JP3036500U - Rotating cam type fluid pressure device - Google Patents

Abstract

(57) [Abstract] [Purpose] To make a rotary cam type fluid pressure device compact with less pulsation. [Structure] A substantially cylindrical outer cam 10, an inner cam 12 arranged concentrically with the outer cam 10, nine planetary gears 14, and side plates 18 respectively arranged on both side surfaces of the cam and fixed to the outer cam. , And 20, and the outer cam has five inward projections 1 projecting inwardly on its inner peripheral surface.
An inner peripheral toothed cam surface 10b having 0a is formed,
The inner cam is formed with an outer peripheral tooth profile cam surface 12b having four outer protruding portions 12a protruding outward on the outer peripheral surface thereof, and the inner peripheral tooth profile cam surface and the outer peripheral tooth profile cam surface are directly engaged with each other. There are no related dimensions, and the planetary gears
The cams are arranged so as to always mesh with the tooth-shaped cam surfaces of both cams. The outer cam, the inner cam, both side plates, and two planet gears adjacent to each other form a total of nine fluid chambers. A total of ten communicating channels are formed on one of the side plates.

Description

[Detailed description of the invention]

[0001]

[Industrial applications]

 The present invention relates to a rotary cam type fluid pressure device.

[0002]

[Prior art]

 A conventional rotary cam type fluid pressure device is disclosed in Japanese Patent Publication No. 51-32784. The rotary cam type fluid pressure device shown in this figure has an inner cam arranged concentrically with a cylindrical outer cam, and a total of seven planetary gears are arranged between both cams. There is. The outer cam has a tooth-shaped cam surface on the inner peripheral surface of which four inwardly projecting projections are formed. In addition, the inner cam has a tooth-shaped cam surface on the outer peripheral surface of which three outwardly projecting portions that project outward are formed. The inner cam is fixed so as not to rotate, and the outer cam is rotatable in a predetermined direction without engaging with the inner cam. The planetary gears are always engaged with the tooth profile cam surfaces of both cams, and are allowed to move in a planetary motion according to the rotation of the outer cam. The inner cam is provided with two sets of three channels each opening at a plurality of positions on the outer peripheral surface thereof. That is, the number of flow paths is one less than the total number of protrusions. A total of seven fluid chambers are formed by the inner cam, the outer cam, the two planetary gears, and the disks (side plates) on both sides. As the outer cam rotates, each planet gear will move along the cam surface of the outer cam. As a result, the fluid chamber in the state of communicating with the flow passage of one set is always in the volume increasing process in which the volume increases, and the volume of the fluid chamber in the state of communicating with the flow passage of the other set is always decreasing. It is in the process of volume reduction. In addition, the fluid chamber that is not in communication with any of the flow paths is in the neutral stroke (stroke with the minimum volume or stroke with the maximum volume). Therefore, the outer cam is rotated in one direction by injecting high-pressure working fluid into the fluid chamber on the volume increasing stroke side from one of the flow paths, and in response to this rotation, the low pressure from the fluid chamber on the volume decreasing stroke side is generated. The working fluid will flow out to the other pair of flow paths (switching the high and low pressures will cause the outer cam to rotate in the opposite direction). That is, the rotary cam type fluid pressure device can be operated as a motor. By forcibly rotating the outer cam, the working fluid is sucked into the fluid chamber on the volume increasing stroke side from one of the flow paths of the pair, and receives the compression action from the fluid chamber on the volume reducing stroke side. If the high-pressure working fluid is discharged to the other pair of flow paths, the rotary cam type fluid pressure device can be operated as a pump.

[0003]

[Problems to be solved by the device]

 However, in the conventional rotary cam type fluid pressure device as described above, the pulsation rate during one rotation (the pulsation rate of the rotation speed when used as a motor, the pulsation rate of the discharge amount when used as a pump). ) Is a big problem. According to the result calculated by the present inventor, the pulsation rate during one rotation when the cam is designed in the optimum shape was 2.5%. Further, there is another problem that the ratio of the displacement volume to the apparatus volume (hereinafter referred to as “volume ratio” in the present specification) cannot be increased so much, which is not economical. Furthermore, since it is necessary to process the flow path on the outer cam at an angle that is inclined with respect to the outer peripheral surface of the outer cam, it is not only difficult to process the flow path, but it is also difficult to secure the positional accuracy of the flow path. There is also the problem that The present invention aims to solve such a problem.

