Transmission

Abstract

To enable easy replacement of a member which receives a load from a transmission mechanism in a transmission.SOLUTION: A transmission 100 includes: a transmission mechanism 40 which is connected to a hydraulic motor 20 to change a speed of output rotation of the hydraulic motor 20; a cylindrical rotation housing 15 which houses the transmission mechanism 40 and is rotated by transmission of the output rotation whose speed is changed; a cover 50 which is provided at an opening end 15a of the rotation housing 15 which is opened at the opposite side of the hydraulic motor 20 with respect to the transmission mechanism 40 and closes the opening end 15a; a carrier plate 47 provided on an end surface facing the cover 50 in the transmission mechanism 40; and a plug 54a which is provided so as to be attachable to or detachable from the cover 50 from the opposite side of the carrier plate 47. The plug 54a protrudes from the cover 50 to the carrier plate 47 and may support a thrust load exerted from the transmission mechanism 40 on the carrier plate 47.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a transmission. [Background technology]

[0002] Patent Document 1 discloses a transmission that includes a fixed housing that houses a hydraulic motor, a speed change mechanism that changes the output rotation of the hydraulic motor shaft, a rotating housing that houses the speed change mechanism and to which the changed output rotation is transmitted and rotates, and a cover that closes the open end of the rotating housing. The speed change mechanism described in Patent Document 1 is a planetary gear mechanism that includes a sun gear provided on the shaft of the hydraulic motor, an inner gear provided on the inner wall of the rotating housing, and multiple planetary gears that mesh with both the sun gear and the inner gear. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-116055 Summary of the Invention [Problem to be solved by the invention]

[0004] In the transmission described in Patent Document 1, when the planetary gear and inner gear mesh obliquely with each other relative to the axial direction of the shaft, a thrust load (a load along the axial direction of the shaft) is generated in the transmission mechanism due to a reaction force of the force acting from the planetary gear to the inner gear. This load generated in the transmission mechanism acts on the cover. In the transmission described in Patent Document 1, even if the cover wears due to the load generated in the transmission mechanism, it is not possible to check for wear or replace the cover without removing the cover. Therefore, it is not easy to check for wear or replace the cover.

[0005] The present invention has been made in view of the above-mentioned problems, and has as its object to easily check for wear and replace members that receive loads from a speed change mechanism in a transmission. [Means for solving the problem]

[0006] The present invention is a transmission comprising: a speed change mechanism connected to a drive source and changing the output rotation of the drive source; a cylindrical rotating housing that houses the speed change mechanism and rotates when the changed output rotation is transmitted; a cover that is provided at an open end of the rotating housing that opens on the opposite side of the speed change mechanism from the drive source and closes the open end; a plate that is provided on an end face of the speed change mechanism that faces the cover; and a plug that is detachably provided on the cover from the opposite side to the plate, wherein the plug protrudes from the cover toward the plate and is capable of supporting a thrust load acting on the plate from the speed change mechanism.

[0007] In this invention, the plug, which is detachably attached to the cover, bears the thrust load generated by the transmission mechanism. Therefore, wear on the plug can be checked simply by removing the plug from the cover, and if the wear on the plug is significant, only the plug needs to be replaced. This makes it easy to check for wear and replace a component that bears the load from the transmission mechanism.

[0008] The present invention is also characterized in that the cover is provided with a through hole for determining the amount of lubricant that is sealed in the gear chamber that houses the transmission mechanism and can lubricate the transmission mechanism, and the plug is detachably provided in the through hole and seals the through hole.

[0009] In this invention, the plug attached to the through hole provided in the cover to regulate the amount of lubricant in the gear chamber bears the thrust load generated by the transmission mechanism. In other words, by using an existing plug, it is possible to easily check for wear and replace the member in the transmission that bears the load from the transmission mechanism without adding a new part.

