respect to the outer ring raceway surface, so that a gap between the bottom surface and the outer ring raceway surface gradually extends axially from the small diameter ring section towards the large diameter ring section.

[0034] In this case, the gap between the bottom surface and the outer ring raceway surface widens on the side with the larger diameter, where the turbulence effect is higher than on the side with the smaller diameter. Therefore, it is possible to increase the amount of lubricating oil flowing through the section on the side with the larger diameter, i.e., the section with a higher turbulence effect and a greater contribution to the pumping motion. This effectively reduces the pumping motion.

[0035] Additionally, in the aforementioned tapered roller bearing, it is preferable that the recessed section be positioned on a central axis of the outer ring raceway surface. In this case, sliding contact surfaces provided on a radially outer side surface of each columnar section can be located on the axially opposite sides of the recessed section. Thus, even if the recessed section is located on the radially outer side surface of the columnar section, the two sliding contact surfaces, which are axially separated, slid in contact on the axially opposite sides of the recessed section, preventing the cage from tilting while the sliding contact surfaces remain in constant sliding contact with the outer ring raceway surface.

[0036] In the aforementioned tapered roller bearing, the axial length of the recessed section can be defined within a range that is equal to or greater than 40% of the axial length of the outer ring raceway surface and equal to or less than 70% of the axial length of the outer ring raceway surface. If the axial length of the recessed section is less than 40% of the axial length of the outer ring raceway surface, the damping effect of the pumping motion is significantly impaired. If the axial length of the recessed section is greater than 70% of the axial length of the outer ring raceway surface, it becomes difficult to ensure a sufficient area for the respective sliding contact surface on the radially outer side surface of the columnar section.If the axial length of the recessed section is defined within a range equal to or greater than 40% of the axial length of the outer ring running surface and equal to or less than 70% of the axial length of the outer ring running surface, it is possible to effectively reduce the pumping motion while ensuring an area required as the respective sliding contact surface in the radially outer side surface of the column-shaped section.

[0037] In addition, in the aforementioned tapered roller bearing, it is preferable that a gap between a bottom surface of the recess section and the outer ring raceway surface is defined such that it is at least ten times larger than a gap required for the outer ring raceway surface and the sliding contact surface so that they are in sliding contact with each other at a bearing operating temperature.

[0038] If the gap between the bottom surface and the outer ring raceway surface is less than 10 times the gap required for the outer ring raceway surface and the sliding contact surface to be in sliding contact at the bearing operating temperature, it is difficult to get the lubricating oil to flow satisfactorily between adjacent pockets near the outer ring raceway surface. This worsens the pumping motion dampening effect. Therefore, if the gap between the bottom surface and the outer ring raceway surface is at least 10 times the gap required for the outer ring raceway surface and the sliding contact surface to be in sliding contact at the bearing operating temperature, the pumping motion can be effectively dampened.

[0039] In the aforementioned tapered roller bearing, an annular gap can be formed between an inner circumferential surface of the small-diameter ring section and an outer circumferential surface of the small shoulder section, the amount of lubricating oil, equal to or greater than a necessary amount, being restricted from flowing into the annular space; and a radially inner side surface of each column-shaped section is designed as a guide surface extending from an end section of the inner circumferential surface of the small-diameter ring section towards a base-end section of a large shoulder section provided on the other axial end face of the inner ring, so that the lubricating oil flowing through the annular gap into the annular space is guided to the base-end section of the large shoulder section.

[0040] In this case, a portion of the lubricating oil flowing through the annular gap from the outside of the bearing and into the annular space is transferred from the inner circumferential surface of the small-diameter annular section to the inner circumferential surface of each columnar section. Furthermore, since the inner circumference of the columnar section acts as a guide surface for directing the lubricating oil to the base end of the large shoulder section, the lubricating oil transferred to the inner circumferential surface of the columnar section can be directed to the base end of the large shoulder section. Thus, while the amount of lubricating oil flowing into the annular space is limited, the lubricating oil within the annular space can be aggressively directed to the immediate vicinity of a contact area, where the end face of each tapered roller and the large shoulder section make gentle sliding contact.Consequently, it is possible to reduce the sliding friction resistance between the end face of the tapered roller and the large shoulder section, while limiting the amount of lubricating oil flowing into the annular space. Furthermore, it is possible to suppress the occurrence of seizing caused by insufficient lubricating oil.

[0041] Additionally, in the aforementioned tapered roller bearing, it is preferable that the radially inner side surface be inclined relative to the inner ring raceway surface, such that the gap between the radially inner side surface and the inner ring raceway surface gradually narrows axially from the small-diameter ring section towards the large-diameter ring section. In this case, the lubricating oil can be guided smoothly, evenly, and gently across the inner circumferential surface of each columnar section to the base end of the large shoulder section, where there is no step or similar feature in the axial direction.

[0042] In the aforementioned tapered roller bearing, a groove section, radially recessed outwards, can be formed axially in the radially inner side surface. In this case, the lubricating oil transferred from the inner circumferential surface of the small-diameter annular section to the radially inner side surface of the columnar section can be retained in the groove section. Furthermore, the lubricating oil retained in the groove section can be guided along the groove section to the base end of the large shoulder section. Thus, the lubricating oil can be guided more reliably to the base end of the large shoulder section.

[0043] Additionally, in the aforementioned tapered roller bearing, the size of the annular gap at a bearing operating temperature can be specified such that it is larger than the size of a gap required for the outer ring raceway surface and the sliding contact surface to be in sliding contact with each other at a bearing operating temperature, and is at most three times the size of the gap.

[0044] The outer circumferential surface of the small shoulder section has a lower accuracy than the outer ring raceway surface, which is a (re-)machined surface with comparatively high accuracy / precision. Consequently, if the size of the annular gap at the bearing operating temperature is equal to or smaller than the gap required for the outer ring raceway surface and the sliding contact surface to be in sliding contact at that temperature, the annular gap can be narrowed more than necessary. This poses a risk of insufficient lubricating oil flow.

[0045] On the other hand, if the size of the annular gap at the bearing operating temperature is more than three times the size of the gap required for the outer ring raceway surface and the sliding contact surface to be in sliding contact with each other at the bearing operating temperature, there is a risk that more lubricating oil than necessary will be allowed to flow in.

[0046] If the size of the annular gap at the bearing operating temperature is specified to be larger than the size of the gap required for the outer ring raceway surface and the sliding contact surface to be in sliding contact with each other at the bearing operating temperature, and is at most three times the size of the required gap, the flow rate of the lubricating oil can be precisely limited.

[0047] To achieve the aforementioned second objective, the invention provides a tapered roller bearing comprising: an inner ring having an inner ring raceway surface; an outer ring arranged on an outer circumferential side of the inner ring and concentric to the inner ring, and having an outer ring raceway surface opposite the inner ring raceway surface; a plurality of tapered rollers positioned to roll between the inner ring raceway surface and the outer ring raceway surface;and a cage arranged in an annular space between the inner ring and the outer ring, holding the conical rollers, the cage comprising a small-diameter ring section, a large-diameter ring section opposite the small-diameter ring section at a predetermined distance, and a plurality of columnar sections situated between the small-diameter ring section and the large-diameter ring section, wherein spaces surrounded by adjacent columnar sections, the small-diameter ring section and the large-diameter ring section are designed as pockets to receive the conical rollers;the small-diameter ring section is arranged between a small shoulder section provided on an axial end face of the inner ring and an axial end section of the outer ring, and an inner circumferential surface and an outer circumferential surface of the small-diameter ring section can be in sliding contact with the small shoulder section and the axial end section of the outer ring, so that an annular opening section formed by the small shoulder section and the axial end section of the outer ring is closed, while an annular gap is formed between an inner circumferential surface of the small-diameter ring section and an outer circumferential surface of the small shoulder section to limit excess lubricating oil flowing into the annular space for the lubrication of the tapered roller bearing;and a radially inner side surface of each column-shaped section is designed as a guide surface extending from an end section of the inner circumferential surface of the small-diameter ring section towards a base-end section of a large shoulder section provided on the other axial end face of the inner ring, so that the lubricating oil flowing through the annular gap into the annular space is guided to the base-end section of the large shoulder section.

[0048] According to the tapered roller bearing configuration described above, the amount of lubricating oil flowing into the annular space can be suppressed by the small-diameter annular section. This reduces the torque loss caused by the rolling viscosity resistance of the tapered roller bearing and the turbulence resistance of the lubricating oil.

[0049] While the amount of lubricating oil flowing into the annular space is limited, a portion of the lubricating oil flowing from the outside of the bearing through the annular gap and into the annular space is transferred from the inner circumferential surface of the small-diameter annular section to the inner circumferential surface of each columnar section. Furthermore, since the inner circumference of the columnar section acts as a guide surface for directing the lubricating oil to the base-end section of the large shoulder section, the lubricating oil transferred to the inner circumferential surface of the columnar section can be guided to the base-end section of the large shoulder section.While the amount of lubricating oil flowing into the annular space is limited, the lubricating oil can thus be aggressively / proactively / intensively supplied to the immediate vicinity of a contact point where the end face of each tapered roller and the large shoulder section gently / frictionlessly slide into contact. Consequently, it is possible to reduce the sliding friction between the end face of the tapered roller and the large shoulder section, while limiting the amount of lubricating oil flowing into the annular space to reduce rotational torque. Furthermore, it is possible to suppress the occurrence of seizing caused by insufficient lubrication.

[0050] Additionally, in the aforementioned tapered roller bearing, it is preferable that the radially inner side surface be inclined relative to the inner ring raceway surface, such that the gap between the radially inner side surface and the inner ring raceway surface gradually narrows axially from the small-diameter ring section towards the large-diameter ring section. In this case, the lubricating oil can be guided smoothly and frictionlessly to the base-end section of the large shoulder section through the inner circumferential surface of each columnar section, where no step or similar feature is present in the axial direction.

