Gear reducer for series hybrid vehicles

Abstract

This reduces the rattling noise while suppressing contamination from thermosetting resin between the male and female splines. [Solution] The reduction gear for a series hybrid vehicle comprises a male spline 15 having a plurality of male teeth 15a formed on the outer circumference of the shaft 14 of the power generation motor generator 2, a female spline 17 having a plurality of female teeth 17a formed on the inner circumference of a cylindrical shaft member 16 provided in the reduction gear 8 into which the male spline 15 is inserted, and a thermosetting resin 18 disposed between each male tooth 15a and a tooth groove 17b formed by each male tooth 15a and two adjacent female teeth 17a.

Description

Technical Field

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[0001] The present invention relates to a speed reducer for a series hybrid vehicle, particularly to a speed reducer having a first spline and a second spline that fits with the first spline.

Background Art

[0002] Patent Document 1 relates to a speed reducer, which includes a male spline having a plurality of male tooth portions and a female spline having a plurality of female tooth portions into which the male spline is inserted. Between each male tooth portion and a tooth groove formed by two adjacent female tooth portions adjacent to each male tooth portion, buffer material particles made of rubber are filled.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, the buffer material particles made of rubber contribute to reducing the tooth impact noise caused by the impact when the male tooth portions of the male spline mesh with the female tooth portions of the female spline. However, when a large torque acts on the speed reducer, there is a problem that the buffer material particles are damaged due to excessive force or compression applied to the buffer material particles, resulting in contamination (foreign matter).

[0005] The present invention has been devised in view of the conventional situation, and one of its objectives is to provide a speed reducer that can suppress the generation of contamination caused by the thermosetting resin between the first spline and the second spline while reducing the tooth impact noise.

Means for Solving the Problems

[0006] The present invention relates to a reduction gear for a series hybrid vehicle, and the reduction gear comprises: a first spline having a plurality of first teeth formed on a first shaft member provided on an internal combustion engine or a power generation motor generator; a second spline having a plurality of second teeth formed on a second shaft member provided on the reduction gear, the second teeth fitting with the first teeth; and a thermosetting resin disposed between each first tooth and a tooth groove formed by each first tooth and two adjacent second teeth. [Effects of the Invention]

[0007] Thermosetting resins have higher rigidity than rubber, making them less susceptible to damage even when subjected to excessive force or compression from high torque applied from an internal combustion engine to a reduction gear.

[0008] Therefore, according to the present invention, it is possible to reduce the ratcheting noise while suppressing the generation of contamination from thermosetting resin between the first spline and the second spline. [Brief explanation of the drawing]

[0009] [Figure 1] This is an explanatory diagram illustrating the configuration of a series hybrid vehicle in one embodiment. [Figure 2] This is a process diagram showing the heating step of the male spline and the application step of the thermosetting resin in the manufacturing method of a gearbox according to one embodiment. [Figure 3] This is a process diagram showing the insertion step of a male spline in a manufacturing method of a gearbox according to one embodiment. [Modes for carrying out the invention]

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] Figure 1 schematically shows the configuration of a series hybrid vehicle 1 according to one embodiment. This series hybrid vehicle 1 comprises a power generation motor generator 2 that mainly operates as a generator, an internal combustion engine 3 used as a power generation internal combustion engine that drives the power generation motor generator 2 in response to power generation demands, a drive motor generator 5 that mainly operates as a motor to drive the drive wheels 4, 4, a battery 6 that temporarily stores the generated electricity, and an inverter device 7 that performs power conversion between the battery 6 and the motor generators 2, 5. The power generation motor generator 2 is connected to the internal combustion engine 3 via a reduction gear 8 having male splines 15 and female splines 17, which will be described later. The reduction gear 8 reduces the rotational force from the internal combustion engine 3 and transmits it to the power generation motor generator 2. The electricity obtained by the internal combustion engine 3 driving the power generation motor generator 2 is stored in the battery 6 via the inverter device 7. The drive motor generator 5 is connected to the drive shaft 10 for the drive wheels 4, 4 via a reduction gear 9 composed of various gears, etc. The traction motor generator 5 is driven and controlled via an inverter device 7 using power from the battery 6. The power generated during regeneration by the traction motor generator 5 is also stored in the battery 6 via the inverter device 7.