[0010] The present invention is also characterized in that the cover has a main body portion in the center of which the plug is attached, and an annular mounting portion formed on the outer periphery of the main body portion and attached to the open end of the rotating housing, the main body portion having a bottom portion to which the plug is attached and a tapered portion connecting the bottom portion and the mounting portion, and the tapered portion is inclined so that the bottom side is positioned close to the plate.

[0011] In this invention, the main body of the cover has a bottom portion to which the plug is attached and a tapered portion connecting the bottom portion and the attachment portion. This allows the main body and the plate to face each other while reducing the thickness of the portion of the main body to which the plug is attached compared to when the tapered portion is not provided. This allows the main body to be thinner and plugs of a standard length to be used, thereby reducing the manufacturing cost of the transmission. [Effects of the Invention]

[0012] According to the present invention, it is possible to easily check for wear and replace members that receive a load from a speed change mechanism in a transmission. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a cross-sectional view of a transmission-equipped motor including a transmission according to a first embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, a transmission 100 according to this embodiment of the present invention and a transmission-equipped motor 101 as a drive device including the same will be described with reference to the drawings.

[0015] The transmission-equipped motor 101 is used, for example, as a travel motor mounted on the axle of a crawler-type working machine such as a hydraulic excavator to drive the crawler belt. As shown in Fig. 1, the transmission-equipped motor 101 includes a hydraulic motor 20 as a drive source, and a transmission 100 connected to a motor shaft (not shown) of the hydraulic motor 20 to reduce the output rotation of the motor shaft.

[0016] The transmission 100 includes a speed change mechanism 40 that changes the output rotation of the hydraulic motor 20, a fixed housing 10 that houses the hydraulic motor 20, a cylindrical rotating housing 15 that houses the speed change mechanism 40 and rotates by receiving the changed output rotation, a cover 50 that is provided on the inner periphery of an open end 15a of the rotating housing 15 and closes the open end 15a of the rotating housing 15, and a plug 54a that is detachably provided on the cover 50. The speed change mechanism 40 is a planetary gear mechanism, and its specific configuration will be described later. The fixed housing 10, the rotating housing 15, and the cover 50 form a housing 1 of the transmission 100.

[0017] The rotating housing 15 rotates relative to the fixed housing 10. An open end 15a of the rotating housing 15 is the end of the rotating housing 15 that opens on the opposite side of the hydraulic motor 20 (the right side in FIG. 1) from the transmission mechanism 40. A sprocket (not shown) is connected to the outer circumferential surface of the rotating housing 15. When the rotating housing 15 and the sprocket rotate together, a crawler belt (not shown) that meshes with the sprocket circulates, causing the vehicle to move.

[0018] The fixed housing 10 and the rotating housing 15 are arranged inside the path along which the crawler belt circulates. The rotating housing 15 is rotatably supported via bearings 3 on the fixed housing 10, which is connected to the vehicle body 102 as an external member, and rotates around its central axis.

[0019] The fixed housing 10 has a fixed flange portion 12 formed to protrude from the outer peripheral surface of the main body portion 11 and attached to the vehicle body 102 .

[0020] The cover 50 is formed in a disk shape and is attached to the inner circumferential surface of the open end 15a of the rotary housing 15. The plug 54a is provided in the center of the cover 50. The specific configurations of the cover 50 and the plug 54a will be described in detail later.

[0021] A gear chamber 4 that houses the speed change mechanism 40 is defined by the inner surface of the rotating housing 15, the outer surface of the main body 11 of the fixed housing 10, and the inner surface of the cover 50. Lubricating oil is sealed in the gear chamber 4 as a lubricant that can lubricate the speed change mechanism 40.

[0022] A rotating flange 16 is formed on the rotating housing 15, protruding annularly from the outer circumferential surface. The sprocket is fastened to the rotating flange 16 with a plurality of bolts (not shown), and rotates together with the rotating housing 15.