[0051] In the aforementioned tapered roller bearing, a groove section can be formed axially in the radially inner side surface, which is recessed radially outwards. In this case, the lubricating oil transferred from the inner circumferential surface of the small-diameter annular section to the radially inner side surface of the columnar section can be retained in the groove section.

[0052] Furthermore, the lubricating oil held in the groove section can be guided along the groove section to the base-end section of the large shoulder section. This allows the lubricating oil to be guided more reliably to the base-end section of the large shoulder section.

[0053] Additionally, in the aforementioned tapered roller bearing, the size of the annular gap at a bearing operating temperature may be specified such that it is larger than the size of a gap required for the outer ring raceway surface and a sliding contact surface to be in sliding contact with each other at a bearing operating temperature, and is at most three times the size of the gap.

[0054] The outer circumferential surface of the small shoulder section has a lower accuracy than the outer ring raceway surface, which is machined with a comparably high precision. Consequently, if the annular gap at the bearing operating temperature is equal to or smaller than the gap required for the outer ring raceway surface and the sliding contact surface to be in sliding contact at that temperature, the annular gap may be narrowed more than necessary. This poses a risk of insufficient lubricating oil flow.

[0055] On the other hand, if the size of the annular gap at the bearing operating temperature is greater than three times the size of the gap required for the outer ring raceway surface and the sliding contact surface to be in sliding contact with each other at the bearing operating temperature, there is a risk that lubricating oil will flow in more than necessary or in excess.

[0056] If the size of the annular gap at the bearing operating temperature is specified to be larger than the size of the gap required for the outer ring raceway surface and the sliding contact surface to be in sliding contact with each other at the bearing operating temperature, and to be at most three times the size of the gap, the lubricating oil flow rate can be precisely limited.

[0057] In the aforementioned tapered roller bearing, it is preferable that a sliding contact surface is provided in a radially outer side surface of each column-shaped section and is in sliding contact with the outer ring raceway surface, so that the cage is radially positioned through the outer ring raceway surface.

[0058] In this case, the cage, guided by the outer ring raceway surface, can rotate continuously and precisely between the inner and outer rings, and the small-diameter ring section that seals the annular opening can also rotate continuously and precisely. Consequently, the annular opening can be sealed so reliably that the amount of lubricating oil entering the ring can be precisely controlled.

[0059] On the other hand, if the columnar sections of the cage are in sliding contact with the outer ring raceway surface, the turbulence effect of the lubricating oil near the outer ring raceway surface can be improved in the aforementioned tapered roller bearing, thus enhancing the pumping action effect due to the increasing flow rate of the lubricating oil. This, in turn, improves the effect of drawing external lubricating oil into the annular space.

[0060] With reference to this point, a recessed section can be provided in the radially outer side surface of each columnar section, and is radially recessed so that adjacent pockets are interconnected. In this case, the lubricating oil near the outer ring raceway surface can be directed to flow between adjacent pockets to weaken the turbulence effect, thereby suppressing an excessive increase in the lubricating oil flow rate. Thus, the pumping action effect can be weakened to prevent the lubricating oil from flowing excessively into the annular space. Consequently, the amount of lubricating oil entering the annular space, which is an interior space of the bearing, can be precisely limited.

[0061] To achieve the aforementioned third objective, the invention provides a tapered roller bearing comprising: an inner ring having an inner ring raceway surface and a large shoulder section in an axial end section; an outer ring arranged on an outer circumferential side of the inner ring and concentric to the inner ring, and having an outer ring raceway surface opposite to the inner ring raceway surface; and a plurality of tapered rollers arranged to roll between the two raceway surfaces.and a cage arranged in an annular space between the inner and outer rings, which holds the tapered rollers, wherein: the cage is a small-diameter ring section, a large-diameter ring section with a predetermined distance opposite the small-diameter ring section, and a plurality of columnar sections located between the two ring sections, wherein spaces surrounded by adjacent columnar sections and the ring sections are designed as pockets to receive the tapered rollers; a sliding contact surface is provided in a radially outer side surface of each columnar section, and is in sliding contact with the outer ring raceway surface, such that the cage is radially positioned by the outer ring raceway surface;an end section of a radially inner side surface of each columnar section is located on a side of the large-diameter ring section, on a radially inner side of an outer circumferential surface of the large shoulder section at an axial end section of the inner ring; and an inner circumferential side of a circumferential side surface of each columnar section is formed as a curved surface along a rolling surface of each tapered roller, and a circumferential width W2 of the radially inner side surface of each columnar section is further formed than a circumferential width W1 of the radially outer side surface of each columnar section.;

[0062] According to the configuration described above, when the column-shaped sections are in sliding contact with the outer ring raceway surface, the cage is positioned and guided radially to the outer ring raceway surface in order to rotate on / against it. Therefore, the cage can rotate continuously and precisely between the inner and outer rings.

[0063] Additionally, since the column-shaped sections are in sliding contact with the outer ring raceway surface, the lubricating oil can be prevented from flowing into the bearing interior, thus reducing the rolling viscosity resistance (depending on the amount of lubricating oil flowing in) or the turbulence resistance of the lubricating oil. This can reduce the torque loss of the tapered roller bearing.

[0064] Furthermore, the lubricating oil on the rolling surfaces of the tapered rollers can be scraped off by the inner circumferential surfaces of the columnar sections, thus reducing the amount of lubricating oil between each bearing ring and each tapered roller. This reduces the rolling viscosity resistance, thereby further reducing torque loss.

[0065] Additionally, because the cage is radially positioned as described above, the distance between the inner circumferential surface of each columnar section and the rolling surface of each tapered roller can be correctly maintained. This allows the lubricating oil to be effectively scraped from the rolling surfaces.

[0066] A gap in a radial direction between the inner circumferential side of each columnar section and the rolling surface can be larger than a gap in the same radial direction between the radially outer side surface of each columnar section and the outer ring raceway surface. According to this configuration, the outer ring can be well guided by the cage, and the torque loss caused by the contact between the cage and each tapered roller can be reduced.

[0067] Furthermore, in the radially inner side surface of each column-shaped section, a circumferential width W4 of the end section on the side of the ring section of large diameter can be more developed than a circumferential width W3 of an end section on a side of the ring section of small diameter.

[0068] According to this configuration, the area where the circumferential side surface of each columnar section overlaps with each tapered roller increases towards the large-diameter ring section when the columnar section is viewed radially. Thus, lubricating oil adhering to the side of the inner ring raceway surface of the tapered roller's rolling surface can be more effectively scraped off in a position closer to the large-diameter ring section. Therefore, the lubricating oil between each bearing ring and each tapered roller can be prevented from remaining on the side of the large-diameter ring section, and the lubricating oil can be released more quickly to the outside of the bearing. Consequently, the rolling viscosity resistance can be further reduced, thus further minimizing torque loss.

[0069] Additionally, the ratio W4 / W3 of the circumferential width W4 to the circumferential width W3 can be larger than the ratio R2 / R1 of a maximum outer diameter R2 to a minimum outer diameter R1 in each tapered roller.

[0070] According to this configuration, the portion where the circumferential side surface of each columnar section overlaps with each tapered roller, when the columnar section is considered radially, can be larger towards the large-diameter ring section than in the aforementioned case where the circumferential width W4 is larger than the circumferential width W3. This allows the lubricating oil adhering to the inner-ring raceway surface of the tapered roller's rolling surface to be scraped off more effectively at a position closer to the large-diameter ring section. Therefore, the lubricating oil can be transferred more quickly to the outer surface of the bearing. Consequently, the rolling viscosity resistance can be further reduced, thus further minimizing torque loss.

[0071] Furthermore, a guide groove or groove section for guiding lubricating oil to the large shoulder section can be axially formed in the radially inner side surface of each column-shaped section.

[0072] According to this configuration, the lubricating oil scraped from the rolling surfaces of each tapered roller by the circumferential side surface of each columnar section can be retained in the groove section. The lubricating oil can be prevented from returning to the rolling surfaces or similar. Additionally, the lubricating oil retained in the groove section can be guided along the groove section to the large shoulder section. Thus, the sliding frictional resistance between the large-diameter side end face of each tapered roller and the large shoulder section can be reduced, thereby suppressing the occurrence of seizing caused by insufficient lubrication.

[0073] Additionally, the width of the guide groove or groove section can gradually increase in the direction of the ring section with a large diameter.

[0074] Since the lubricating oil is scraped from the rolling surfaces of each tapered roller by the circumferential side surfaces, which extend axially in each columnar section, the amount of lubricating oil stored in the groove section increases towards the larger-diameter annular section. However, according to the configuration described above, the width of the groove section gradually increases towards the larger-diameter annular section. Therefore, it is possible to prevent the lubricating oil from overflowing the groove section and returning to the rolling surface or similar.

[0075] Additionally, a power transmission device according to the invention is characterized by: a transmission shaft; the aforementioned tapered roller bearing; and a bearing / support which rotatably / rotatably supports the transmission shaft through / over the tapered roller bearing.

[0076] According to this configuration, the transmission shaft is supported / mounted on the support / bearing by the tapered roller bearing according to the invention, which makes it possible to reduce torque loss, so that the power loss during power transmission through the transmission shaft can be reduced. Advantages of the invention

[0077] According to one configuration of the invention, it is possible to provide a tapered roller bearing which makes it possible to precisely suppress the amount of lubricating oil flowing into an interior of the bearing in order to reduce torque loss, and to provide a power transmission device which uses / employs / utilizes the tapered roller bearing.