[0012] The inverter device 7 is controlled by the vehicle-side controller 11, which controls the vehicle's movement. In other words, the operation of the motor generators 2 and 5 is controlled via the control of the inverter device 7 by the vehicle-side controller 11. The vehicle-side controller 11 receives signals such as the vehicle's accelerator opening, vehicle speed, and brake operation amount, as well as a signal indicating the charge status (so-called SOC) of the battery 6.

[0013] Furthermore, the internal combustion engine 3 is controlled by the engine controller 12. The engine controller 12 and the vehicle-side controller 11 are connected via the vehicle network 13, and they exchange signals with each other. The internal combustion engine 3 that drives the power generation motor generator 2 is operated via the engine controller 12 in response to power generation requests from the vehicle side, including the charge state (SOC) of the battery 6. In other words, when the engine controller 12 receives a power generation request from the vehicle-side controller 11 in accordance with the vehicle's accelerator pedal opening, vehicle speed, etc., the internal combustion engine 3 is controlled in response to that power generation request.

[0014] Figure 2 is a process diagram showing the heating step of the male spline 15 and the application step of the thermosetting resin in the manufacturing method of a gearbox 8 according to one embodiment. Figure 3 is a process diagram showing the insertion step of the male spline 15 into the female spline 17 in the manufacturing method of a gearbox 8 according to one embodiment. In Figure 3, the number of male teeth 15a and female teeth 17a is shown less than in Figure 2 in order to emphasize the insertion of the male spline 15 into the female spline 17. Also, in Figure 3, a part of the male spline 15 is shown in cross-section to make the thermosetting resin 18 clearer.

[0015] The reduction gear 8 has a male spline 15 formed on the outer circumference of a metal shaft 14 (first shaft member) provided on the power generation motor generator 2, and a female spline 17 formed on a cylindrical metal second shaft member 16 provided on the reduction gear 8.

[0016] The male spline 15 is inserted into a cylindrical second shaft member 16 having a female spline 17. As shown in Figure 1, the male spline 15 has a plurality of male teeth 15a formed on a certain region of the outer circumference of the cylindrical shaft 14, from one axial end 14a of the shaft 14 to the other axial end (not shown). The male teeth 15a are teeth that protrude radially outward from the outer circumference of the shaft 14. A thermosetting resin 18 is applied to the portion of the shaft 14 where the plurality of male teeth 15a are formed. More specifically, a relatively rigid thermosetting resin 18, such as phenolic resin, melamine resin, or epoxy resin, is applied to the outer circumference of the shaft 14 (the outer circumference 14b between two adjacent male teeth 15a in the circumferential direction of the shaft 14, see Figure 2) and the outer surface facing outward of each male tooth 15a (both side surfaces S1 and the tip surface S2 of each male tooth 15a, see Figure 2). In other words, the thermosetting resin 18 is placed between each male tooth portion 15a and the tooth groove 17b formed by each male tooth portion 15a and two female tooth portions 17a adjacent to it (described later). The coating thickness of the thermosetting resin 18 is set to be such that it completely fills the gap between the male spline 15 and the female spline 17 when the male spline 15 without the thermosetting resin 18 is inserted into the female spline 17.

[0017] The female spline 17 has a plurality of female teeth 17a formed on the inner circumference of the cylindrical second shaft member 16. The female teeth 17a are teeth that protrude radially inward from the inner circumference of the second shaft member 16. The female teeth 17a extend from the shaft end 16a of the second shaft member 16, the side into which the male spline 15 is inserted, toward the shaft end 16b by the same axial length as the male teeth 15a. When the male spline 15 is inserted into the female spline 17, the female teeth 17a are fitted with the male teeth 15a via the thermosetting resin 18.

[0018] Next, a method for manufacturing a gearbox 8 according to one embodiment will be described with reference to Figures 1 and 2.