[0023] A floating seal 5 is provided between the fixed housing 10 and the rotating housing 15. The floating seal 5 seals the hydraulic oil in the transmission 100 so that it does not leak out when the rotating housing 15 rotates, and also prevents foreign matter from entering the transmission 100 from the outside.

[0024] In addition, a labyrinth seal 6 is formed between the fixed housing 10 and the rotating housing 15 to prevent foreign matter such as mud from entering from the outside of the floating seal 5. The labyrinth seal 6 is formed by the gap between the opposing end faces of the fixed housing 10 and the rotating housing 15.

[0025] The hydraulic motor 20 is provided inside the main body 11 of the fixed housing 10. The hydraulic motor 20 is, for example, a swash plate type piston motor that is rotationally driven by the supply and discharge of hydraulic oil (hydraulic fluid). Note that the motor may be other than the hydraulic motor 20 (hydraulic motor), and for example, an electric motor may be used. Since the hydraulic motor 20 can have a known configuration, it is shown in a simplified form in FIG. 1 and a detailed description thereof will be omitted in this specification.

[0026] The transmission 100 includes a drive shaft 31 that is coaxially connected to the motor shaft of the hydraulic motor 20 and to which the output rotation of the motor shaft is transmitted. The transmission mechanism 40 reduces the speed of the output rotation of the motor shaft of the hydraulic motor 20 transmitted through the drive shaft 31 and transmits it to the rotating housing 15. The drive shaft 31 and the motor shaft of the hydraulic motor 20 are connected by, for example, a spline connection. Note that the rotating housing 15 and the drive shaft 31 are arranged coaxially, and therefore, hereinafter, the axial direction of the rotating housing 15 and the drive shaft 31 will also be simply referred to as the "axial direction," and the radial direction of the rotating housing 15 and the drive shaft 31 will also be simply referred to as the "radial direction."

[0027] The transmission mechanism 40 is a planetary gear mechanism and includes a sun gear 41 provided on the drive shaft 31, an inner gear 42 formed on the inner circumferential surface of the rotating housing 15 and extending in the axial direction, a plurality of planetary gears 43 meshing with both the sun gear 41 and the inner gear 42, a planetary carrier 44 supporting each planetary gear 43, a second-stage sun gear 45 meshing with the planetary carrier 44, and a plurality of planetary gears 46 meshing with both the sun gear 45 and the inner gear 42. The end faces of the drive shaft 31, the sun gear 41, and each planetary gear 43 facing the cover 50 are located on the same plane.

[0028] When the motor shaft of the hydraulic motor 20 is driven to rotate, the drive shaft 31 connected to the motor shaft rotates in conjunction with the rotation of the motor shaft. The output rotation of the drive shaft 31 acts on the inner gear 42 via the sun gear 41 and planetary gears 43, and the second-stage sun gear 45 and planetary gears 46, and is then transmitted to the rotating housing 15. In the transmission 100 of this embodiment, the planetary gears 43 and the inner gear 42, and the planetary gears 46 and the inner gear 42, are meshed obliquely with each other relative to the axial direction. Therefore, a thrust load (a load along the axial direction) is generated in the transmission mechanism 40 due to a reaction force of the forces acting on the inner gear 42 from the planetary gears 43 and 46. The thrust load generated in the transmission mechanism 40 varies depending on the circumferential position of the transmission mechanism 40; specifically, the thrust load acting on each planetary gear 43 is different.

[0029] Therefore, in order to equalize the variations in the thrust load generated in the transmission mechanism 40, the transmission 100 includes a carrier plate 47 provided on the end face of the transmission mechanism 40 facing the cover 50. The carrier plate 47 receives the thrust load generated in the transmission mechanism 40 and has the function of equalizing the thrust load generated in the transmission mechanism 40. The carrier plate 47 is provided across the end faces of the drive shaft 31, the sun gear 41, and each planetary gear 43 facing the cover 50, and is fixed to each planetary carrier 44 with bolts 49. Note that the carrier plate 47 may also be fixed to each planetary carrier 44 with a pin or the like. The thrust load generated in the transmission mechanism 40 acts on a plug 54a provided on the cover 50 via the single carrier plate 47, which has a large area. The thrust load of the transmission mechanism 40 that the plug 54a receives is equalized by the carrier plate 47, so that the carrier plate 47 and the plug 54a come into surface contact with each other without uneven contact, thereby preventing uneven wear of the carrier plate 47 and the plug 54a.