[0004]

[Means for Solving the Problems]

 In the present invention, the outer cam has five inward projections and the inner cam has four outer projections, or the outer cam has six inner projections and the inner cam has six inner projections. The above problem is solved by setting the number of the outward protruding portions of the frame to five. That is, the rotary cam type fluid pressure device of the present invention comprises a substantially cylindrical outer cam (10), an inner cam (12) arranged concentrically with the outer cam (10), a plurality of planetary gears (14), and a cam (10). , 12), which are respectively arranged on both side surfaces of the outer cam (10), and have side plates (18, 20) fixed to the outer cam (10). An inner peripheral toothed cam surface (10b) having a plurality of inward protruding portions (10a) protruding inward is formed on the surface, and the inner cam (12) protrudes outward on the outer peripheral surface thereof. An outer peripheral tooth profile cam surface (12b) having a plurality of outward protrusions (12a) is formed, and the inner peripheral tooth profile cam surface (10b) and the outer peripheral tooth profile cam surface (12b) are not directly engaged with each other. The planet gear (14) is provided with toothed cam surfaces (10b and 12b) of both cams. And the outer cam (10), the inner cam (12), the side plates (18 and 20), and the two planetary gears (14) adjacent to each other form a fluid chamber. The number of inward protrusions (10a) is five and the number of outward protrusions (12a) is four. Yes, the number of planet gears (14) and the number of fluid chambers (A, B, C, D, E, F, G, H, I) correspond to the sum of the numbers of both protrusions (10a, 12a). There are 9 each, and the number of flow paths (20a1, 20a2, 20a3, 20a4, 20a5, 20b1, 20b2, 20b3, 20b4, 20b5) is one from the sum of the numbers of both protrusions (10a, 12a). There are many ten, and these ten Road is characterized in that it is provided on one side plate (20) any of the above side plates (18 and 20). Also, the number of inward projections is 6, the number of outward projections is 5, and the number of planet gears and the number of fluid chambers are 11 each corresponding to the sum of the numbers of both projections. In addition, the number of flow paths is 12, which is one more than the sum of the numbers of both protrusions, and these 12 flow paths are one of the side plates (18 and 20). It is characterized by being provided in. The drive shaft (16) has a crowned spline shaft portion (16a), and the inner cam (12) has a spline hole (12c). ) Is formed, and the drive shaft (16) is splined to the inner cam (12). The reference numerals in parentheses indicate the corresponding parts of the embodiment.

[0005]

[Action]

 Generally, the pulsation rate of a rotary cam type fluid pressure device tends to decrease as the number of protrusions (the number of cams) increases, and conversely the volume ratio can increase as the number of protrusions decreases. There is a tendency, but depending on the shape of the cam, when both the number of protrusions on the outer cam and the number of protrusions on the inner cam are made to be a specific combination, both the pulsation rate and the volumetric ratio are simultaneously improved. I found that That is, the number of protrusions of the outer cam is 5 and the number of protrusions of the inner cam is 4 is optimal, and the next best combination is that the number of protrusions of the outer cam is 6 and that of the inner cam is 6 It was found that there were five protrusions in the. With other combinations, it is difficult to improve both the pulsation rate and the volumetric rate at the same time compared to the conventional method. For example, when the number of protrusions is 7 for the outer cam and 5 for the inner cam, the pulsation rate is increased by 37% and the volume ratio is 10% compared to the conventional case where the outer cam is 4 and the inner cam is 3. %Decrease. When the number of protrusions is 7 for the outer cam and 6 for the inner cam, it becomes virtually impossible to form a flow path communicating with the fluid chamber. On the other hand, when the number of protrusions is 5 for the outer cam and 4 for the inner cam, the pulsation rate can be reduced by 40% and the volume rate can be increased by 7% as compared with the conventional case. You can When the number of protrusions of the inner cam is 5 with respect to the number of protrusions 6 of the outer cam, the pulsation rate can be reduced by 60% and the volume ratio can be increased by 4%. . When the spline shaft part of the drive shaft is crowned to be spline-coupled to the inner cam, the inner cam swings in the axial direction even when a bending moment acts on the drive shaft. Since this can be prevented, the amount of hydraulic oil that leaks between the inner cam and the side plate can be reduced, and the power loss can be reduced.

