Speed reduction device

Abstract

The invention provides a speed reducer, and belongs to the field of speed reducers. The speed reducer comprises a speed reducer body and an input shaft structure. The input shaft structure at least comprises an inner spline sleeve, an input gear shaft and a first sealing piece. A supporting flange can be further included according to needs. The input gear shaft is provided with teeth meshed with the planetary gear of the speed reducer main body, the input gear shaft and the planetary gear are helical gears with opposite rotation directions, and the ratio of the number of the teeth of the planetary gear of the speed reducer main body to the number of the teeth of the input gear shaft is 4.5-6; the input shaft structure penetrates through an input planet carrier, an output planet carrier and a middle hole of the cycloid gear of the speed reducer body, and the tooth portion of the input shaft structure is meshed with the planet gear to form first-stage speed reduction. And a cycloidal gear of the speed reducer main body is driven by the crankshaft, and the cycloidal gear is meshed with the pin gear and the pin gear housing to form second-stage speed reduction. The speed reducer has the advantages of being low in noise, good in movement stability and long in service life under the condition of high speed ratio.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of speed reducers, and particularly relates to a speed reduction device. Background Art

[0002] The speed reduction device, especially the special example of the cycloid pinwheel planetary speed reducer of the present invention, has the advantages of large transmission ratio, compact structure, high load-bearing capacity, high transmission efficiency, smooth transmission, small vibration and noise, etc., and can be used in supporting various mechanical equipment in all walks of life.

[0003] In the prior art, the input shaft and the planetary gear of the cycloid pinwheel planetary speed reducer are straight-tooth involute gears. When the size of the speed reducer is determined and the number of teeth of the cycloid gear is determined, the ratio of the number of teeth of the planetary gear to the number of teeth of the input shaft determines the reduction ratio of the speed reducer. In the case where a speed reducer with as high a speed ratio as possible is required, the straight gear transmission will generate relatively large vibration and noise, and the gear of the input shaft needs to be made small enough. At this time, the strength of the gear of the input shaft is weak, and early failure is likely to occur during use, affecting the service life of the speed reducer. Summary of the Invention

[0004] The technical problem to be solved by the present invention is: aiming at the existing deficiencies, to provide a speed reduction device which has low noise, better motion smoothness and longer service life under the condition of a high speed ratio.

[0005] To solve the above technical problem, the present invention provides a speed reduction device, including a speed reducer main body and an input shaft structure. The input shaft structure includes a support flange, an internal spline sleeve, an input gear shaft and a first seal; the support flange is fixedly connected to the speed reducer main body; the inner wall surface of the central hole of the support flange is provided with an outer raceway of a bearing; the internal spline sleeve is sleeved in the central hole of the support flange, the outer wall surface of the internal spline sleeve is provided with an inner raceway of a bearing, and an internal spline is provided at the inner hole of the internal spline sleeve; a plurality of steel balls and a cage are arranged between the outer raceway of the bearing and the inner raceway of the bearing, thus forming a bearing;

[0006] The input gear shaft is arranged in the central hole of the speed reducer main body; the input gear shaft is fixedly connected to the internal spline sleeve; teeth meshing with the planetary gear of the speed reducer main body are provided on the input gear shaft, and the two are helical gears with opposite helix directions. The ratio of the number of teeth of the planetary gear of the speed reducer main body to the number of teeth of the input gear shaft is 4.5 - 6; the seal is placed in the annular region between the support flange and the internal spline sleeve to seal the space on the side where the bearing is located.

[0007] The present invention also provides another speed reduction device, which includes a speed reducer main body and an input shaft structure. The input shaft structure includes an internal spline sleeve, an input gear shaft, and a first seal. On the inner wall surface of one end of the central hole of the speed reducer main body, there is an outer raceway of a bearing. The internal spline sleeve is sleeved in the central hole of the speed reducer main body. On the outer wall surface of the internal spline sleeve, there is an inner raceway of the bearing opposite to the outer raceway of the bearing. On the inner hole of the internal spline sleeve, there is an internal spline. Between the outer raceway of the bearing and the inner raceway of the bearing, there are multiple steel balls and a cage, thus forming a bearing.