[0030] Next, a specific description will be given of the configuration of the cover 50. As shown in Fig. 1, the cover 50 has a disk-shaped main body 51 to which a plug 54a is attached at the center, and an annular mounting portion 52 formed on the outer periphery of the main body 51 and attached to the inner circumferential surface of the open end 15a of the rotating housing 15.

[0031] The main body 51 has a bottom 51a that is approximately perpendicular to the central axis of the rotating housing 15, and a tapered portion 51b that connects the bottom 51a and the mounting portion 52. The main body 51 is formed in a so-called mortar shape (a bottomed conical cylindrical shape) with the bottom 51a as the bottom. An oil dip port 53a (described later) is provided in the bottom 51a, and a plug 54a is attached to the oil dip port 53a. The tapered portion 51b is provided in an annular shape extending between the bottom 51a and the mounting portion 52, and its entire circumference is inclined with respect to the central axis of the rotating housing 15. The tapered portion 51b is inclined so that the bottom 51a side is positioned close to the carrier plate 47.

[0032] The mounting portion 52 is provided continuous with the tapered portion 51b of the main body portion 51 and is formed substantially perpendicular to the central axis of the rotary housing 15. The outer peripheral surface of the mounting portion 52 contacts the inner peripheral surface of the open end 15a of the rotary housing 15. An annular seal groove 50a is formed around the entire circumference of the outer peripheral surface of the mounting portion 52. An O-ring 70 is housed in the seal groove 50a to seal between the mounting portion 52 and the inner peripheral surface of the rotary housing 15. The mounting portion 52 has a plurality of protrusions 52a formed at its radially outer end that protrude in the axial direction toward the speed change mechanism 40. The protrusions 52a contact the inner gear 42 in the axial direction, thereby aligning the cover 50 in the axial direction. In this manner, the end of the cover 50 (specifically, the protrusions 52a of the mounting portion 52) contacts the inner gear 42 in the axial direction, thereby closing the open end 15a of the rotary housing 15. The cover 50 does not necessarily have to be attached to the inner peripheral surface of the open end 15a of the rotary housing 15, but may be configured to be provided at the open end 15a of the rotary housing 15 and close the open end 15a.

[0033] The cover 50 is also provided with an injection port (not shown) for injecting lubricating oil into the gear chamber 4, an oil dip port 53a as a through-hole for determining the amount of lubricating oil, and a discharge port 53b for discharging the lubricating oil in the gear chamber 4 to the outside of the gear chamber 4. The injection port is not shown in FIG. 1. The injection port, oil dip port 53a, and discharge port 53b penetrate the cover 50 in the thickness direction. The injection port and discharge port 53b are provided in the mounting portion 52, and the oil dip port 53a is provided in the center of the bottom portion 51a of the main body portion 51. The oil dip port 53a is provided coaxially with the drive shaft 31.

[0034] The cover 50 is also provided with a plug (not shown) that seals the fill port, a plug 54a that seals the oil dip port 53a, and a plug 54b that seals the discharge port 53b. The plugs that seal the fill ports are not shown in FIG. 1. The plug 54a is detachably attached to the oil dip port 53a by screw connection from the side opposite the carrier plate 47, and seals the oil dip port 53a. The plug 54b is detachably attached to the discharge port 53b by screw connection from the side opposite the carrier plate 47, and seals the discharge port 53b. The same applies to the plugs that seal the fill ports.