[0078] According to another configuration of the invention, it is possible to provide a tapered roller bearing which makes it possible to limit the amount of lubricating oil flowing into an interior of the bearing in order to reduce the rotational torque, while reducing the sliding friction resistance in order to suppress the occurrence of seizing, and to provide a power transmission device which uses the tapered roller bearing. Brief description of the drawings [ Fig. 1] Fig. Figure 1 shows an axial sectional view of a tapered roller bearing according to an embodiment of the invention. [ Fig. 2] Fig. Figure 2 shows a partial perspective view of a cage as seen from the outer perimeter. [ Fig. 3] Fig. Figure 3 shows a partial sectional view of the cage as seen from the inner perimeter. [ Fig. 4] Fig. Figure 4 shows an axial sectional view of the tapered roller bearing, which represents a section of a column-shaped section. [ Fig. 5] Fig. 5 shows a sectional view along the arrow direction of line VV in Fig. 4. [ Fig. 6] Fig. Figure 6 shows a partially enlarged view of Fig. 5. [ Fig. 7] Fig. Figure 7 shows an explanatory view in which the columnar section etc. is shown in Fig. 6 viewed from the radially inner side. [ Fig. 8] Fig. Figure 8 shows an illustrative view of a power transmission device according to an embodiment of the invention. [ Fig. 9] Fig. 9(a) and Fig. Figure 9(b) shows main section views of a columnar section, which represents a modification / amendment example of a deepening section. [ Fig. 10] Fig. 10(a), Fig. 10(b) and Fig. Figure 10(c) shows main section views of a columnar section, which is a modification example of a grooved section. [ Fig. 11] Fig. Figure 11 shows an explanatory view that represents a modification example of a radially inner side surface. [ Fig. 12] Fig. Figure 12 shows an explanatory view that represents another modification example of a radially inner side surface. [ Fig. 13] Fig. Figure 13 shows an axial sectional view, which represents a related tapered roller bearing or a tapered roller bearing from the prior art. Embodiments of the invention

[0079] A preferred embodiment of the invention is described below with reference to the accompanying drawings. Fig. Figure 1 shows an axial sectional view of a tapered roller bearing according to the embodiment of the invention.

[0080] A tapered roller bearing 1 has an inner ring 2, an outer ring 3 which is arranged on the outer circumferential side of the inner ring 2 and concentric to the inner ring 2, and a plurality of tapered rollers 4 which are arranged between the inner and outer rings 2 and 3.

[0081] The inner ring 2 is a ring-shaped part made of bearing steel, steel for mechanical engineering, or similar materials. An inner ring raceway surface 2a is formed on the outer circumference of the inner ring 2, allowing the tapered rollers 4 to roll on the inner ring raceway surface 2a.

[0082] The outer ring 3 is also a ring-shaped component, manufactured in the same way as the inner ring 2 from bearing steel, engineering steel, or similar materials. An outer ring raceway surface 3a is formed on the inner circumference of the outer ring 3, such that the outer ring raceway surface 3a is opposite to the inner ring raceway surface 2a, allowing the tapered rollers 4 to roll on the outer ring raceway surface 3a. The raceway surfaces 2a and 3a are precision-machined (super-finished).

[0083] The tapered rollers 4 are parts made of bearing steel or similar material. The tapered rollers 4 are mounted to roll between the inner ring raceway surface 2a and the outer ring raceway surface 3a. One small-diameter end face 4a and one large-diameter end face 4b of each tapered roller are precision-machined (super-finished).

[0084] The tapered roller bearing 1 has a holder / cage 10 which holds the tapered rollers 4.

[0085] Fig. Figure 2 shows a partial perspective view of cage 10, viewed from the outer perimeter. Fig. Figure 3 shows a partial perspective view of cage 10, viewed from the inner perimeter. As in Fig. 1 to Fig. As shown in Figure 3, the cage 10 is a part made of a synthetic resin and manufactured by injection molding or a similar process. The cage 10 has a pair of ring sections 11 and 12 (a small-diameter ring section 11 and a large-diameter ring section 12) which are opposite each other at a predetermined distance, and a plurality of columnar sections 13 which are arranged circumferentially at predetermined intervals between the ring sections 11 and 12. Spaces enclosed by the paired ring sections 11 and 12 and two adjacent columnar sections 13 form pockets 14 for receiving and holding the respective conical rollers 4.

[0086] The cage 10 is arranged in a bearing interior S, which is an annular space formed between the inner ring 2 and the outer ring 3. The cage 10 receives the tapered rollers 4 in the pockets 14 and holds the tapered rollers 4 in such a way that the tapered rollers 4 can be arranged circumferentially at substantially equal intervals.

[0087] Of the two ring sections 11 and 12, the ring section side surfaces 11c and 12c facing the pockets 14 are in sliding contact with the small-diameter lateral end face 4a / end face on the small-diameter side 4a and the large-diameter lateral end face / end face on the large-diameter side 4b of each tapered roller 4, so that the cage 10 can be restricted from moving axially. That is, the two ring sections 11 and 12 are in sliding contact with the end faces 4a and 4b of the tapered rollers 4 to position the cage 10 axially.

[0088] Additionally, the cage 10 has radially outer side surfaces 13a of the columnar sections 13 formed to be in sliding contact with the outer ring raceway surface 3a, so that the radially outer side surfaces 13a can rotate circumferentially relative to the outer ring raceway surface 3a while slidingly contacting it. Thus, the cage 10 is radially positioned by the outer ring raceway surface 3a.

[0089] The small-diameter ring section 11 of the cage 10 is an annular part configured to have a radial thickness exactly equal to the radial thickness of each column-shaped section 13. The small-diameter ring section 11 is positioned between a small shoulder section 5, located on an axial end face of the inner ring 2, and an axial end section 6 of the outer ring 3. Thus, an inner circumferential surface 11a and an outer circumferential surface 11b of the small-diameter ring section 11 can be in sliding contact with the small shoulder section 5 and the axial end section 6 of the outer ring 3 to close a small-diameter lateral opening section / opening section on the small-diameter side A1, which is formed by the small shoulder section 5 and the axial end section 6 of the outer ring 3.

[0090] The outer circumferential surface 11b of the small-diameter ring section 11 is designed as a conical surface extending directly from a radially outer side surface 13a of each columnar section 13, and is in sliding contact with the outer ring raceway surface 3a. A gap (clearance) required to ensure that the outer ring raceway surface 3a and the radially outer side surface 13a of the columnar section 13 are in sliding contact with each other at the operating temperature at which the tapered roller bearing 1 is to be operated is provided between the outer ring raceway surface 3a and the radially outer side surface 13a.A first annular gap K1, which is a gap that is the same size as the aforementioned free space, is provided between the outer circumferential surface 11b of the ring section of small diameter 11 and an inner circumferential surface 6a of one axial end section 6 of the outer ring 3.

[0091] The inner circumferential surface 11a of the small-diameter ring section 11 is essentially cylindrical. Consequently, there is a difference in the angle of inclination between the inner circumferential surface 11a and a radially inner side surface 13b, which, like the radially outer side surface 13a, is formed as a conical surface.

[0092] A second annular gap K2 is provided as a gap that is required to ensure that the inner circumferential surface 11a of the small diameter ring section 11 and an outer circumferential surface 5a of the small shoulder section 5 are in sliding contact with each other, also between the inner circumferential surface 11a of the small diameter ring section 11 and the outer circumferential surface 5a of the small shoulder section 5.

[0093] In this way, the small-diameter ring section 11 closes the small-diameter lateral opening section A1, while the annular gaps K1 and K2 are secured by the small shoulder section 5 and the single axial end section 6 of the outer ring 3, respectively. The annular gaps K1 and K2, which are formed on an axial end face when the small-diameter lateral opening section A1 is closed, serve as inlets through which lubricating oil can flow into the bearing interior S to lubricate the tapered roller bearing 1.

[0094] When the inner and outer rings 2 and 3 rotate relative to each other in the tapered roller bearing 1, the lubricating oil present in the bearing interior S is agitated / swirled by the rotations / rollings of the tapered rollers 4 etc., and a centrifugal force acts on the lubricating oil in such a way that a pumping motion can be generated to move the lubricating oil within the bearing interior S from a part of smaller diameter to a part of larger diameter on each raceway surface 2a, 3a.

[0095] The tapered roller bearing 1 according to the embodiment is usually used in a condition in which the tapered roller bearing 1 is partially or completely immersed in the lubricating oil.

[0096] Thus, due to the aforementioned pumping action, the lubricating oil flows through the small-diameter lateral opening section A1 into the bearing interior S. However, according to the embodiment, the small-diameter annular section 11 in the tapered roller 1 closes the small-diameter lateral opening section A1, while ensuring the annular gaps K1 and K2 remain open. Therefore, the lubricating oil flowing into the bearing interior S is limited to the oil passing through the annular gaps K1 and K2.

[0097] The first annular gap K1 and the second annular gap K2 allow the lubricating oil to flow through here, but limit the excess lubricating oil (more than necessary) for lubrication within the tapered roller bearing 1 from flowing into the bearing interior S.

[0098] This means that the small diameter ring section 11 closes the small diameter side opening section A1 in order to limit the excess lubricating oil flowing into the bearing interior S.

[0099] If the amount of lubricating oil flowing into the bearing interior S is greater than is necessary for lubrication, there is a risk that the rotational torque of the tapered roller bearing 1 may be increased due to the turbulence resistance of the lubricating oil or the rolling viscosity resistance.

[0100] With regard to this point, the amount of lubricating oil flowing into the bearing interior S is limited (suppressed) by the small diameter ring section 11 according to the embodiment, so that the rotational torque of the tapered roller bearing 1 can be reduced.

[0101] Here, the amount of lubricating oil required to lubricate the tapered roller bearing 1 is small. If a small gap is provided to allow the lubricating oil to flow into the bearing interior S, the necessary amount of lubricating oil can be ensured.

[0102] Consequently, the gap sizes of the first annular gap K1 and the second annular gap K2 are set to values ​​that are as small as possible within a range that allows the lubricating oil to flow through here, but does not affect the operation of each section.

[0103] As described above, the gap size of the first annular gap K1 is set such that it is the same size as the clearance required to ensure that the outer ring raceway surface 3a and the radially outer side surface 13a are in sliding contact with each other at an operating temperature at which the tapered roller bearing 1 should be operated.