[0006]

【Example】

 1 and 2 show an embodiment of the present invention. The substantially cylindrical outer cam 10 is provided with an inner peripheral tooth-shaped cam surface 10b having a total of five inward projecting portions 10a evenly formed on the inner peripheral surface thereof. On the inner peripheral side of the outer cam 10, a columnar inner cam 12 having a substantially rectangular cross section is arranged concentrically with the inner cam 12. The inner cam 12 is formed with an outer peripheral tooth-shaped cam surface 12b having a total of four outer protruding portions 12a evenly formed on the outer peripheral surface of the inner cam 12. The inner peripheral tooth-shaped cam surface 10b and the outer peripheral tooth-shaped cam surface 12b are dimensioned such that they do not directly engage with each other. A spline hole 12c penetrating in the axial direction is formed on the axial center side of the inner cam 12. As shown in FIG. 2, a front side plate (side plate) 18 and a rear side plate (side plate) 20 are arranged on both side surfaces of the outer cam 10 and the inner cam 12, respectively. The front plate 18, the outer cam 10, and the rear plate 20 are respectively aligned with and aligned with the centering rings 32 and 34, the positioning pins 38, and 40, and the plurality of bolts 42, 44, respectively. It is designed to be integrally fastened. In this way, the outer cam 10 and the front plate 18 are centered by the centering ring 32 and the positioning pin 38, and the outer cam 10 and the rear plate 20 are centered by the centering ring 34 and the positioning pin 40. By aligning with each other, the influence of the mutual clearance based on the fitting tolerance can be canceled out, and each position accuracy can be secured. It is also possible to prevent local deformation of the front plate 18, the rear plate 20, etc. caused by the centering rings 32 and 34, the force of the fluid, and the contact force acting between the gears. A bearing 24 is attached to the front side plate 18, and a bearing 26 is attached to the rear side plate 20. The drive shaft 16 is arranged so as to penetrate the inner cam 12 described above. The drive shaft 16 is formed with a spline shaft portion 16a that is crowned. The spline shaft portion 16 a of the drive shaft 16 is fitted in the spline hole 12 c of the inner cam 12. The drive shaft 16 is rotatably supported by bearings 24 and 26, and the shaft end side protruding outward from the front plate 18 is connected to a driven device (not shown). The inner ring side of the bearing 26 of the rear side plate 20 is integrally fixed to the drive shaft 16 by a bearing nut 28 screwed into the drive shaft 16, and the outer ring side is prevented from coming off by a cover 22. The cover 22 is fixed to the rear plate 20 with bolts 46. The front side plate 18 is adapted to be fixed to the fixing part via a bracket (not shown) fitted to the stepped part of the front side plate 18. A total of nine planetary gears 14 are capable of planetary movement in the clearance between the inner peripheral cam surface 10b of the outer cam 10 and the outer peripheral cam surface 12b of the inner cam 12 so as to always mesh with both cam surfaces 10b and 12b. It is located in. That is, the planetary gear 14 is capable of moving (revolving) along the inner peripheral tooth-shaped cam surface 10b of the outer cam 10 while always engaging with the cam surfaces 10b and 12b and rotating. As shown in FIG. 1 by the inner surface of the front plate 18, the inner surface of the rear plate 20, the inner peripheral tooth cam surface 10b of the outer cam 10, the outer peripheral tooth cam surface 12b of the inner cam 12, and the two planetary gears 14, A total of nine fluid chambers A, B, C, D, E, F, G, H, and I are respectively configured. The rear side plate 20 is provided with two sets of openings, each of which opens at a predetermined position on the inner surface thereof, for a total of ten channels. That is, the five one-side flow passages 20a1, 20a2, 20a3, 20a4, and 20a5 are evenly distributed over the entire circumference on the inner surface of the predetermined circle (indicated simply as 20a unless otherwise specified). Are arranged respectively, and five other side flow passages 20b1, 20b2, 20b3, 20b4, and 20b5 are provided at positions shifted by a half pitch from the one side flow passage 20a (only 20 if not particularly distinguished from each other). b)) are arranged respectively. A seal member 30 seals between the front side plate 18 and the drive shaft 16, and a seal member 36 seals between the rear side plate 20 and the cover 22. The outer cam 10, the inner cam 12, the planetary gear 14, the drive shaft 16, the front side plate 18, the rear side plate 20 and the like constitute a rotary cam type fluid pressure device. When a high-pressure working fluid is caused to flow into a fluid chamber (for example, A, C, F, H in the arrangement state shown in the drawing) on the side of the volume increasing process from a pressure source (not shown) through the one-side passage 20a, the inner cam 12 is forcibly rotated in the clockwise direction shown by the arrow in the figure, and the fluid chamber on the volume reduction stroke side (B, E, G, I in the same state) in response to the rotation of the inner cam 12. Thus, the working fluid having a low pressure flows out to the other flow path 20b. That is, it is possible to make the rotary cam type fluid pressure device act as a motor. As a result, the driven shaft (not shown) can be rotated by the drive shaft 16. The fluid chamber D is a neutral chamber in the illustrated state.