[0035] To fill the gear chamber 4 with lubricating oil, the transmission 100 is oriented as shown in FIG. 1, and with the plug 54b attached to the discharge port 53b, the lubricating oil is poured into the fill port. The lubricating oil is then poured in until it overflows from the oil dipstick port 53a. In this way, the oil dipstick port 53a determines the amount of lubricating oil that is poured into the gear chamber 4.

[0036] The plug 54a attached to the oil dip port 53a protrudes from the cover 50 toward the carrier plate 47 and faces the carrier plate 47 with a small gap between them. As a result, when a thrust load generated in the transmission mechanism 40 acts on the carrier plate 47, the carrier plate 47 comes into contact with and is supported by the plug 54a. At this time, the carrier plate 47 comes into contact only with the plug 54a, not with the cover 50. The thrust load of the transmission mechanism 40 that the plug 54a receives through the carrier plate 47 is smaller than the connecting force due to the threaded connection between the oil dip port 53a and the plug 54a. Therefore, the plug 54a will not fall off the oil dip port 53a when it receives the thrust load generated in the transmission mechanism 40.

[0037] Furthermore, the plug 54a, which receives the thrust load generated by the transmission mechanism 40, is supported by the bottom 51a of the main body 51. Therefore, the bottom 51a receives a force from the plug 54a in the direction of the thrust load generated by the transmission mechanism 40 (to the right in FIG. 1). Because the main body 51 is formed in a so-called cone shape with the bottom 51a as the base, the bottom 51a is less likely to displace in the direction of the thrust load generated by the transmission mechanism 40. Therefore, the cover 50 has high strength against the force received from the plug 54a.

[0038] Furthermore, a holding portion 55 that protrudes in the axial direction toward the carrier plate 47 is provided on the tapered portion 51b of the main body 51 of the cover 50. The holding portion 55 is provided to hold the cover 50 when the cover 50 is processed. Note that the holding portion 55 may be provided somewhere other than the tapered portion 51b. Furthermore, as will be described later, in cases where the cover 50 can be processed while holding the inner circumferential surface of the protruding portion 52a of the mounting portion 52, the holding portion 55 does not need to be provided.

[0039] Next, processing of the cover 50 and the plug 54a will be described.

[0040] Before the cover 50 is attached to the rotating housing 15, it is machined to form an annular seal groove 50a and to drill holes to form an injection port, an oil check port 53a, and a discharge port 53b. The outer peripheral surface of the mounting portion 52 of the cover 50 is also smoothed, and the contact surface of the protruding portion 52a of the mounting portion 52 with the inner gear 42 is smoothed. Specifically, the smoothing of the outer peripheral surface of the mounting portion 52 and the smoothing of the contact surface of the protruding portion 52a of the mounting portion 52 with the inner gear 42 are performed at the same time by lathe machining or the like while holding the retaining portion 55 or the inner peripheral surface of the protruding portion 52a of the mounting portion 52. Performing the smoothing all at once shortens the machining time for the cover 50 and makes machining the cover 50 easier.

[0041] Furthermore, the surface of the plug 54a that faces the carrier plate 47 is smoothed. Specifically, the plug 54a is subjected to gas soft nitriding and cutting before being attached to the oil dipstick port 53a. This reduces the frictional force that occurs between the carrier plate 47 and the plug 54a.

[0042] Here, let's consider a case where multiple support portions protruding toward the carrier plate are provided in the center of the cover, and the support portions, which are part of the cover, bear the thrust load generated by the transmission mechanism. When the thrust load generated by the transmission mechanism acts on the carrier plate, the carrier plate comes into contact with the end face of the support portion protruding and is supported. In this case, even if the support portions wear due to the thrust load generated by the transmission mechanism, it is impossible to check for wear on the support portions without removing the cover. Furthermore, even if only the support portions are worn, the entire cover must be replaced. Therefore, it is not easy to check for wear and replace the cover.