[0104] If the tapered roller bearing 1, for example, measures 30 to 40 mm in inner diameter and 70 to 80 mm in outer diameter, the clearance required for the outer ring raceway surface 3a and the radially outer side surface 13a to be in sliding contact with each other at the operating temperature at which the tapered roller bearing 1 should be operated is specified such that it is at least 100 µm between these diameters. If the clearance is less than 100 µm, there is a risk that the (contact) surface pressure between the radially outer side surface 13a of the cage 10 and the outer ring raceway surface 3a may be so high that the cage 10 cannot make smooth / frictionless contact with the outer ring raceway surface 3a.

[0105] If the clearance is specified to be equal to or greater than at least 100 µm, the cage 10 and the outer ring raceway surface 3a can be in soft / gentle / smooth / effortless sliding contact with each other.

[0106] Additionally, as described above, the first annular gap K1 is defined such that it is the same size as the aforementioned free space. Therefore, the first annular gap K1 is defined in the same way as the free space, and is to be at least 100 µm.

[0107] If the operating temperature at which the tapered roller bearing 1 should be operated is 150 °C, the clearance that is thus set at a normal temperature is shifted from its intended clearance below the operating temperature due to a difference in the coefficient of thermal expansion between different materials of the outer ring 3 and the cage 10.

[0108] Therefore, if the tapered roller bearing 1 has the aforementioned dimensions and the cage 10 is made of polyphenylene sulfite (PPS), the clearance is set to be at least 200 µm at normal temperature when comparing these diameters. If the outer ring 3 and the cage 10 expand thermally at the operating temperature of 150 °C, the clearance can thus be set to be at least 100 µm when comparing these diameters.

[0109] The gap size of the second annular gap K2 at operating temperature is specified to be larger than the free space and gap size of the first annular gap K1 at operating temperature, and to be at most twice as large as the free space and gap size of the first annular gap K1.

[0110] The outer circumferential surface 5a of the small shoulder section 5 has a lower accuracy / precision than the outer ring raceway surface 3a, which is a machined (e.g., finely machined, super-finished) surface with comparatively high accuracy / precision. Consequently, if the size of the second annular gap K2 at operating temperature is equal to or smaller than the clearance required for the outer ring raceway surface 3a and the radially outer side surface 13a to be in sliding contact at the bearing operating temperature, there is a risk that the second annular gap K2 may be narrowed more than necessary. This, in turn, creates a risk that the required lubricating oil flow rate cannot be guaranteed.Furthermore, there is a risk that the (contact) surface pressure between the outer ring raceway surface 3a and the radially outer side surface 13a may be greater than necessary to generate a rotational resistance between the outer ring 3 and the cage 10.

[0111] On the other hand, if the size of the second annular gap K2 at operating temperature is more than three times the size of the free space at bearing operating temperature, there is a risk that more lubricating oil than necessary for lubrication may be allowed to flow in.

[0112] If the size of the second annular gap K2 at operating temperature is specified to be larger than the free space at bearing operating temperature and at most three times the size of the free space, the lubricating oil inflow quantity can be limited exactly / correctly.

[0113] For example, if the clearance between the diameters at normal temperature is set to 200 µm and the clearance at operating temperature is 100 µm, the gap size of the second annular gap K2 is set to be greater than 100 µm but equal to or less than 200 µm at normal temperature, and greater than 200 µm but equal to or less than 300 µm at operating temperature.

[0114] Although the case in which the size of the second annular gap K2 at operating temperature is set to be a maximum of three times the size of the free space has been described above, it is more advantageous to set the size of the second annular gap K2 at operating temperature to be a maximum of twice the size of the free space. This allows the lubricating oil flow rate to be limited more precisely.

[0115] In this way, the gap sizes of the first annular gap K1 and the second annular gap K2 are set to values ​​that are as small as possible within a range that allows the lubricating oil to flow through, but does not affect the operation of each section.

[0116] The large diameter ring section 12 of the cage 10 is an annular part that is arranged between a large shoulder section 7, which is provided on the other axial end face of the inner ring 2, and the other axial end section 8 of the outer ring 3.

[0117] The radial thickness of the large-diameter ring section 12 is smaller than the radial thickness of each columnar section 13. Thus, as in Fig. 2 and Fig. As shown in Figure 3, the large-diameter ring section 12 is designed such that the radially inner side surface 13b and the radially outer side surface 13a of each columnar section 13 can form radial steps with the inner circumferential surface 12a and the outer circumferential surface 12b of the large-diameter ring section 12. That is, the columnar section 13 has an inner circumferential end surface 13c, which connects the step between the radially inner side surface 13b of the columnar section 13 and the inner circumferential surface 12a of the large-diameter ring section 12, and has an outer circumferential end surface 13d, which connects the step between the radially outer side surface 13a of the columnar section 13 and the outer circumferential surface 12b of the large-diameter ring section 12.

[0118] As in Fig. As shown in Figure 1, the large-diameter ring section 12 is arranged in a large-diameter lateral opening section / annular opening section on the large-diameter side A2, which is formed by the large shoulder section 7 and the other axial end section 8. A comparatively large gap is formed between the inner circumferential surface 12a of the large-diameter ring section 12 and an outer circumferential surface 7a of the large shoulder section 7. Additionally, a comparatively large gap is also formed between the outer circumferential surface 12b of the large-diameter ring section 12 and an inner circumferential surface 8a of the other axial end section 8. These gaps, which are formed between the large-diameter ring section 12 and the inner and outer rings 2 and 3, are such that they are larger than the aforementioned annular gaps K1 and K2.

[0119] These gaps, which are formed in the annular opening section A2 on the other end face and are formed between the ring section of large diameter 12 and the inner and outer rings 2 and 3, serve as outlet nozzles / outlet interfaces for the lubricating oil, which flows into the bearing interior S due to the aforementioned pumping movement.

[0120] This means that the lubricating oil, which flows into the bearing interior S due to the aforementioned pumping action, is used for lubrication in the bearing interior S and is discharged through the annular opening section A2 on the other end face.

[0121] In this embodiment, the gaps formed between the large-diameter ring section 12 and the inner and outer rings 2 and 3 are larger than the aforementioned annular gaps K1 and K2. Consequently, the lubricating oil, which would otherwise flow outwards to the outside of the tapered roller bearing 1, can be quickly discharged to the outside.

[0122] Fig. Figure 4 shows an axial sectional view of the tapered roller bearing 1, which represents a section of a column-shaped section 13.

[0123] See also Fig. 2 and Fig. 3. Each column-shaped section 13 of the cage 10 is positioned radially through the outer ring raceway surface 3a when the radially outer side surface 13a is rotated circumferentially relative to the outer ring raceway surface 3a while in sliding contact with the outer ring raceway surface 3a.

[0124] In the radially outer side surface 13a of the columnar section 13, a small-diameter lateral sliding contact surface is provided on the small-diameter side 15, and a large-diameter lateral sliding contact surface is provided on the large-diameter side 16, respectively, in the axial direction on the side of the small-diameter ring section 11 and in the axial direction on the side of the large-diameter ring section 12. The sliding contact surface on the small-diameter side 15 and the sliding contact surface on the large-diameter side 16 are each designed as curved surfaces along the outer ring raceway surface 3a and are designed to be in sliding contact with the outer ring raceway surface 3a.The sliding contact surface on the small diameter side 15 and the sliding contact surface on the large diameter side 16 are in sliding contact with the outer ring raceway surface 3a in such a way that the cage 10 can be positioned radially through the outer ring raceway surface 3a.

[0125] Furthermore, as described above, the inner circumferential surface 11a of the small-diameter ring section 11 in the cage 10 is designed such that it is in sliding contact with the outer circumferential surface 5a of the small shoulder section 5 of the inner ring 2. The inner circumferential surface 11a of the small-diameter ring section 11 is cylindrical parallel to the axial direction in order to be in sliding contact with the cylindrical outer circumferential surface 5a.

[0126] On the other hand, the sliding contact surface on the small diameter side 15 and the sliding contact surface on the large diameter side 16 are designed as conical surfaces which are in sliding contact with the outer ring raceway surface 3a.

[0127] In this way, the cage is in sliding contact with the outer circumferential surface 5a on the side of the inner ring 2 and with the outer ring raceway surface 3a on the side of the outer ring 3. The outer circumferential surface 5a and the outer ring raceway surface 3a are formed with different angles of inclination relative to each other. Due to this configuration, the cage 10 can be securely positioned radially.

[0128] Additionally, since the sliding contact surface on the small-diameter side 15 is in sliding contact with the outer ring raceway surface 3a, the lubricating oil can be prevented from flowing into the bearing interior S between the cage 10 and the outer ring raceway surface 3a, thus reducing the rolling viscosity resistance depending on the amount of lubricating oil flowing in or the turbulence resistance of the lubricating oil. This reduces the torque loss of the tapered roller bearing 1.

[0129] A recessed section 17, radially recessed / recessed relative to the sliding contact surface on the small-diameter side 15 and the sliding contact surface on the large-diameter side 16, is formed between the sliding contact surface on the small-diameter side 15 and the sliding contact surface on the large-diameter side 16. Such a recessed section 17 is formed in each column-shaped section 13. The recessed section 17 is positioned to be located substantially in the center of the outer ring raceway surface 3a in the axial direction. The sliding contact surface on the small-diameter side 15 and the sliding contact surface on the large-diameter side 16 are located on axially opposite sides of the recessed section 17.

[0130] In this way, the sliding contact surface on the small-diameter side 15 and the sliding contact surface on the large-diameter side 16 can each be in sliding contact with the end section on the small-diameter side and the end section on the large-diameter side of the outer ring raceway surface 3a in the axial direction. Therefore, even if the recessed section 17 is provided in the radially outer side surface 13a of each columnar section 13, there is no risk of the cage 10 being inclined with respect to the axial direction; rather, the sliding contact surface on the small-diameter side 15 and the sliding contact surface on the large-diameter side 16 can be designed such that they are in constant sliding contact with the outer ring raceway surface 3a.