The theoretical volume Vth of the rotary cam type fluid pressure device can be obtained by the following equation (1).

(Equation 1) Here, Nro: the number of inner protrusions 10a of the outer cam 10 Nri: the number of outer protrusions 12a of the inner cam 12 Vmx: displacement volume of the fluid chambers A to I at the maximum Vmn: fluid chambers A to I When the device is used as a pump having a constant rotation speed, the pulsation rate Dth of the flow rate during one rotation can be obtained by the following equation (2).

(Equation 2) Here, Qmx: maximum discharge amount during one rotation Qmn: minimum discharge amount during one rotation Wr: angular velocity of the inner cam 12 Vth: theoretical volume (according to equation (1)) Further, the volume ratio η is calculated by the following equation ( It should be simply calculated according to 3).

(Equation 3) However,

(Equation 4)

(Equation 5) Here, Rmn: minimum gear radius of inner cam 12 Hrl: height of outer protruding portion 12a of inner cam 12 Rp: radius of planet gear 14 Nr: number of planet gears Vch: displacement volume of one fluid chamber θ: rotation angle of the inner cam 12 Wp: width of the planetary gear 14

Next, the operation of this embodiment will be described. The device shall be driven as a motor. When the high-pressure working fluid flows from the pressure source (not shown) into the fluid chamber on the volume increasing stroke side through the one-side flow path 20a, the inner cam 12 is rotated in the clockwise direction indicated by the arrow in the drawing, As the cam 12 rotates, the working fluid having a low pressure is discharged from the fluid chamber on the side of the volume reduction stroke. Since such an operation is sequentially repeated for the fluid chamber on the side of the volume increasing process, the inner cam 12 is continuously rotated. This allows the rotary cam type fluid pressure device to act as a motor. That is, a driven device (not shown) can be driven via the drive shaft 16. Since the spline shaft portion 16a of the drive shaft 16 is crowned, even if a bending moment acts on the drive shaft 16, the inner cam 12 that is spline-coupled with the bending moment does not The force to swing in the axial direction does not act. Therefore, it is possible to reduce the amount of hydraulic oil that leaks between the inner cam 12 and the side plate 18 and between the inner cam 12 and the side plate 20, respectively, and the frictional force between them can be small, so the loss power is also small. can do.

(Results of Performance Calculation) When various cam surface shapes are calculated by using the equations (1) to (3) and the best ones are collectively shown for each number of protrusions, as shown in FIG. Become. Therefore, it is only the configuration of the present invention that both the pulsation rate and the volumetric rate can be improved as compared with the conventional four protrusions of the outer cam and three protrusions of the inner cam. Recognize. It should be noted that the calculation was made for the case of the protruding portions 5: 3, 6: 4, 6: 3, 7: 4, 7: 3, 8: 7, 8: 6, 9: 6, 10: 6, etc. 4: It is not shown in Fig. 3 because it is not as good as that of 3 or it becomes impossible to design and it is troublesome.

In the description of the above embodiment, the flow paths 20a1, 20a2, 20a3, 20a4, 20a5, 20b1, 20b2, 20b3, 20b4, 20b5 are formed in the rear side plate 20, respectively. It is also possible to form it on the front side plate 18 without forming it on the rear side plate 20. In the description of the above embodiment, the case where the outer cam has five protrusions and the inner cam has four protrusions has been described. However, in the case where the outer cam has six protrusions and the inner cam has five protrusions, Means that the number of planetary gears is 11 corresponding to the sum of the number of protrusions, and the number of flow paths is 12 in total.