[0008] The input gear shaft is arranged in the central hole of the speed reducer main body; the input gear shaft is fixedly connected with the internal spline sleeve; on the input gear shaft, there are teeth meshing with the planetary gear of the speed reducer main body, and the two are helical gears with opposite helix directions. The ratio of the number of teeth of the planetary gear of the speed reducer main body to the number of teeth of the input gear shaft is 4.5 - 6. The seal is placed in the annular area between the speed reducer main body and the internal spline sleeve, sealing the space on the side where the bearing is located.

[0009] According to a preferred embodiment of the present invention, the outer raceway of the bearing on the support flange and the inner raceway of the bearing on the internal spline sleeve are respectively composed of two arcs; the bearing formed by the cage and multiple steel balls with the outer raceway and the inner raceway of the bearing is a four-point angular contact ball bearing.

[0010] According to a preferred embodiment of the present invention, the speed reducer main body includes a pin gear housing, an input planet carrier, an output planet carrier, a cycloidal gear, pin teeth, a crankshaft, and a planetary gear. The input shaft structure passes through the central holes of the input planet carrier, the output planet carrier, and the cycloidal gear, and its tooth part meshes with the planetary gear to form a first-stage speed reduction; the planetary gear is installed on the crankshaft; the cycloidal gear is driven by the crankshaft, and the cycloidal gear meshes with the pin teeth and the pin gear housing to form a second-stage speed reduction.

[0011] According to a preferred embodiment of the present invention, a second seal is arranged in the annular area between the pin gear housing and the output planet carrier. The second seal is a skeleton oil seal, which is provided with a main lip and a dust lip on each side of the main lip.

[0012] The bearing of the present invention supports the internal spline shaft and the input gear shaft, and can bear the axial component force of the meshing force generated when the gear of the input gear shaft rotates forward and backward.

[0013] As a preferred embodiment of the present invention, the first seal and the second seal are skeleton oil seals, which are provided with a main lip and a dust lip on each side of the main lip. It can overcome the problem that foreign matters such as iron powder inside the speed reduction device easily enter the contact surface between the main lip and the shaft and scratch the main lip, resulting in early leakage of the lubricating medium, thereby improving the sealing performance of the speed reducer and ensuring the service life of the speed reducer.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] Since the present invention adopts an input gear shaft gear with helical teeth and a planetary gear of a speed reducer, the meshing performance is good, the transmission is stable and the noise is small; under the conditions of the same number of teeth and tooth width, the meshing process of the helical gear is longer than that of the spur gear, that is, the contact ratio is larger, reducing the load on each pair of gears, thereby improving the load-bearing capacity of the gears and prolonging the service life of the gears of the high-speed ratio reduction device.

[0016] Since the present invention adopts a four-point angular contact ball bearing with raceways made on the internal spline shaft and the support flange, compared with the deep groove ball bearing used in the prior art, within a limited space, the bearing structure is more compact, the number of steel balls increases, the load-bearing capacity is improved, and it can withstand the axial component of the meshing force in opposite directions generated when the input gear shaft gear rotates forward and backward. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a cross-sectional view of the reduction device according to the first embodiment of the present invention;

[0018] Figure 2 is Figure 1 the right view of;

[0019] Figure 3 is Figure 1 the enlarged view at A in;

[0020] Figure 4 is Figure 3 the structural schematic diagram of the cage in;

[0021] Figure 5 It is a flowchart of the installation method of the input shaft structure of the reduction device according to the first embodiment of the present invention;

[0022] Figure 6 It is a cross-sectional view of the reduction device according to the second embodiment of the present invention;

[0023] Figure 7 It is a flowchart of the installation method of the input shaft structure of the reduction device according to the second embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0025] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative positional relationship, movement conditions, etc. between components in a specific posture (as shown in the attached drawings). If the specific posture changes, the directional indication will also change accordingly.

[0026] In the description of the present invention, the meaning of "a plurality of" is at least two, for example, three, four, etc., unless otherwise clearly and specifically defined.