[0131] In addition, the depression section 17 is deepened over the entire circumference of the columnar section 13, so that adjacent pockets 14 are connected to each other.

[0132] Here, in the tapered roller bearing 1 according to the embodiment, the amount of lubricating oil flowing into the bearing interior S can be suppressed by the small diameter ring section 11 of the cage 10, so that the torque loss can be reduced.

[0133] Additionally, the column-shaped sections 13 are in sliding contact with the outer ring raceway surface 3a, allowing the cage 10 of the tapered roller bearing 1 to be radially positioned and guided by the outer ring raceway surface 3a for rotation. Thus, the cage 10 can rotate continuously and precisely between the inner and outer rings 2 and 3, and the small-diameter ring section 11, which closes the small-diameter lateral opening section A1, can also rotate continuously and precisely. Consequently, the small-diameter lateral opening section A1 can remain permanently closed, and the amount of lubricating oil flow can be precisely controlled.

[0134] However, when the columnar sections 13 of the cage 10 are in sliding contact with the outer ring raceway surface 3a in the tapered roller bearing 1, the turbulence effect of the lubricating oil near the outer ring raceway surface 3a is improved, thus enhancing the pumping action effect through the increased flow rate of the lubricating oil. This, in turn, improves the effect of drawing external lubricating oil into the bearing interior S.

[0135] With regard to this point, in the tapered roller bearing 1 according to the embodiment, the recessed section 17 is provided in the radially outer side surface 13 of the cage 10 and radially recessed, so that adjacent pockets 14 are interconnected. Thus, the lubricating oil near the outer ring raceway surface 3a can be forced to flow between adjacent pockets 14 to weaken the turbulence effect and thus prevent the flow rate of the lubricating oil from increasing excessively. This weakens the effect of the pumping motion, preventing the lubricating oil from flowing excessively into the bearing interior S. Consequently, the amount of lubricating oil flowing into the bearing interior S can be precisely limited.

[0136] In this way, the amount of lubricating oil flowing into the bearing interior S in the tapered roller bearing 1 according to the embodiment can be precisely suppressed / limited in order to reduce the torque flow.

[0137] A bottom surface 17a of each recess section 17 is formed as an arc with its center on the central axis of the tapered roller bearing 1 in the axial direction. Additionally, a gap T ( Fig. 4) between the bottom surface 17a of the recessed section 17 and the outer ring raceway surface 3a, specified to be at least ten times larger than the gap (the aforementioned free space) required to ensure that the two sliding contact surfaces 15 and 16 are in sliding contact with the outer ring raceway surface 3a at the operating temperature at which the tapered roller bearing 1 should be operated.

[0138] If, for example, the clearance at the operating temperature of 150 °C is set to 100 µm, as described above, the gap T is set to be at least 1 mm.

[0139] If the gap T is less than ten times the free space at the operating temperature of the tapered roller bearing 1, it is difficult to allow the lubricating oil near the outer ring raceway surface 3a to flow satisfactorily between adjacent pockets 14. This impairs the pumping motion damping effect. Therefore, the gap T is set to be at least ten times the free space at operating temperature to effectively dampen the pumping motion.

[0140] Furthermore, if the gap T increases, the amount of lubricating oil flowing through the recessed section 17 can be increased, thus weakening the effect of the pumping action. However, if the gap T is too large, the radial thickness of the columnar section 13 is reduced. This could compromise the strength of the columnar section 13. Therefore, the gap T is set within a range that ensures the necessary strength of the columnar section 13.

[0141] Since the circumferential speed of the columnar section 13 is higher on the larger diameter side, the effect of the lubricating oil turbulence is enhanced, and the larger diameter section contributes more to the pumping motion. Conversely, if the amount of lubricating oil flowing through the recessed section 17 increases as described above, the effect of the pumping motion may be weakened.

[0142] Consequently, the bottom surface 17a of the recessed section 17 in the embodiment is designed such that it is linearly inclined with respect to the outer ring raceway surface 3a, so that the gap T can gradually extend axially from the ring section of small diameter 11 towards the ring section of large diameter 12.

[0143] In this way, the gap T widens on the large-diameter side, where the turbulence effect is higher than on the small-diameter side. Therefore, it is possible to increase the amount of lubricating oil flowing through the gap T into a section closer to the large-diameter ring section 12, which exhibits a higher turbulence effect and contributes more to the pumping motion. Thus, the pumping motion can be effectively reduced with a balanced ratio / equilibrium between the small-diameter and large-diameter sides.

[0144] Additionally, the radial depth of the recessed section 17 can be reduced in a portion on the side with a small diameter, which contributes relatively little to the pumping motion in the columnar section 13. Therefore, the radial thickness of the columnar section 13 does not need to be significantly reduced. This means that, in this case, the recessed section 17 is designed such that its radial depth can increase only to the necessary extent, advantageously to ensure the required strength of the columnar section 13.

[0145] An axial length L ( Fig. 4) The axial length of the recessed section 17 is defined within a range of 40% or less than 70% of the axial length of the outer ring raceway surface 3a. If the axial length L of the recessed section 17 is less than 40% of the axial length of the outer ring raceway surface 3a, the damping effect of the pumping motion is significantly impaired. If the axial length L of the recessed section 17 is greater than 70% of the axial length of the outer ring raceway surface 3a, it is difficult to ensure a range sufficient for each of the two sliding contact surfaces 15 and 16 on the radially outer side surface 13a.If the axial length L of the recessed section 17 is set within a range equal to or greater than 40% of the axial length of the outer ring raceway surface 3a and equal to or less than 70% of the same, it is possible to effectively weaken the pumping motion while ensuring an area required as each of the two sliding contact surfaces 15 and 16.

[0146] Fig. 5 shows a sectional view along the arrow direction of line VV in Fig. 4. Fig. Figure 6 shows a partially enlarged view of Fig. 5.

[0147] As in Fig. 4 to Fig. As shown in Figure 6, the radially inner side surface 13b of each column-shaped section 13 is arranged on the radially inner side of a pitch circle / rolling circle C, the center of which is on the axis of each tapered roller 4, and an end section of the radially inner side surface 13b on the side of the large diameter ring section 12 is arranged on the radially inner side of the outer circumferential surface of the large shoulder section 7.

[0148] A circumferential side surface 13e of each columnar section 13, which faces the inside of each pocket 14, is defined by a flat surface section 20 and a curved surface section 21, as shown in Fig. Figure 5 shows the formation. The flat surface section 20 extends like a flat surface in the radial direction from a circumferential edge 13a1 of the radially outer side surface 13a inwards. The curved surface section 21, which is connected to a radial end section of the flat surface section 20, extends further inwards in the radial direction.

[0149] Each flat surface section 20 extends to a position beyond the approximate midpoint of the radial distance between the outer ring raceway surface 3a and the inner ring raceway surface 2a. In other words, the radially inner end section of the flat surface section 20 is located on the inner diameter side of the rolling circle of each tapered roller 4. The flat surface section 20 is formed as a flat surface axially parallel to a straight line P, by which the axial center of the tapered roller 4 received in the pocket 14, facing the flat surface section 20, is connected to the axial center of the tapered roller bearing 1. Thus, opposing flat surface sections 20 forming a pocket 14 are axially parallel to each other.The circumferential distance / distance in the direction of rotation between the opposing flat surface sections 20 is designed to be slightly larger than the outer diameter of the tapered roller 4, so that a small gap can be provided between a rolling surface 4c of the tapered roller 4 and each flat surface section 20.

[0150] In this way, the opposing flat surface sections 20 forming a pocket 14 are axially parallel to each other, so that the holding capacity of the tapered roller 4 can be improved.

[0151] The curved surface section 21 is designed as a surface curved along the rolling surface of the tapered roller 4. The curved surface section 21 extends from a radial end section of the flat surface section 20 to a circumferential edge (distal end) 13b1 of the radially inner side surface 13b of the columnar section 13. The edge (distal end) 13b1 can be considered a radially inner edge of the curved surface section 21. A connection point H between the flat surface section 20 and the curved surface section 21 is located on the radially inner side of the rolling circle C, the center of which lies on the axis of the tapered roller 4.

[0152] The curved surface section 21 is designed as a curved surface along the side of the inner ring raceway surface 2a of the rolling surface 4c of the tapered roller 4. The circumference of the curved surface section 21 of the columnar section 13 gradually widens inwards in the radial direction. A circumference W2 of the radially inner side surface 13b is designed to be wider than a circumference W1 of the radially outer side surface 13a of the columnar section 13.

[0153] Additionally, an angled section (a distal end section or a corner section) 30 is formed by a circumferential end section of the radially inner side surface 13b and the radially inner end section of the curved surface section 21. The distal end of the angled section 30 is formed as the circumferential edge (radially inner edge of the curved surface section 21) 13b1 of the radially inner side surface 13b. The angle between the circumferential end section of the radially inner side surface 13b and the radially inner end section of the curved surface section 21 is acute or preferably equal to or less than 60°. Thus, the angled section 30 is acute.

[0154] According to the configuration described above, the curved surface section 21 can be located near the side of the inner ring raceway surface 2a of the rolling surface 4c of the tapered roller 4. This allows excess lubricating oil (more than required for lubrication) adhering to the side of the inner ring raceway surface 2a of the rolling surface 4c to be scraped off by the curved surface section 21.

[0155] In particular, the radially inner end section of the curved surface section 21 is the closest to the side of the inner ring raceway surface 2a of the rolling surface 4c, while the angled section 30, formed by the radially inner end section of the curved surface section 21 and the circumferential end section of the radially inner side surface 13b, is acute-angled. Consequently, excess lubricating oil can be effectively scraped from the side of the inner ring raceway surface 2a of the rolling surface 4c by the angled section 30. When this scraping occurs, excess lubricating oil between the inner and outer rings 2 and 3, and each of the tapered rollers 4, can be reduced to decrease rolling viscosity. Thus, the torque loss can be further reduced.