[0043] In contrast, in the transmission 100 of this embodiment, the plug 54a, which is detachably attached to the cover 50, bears the thrust load generated by the transmission mechanism 40. The plug 54a is attached to the cover 50 by a screw connection, and can be easily removed from the cover 50. Therefore, wear on the plug 54a can be checked simply by removing the plug 54a from the cover 50, and if wear on the plug 54a is significant, only the plug 54a needs to be replaced. This makes it easy to check for wear and replace members that receive loads from the transmission mechanism 40.

[0044] Furthermore, if there is an abnormality in the transmission mechanism 40, the plug 54a will be subjected to a large thrust load, causing the plug 54a to wear out more quickly than usual. In the transmission 100, wear can be easily checked by removing the plug 54a from the cover 50, so by periodically checking the wear on the plug 54a, it is possible to check for abnormalities in the transmission mechanism 40. In other words, the plug 54a can also be used as a tool to detect abnormalities in the transmission mechanism 40.

[0045] Furthermore, plug 54a is an existing part that is provided in oil check port 53a for determining the amount of lubricating oil in gear chamber 4. In other words, by using the existing plug 54a, it is possible to easily check for wear and replace members that receive loads from speed change mechanism 40 in transmission 100 without adding new parts.

[0046] Furthermore, the main body 51 of the cover 50 has a bottom 51a to which the plug 54a is attached and a tapered portion 51b connecting the bottom 51a and the attachment portion 52. This allows the main body 51 and the carrier plate 47 to face each other while reducing the thickness of the portion of the main body 51 to which the plug 54a is attached (the bottom 51a) compared to when the tapered portion 51b is not provided. This allows the main body 51 to be thin, and a plug of a standard length to be used as the plug 54a. Furthermore, because the axial length of the oil dipstick port 53a is short, the oil dipstick port 53a can be easily machined. This reduces the manufacturing cost of the transmission 100.

[0047] Furthermore, in the transmission 100 of this embodiment, the axial end 42a (right side in FIG. 1) of the inner gear 42 intersects with an extension line along the radial direction of the carrier plate 47. In other words, the axial length of the inner gear 42 is set to a length such that the end 42a of the inner gear 42 intersects with an extension line along the radial direction of the carrier plate 47. In other words, the axial length of the inner gear 42 is shortened.

[0048] By shortening the axial length of the inner gear 42, the time required to process the inner gear 42 into the rotating housing 15 is shortened, thereby reducing the manufacturing cost of the transmission 100. Furthermore, since the protrusion 52a of the cover 50 comes into axial contact with the end 42a of the inner gear 42 and is aligned with the rotating housing 15, the axial length of the inner gear 42 is shortened, thereby reducing the axial length of the entire transmission 100. Therefore, the manufacturing cost of the transmission 100 can be further reduced.

[0049] In a transmission in which a plurality of support portions protruding toward the carrier plate are provided at the center of the cover and the support portions, which are part of the cover, bear the thrust load generated by the transmission mechanism, smoothing is performed on the end surfaces of the support portions that come into contact with the carrier plate to reduce the frictional force generated between the carrier plate and the cover. Furthermore, the cover of this transmission also undergoes smoothing processing performed on the cover 50 (smoothing the outer peripheral surface of the mounting portion 52 and smoothing the contact surface 52b of the protruding portion 52a of the mounting portion 52 with the inner gear 42). However, with a processing device such as a lathe, when the inside of the cover, such as the inner peripheral surface of the protruding portion 52a of the mounting portion 52, is held, the portion that holds the cover and the portion that is smoothed for the support portions interfere with each other. In other words, smoothing of the support portions cannot be performed while the inside of the cover is held. Therefore, in order to smooth the end surfaces of the support portions, it is necessary to hold the surface of the cover. In this way, in a transmission in which the support portion, which is part of the cover, receives the thrust load generated by the transmission mechanism, smoothing the end surface of the support portion, smoothing the outer surface of the mounting portion 52, and smoothing the contact surface 52b of the mounting portion 52 cannot be performed consecutively because it requires changing the holding position of the cover.