[0027] In the present invention, unless otherwise clearly specified and limited, terms such as "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or integrated; it can be directly connected or indirectly connected through an intermediate medium, and can be the communication inside two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] Embodiment 1:

[0029] Figure 1 is a schematic structural diagram of the speed reduction device 100 of Embodiment 1. The speed reduction device 100 includes at least one speed reducer main body 200 and an input shaft structure 800. First, in combination with Figure 1 describe the composition of the speed reducer main body 200.

[0030] The speed reducer main body 200 of the speed reduction device 100 includes a pin tooth housing 1, a planetary carrier 2, a plurality of crankshaft assemblies 7, and two cycloidal gears 6a, 6b. A plurality of pin teeth 4 are arranged in the tooth grooves of the pin tooth housing 1. The planetary carrier 2 includes an output planetary carrier 2a and an input planetary carrier 2b that are fixedly connected. The crankshaft assembly 7 includes a crankshaft 71, a planetary gear 72, needle roller bearings 74a and 74b installed on two eccentric shaft diameters of the crankshaft 71, and tapered roller bearings 73a and 73b installed on the shaft diameters at both ends of the crankshaft 71. The crankshaft 71 drives the cycloidal gears 6a, 6b respectively through the needle roller bearings 74a and 74b, and is supported by the output planetary carrier 2a and the input planetary carrier 2b through the tapered roller bearings 73a and 73b. The crankshaft assembly 7 rotates around the axis a Y rotates. The two cycloidal gears 6a, 6b are engaged with the pin teeth 4, and the number of teeth of the two cycloidal gears 6a, 6b is less than the number of the pin teeth 4; in this embodiment, the number is only one less. The planetary carrier 2 is supported by two bearings 5a and 5b installed on the pin tooth housing 1 and can rotate around the axis a XRotation. A second seal 3 is provided between the output planet carrier 2a and the pin gear housing 1. The second seal 3 is a skeleton oil seal, which is provided with a main lip and a dust-proof lip on each side of the main lip, and can overcome the problem that foreign matters such as iron powder inside the reduction gear are easily introduced into the mating surface between the main lip and the output planet carrier and scratch the main lip, resulting in early leakage of the lubricating medium. Thus, the sealing performance of the reducer is improved, and the service life of the reducer is ensured.

[0031] The reduction gear 100 with the reducer main body 200 can be used for the joint parts of industrial robots, the rotating parts of various industrial equipment, etc. As an example, one of the pin gear housing 1 and the planet carrier 2 can be fixed on the machine base, and the other is connected to the output member to realize the rotational work of the output member relative to the machine base.

[0032] In many applications of industrial robots or other precision industrial equipment, there are occasions where a high reduction ratio is required for the reduction gear. Sometimes the reduction ratio needs to reach more than 200. Under the condition that the number of teeth of the cycloid gear is fixed, the ratio of the number of teeth of the planetary gear 72 of the reducer main body 200 to the number of teeth of the input gear needs to be large enough. To give full play to the high reduction ratio performance of the reduction gear 100, an input shaft structure 800 is arranged in the planet carrier 2, the inner holes of the cycloid wheels 6a and 6b of the reducer main body 200. The input shaft structure 800 includes an inner spline sleeve 801 provided with an inner spline 8013 press-fitted into one body by interference fit, an input gear shaft 802 provided with a helical gear, a support flange 803, a seal 804, as well as a plurality of steel balls 808 and a cage 807.

[0033] The gear of the input gear shaft 802 and the planetary gear 72 of the reducer are helical gears with opposite helix directions. In this embodiment, the ratio of the number of teeth of the planetary gear of the reducer to the number of teeth of the input gear shaft is 4.5 - 6, forming the first stage of reduction.

[0034] Figure 3 The bearing outer raceways 8031 and 8032 on the middle support flange 803 are two arcs with a radius of curvature of Re and a center distance of Xe, and the bearing inner raceways 8011 and 8012 on the inner spline sleeve 801 are two arcs with a radius of curvature of Ri and a center distance of Xi; the cage 807 and multiple steel balls 808 with a diameter of Dw and the bearing formed by the bearing outer raceway and the bearing inner raceway are four-point angular contact ball bearings. The bearing supports the inner spline shaft 801 and the input gear shaft 802, and can bear the axial component of the meshing force generated when the gear of the input gear shaft 802 rotates in both forward and reverse directions.