[0156] Additionally, in the aforementioned event, the sliding contact surface on the small diameter side 15 and the sliding contact surface on the large diameter side 16 are in sliding contact with the outer ring raceway surface 3a, so that the cage 10 can be radially positioned by the outer ring raceway surface 3a. Thus, the interval (gap or distance) between the curved surface section 21 and the rolling surface 4c of the tapered roller 4 can be maintained correctly / exactly, and excess lubricating oil can be effectively scraped off.

[0157] Furthermore, assuming that the radial length D of the clearance (gap) between the outer ring raceway surface 3a and the radially outer side surface 13a of each columnar section 13 is fixed at 100 µm, as described above, the columnar section 13, i.e., the cage 10, can move 100 µm outwards in the radial direction. To prevent the circumferential side surface 13e of the columnar section 13 from contacting the rolling surface 4c of the tapered roller 4 due to this movement, a radial distance L1 from the junction H between the flat surface section 20 and the curved surface section 21 to the rolling circle C is fixed at approximately 200 µm.

[0158] Additionally, the interval (distance) between the curved surface section 21 and the rolling surface 4c of the tapered roller 4 is specified as being 200 to 800 µm long with respect to the radial direction of the tapered roller 4. With this interval set to 200 to 800 µm, a correct quantity of lubricating oil can be easily maintained between the curved surface section 21 and the rolling surface 4c of the tapered roller 4 due to surface tension. Thus, the tapered roller 4 can roll smoothly and easily, reducing torque loss.

[0159] The reason the aforementioned interval is larger than 200 µm is to prevent the curved surface section 21 and the tapered roller 4 from touching each other, even when the cage 10 moves 100 µm outwards in the radial direction, as described above. In other words, if the aforementioned interval were smaller than 200 µm, the curved surface section 21 and the tapered roller 4 would touch each other so readily that the outer ring 3 could not be properly guided by the cage 10.

[0160] On the other hand, if the aforementioned interval is greater than 800 µm, a correct / exact quantity of lubricating oil cannot be easily retained between the curved surface section 21 and the rolling surface 4c of the tapered roller 4. Furthermore, if the interval is greater than 800 µm, excess lubricating oil cannot be effectively scraped from the rolling surface 4c of the tapered roller 4.

[0161] Furthermore, if the gap (interval) between the curved surface section 21 and the rolling surface 4c of the tapered roller 4 is defined as described above, the length E of the gap between the radially inner edge 13b1 of the curved surface section 21 and the rolling surface 4c, with respect to the radial direction of the tapered roller bearing (i.e., minimum length of the gap between the curved surface section 21 and the rolling surface 4c, with respect to the radial direction of the tapered roller bearing) is greater than the radial length D of the gap (clearance) between the outer ring raceway surface 3a and the radially outer side surface 13a of the columnar section 13. Thus, the outer ring 3 can be well guided by the cage 10, while the torque loss caused by the contact between the cage 10 and the tapered roller 4 can be reduced.

[0162] The radially inner side surface 13b of the column-shaped section 13 is designed such that its circumference extends from the ring section of small diameter 11 towards the ring section of large diameter 12, as shown in Fig. As shown in Figure 3, it can gradually increase. In addition, the radially outer side surface 13a of the column-shaped section 13 is also designed such that its circumference can increase / rise in the same way from the ring section of small diameter 11 towards the ring section of large diameter 12.

[0163] The radially inner side surface 13b is designed such that the increase in the circumferential width, which increases in the direction of the ring section of large diameter 12, is greater than in the radially outer side surface 13a.

[0164] With reference to Fig. 4. The radially inner side surface 13b of the columnar section 13 extends in a straight line between an axial inner edge 11a1 of the inner circumferential surface 11a (inner circumferential surface end section) of the small-diameter ring section 11 and an inner circumferential edge 13c1 of the inner circumferential end surface 13c. The inner circumferential edge 13c1 of the columnar section 13 extends to the immediate vicinity of a base end section 7b of the large shoulder section 7. Thus, the radially inner side surface 13b extends from the axially inner edge 11a1 of the small-diameter ring section 11 towards the base end section 7b of the shoulder section 7.

[0165] More precisely, the radially inner side surface 13b of the column-shaped section 13 is inclined such that its diameter can increase axially from the small-diameter ring section 11 towards the large-diameter ring section 12. Furthermore, the radially inner side surface 13b is designed as a slope inclined towards the inner ring race surface 2a, so that the gap between the radially inner side surface 13b and the inner ring race surface 2a can be gradually narrowed axially from the small-diameter ring section 11 towards the large-diameter ring section 12.

[0166] Fig. Figure 7 shows an explanatory view in which the columnar section 13 etc. is shown in Fig. 6 viewed from the radially inner side.

[0167] As in Fig. As shown in Figure 7, the circumferential edge 13b1 of the radially inner side surface 13b of each columnar section 13 is formed as a straight line inclined with respect to the axial direction. In the radially inner side surface 13b, the circumferential width W4 in the end section on the side of the large-diameter ring section 12 is larger than the circumferential width W3 in the end section on the side of the small-diameter ring section 11. Thus, the portion G where the circumferential side surface 13e of each columnar section 13 overlaps with each tapered roller 4 increases towards the large-diameter ring section 12 when the columnar section 13 is viewed radially. Furthermore, the ratio W4 / W3 of the circumferential width W4 to the circumferential width W3 is larger than the ratio R2 / R1 of the maximum outer diameter R2 to the minimum outer diameter R1 in each tapered roller.Thus, the overlapping part G can be made larger in the direction of the ring section with large diameter 12.

[0168] If the radially inner side surface 13b of each columnar section 13 is designed in this way, excess lubricating oil adhering to the side of the inner ring raceway surface 2a of the rolling surface 4c of each tapered roller 4 can be more satisfactorily scraped off in a position closer to the large-diameter ring section 12. Therefore, there is no risk of excess lubricating oil remaining between each of the inner and outer rings 2 and 3 and each tapered roller 4 on the side of the large-diameter ring section 12; instead, the excess lubricating oil can be released more quickly to the outside of the bearing 1. Consequently, the rolling viscosity can be further reduced, thus further reducing torque loss.

[0169] As described above, the second annular gap K2, through which lubricating oil more than is required to lubricate the tapered roller bearing 1 can be restricted from flowing into the bearing interior S, is provided between the inner circumferential surface 11a of the small diameter ring section 11 and the outer circumferential surface 5a of the small shoulder section 5.

[0170] Consequently, while the amount of lubricating oil flowing into the bearing interior S is limited, some of the lubricating oil flowing into the bearing interior S through the second annular gap K2 due to the pumping motion is transferred from the inner circumferential surface 11a of the small diameter annular section 11 to the radially inner side surface 13b of each columnar section 13.

[0171] The radially inner side surface 13b of the columnar section 13 is inclined such that its diameter increases axially from the small-diameter ring section 11 to the large-diameter ring section 12. Consequently, when lubricating oil is transferred to the radially inner side surface 13b, the oil moves further along this surface due to centrifugal force caused by the rotation of the cage 10. Since the radially inner side surface 13b extends from the axially inner edge 11a1 of the small-diameter ring section 11 towards the base-end section 7b of the large shoulder section 7, the lubricating oil moving along the radially inner side surface 13b is guided to the base-end section 7b of the large shoulder section 7.

[0172] In this way, the radially inner side surface 13b forms a guide surface through which lubricating oil, which flows through the second annular gap K2 into the bearing interior S, can be guided to the base end section 7b of the large shoulder section 7.

[0173] Thus, the lubricating oil flowing through the second annular gap K2 and transferred to the radially inner side surface 13b can be directed to the base end section 7b of the large shoulder section 7. While limiting the amount of lubricating oil flowing into the bearing interior S in this way, the lubricating oil in the bearing interior S can be aggressively directed to the immediate vicinity of a contact area where the large-diameter lateral end face 4b of each tapered roller 4 and the large shoulder section 7 make smooth, frictionless contact. Consequently, it is possible to reduce the sliding friction between the large-diameter lateral end face 4b of the tapered roller 4 and the large shoulder section 7 while limiting the amount of lubricating oil flowing into the bearing interior S, thereby reducing the rotational torque.It is therefore possible to suppress the occurrence of seizing caused by a lack of lubricating oil.

[0174] This means that, according to the embodiment, the amount of lubricating oil flowing into the bearing chamber S is limited in order to suppress the rolling viscosity resistance, which depends on the amount of lubricating oil flowing into the bearing chamber S, or the turbulence resistance of the lubricating oil, thereby reducing torque loss. At the same time, the lubricating oil flowing into the bearing chamber S is guided and aggressively / intensively supplied to a sliding part that requires lubrication in order to reduce sliding friction resistance. Thus, the occurrence of seizing can be suppressed.

[0175] Additionally, since the circumferential side surface 13e of each columnar section 13 is formed by the flat surface section 20 and the curved surface section 21, as described above, the circumferential width W2 of the radially inner side surface 13b is designed to be wider than the circumferential width in the flat surface section 20 of the columnar section 13. Consequently, for example, the area of ​​the radially inner side surface 13b is larger than in the case where the circumferential side surface 13e is formed as a straight line extending radially.

[0176] Thus, it is possible to increase the amount of lubricating oil that can be transferred along the radial inner side surface 13b, i.e., the amount of lubricating oil that can be guided.

[0177] Furthermore, as in Fig. 4 to Fig. Figure 7 shows a groove section 25 in the radially inner side surface 13b, which is recessed radially outwards, essentially at the circumferential center. Such a groove section 25 is formed in each column-shaped section 13. The groove section 25 is recessed in a semicircular / semicircular shape. The groove section 25 extends axially over the entire axial area of ​​the radially inner side surface 13b.

[0178] In addition, the width of the groove section 25 is designed to gradually increase towards the ring section of large diameter 12.