[0050] In contrast, in transmission 100 of this embodiment, the plug 54a bears the thrust load generated by the speed change mechanism 40, so there is no need to smooth the support portion, which is part of the cover. Therefore, the smoothing of cover 50 (smoothing of the outer peripheral surface of mounting portion 52 and smoothing of contact surface 52b of mounting portion 52) can be performed at one time without changing the holding position of cover 50.

[0051] According to the present embodiment described above, the following advantageous effects are achieved.

[0052] In the transmission 100, the plug 54a, which is detachably mounted on the cover 50, bears the thrust load generated by the transmission mechanism 40. Therefore, wear on the plug 54a can be checked simply by removing the plug 54a from the cover 50, and if wear on the plug 54a is significant, only the plug 54a needs to be replaced. This makes it easy to check for wear and replace members that bear loads from the transmission mechanism 40.

[0053] Since the plug 54a is an existing part provided in the oil check port 53a for determining the amount of lubricating oil in the gear chamber 4, it is possible to easily check for wear and replace components in the transmission 100 that receive loads from the speed change mechanism 40 without adding any new parts.

[0054] In transmission 100, main body 51 of cover 50 has bottom 51a to which plug 54a is attached and tapered portion 51b connecting bottom 51a and attachment portion 52, so that the thickness of the portion of main body 51 to which plug 54a is attached can be reduced while main body 51 and carrier plate 47 face each other. Therefore, the thickness of main body 51 can be reduced and a plug of a general length can be used as plug 54a, thereby reducing the manufacturing cost of transmission 100.

[0055] Next, modifications of the above embodiment will be described. The following modifications are also within the scope of the present invention, and it is also possible to combine the configurations described in the following different modifications.

[0056] In the above embodiment, the transmission mechanism 40 is a planetary gear mechanism, but is not limited to this, and the transmission mechanism 40 may be another gear mechanism or may be configured by combining a plurality of gear mechanisms.

[0057] In the above embodiment, the cover 50 has a main body portion 51 and an attachment portion 52, and the main body portion 51 is formed in a so-called cone shape having a bottom portion 51a and a tapered portion 51b. However, the configuration of the cover 50 is not limited to this. The cover 50 may be configured in any manner as long as it is provided on the inner periphery of the open end 15a of the rotating housing 15, closes the open end 15a, and the plug 54a protrudes from the cover 50 toward the carrier plate 47 and can support the thrust load acting on the carrier plate 47 from the speed change mechanism 40.

[0058] In the above embodiment, the plug 54a that receives the thrust load generated in the speed change mechanism 40 is an existing plug that is provided in the oil check port 53a that determines the amount of lubricating oil in the gear chamber 4. However, the plug 54a is not limited to this, and may be a plug that is newly added to an existing transmission in order to receive the thrust load generated in the speed change mechanism 40.

[0059] The configuration, operation, and effects of the embodiment of the present invention will be described below.

[0060] The transmission 100 comprises a transmission mechanism 40 connected to a hydraulic motor 20 as a drive source and changing the output rotation of the hydraulic motor 20, a cylindrical rotating housing 15 that houses the transmission mechanism 40 and rotates when the changed output rotation is transmitted to it, a cover 50 that is provided at an opening end 15a of the rotating housing 15 that opens on the side opposite the hydraulic motor 20 with respect to the transmission mechanism 40 and closes the opening end 15a, a carrier plate 47 that is provided on the end face of the transmission mechanism 40 that faces the cover 50, and a plug 54a that is removably provided on the cover 50 from the side opposite the carrier plate 47, and the plug 54a protrudes from the cover 50 towards the carrier plate 47 and is capable of supporting a thrust load acting on the carrier plate 47 from the transmission mechanism 40.