[0035] An inner spline 8013 is provided at the inner hole of the inner spline shaft sleeve 801. During operation, the outer spline on the motor shaft is inserted into the spline shaft sleeve, and the driving of the reduction gear can be realized, making the structure simple and the connection convenient.

[0036] The first seal 804 is a skeleton oil seal, which is provided with a main lip and a dust lip on each side of the main lip, and can overcome the problem that foreign matters such as iron powder inside the reduction gear are easily introduced into the fitting surface of the inner spline sleeve 801 of the main lip and scratch the main lip, resulting in early leakage of the lubricating medium. Thus, the sealing performance of the reducer is improved, and the service life of the reducer is guaranteed.

[0037] Figure 5 A method for installing the input shaft structure 800 of the above embodiment of the present invention into the reducer main body 200 includes the following steps:

[0038] Step S501: The inner spline shaft 801 passes through the inner hole of the support flange 803, and the two are eccentrically placed, that is, they are in contact on one side in the radial direction, and a plurality of steel balls 808 are sequentially placed into the bearing raceways on the other side in the radial direction of the two;

[0039] Step S502: The plurality of steel balls 808 are evenly distributed in the bearing raceway in the circumferential direction. At this time, the inner spline shaft 801 passes through the support flange 803, and the axes of the two coincide;

[0040] Step S503: Align the ball retaining grooves of the cage 807 with the plurality of steel balls 808 and lock them;

[0041] Step S504: Insert the above components into the middle hole of the reducer main body 200, so that the teeth of the input gear shaft 802 mesh with the teeth of the planetary gear 72;

[0042] Step S505: Fasten the support flange 803 to the output planet carrier 2a with screws 805. An O-ring 806 is provided in the groove on the joint surface of the two;

[0043] Step S506: Press the first seal 804 into the annular area between the support flange 803 and the inner spline shaft 801.

[0044] Embodiment 2:

[0045] As Figure 6 shown, in Embodiment 2 of the present invention, the composition and working mode of the reducer main body 200 are the same as those of the reducer main body 200 in the first embodiment.

[0046] The input shaft structure 800 in Embodiment 2 of the present invention is different from the input shaft structure 800 in Embodiment 1 of the present invention in that the outer raceway of its bearing is provided on the output planet carrier 2a, and the support flange is omitted.

[0047] Figure 7 A method for installing the input shaft structure 800 of the above embodiment of the present invention into the reducer main body 200 includes the following steps:

[0048] Step S701: The internal spline shaft 801 passes through the inner hole of the output planet carrier 2a, and the two are eccentrically placed, that is, they are in contact on one side in the radial direction. A plurality of steel balls 808 are sequentially placed into the bearing raceways on the other side in the radial direction of the two;

[0049] Step S702: The plurality of steel balls 808 are evenly distributed in the bearing raceway in the circumferential direction. At this time, the internal spline shaft 801 passes through the output planet carrier 2a, and the axes of the two coincide;

[0050] Step S703: Align the ball retaining grooves of the cage 807 with the plurality of steel balls 808 and hold them;

[0051] Step S704: Install the planet gear 72 of the speed reducer main body 200 onto the crankshaft 71, so that the teeth of the planet gear 72 mesh with the teeth of the input gear shaft 802;

[0052] Step S705: Press the first seal 804 into the annular region between the output planet carrier 2a and the internal spline shaft 801.

[0053] Since the present invention adopts the design that the input gear and the planet gear are helical gears, it overcomes the problems in the prior art that the input gear of the high speed ratio reduction device has insufficient strength and is easy to be damaged, and has a large noise at high speed, thereby improving the service life of the speed reducer.

[0054] Since the present invention adopts the setting of bearing raceways on the input gear shaft and the support flange or the planet carrier, and forms a four-point angular contact ball bearing with the steel balls and the cage, the bearing capacity of the bearing is maximized in a limited space and can withstand two axial forces in different directions generated by the forward and reverse rotation of a pair of helical gears, overcoming the problems in the prior art that the deep groove ball bearing used to support the input gear shaft cannot withstand its axial force, and using a pair of tapered roller or angular contact ball bearings to support the input gear shaft will make the structure complex and difficult to install.