[0179] If the groove section 25 is formed in the radially inner side surface 13b, the lubricating oil flowing through the second annular gap K2 and transferred to the radially inner side surface 13b can be retained in the groove section 25. Furthermore, the lubricating oil retained in the groove section 25 can be guided along the groove section 25 to the base-end section 7b of the large shoulder section 7. Thus, the lubricating oil can be supplied to the base-end section 7b of the large shoulder section 7 more reliably.

[0180] Additionally, the lubricating oil, which is scraped from the rolling surface 4c of the tapered roller 4 by the curved surface section 21 of the circumferential side surface 13e, can be retained in the groove section 25. The lubricating oil can thus be prevented from returning to the rolling surface 4c of the tapered roller 4 or similar surfaces. Furthermore, since the lubricating oil is scraped from the axially extending curved surface section 21 as described above, the quantity of lubricating oil stored in the groove section 25 increases towards the large-diameter annular section 12. However, the width of the groove section 25 gradually increases towards the large-diameter annular section 12. Consequently, the lubricating oil can be prevented from overflowing the groove section 25 and returning to the rolling surface 4c, etc.

[0181] Additionally, according to the embodiment, the radially inner side surface 13b of each column-shaped section 13 is inclined with respect to the inner ring raceway surface 2a such that a gap between the radially inner side surface 13b and the inner ring raceway surface 2a can be axially narrowed gradually from the small-diameter ring section 11 towards the large-diameter ring section 12. Consequently, the lubricating oil can be guided smoothly / frictionlessly / easily to the base end section 7b of the large shoulder section 7 through the radially inner side surface 13b if no steps or similar features are present in the axial direction.

[0182] Fig. Figure 8 shows an illustrative view of a power transmission device 31 of a car.

[0183] In the power transmission device 31, as in Fig. As shown in Figure 8, left and right axles / wheel axles 34 and 35 are driven by a differential 33 from a drive shaft 32. The differential 33 is formed in a housing 36, which serves as a bearing / support. The drive shaft 32 and the axles 34 and 35, which serve as transmission shafts, are rotatably mounted on the housing 36 by tapered roller bearings 37 to 39 according to the invention.

[0184] According to this embodiment, the drive shaft 32 and the axles 34 and 35, which serve as transmission shafts, are mounted in the housing 36 by tapered roller bearings 37 to 39 according to the invention, which enable a reduction in torque loss. Thus, the power loss during power transmission through the drive shaft 32 and the axles 34 and 35 can be reduced.

[0185] Furthermore, the invention is not limited to the embodiment mentioned above.

[0186] The aforementioned embodiment shows a case in which the bottom surface 17a of the recessed section 17, which is provided in the radially outer side surface 13a, is designed to be inclined in a straight line with respect to the outer ring raceway surface 3a, so that the gap T can gradually expand axially from the small-diameter ring section 11 towards the large-diameter ring section 12. However, as long as the lubricating oil can flow freely and pumping motion can be suppressed, the bottom surface 17a can also be designed to be parallel to the radially outer side surface 13a, or the bottom surface 17a can be circular or curved.

[0187] Additionally, the aforementioned embodiment shows a case in which the shape of the bottom surface 17a of the recessed section 17, viewed axially, is formed as a circular arc whose center lies on the axial center / central axis of the tapered roller bearing 1. However, as in Fig. As shown in Figure 9(a), the shape of the base surface 17a, viewed axially, can be formed as a circular arc with a smaller radius, so that the gap with the outer ring raceway surface 3a can increase from the circumferential center of the base surface 17a towards the flat surface section 20. In this case, the lubricating oil can be guided smoothly into and flow through the gap between the recessed section 17 and the outer ring raceway surface 3a.

[0188] Additionally, as in Fig. As shown in Figure 9(b), the shape of the base surface 17a, viewed axially, can also be triangular. In this case as well, the lubricating oil can easily flow into the gap between the recessed section 17 and the outer ring raceway surface 3a in the same way as in Figure 9(b). Fig. 9(a) be led and pass through.

[0189] Additionally, the aforementioned embodiment shows an example in which the recessed sections 17 of the radially outer side surfaces 13a are provided in all columnar sections 13, wherein the recessed sections 17 need not be present / provided in all columnar sections 13, but a suitable modification can be made. For example, the recessed sections 17 can be provided in any of the other columnar sections 13 that are arranged circumferentially.

[0190] The embodiment described above shows a case in which the groove section 25, which is provided in the radially inner side surface 13b, is formed as a groove that is semicircularly recessed / hollowed out. However, the groove section 25 can, for example, be rectangular, triangular, or similar, as shown in Fig. 10(a) or (b) shown, provided that lubricating oil can be retained within the groove section 25. Alternatively, the groove section 25 may be formed by a recess that extends substantially over the entire radial area of ​​the radially inner side surface 13b, as shown in Fig. 10(c) shown. In this case, lubricating oil can be retained essentially over the entire radial area of ​​the radially inner side surface 13b, so that more lubricating oil can be collected and directed to the base-end section 7b of the large shoulder section 7.

[0191] Furthermore, in the aforementioned embodiment, the circumferential edge 13b1 of the radially inner side surface 13b in each column-shaped section is formed as a straight line when the column-shaped section is viewed in the radial direction. However, the circumferential edge 13b1 can be curved convex all around, as shown in Fig. 11 shown, or curved concave, as in Fig. 12 shown, be trained.

[0192] The present application is based on a Japanese patent application (Japanese patent application no. 2013-242043) filed on November 22, 2013, a Japanese patent application (Japanese patent application no. 2013-242058) filed on November 22, 2013, and a Japanese patent application (Japanese patent application no. 2013-261376) filed on December 18, 2013. Industrial applicability

[0193] According to one configuration of the invention, it is possible to provide a tapered roller bearing which allows the amount of lubricating oil flowing into the interior of the bearing to be precisely controlled in order to reduce torque loss, and to provide a power transmission device which utilizes the tapered roller bearing. Additionally, according to another configuration of the invention, it is possible to provide a tapered roller bearing which allows sliding friction resistance to be reduced in order to prevent seizing, while limiting the amount of lubricating oil flowing into the interior of the bearing in order to reduce rotational torque, and to provide a power transmission device which utilizes the tapered roller bearing. Description of reference numbers and symbols 1 tapered roller bearing 2 inner ring 2a Inner ring running surface 3 Outer ring 3a Outer ring running surface 4 Conical roller 4c rolling surface 5 small shoulder section 5a outer circumferential surface 6 an axial end section 7 large shoulder section 7b Base End Section 10 holders / cage 11 Ring section small diameter 11a inner circumferential surface 11a1 axial inner edge (inner circumferential end section) 12 Ring section large diameter 13 columnar section / column section 13a radial outer side surface 13b radial inner side surface 13b1 Perimeter edge 13e Perimeter surface 14 bags 15 Sliding contact surface on the side of small diameter 16 Sliding contact surface on the side of large diameter 17. In-depth section 17a Floor area 20 flat area section 21 curved surface section 25 groove section 30 angled section 31 Power transmission device 32 Drive shaft (transmission shaft) 33 Differential 34, 35 Axle (Transmission shaft) 36 Housing (bearing / support) 37 to 39 tapered roller bearings A1 lateral opening section of small diameter A2 large diameter lateral opening section K1 first annular gap K2 second annular gap C Pitch circle / rolling circle D Length of the gap between 3a and 13a E Length of the gap between 13b1 and 4c G overlapping part H connection point L axial length of the depression section 17 L1 Distance between H and C P straight line through the axial center of the tapered roller 4 and the tapered roller bearing 1 S Storage interior T gap between 17a and 3a W1 to W4 Scope