[0061] In this configuration, the plug 54a, which is detachably attached to the cover 50, bears the thrust load generated by the transmission mechanism 40. Therefore, wear on the plug 54a can be checked simply by removing the plug 54a from the cover 50, and if wear on the plug 54a is significant, only the plug 54a needs to be replaced. This makes it easy to check for wear and replace members that bear loads from the transmission mechanism 40.

[0062] In addition, in the transmission 100, the cover 50 is provided with an oil dipstick port 53a as a through hole for determining the amount of lubricant that is sealed in the gear chamber 4 in which the transmission mechanism 40 is housed and can lubricate the transmission mechanism 40, and the plug 54a is detachably provided in the oil dipstick port 53a and seals the oil dipstick port 53a.

[0063] In this configuration, the plug 54a attached to the oil check port 53a provided in the cover 50 to regulate the amount of lubricant in the gear chamber 4 receives the thrust load generated in the transmission mechanism 40. In other words, by using the existing plug 54a, it is possible to easily check for wear and replace members in the transmission 100 that receive the load from the transmission mechanism 40 without adding a new component.

[0064] In addition, in the transmission 100, the cover 50 has a main body portion 51 in the center of which the plug 54a is attached, and an annular mounting portion 52 formed on the outer periphery of the main body portion 51 and attached to the open end 15a of the rotating housing 15, and the main body portion 51 has a bottom portion 51a to which the plug 54a is attached, and a tapered portion 51b connecting the bottom portion 51a and the mounting portion 52, and the tapered portion 51b is inclined so that the bottom portion 51a side is positioned close to the carrier plate 47.

[0065] In this configuration, the main body 51 of the cover 50 has a bottom 51a to which the plug 54a is attached, and a tapered portion 51b that connects the bottom 51a and the attachment portion 52. This allows the main body 51 to face the carrier plate 47 while reducing the thickness of the portion of the main body 51 to which the plug 54a is attached, compared to when the tapered portion 51b is not provided. This allows the thickness of the main body 51 to be reduced and a plug of a general length to be used as the plug 54a, thereby reducing the manufacturing cost of the transmission 100.

[0066] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments. [Explanation of symbols]

[0067] 100...transmission, 4...gear chamber, 15...rotating housing, 15a...open end, 20...drive source (hydraulic motor), 31...drive shaft (shaft), 40...transmission mechanism, 47...carrier plate (plate), 50...cover, 51...main body, 51a...bottom, 51b...tapered portion, 52...mounting portion, 53a...oil check port (through hole), 54a...plug

Claims

1. a speed change mechanism connected to a drive source and configured to change the speed of an output rotation of the drive source; a cylindrical rotating housing that accommodates the speed change mechanism and is rotated by the output rotation whose speed is changed; a cover provided at an open end of the rotating housing that opens to a side opposite the driving source with respect to the speed change mechanism, the cover closing the open end; a plate provided on an end surface of the transmission mechanism facing the cover; a plug that is detachably attached to the cover from the opposite side to the plate, The plug protrudes from the cover toward the plate and is capable of supporting a thrust load acting on the plate from the transmission mechanism.

2. the cover is provided with a through hole for determining an amount of lubricant that is sealed in a gear chamber in which the speed change mechanism is housed and that is capable of lubricating the speed change mechanism; 2. The transmission according to claim 1, wherein the plug is detachably provided in the through hole to seal the through hole.

3. the cover has a main body portion at the center of which the plug is attached, and an annular attachment portion formed on an outer periphery of the main body portion and attached to the open end of the rotating housing, the main body portion has a bottom portion to which the plug is attached and a tapered portion connecting the bottom portion and the attachment portion, 3. The transmission according to claim 1, wherein the tapered portion is inclined so that the bottom side is disposed adjacent to the plate.

4. A transmission as described in any one of claims 1 to 3, characterized in that the plug is removably attached to the cover by a screw connection.

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