[0055] The above-described embodiments only represent the embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. A deceleration device, characterized in that, It includes a reducer main body and an input shaft structure. The input shaft structure includes a support flange, an internal spline sleeve, an input gear shaft, and a first seal. The support flange is fixedly connected to the reducer main body. The inner wall surface of the central hole of the support flange is provided with an outer raceway of a bearing. The internal spline sleeve is sleeved in the central hole of the support flange. An inner raceway of a bearing is provided on the outer wall surface of the internal spline sleeve opposite to the outer raceway of the bearing. An internal spline is provided at the inner hole of the internal spline sleeve. A plurality of steel balls and a cage are arranged between the outer raceway of the bearing and the inner raceway of the bearing, thus forming a bearing. The input gear shaft is arranged in the central hole of the reducer main body. The input gear shaft is fixedly connected to the internal spline sleeve. Teeth meshing with the planetary gear of the reducer main body are provided on the input gear shaft, and the two are helical gears with opposite helix directions. The ratio of the number of teeth of the planetary gear of the reducer main body to the number of teeth of the input gear shaft is 4.5 - 6. The seal is placed in the annular area between the support flange and the internal spline sleeve to seal the space on the side where the bearing is located.

2. A deceleration device, characterized in that, It includes a reducer main body and an input shaft structure. The input shaft structure includes an internal spline sleeve, an input gear shaft, and a first seal. The inner wall surface of one end of the central hole of the reducer main body is provided with an outer raceway of a bearing. The internal spline sleeve is sleeved in the central hole of the reducer main body. An inner raceway of a bearing is provided on the outer wall surface of the internal spline sleeve opposite to the outer raceway of the bearing. An internal spline is provided at the inner hole of the internal spline sleeve. A plurality of steel balls and a cage are arranged between the outer raceway of the bearing and the inner raceway of the bearing, thus forming a bearing. The input gear shaft is arranged in the central hole of the reducer main body. The input gear shaft is fixedly connected to the internal spline sleeve. Teeth meshing with the planetary gear of the reducer main body are provided on the input gear shaft, and the two are helical gears with opposite helix directions. The ratio of the number of teeth of the planetary gear of the reducer main body to the number of teeth of the input gear shaft is 4.5 - 6. The seal is placed in the annular area between the reducer main body and the internal spline sleeve to seal the space on the side where the bearing is located.

3. The speed reduction device according to claim 1 or 2, characterized in that, The input gear shaft and the internal spline sleeve are press - fitted into one body by interference fit.

4. The speed reduction device according to claim 1 or 2, characterized in that, The outer raceway of the bearing and the inner raceway of the bearing on the internal spline sleeve are respectively composed of two arcs. The bearing formed by the cage and a plurality of steel balls with the outer raceway of the bearing and the inner raceway of the bearing is a four - point angular contact ball bearing.

5. The input shaft structure according to claim 1 or 2, characterized in that, An internal spline is provided at the inner hole of the internal spline shaft sleeve. During operation, the external spline on the external motor shaft is inserted into the spline shaft sleeve to drive the reduction device.

6. The speed reduction device according to claim 1 or 2, characterized in that, The first seal is a skeleton oil seal, which is provided with a main lip and a dust lip on each side of the main lip.

7. The speed reduction device according to claim 1 or 2, characterized in that, The reducer main body includes a pin - tooth housing, an input planet carrier, an output planet carrier, a cycloid gear, pin teeth, a crankshaft, and a planetary gear. The input shaft structure passes through the central holes of the input planet carrier, the output planet carrier, and the cycloid gear, and its tooth part meshes with the planetary gear to form a first - stage reduction. The planetary gear is installed on the crankshaft. The cycloid gear is driven by the crankshaft, and the cycloid gear meshes with the pin teeth and the pin - tooth housing to form a second - stage reduction.

8. The speed reducer according to claim 1 or 2, characterized in that A second seal is provided in the annular region between the pin gear housing and the output planet carrier. The second seal is a skeleton oil seal, which is provided with a main lip and a dust lip on each side of the main lip.

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