Claims

[1] Tapered roller bearing (1), with: an inner ring (2) having an inner ring raceway surface (2a); an outer ring (3) which is arranged on an outer circumferential side of the inner ring (2) and concentric to the inner ring (2), and which has an outer ring raceway surface (3a) which is opposite the inner ring raceway surface (2a); a plurality of tapered rollers (4) which are positioned to roll between the inner ring raceway surface (2a) and the outer ring raceway surface (3a); and a cage (10) arranged in an annular space between the inner ring (2) and the outer ring (3), which holds the conical rollers (4), wherein: the cage (10) includes a ring section of small diameter (11), a ring section of large diameter (12) which is opposite the ring section of small diameter (11) at a certain distance, and a plurality of columnar sections (13) which lie between the ring section of small diameter (11) and the ring section of large diameter (12), wherein spaces surrounded by adjacent columnar sections (13), the ring section of small diameter (11) and the ring section of large diameter (12) are formed as pockets (14) which accommodate the conical rollers (4); the small-diameter ring section (11) is arranged between a small shoulder section (5) provided on an axial end face of the inner ring (2) and an axial end section (6) of the outer ring (3), and an inner circumferential surface (11a) and an outer circumferential surface (11b) of the small-diameter ring section (11) can be in sliding contact with the small shoulder section (5) and the one axial end section (6) of the outer ring (3), so that an annular opening section, which is made up of the small shoulder section (5) and the one axial end section (6) of the outer ring (3), is closed; a sliding contact surface (15, 16) is provided in a radially outer side surface (13a) of each columnar section (13), and is in sliding contact with the outer ring raceway surface (3a), so that the cage (10) is radially positioned by the outer ring raceway surface (3a), and a recessed section (17) is provided in the radially outer side surface (13a) of each columnar section (13), and is radially recessed, so that adjacent pockets (14) are in contact with each other; and a bottom surface (17a) of the depression section (17) is a slope which is inclined with respect to the outer ring raceway surface (3a) such that a gap T between the bottom surface (17a) and the outer ring raceway surface (3a) gradually extends axially from the small diameter ring section (11) towards the large diameter ring section (12). [2] Tapered roller bearing (1) according to claim 1, wherein the recessed section (17) is provided such that it is positioned on a central axis of the outer ring raceway surface (3a). [3] Tapered roller bearing (1) according to one of claims 1 or 2, wherein an axial length L of the recess section (17) is defined within a range which is equal to or greater than 40% of an axial length of the outer ring raceway surface (3a) and equal to or less than 70% of the axial length of the outer ring raceway surface (3a). [4] Tapered roller bearing (1) according to any one of claims 1 to 3, wherein a gap T between a bottom surface (17a) of the recess section (17) and the outer ring raceway surface (3a) is defined such that it is at least ten times as large as a gap required for the outer ring raceway surface (3a) and the sliding contact surface (15, 16) to be in sliding contact with each other at a bearing operating temperature. [5] Tapered roller bearing (1) according to claim 1, wherein: an annular gap K2 is formed between an inner circumferential surface (11a) of the small-diameter ring section (11) and an outer circumferential surface (5a) of the small shoulder section (5), which limits excess lubricating oil from flowing into the annular space for lubrication purposes; and a radially inner side surface (13a) of each column-shaped section (13) is designed as a guide surface extending from an end section of the inner circumferential surface (11a) of the small-diameter ring section (11) towards a base end section (7b) of a large shoulder section (7) provided on the other axial end face of the inner ring (2), so that the lubricating oil flowing through the annular gap K2 into the annular space is guided to the base end section (7b) of the large shoulder section (7). [6] Tapered roller bearing (1) according to claim 5, wherein the radially inner side surface (13b) is a slope which is inclined with respect to the inner ring raceway surface (2a) such that a gap between the radially inner side surface (13b) and the inner ring raceway surface (2a) is gradually narrowed axially from the small diameter ring section (11) towards the large diameter ring section (12). [7] Tapered roller bearing (1) according to claim 5 or 6, wherein a groove section (25) which is radially recessed outwards is formed axially in the radially inner side surface (13b). [8] Tapered roller bearing (1) according to any one of claims 5 to 7, wherein the size of the annular gap K2 at a bearing operating temperature is specified such that it is larger than the size of a gap required for the outer ring raceway surface (3a) and the sliding contact surface (15, 16) to be in sliding contact with each other at a bearing operating temperature, and is at most three times the size of the gap. [9] Tapered roller bearing (1) according to claim 1, wherein: an end section of a radially inner side surface (13b) of each column-shaped section (13) is arranged on a side of the large-diameter ring section (12), on a radially inner side of an outer circumferential surface (7a) of a large shoulder section (7) of an axial end section of the inner ring (2); and an inner circumferential side of a circumferential side surface (13e) of each columnar section (13) is formed as a curved surface along a rolling surface (4a) of each tapered roller (4), and a circumferential width W2 of the radially inner side surface (13b) of each columnar section (13) is further formed than a circumferential width W1 of the radially outer side surface (13a) of each columnar section (13). [10] Tapered roller bearing (1) according to claim 9, wherein a gap in a radial direction between the inner circumferential side of each column-shaped section (13) and the rolling surface (4a) is larger than a gap in the same radial direction between the radially outer side surface (13a) of each column-shaped section (13) and the outer ring raceway surface (3a). [11] Tapered roller bearing (1) according to claim 9 or 10, wherein, in the radially inner side surface (13b) of each column-shaped section (13) a circumferential width W4 of the end section on the side of the ring section of large diameter (12) is further developed than a circumferential width W3 of an end section on a side of the ring section of small diameter (11). [12] Tapered roller bearing (1) according to claim 11, wherein a ratio W4 / W3 of the circumferential width W4 to the circumferential width W3 is larger than a ratio R2 / R1 of a maximum outer diameter R2 to a minimum outer diameter R1 in each of the tapered rollers (4). [13] Tapered roller bearing (1) according to any one of claims 9 to 12, wherein a groove section 25 for guiding lubricating oil to the large shoulder section (7) is axially formed in the radially inner side surface (13b) of each column-shaped section (13). [14] Tapered roller bearing (1) according to claim 13, wherein the width of the groove section 25 gradually increases towards the ring section of large diameter (12). [15] Power transmission device, comprising a power transmission shaft (32, 33, 34, 35); the tapered roller bearing (1) according to any one of claims 1 to 14; and a support (36) which rotatably supports the power transmission shaft (32, 33, 34, 35) over the tapered roller bearing (1). [16] Tapered roller bearings (1), with: an inner ring (2) having an inner ring raceway surface (2a); an outer ring (3) which is arranged on an outer circumferential side of the inner ring (2) and concentric to the inner ring (2), and which has an outer ring raceway surface (3a) which is opposite the inner ring raceway surface (2a); a plurality of tapered rollers (4) which are positioned to roll between the inner ring raceway surface (2a) and the outer ring raceway surface (3a); and a cage (10) arranged in an annular space between the inner ring (2) and the outer ring (3), which holds the conical rollers (4), wherein: the cage (10) includes a small-diameter ring section (11), a large-diameter ring section (12) opposite the small-diameter ring section (11) at a predetermined distance, and a plurality of columnar sections (13) located between the small-diameter ring section (11) and the large-diameter ring section (12), wherein spaces surrounded by adjacent columnar sections (13), the small-diameter ring section (11) and the large-diameter ring section (12) are formed as pockets (14) that accommodate the conical rollers (4); The small-diameter ring section (11) is arranged between a small shoulder section (5) provided on an axial end face of the inner ring (2) and an axial end section of the outer ring (2), and an inner circumferential surface (11a) and an outer circumferential surface (11b) of the small-diameter ring section (11) can be in sliding contact with the small shoulder section (5) and the axial end section (6) of the outer ring (3), so that an annular opening section formed by the small shoulder section (5) and the axial end section (6) of the outer ring (3) is closed, while an annular gap K2 is formed between an inner circumferential surface (11a) of the small-diameter ring section (11) and an outer circumferential surface (5a) of the small shoulder section (5) in order to limit excess lubricating oil from flowing into the annular space for the lubrication of the tapered roller bearing (1); and a radially inner side surface (13b) of each column-shaped section (13) is designed as a guide surface, extending from an end section, which is an axial inner edge (11a1) of the inner circumferential surface (11a) of the small-diameter ring section (11), towards a base end section (7b) of a large shoulder section (7) provided on the other axial end face of the inner ring (2), so that the lubricating oil flowing through the annular gap K2 into the annular space is guided to the base end section (7b) of the large shoulder section (7). [17] Tapered roller bearing (1) according to claim 16, wherein the radially inner side surface (13b) is a slope which is inclined with respect to the inner ring raceway surface (2a) such that a gap between the radially inner side surface (13b) and the inner ring raceway surface (2a) is axially gradually narrowed from the small diameter ring section (11) towards the large diameter ring section (12). [18] Tapered roller bearing (1) according to claim 16 or 17, wherein a groove section (25) is formed axially in the radially inner side surface (13b) which is recessed radially outwards. [19] Tapered roller bearing (1) according to any one of claims 16 to 18, wherein the size of the annular gap K2 at a bearing operating temperature is specified such that it is larger than the size of a gap required for the outer ring raceway surface (3a) and a sliding contact surface (15, 16) to be in sliding contact with each other at a bearing operating temperature, and is at most three times the size of the gap. [20] Tapered roller bearing (1) according to claim 16, wherein a sliding contact surface (15, 16) is provided in a radially outer side surface (13a) of each column-shaped section (13) and is in sliding contact with the outer ring raceway surface (3a) such that the cage (10) is radially positioned through the outer ring raceway surface (3a). [21] Tapered roller bearing (1) according to claim 20, wherein a recessed section (17) is provided in the axially outer side surface of each column-shaped section (13) and is radially recessed so that adjacent pockets (14) are connected to each other. [22] Tapered roller bearing (1) according to claim 16, wherein: a sliding contact surface (15, 16) is provided in a radially outer side surface (13a) of each column-shaped section (13), and is in sliding contact with the outer ring raceway surface (3a), so that the cage (10) is radially positioned through the outer ring raceway surface (3a); an end section of a radially inner side surface (13b) of each column-shaped section (13) is arranged on a side of the large-diameter ring section (12), on a radially inner side of an outer circumferential surface of a large shoulder section (7) at an axial end section (6) of the inner ring (2); and an inner circumferential side of a circumferential side surface (13e) of each columnar section (13) is formed as a curved surface along a rolling surface of each tapered roller (4), and a circumferential width W2 of the radially inner side surface (13b) of each columnar section (13) is further formed than a circumferential width W1 of the radially outer side surface (13a) of each columnar section (13). [23] Tapered roller bearing (1) according to claim 22, wherein a gap in a radial direction between the inner circumferential side of each column-shaped section (13) and the rolling surface (4a) is larger than a gap in the same radial direction between the radially outer side surface (13a) of each column-shaped section (13) and the outer ring raceway surface (3a). [24] Tapered roller bearing (1) according to claim 22 or 23, wherein, in the radially inner side surface (13b) of each column-shaped section (13), a circumferential width W4 of the end section on the side of the ring section of large diameter (12) is further formed than a circumferential width W3 of an end section on a side of the ring section of small diameter (11). [25] Tapered roller bearing (1) according to claim 24, wherein a ratio W4 / W3 of the circumferential width W4 to the circumferential width W3 is larger than a ratio R2 / R1 of a maximum outer diameter R2 to a minimum outer diameter R1 in each tapered roller (4). [26] Tapered roller bearing (1) according to any one of claims 22 to 25, wherein a groove section 25 for guiding lubricating oil to the large shoulder section (7) is axially formed in the radially inner side surface (13b) of each column-shaped section (13). [27] Tapered roller bearing (1) according to claim 26, wherein the width of the groove section 25 gradually increases in the direction of the ring section of large diameter (12). [28] Power transmission device, comprising a power transmission shaft (32, 33, 34, 35); the tapered roller bearing (1) according to any one of claims 16 to 27; and a support (36) which rotatably supports the power transmission shaft (32, 33, 34, 35) over the tapered roller bearing (1).

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