[0019] First, in the heating process schematically shown in FIG. 1, for example, using a high-frequency heating device outside the figure, the male spline 15 of the shaft 14 is heated. At the time of this heating, the male spline 15 is heated at a predetermined temperature such that the strength of the male spline 15 of the metal shaft 14 does not decrease. In this embodiment, the temperature is 150° C. or lower. Alternatively, instead of the high-frequency heating device, an oven may be used to heat the male spline 15.

[0020] After the male spline 15 is heated, in the coating process schematically shown in FIG. 1, the thermosetting resin 18 is applied to the male spline 15.

[0021] In the insertion process of the male spline 15 into the female spline 17 shown in FIG. 3, after the thermosetting resin 18 is applied and before the thermosetting resin 18 is cured, the male spline 15 is inserted into the female spline 17. After the insertion, the thermosetting resin 18 is disposed between each male tooth portion 15a and the tooth groove 17b formed by two female tooth portions 17a adjacent to each male tooth portion 15a. Then, the thermosetting resin 18 cures with the remaining heat while being cooled. The cured thermosetting resin 18 is firmly held between the male tooth portion 15a and the tooth groove 17b, and remains held even if a high torque is input from the internal combustion engine 3 to the reduction gear 8 during the operation of the internal combustion engine 3, and does not flow out from the shaft end portions 16a, 16b of the second shaft member 16 having the female spline 17.

[0022] As described above, in this embodiment, the reduction gear 8 for the series hybrid vehicle 1 includes a male spline 15 having a plurality of male tooth portions 15a and a female spline 17 having a plurality of female tooth portions 17a into which the male spline 15 is inserted. The thermosetting resin 18 is disposed between each male tooth portion 15a and each tooth groove 17b. Since the thermosetting resin 18 functions as a cushioning material between each male tooth portion 15a and each tooth groove 17b, it reduces the knocking noise caused by the collision between the male tooth portion 15a and the female tooth portion 17a when a high torque acts on the reduction gear 8 from the internal combustion engine 3. Further, the thermosetting resin 18 has higher rigidity than rubber and is less likely to be damaged even when an excessive force or compression acts when a high torque acts on the reduction gear 8 from the internal combustion engine 3. Therefore, in this embodiment, it is possible to suppress the generation of contamination due to the breakage of the thermosetting resin 18 between the male spline 15 and the female spline 17 while reducing the knocking noise.

[0023] Further, in this embodiment, since the knocking noise is reduced by the thermosetting resin 18, it is possible to reduce the size of the damper for knocking noise countermeasures provided between the internal combustion engine 3 and the reduction gear 8 and reduce the manufacturing cost of the series hybrid vehicle 1.

[0024] In the above embodiment, an example in which the male spline 15 is formed on the outer periphery of the shaft 14 of the power generation motor generator 2 has been described. However, the present invention can also be applied to an example in which the male spline 15 is formed on the outer periphery of the shaft provided in the internal combustion engine 3.

[0025] Also, in the above embodiment, an example in which the male spline 15 is formed on the outer periphery of the shaft 14 of the power generation motor generator 2 and, on the other hand, the female spline 17 is formed on the inner periphery of the second shaft member 16 has been described. However, the male spline 15 may be formed on the shaft member 16 and the female spline 17 may be formed on the shaft 14 of the power generation motor generator 2. In this case, the shaft member 16 is replaced with a cylindrical member, and further, the shaft 14 is replaced with a cylindrical member.

Explanation of reference numerals

Claims

1. A reduction gear for a series hybrid vehicle that reduces the rotational force from an internal combustion engine and transmits it to a power generation motor generator, A first spline having a plurality of first teeth formed on a first shaft member provided on the internal combustion engine or the power generation motor generator, The reduction gear has a second shaft member formed on which a plurality of second teeth are formed, and the second spline has second teeth that engage with the first teeth, A thermosetting resin is disposed between each first tooth portion and the tooth groove formed by the two second teeth portions adjacent to each first tooth portion. A reduction gear for series hybrid vehicles equipped with a gearbox.

2. The first shaft member is formed in a cylindrical shape, The plurality of first teeth protrude radially outward from the outer circumference of the first shaft member, The thermosetting resin is applied to the outer circumference of the first shaft member and to the outer surfaces of the plurality of first teeth, characterized in that the reduction gear for a series hybrid vehicle according to claim 1.

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