[0011]

[Effect of the invention]

 As described above, according to the present invention, the pulsation rate during one rotation of the device can be made smaller than that of the conventional device, and the device having a larger displacement volume than the conventional device under the same device volume condition. Can be obtained. Since the side plate is provided with a flow path that communicates with the pressure chamber, processing is simple and it is easy to ensure the accuracy of the opening position of the flow path.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a rotary cam type fluid pressure device according to the present invention.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is a comparative diagram showing the performance of a rotary cam type fluid pressure device.

[Explanation of symbols]

10 Outer cam 10a Inner protrusion 10b Inner peripheral tooth cam surface 12 Inner cam 12a Outer protrusion 12b Outer peripheral tooth cam surface 14 Planetary gear 18 Front side plate (side plate) 20 Rear side plate (side plate) 20a1, 20a2, 20a3, 20a4, 20a5
Flow paths 20b1, 20b2, 20b3, 20b4, 20b5
Channel A, B, C, D, E, F, G, H, I Fluid chamber

Claims (3)

[Utility model registration claims] 1. A substantially cylindrical outer cam (10), an inner cam (12) arranged concentrically with the outer cam, a plurality of planetary gears (14), and on both side surfaces of the cams (10, 12). Side plates (1) that are respectively arranged and fixed to the outer cam (10)
8 and 20), and the outer cam (10) has an inner peripheral toothed cam surface (10b) having a plurality of inward protruding portions (10a) protruding inwardly on the inner peripheral surface thereof. ) Is formed on the inner cam (12), and an outer peripheral tooth-shaped cam surface (12b) having a plurality of outward protruding portions (12a) protruding outward is formed on the outer peripheral surface of the inner cam (12). The circumferential tooth profile cam surface (10b) and the outer circumferential tooth profile cam surface (12b) are not directly meshed with each other, and the planetary gear (14) is
The outer cams (1) are arranged so as to always mesh with the tooth-shaped cam surfaces (10b and 12b) of both cams.
0), inner cam (12), both side plates (18 and 20),
Also, in the rotary cam type fluid pressure device in which the fluid chambers are respectively constituted by the two planetary gears (14) adjacent to each other and the flow paths communicating with these are formed, the number of inward protrusions (10a) 5 and the number of outward protrusions (12a) is 4, the number of planetary gears (14) and fluid chambers (A, B, C, D, E, F, G, H, I). Is 9 in correspondence with the sum of the numbers of both protrusions (10a, 12a) and the flow paths (20a1, 20a2,
20a3, 20a4, 20a5, 20b1, 20b2,
20b3, 20b4, 20b5) is the number of both protrusions (10
a, 12a), which is one more than the sum of the numbers of a, 12a), and the ten flow paths are provided in any one of the side plates (18 and 20). Rotating cam type fluid pressure device. 2. A substantially cylindrical outer cam (10), an inner cam (12) arranged concentrically with the outer cam (10), a plurality of planetary gears (14), and both side surfaces of the cams (10, 12). Side plates (1) that are respectively arranged and fixed to the outer cam (10)
8 and 20), and the outer cam (10) has an inner peripheral toothed cam surface (10b) having a plurality of inward protruding portions (10a) protruding inwardly on the inner peripheral surface thereof. ) Is formed on the inner cam (12), and an outer peripheral tooth-shaped cam surface (12b) having a plurality of outward protruding portions (12a) protruding outward is formed on the outer peripheral surface of the inner cam (12). The peripheral tooth-shaped cam surface (10b) and the outer peripheral tooth-shaped cam surface (12b) are dimensioned so as not to directly mesh with each other, and the planetary gear (14)
Are arranged so as to always mesh with the tooth-shaped cam surfaces (10b and 12b) of both cams, and the outer cam (1
0), inner cam (12), both side plates (18 and 20),
Also, in the rotary cam type fluid pressure device in which the fluid chambers are respectively constituted by the two planetary gears (14) adjacent to each other, and the flow paths communicating with these are formed, the number of inward projecting portions is six. The number of outward protruding portions is 5, the number of planet gears and the number of fluid chambers are 11 each corresponding to the sum of the number of both protruding portions, and the number of flow paths is both protruding. 12 rotations, which is one more than the sum of the number of parts, and the 12 flow paths are provided in any one of the side plates (18 and 20). Cam type fluid pressure device. 3. A drive shaft (16) is provided, the drive shaft (16) is provided with a crowned spline shaft portion (16a), and the inner cam (12) is provided with a spline hole. The rotary cam type fluid pressure device according to claim 1 or 2, wherein (12c) is formed, and the drive shaft (16) is splined to the inner cam (12).